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 LIBRARY 
 
 UNIVERSITY OF CALIFORNIA. 
 
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 EDUC. 
 
THE ELEMENTS 
 
 OF THE 
 
 PSYCHOLOGY or COGNITION 
 
 \ 
 
 Rev. EGBERT JARDINE, B.D., D.Sc. Edin., 
 
 ]iX-PBIKCIPAL OP THB GEITBRAL ASSEMBLY'S COLLEGE, CALCUTTA, 
 
 Author of " What to Believe," etc. 
 
 REVISED AND IMPROVED 
 
 LO] 
 
 MACMILLAN & CO. 
 
 1884. 
 
CHAHLES DICKEWS AXD EVAX3, 
 CBTSTAL PALACE PBES?. 
 
 '4^<^ 
 
 V 
 
 BF3II 
 
 1 ssi- 
 
 
 EDUC. 
 PSYC;: 
 UBRAi.Y 
 
n^l 
 
 PKEFACE TO FIEST EDITION. 
 
 The present work professes to be an introduction 
 to a very interesting and important subject of 
 study, — the psycliology of the intellectual part of 
 tbe human mind. It is designed principally for 
 the use of students who are beginning their 
 philosophical studies, and the writer has therefore 
 endeavoured to express himself in as clear and 
 simple language as possible. But while intended 
 primarily for this class of readers, it is hoped 
 that those who have already made the acquaintance 
 of the subject will find something to interest 
 them. 
 
 The writer is ready to admit that one principal 
 object which he kept before his mind in the pre- 
 paration of the book was to show the inadequacy 
 and unsatisfactoriness of a prevailing system of 
 psychology which may be indicated by the word 
 "phenomenalism.^' At the same time he admits 
 also having received much assistance at various 
 
PREFACE. 
 
 times in matters of psychological analysis from 
 writers who have supported that system. For 
 valuable suggestions regarding the process of 
 reasoning, particular acknowledgments are duo 
 to Mr. Herbert Spencer, who, in his " Principles 
 of Psychology," has given an admirable exposition 
 of the nature of the reasoning process. 
 
 The author has no intention to deprecate criti- 
 cism of any of the doctrines which he has attempted 
 to establish. The only consideration which he 
 wishes to urge upon the critic is that the book 
 has been written with considerable haste, in order 
 to secure its publication within a certain limited 
 time. And, therefore, there are probably many 
 details which would be altered if a somewhat 
 longer time had been allowed before giving the 
 work a final revision previous to publication. 
 
PREFACE TO SECOND EDITION. 
 
 The author of this little manual of psychology 
 ventures to offer a Second Edition, revised and 
 considerably improved. He hopes that the favour- 
 able reception accorded to the First Edition will 
 be extended likewise to the Second^ and that it 
 may be still more useful as an introduction to a 
 very interesting and important subject of study. 
 
 Attention is called to the vocabulary of philo- 
 sophical terms at the close of the volume, which 
 will be a valuable help to the uninitiated reader 
 in becoming acquainted with the somewhat un- 
 common phraseology of philosophy. 
 
CONTENTS. 
 
 CHAPTER I. 
 INTBODUGTION. 
 
 SBCTION" PA6K 
 
 I. Sources and Arrangement 1 
 
 II. Criticism of Sources 6 
 
 III. Consciousness . 16 
 
 CHAPTER 11. 
 
 THE ACQUISITION OF PBESENTATIVE 
 KNOWLEDGE. 
 
 1. Analysis of Perception 36 
 
 II. Analysis of Sensation 41 
 
 III. Representation of Sensations .... 54 
 
 IV. Sensations as Objects 62 
 
 Y. Perception . 76 
 
 THEORIES OF PEBGEPTION. 
 
 
 I. General Description and Classification 
 
 93 
 
 II. Descartes 
 
 . 99 
 
 III. Locke 
 
 109 
 
 IV. Berkeley (1684-1753) 
 
 . 116 
 
 V. Hume (1711-1776) 
 
 125 
 
 VI. Reid (1710-1796) 
 
 139 
 
 VII. Kant (1724-1804) . . . . 
 
 153 
 
 VIII. Modern English Psychology . . , , 
 
 158 
 
Till CONTENTS. 
 
 CHAPTER IV. 
 BEPBESENTA TION. 
 
 Vkd-R 
 
 I. Condition of Representation . . . .176 
 II. Laws of Representation 182 
 
 III. Kinds of Representation : Phantasy, Memory, 
 
 Expectation 189 
 
 IV. Imagination in Science and Art . . . .195 
 V. Imagination in Ethics and Religion . . . 207 
 
 A^I. Peculiarities of Representation . . . .211 
 A^II. Representation of Abstractions . . . .214 
 
 CHAPTER V. 
 
 ELABOBATION OF KNOWLEDGE. 
 
 I. Predication 224 
 
 II. Intuition 228 
 
 III. Dependence of Predication upon Intuition . . 234 
 
 IV. Implied Predications 237 
 
 V. The Class ; the Concept ; the Name . . . 245 
 
 VI. Predication again 264 
 
 VII. Reasoning Simulating Inference .... 294 
 
 VIII. Inference .300 
 
 IX. Determining Ground of Inference . . .311 
 
 X. The Form of Inference 324 
 
 XI. Evidence ; Induction ; Deduction . . . 329 
 
 XII. Conclusion 342 
 
 Vocabulary of Philosophical Terms .... 347 
 
THE ELEME]!fTS 
 
 [ PSYCHOLOGY OF COGMTIOI^. 
 
 CHAPTER I. 
 INTBODUCTIOK 
 
 Section I. 
 
 SOURCES AND ARRANGEMENT. 
 
 § 1. The Psycliology of Cognition forms an 
 important part of the philosophy of the human 
 mind, cognition being one of the three great 
 classes of phenomena which, according to the 
 generally accepted division, constitute the mind. 
 The remaining two classes may be designated the 
 Peelings and the Voluntary Activities. These, 
 however, will not come under our special con- 
 sideration, except in so far as they are involved 
 in the first class of phenomena. Cognition is a 
 general name which we may apply to all those 
 mental states in which there is made known in con- 
 sciousness either some affection or activity of the 
 mind itself, or some external quality or object. The 
 
 B 
 
 CHAP. I. 
 SECT. I. 
 
 Classifica- 
 tion and 
 character 
 of cog. 
 nition. 
 
TEE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. I, 
 
 No actual 
 separation 
 of mental 
 •phenomena 
 possible. 
 
 Sources of 
 knowledge 
 regarding 
 the mind. 
 
 Conscious- 
 ness. 
 
 Physical 
 organism. 
 
 Psycliology of Cognition analyses knowledge into its 
 primary elements, and seeks to ascertain tlie nature 
 and laws o£ tlie processes through which all our 
 knowledge passes in progressing from its simplest to 
 its most elaborate condition. It is necessary for 
 scientific purposes to classify mental phenomena, 
 but it must be borne in mind that in actual con- 
 sciousness there is no possibility of separating the 
 one from the other, and it is frequently difiicult to 
 determine to what class a particular phenomenon 
 belongs. In the earliest or simplest stage of know- 
 ledge it is perhaps difiicult to say whether the phe- 
 nomenon should be classed as a Feeling or a Cogni- 
 tion; and, consequently, it will be necessary in this 
 treatise to consider all those primary elements, of 
 whatever character, which enter as constituent parts 
 into our matured knowledge. 
 
 § 2. The materials which we shall require in the 
 systematic exposition of our subject are drawn from 
 various sources, but especially the following : — 
 
 a. Examination and analysis of consciousness. 
 This is the power which every individual possesses 
 of becoming aware of the various feelings and other 
 phenomena which are experienced in his mind. It 
 is the only power by which these phenomena can be 
 directly known or studied, and, consequently, in 
 every system of philosophy it must be appealed to 
 as an authoritative revelation of mental facts. 
 
 6. The anatomy and physiology of the physical 
 organism. Without entering into disputed questions 
 it is universally admitted that the powers of the 
 
PSYCHOLOGY OF COGNITION; 
 
 mind are in some way connected with, and depend 
 upon, tlie faculties of tile body, and more especially 
 that the nervous system, with its centre in the 
 ganglia of the brain and its extremities scattered 
 over the surface of the body, is the principal 
 medium of communication with the external world. 
 Whatever may be the value which a knowledge 
 of the laws and operations of this system of nerves 
 possesses, it may cast some light upon the more 
 refined operations of the mind itself. 
 
 c. The history of human progress or of the re- 
 sults of the continued activity of the human mind. 
 Amongst the most important of these is language. 
 If physiology makes us acquainted with the instru- 
 ment by which the mind operates, the science of 
 language exhibits and analyses the first and most 
 important of the mind^s products. It is only within 
 the last half century that this science has sprung 
 into existence ; but the results which it has already 
 attained are of so great importance in illustrating 
 the history and progress of the human mind and the 
 human race, that the most sanguine hopes may be 
 entertained with reference to the achievements which 
 it is yet destined to accomplish. The progress which 
 has been made in different places and under different 
 conditions in the useful and elegant arts, in science, 
 and in social character and customs, may also afford 
 illustrations of the nature and laws of the human 
 mind. The consciousness which each individual 
 possesses of the working of his own mind may be 
 corrected and enlarged by an observation, of the 
 
 B 2 
 
 CHAP. r. 
 
 SECT, I. 
 
 Results of 
 
 mental 
 
 activity. 
 
 Progress 
 in other 
 elements 
 of life. 
 
TEE ELEMENTS OF THE 
 
 CHAP. I, 
 SECT. I. 
 
 Order of 
 study. 
 
 1. Criti. 
 cdsm of 
 materials. 
 
 gradual and progressive development of the^mind of 
 the nation or race. That such progressive develop- 
 ment has actually taken place^ no one can doubt. 
 The history of religion, of science, of art, as well as 
 of philosophy, is evidence of the fact. To the history 
 of this progress, therefore, the student of philosophy 
 should turn his attention, for in it he will find illus- 
 trations, upon a grand scale, of the operation of 
 mental forces and principles which consciousness 
 reveals to him, upon a small scale, in his own 
 mind. 
 
 § 3. Before proceeding to the consideration of the 
 special subjects of psychology, it is desirable to take 
 a general view of the order in which they should be 
 studied. 
 
 In the first place, it will be necessary to examine 
 critically the sources from which facts regarding the 
 mind are derived, in order to determine their value, 
 their bearing upon the questions under examination, 
 and the nature of the information which they are 
 likely to give. The facts revealed to us in conscious- 
 ness, those made known by a study of our physical 
 organism, and the results of human mental activity, 
 constitute different classes of data from which con- 
 clusions may be drawn regarding the operations and 
 laws of the mind. These different classes of facts 
 give testimony of different kinds and of different 
 value ; and it will be necessary both to pursue an 
 accurate method in the examination of the facts 
 themselves, and to see that no conclusions which 
 they do not warrant are drawn from them. 
 
PSYCEOLOGY OF COGNITION. 
 
 § 4. The next step is the analysis of our mental 
 phenomena into their simplest elements. In the 
 maturity of the human mind the feelings, percep- 
 tions, thoughts, and other phenomena are very com- 
 plex in their nature ; and we cannot thoroughly un- 
 derstand them until they have been resolved into the 
 elements of which they were originally composed. 
 Having determined as accurately as possible the 
 original elements of our knowledge, we may discover 
 the manner in which these elements are combined 
 or modified so as to constitute what is called pre- 
 sentative knowledge — that is, knowledge which is 
 immediately presented to the mind without having 
 undergone any process of repetition, or comparison, 
 and without having inferences drawn from it. In 
 this reduction of knowledge to its simplest elements 
 we shall be led to study the relations between these 
 ultimate mental facts and the parts of the physical 
 organism with which they are more immediately 
 connected, and we shall be able to trace the first 
 beginnings of our knowledge of external things. 
 It will be necessary also to study another process, 
 the repetition or representation of the original 
 elements of our mental activity, since this process 
 plays an important part in the perception of ex- 
 ternal and distant objects. 
 
 § 5. The repetition or representation of the ele- 
 ments of knowledge, introduced as a subsidiary pro- 
 cess in the psychology of perception, must now be 
 studied in its higher and more easily recognised 
 functions as exhibited in phantasy, memory, and 
 
 CHAP. I. 
 SECT. I. 
 
 2. Analysis 
 of present' 
 ative 
 knowledge, 
 
 and coni' 
 hinationof 
 elements 
 into com- 
 plex pro- 
 ducts. 
 
 3. Repre- 
 sentation 
 of mental 
 pheno. 
 mena. 
 
THE ELEMENTS OF THE 
 
 CHAP. 
 SECT. 
 
 4. Elaho. 
 ration of 
 knowledge. 
 
 CHAP. I. 
 SECT. II. 
 
 imagination. These subjects, and certain problems 
 involved in them, form an interestiag chapter in 
 the study of the human mind. 
 
 § 6. The last and highest class of phenomena to 
 which we shall require to turn our attention consists 
 of those complex processes of comparison, general- 
 isation, and inference which are employed in the 
 enlargement and elaboration of our knowledge. 
 The study of the products of these processes is the 
 work of the logician. Logic has to do with the 
 results of the mental processes to which we are 
 referring; but psychology is concerned with the 
 nature of the processes themselves as revealed in 
 consciousness. While, therefore, the objects of our 
 study here will, to a certain extent, coincide with 
 those of the logician, we shall look upon them from 
 a different point of view. It will be our aim to 
 discover the nature and laws of our mental activity 
 exerted in the formation of those predications, 
 general notions, and inferences which form the 
 subject-matter of logic. 
 
 Section II. 
 
 CRITICISM OF SOUECES. 
 
 § 7. In this section it is proposed to examine 
 briefly the sources of our knowledge of the mind, for 
 the purpose of ascertaining the kind and amount of 
 evidence which they are likely to give concerning 
 the mind's processes. These sources we have already 
 arranged into three classes — consciousness, the study 
 
PSYCHOLOGY OF COGNITION. 
 
 of tlie physical organism, and the results wliicli 
 follow from the mind's activity. 
 
 Beginning with the third of these^ as being the 
 most familiar to those who have not devoted much 
 attention to the subject, we may remark that from 
 it we need not expect to obtain much assistance in 
 the study of the more ultimate and elementary 
 phenomena of the human mind. The manifest re- 
 sults of human activity, as seen in language, in 
 mythology, in art, or in religion, are the expression 
 or effects of mental processes of a complex and 
 elaborate kind. They cannot, therefore, throw much 
 light upon the mental problems connected with the 
 first beginnings of knowledge; but they will assist 
 very materially in showing how the more complex 
 mental operations are carried on, how the simpler 
 elements of knowledge are combined and elaborated. 
 Leaving their consideration, therefore, for a future 
 period, we shall examine more carefully the other 
 two sources which we have indicated. 
 
 § 8. A study of the physical organism is without 
 doubt an important preparation for the study of the 
 mind. But the value of the information which it 
 gives has been differently estimated by different 
 students. All are willing to admit that the connec- 
 tion between the body — and especially the nervous 
 system — on the one hand, and the mind on the other, 
 is of a very intimate kind ; and all should, therefore, 
 agree that the study of the one is an important 
 condition of a complete knowledge of the other. 
 But there are diversities of opinion as to the nature 
 
 CHAP. I. 
 SECT. II. 
 
 study of 
 complex 
 mental 
 products. 
 
 Physical 
 organism : 
 different 
 views of 
 its relation 
 to the 
 mind. 
 
TEE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. II. 
 
 (l.)Mind a 
 function of 
 train. 
 
 of the connection between the movements of the 
 nervous system and brain which are distinctly phy- 
 sical, and the elementary phenomena accompany- 
 ing or following them which are distinctly mental. 
 The following are clearly distinguished doctrines 
 upon the subject: — 
 
 (1.) It is held by some that the mind is a function 
 of the brain. In order to understand this, we must 
 bear in mind the relation between function and 
 organ in the vegetable and animal kingdoms. An 
 organ is a constituent part of an organised body 
 which has some definite duty or function to perform. 
 The function of the leg of an animal is to walk or 
 run ; that of the wing of a bird is to beat the air so 
 as to enable the bird to fly. The stomach is a large 
 internal organ of the body, whose function it is to 
 contain the food which we swallow, until it has been 
 prepared for being taken into the blood. The liver 
 is another organ, whose function it is to secrete bile, 
 which is poured into the stomach to assist in the 
 digestion of our food. Every organ has got some 
 special work or function to perform in the body to 
 which it belongs. In the same way, it is argued, the 
 brain has a function to perform in the animal system, 
 and that is to produce the various mental phenomena 
 of which we are conscious. And, acting upon this 
 hasty and crude hypothesis, a set of visionary 
 speculators called phrenologists have thought that 
 they could learn all about the mind, its character, 
 and its laws, by the study of its organ, the brain.* 
 
 * This is the theory of M. Comte, and some of his followers. 
 
F8YCH0L0GY OF COGNITION. 
 
 There are many objections to this hypothesis^ of 
 which we offer the following. 
 
 The functions of all the organs with which we are 
 acquainted are perceived by us either as some 
 material product or some mode of motion. We are 
 able to examine both the organ and the function as 
 ordinary physical phenomena ; both the organ and 
 the function are made known by perception through 
 the senses. But in the case of the brain^ the organ 
 is indeed capable of being examined as we examine 
 any other physical organ — by external observation 
 aided by the employment of the dissecting knife. 
 And if we consider the brain as the centre of 
 nervous force by which the muscles of the body are 
 made to contract, we are able to perceive a function 
 of the brain in its result — ordinary muscular motion. 
 But mental phenomena are directly perceived only 
 by consciousness, and are entirely different in kind 
 from any of the functions of physical organs with 
 which we are acquainted. 
 
 Again, it is admitted by comparative physio- 
 logists that there is a much closer resemblance 
 between the nerve-systems of some animals and 
 that of man than can be made out between the 
 mental o])erations of the former and of the latter. 
 The brain-ganglia of some of the anthropoid apes 
 are exceedingly like those of man ; but between the 
 mental activity of the one and the other there is an 
 impassable gulf ! The organs are very similar; the 
 so-called functions are essentially different. 
 
 The absurdity of this hypothesis will be still 
 
 CHAP. I, 
 SECT. II. 
 
 Ohjections. 
 
10 
 
 TEE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. II. 
 
 (2.) Mind 
 and body 
 tivo inde- 
 pendent 
 substances. 
 
 farther apparent from a consideration of the fact 
 that the alleged function — the mind, actually 
 governs the organ — the brain. The mind con- 
 sciously determines to act in a certain way, issues 
 its commands to the great centre of nerve-force^ 
 the brain, and the nerves and muscles immediately 
 act in obedience to the mandate. 
 
 The same objections apply to that modification 
 of this theory which makes mental phenomena a 
 secretion from the brain, analogous to the bile and 
 other secretions of the glandular organs of the 
 body. 
 
 Hence there is a strong presumption, which may 
 be confirmed as we advance, against the hypothesis 
 that the relation between the nervous system and 
 the phenomena of the mind is identical with, or 
 even analogous to, that between ordinary physical 
 organs and their functions. Consequently, although 
 a knowledge of the nervous system may be of im- 
 portance to the study of mind, we can attach to it 
 at present but a subordinate degree of importance. 
 
 (2.) A second theory of the relation between the 
 mind and the body may be described in the follow- 
 ing manner. The mind and the body are two- 
 entirely different substances possessing entirely 
 different qualities. The mind has been brought 
 into connection with the body, inhabits the body, 
 and uses the body as its instrument of carrying 
 out its purposes and communicating with the ex- 
 ternal world; but they are in nature so entirely 
 different, that there is, and can be, no truly causal 
 
PSYCHOLOGY OF COGNITION. 
 
 II 
 
 connection between tlie phenomena of the one and 
 those of the other. An impression upon an organ is 
 only an occasion on which, by some mysterious 
 power, a sensation is produced in the mind. So the 
 occurrence of a volition or determination in the 
 mind is only an occasion on which, by divine in- 
 terference, a movement is excited in some of the 
 muscles of the body. The connection between the 
 mind and body is only accidental, and might have 
 been otherwise. The one is now inhabiting and 
 employing the other, but has an existence really 
 independent of the other ; and our knowledge of 
 the one cannot be increased to any material extent 
 by a study of the other. Those who hold a theory 
 such as this attach very little importance to the 
 stady of the brain and nervous system as subordi- 
 nate to psychology. It is a degradation of the mind 
 to suppose that any light can be thrown upon its 
 workings by a study of its humble habitation and 
 instrument. Consciousness, therefore, and conscious- 
 ness alone should be resorted to by the student of 
 psychology. 
 
 A theory such as this was held by the older 
 followers of Descartes and the older adherents of 
 the Scottish philosophical school. But there are 
 certain considerations which will prevent us from 
 adopting it as an hypothesis to guide us in our 
 studies. In the first place, the student of psychology 
 has nothing to do with the so-called suhstances of 
 mind or matter ; he has to study only the phenomena, 
 the sensations and the qualities which consciousness 
 
 CHAP. I. 
 SECT. II. 
 
 Cartesian 
 theory. 
 
12 
 
 TEE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. II. 
 
 {3.) Mental 
 and cere- 
 hral events 
 form two 
 partially 
 co-ordi- 
 nate series 
 whose re- 
 lations are 
 not accu- 
 rately 
 known. 
 
 and perception make known to him. And, again, it 
 is unscientific to advance to tlie study of the mind 
 with certain preformed and crude notions regarding 
 its nature, its independence of matter, and other 
 things ; although it is quite possible that more or 
 less definite conclusions regarding these questions 
 may be reached as the result of study. As far 
 as our experience goes, the mind is most intimately 
 connected with our physical organism, and it 
 appears to be the duty of the psychologist to take 
 into account every fact bearing upon his subject, 
 admitted to exist, and learn from it as much as 
 possible. Moreover, it lies within his sphere to study 
 only those phenomena which manifest themselves 
 in our present conditions of existence, and not to 
 speculate or make assertions regarding what might 
 be under other conditions. 
 
 (3.) A third theory respecting the connection 
 between physical and mental phenomena regards 
 them as simple antecedents and consequents, without 
 predicating anything concerning the difference in 
 their nature except in so far as may be learned from 
 actual observation. A certain physical movement 
 or nervous vibration takes place ; it is followed by a 
 sensation. A certain volition is determined in the 
 mind ; it is followed by a muscular movement. The 
 psychologist, aided by the physiologist, may legiti- 
 mately endeavour to discover what particular 
 phenomena of a physical kind always precede or 
 follow certain phenomena of a mental kind, in what 
 order the two series of phenomena occur_, and other 
 
PSYCHOLOGY OF COGNITIOX. 
 
 13 
 
 facts regarding them of a similar kind. But on the 
 other hand, it is not legitimate to assume, without 
 satisfactory reasons, that every mental phenomenon 
 has a physical or nervous antecedent, any more than 
 it is legitimate to take for granted that every organic 
 action is the result of some conscious mental 
 antecedent. As physiologists tell us about certain 
 organic actions which take place in the body alto- 
 gether independent of any mental determination, 
 so there is an d jpriori probability that there are 
 mental activities which are not connected with any 
 particular physical movements. 
 
 This probability is abundantly confirmed from 
 a study of certain classes of mental phenomena 
 which, from their nature, cannot have mere physical 
 antecedents. 
 
 Primitive judgments are of this character. The 
 assertion that two lines are equal, that white is 
 different from green, that thunder follows a flash 
 of lightning, express mental judgments which have 
 for their objects certain things given in sensation, 
 but are not the causal consequents of these things. 
 The mental judgment is the independent action of 
 the mind regarding the relations of certain objects 
 perceived. 
 
 Moral judgments are also of this character. A 
 desire, appetite, or passion takes possession of a 
 person ; originating perhaps in some physical 
 condition, it seeks to bend the will so as to secure 
 possession of its object. But conscience intervenes, 
 pronounces the desire, appetite, or passion to be 
 
 CHAP. I. 
 SECT. II. 
 
 Mental 
 events may 
 he without 
 physical 
 antece- 
 dents. 
 
14 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. I, 
 SECT. II. 
 
 Conscioua- 
 
 wrong, and forbids its object to be sought after. 
 Tliere you have a desire originating in physical 
 antecedents, strongly influencing the mind towards 
 action ; but the intervening moral judgment which 
 pronounces the contemplated action to be wrong 
 and peremptorily forbids it, from what physical 
 antecedent can it proceed? It powerfully and 
 with authority resists the course to which the 
 desire, born of physical conditions, would lead, and 
 hence it cannot be the natural consequent of these 
 antecedents. 
 
 This third theory of the concomitance of the 
 physical and the mental series of phenomena is 
 the one which appears to us nearest the truth as 
 far as we know it. It asserts nothing regarding 
 the relations of mind and matter except what is 
 discovered or inferred from actual observation ; 
 nothing regarding the possible independence of what 
 are actually united. It must be limited, however, 
 to those phenomena in each series which are dis- 
 tinctly shown to have a connection of antecedence 
 or consequence with phenomena of the other series. 
 It is illegitimate to assume that because a certain 
 number of facts in the two series are concomitants^ 
 therefore all are so. And it is also illegitimate 
 to assume that because certain facts of the one 
 series follow facts of the other, there must there- 
 fore be any essential connection between them. 
 
 § 9. We come now to refer to that source of 
 knowledge regarding the mind which, though last 
 in order of consideration, is first in importance. It 
 
I 
 
 PSYCSOLOGY OF COGNITION. 
 
 15 
 
 is by consciousness only tliat we can become directly 
 acquainted witli mental pbenomena. As those phe- 
 nomena are called physical which can be perceived 
 by the senses either alone or aided by artificial 
 contrivances such as the microscope, so those 
 phenomena are called mental which manifest them- 
 selves in consciousness. Since, therefore, conscious- 
 ness is the only means by which we can become 
 directly cognisant of mental phenomena, it follows 
 that the study of the facts revealed in consciousness 
 must always be the principal method of obtaining 
 psychological knowledge. This study, however, as 
 it is one of great importance, is also one of great 
 difiiculty. The art of reflecting upon our own mental 
 operations is one which requires a great deal of at- 
 tention and cultivation in order that we may become 
 proficient in it. This depends partly upon the fact 
 that the energies of human beings are first, and 
 usually continue to be, directed outwards to other 
 persons and external objects. It requires an effort 
 to turn the attention inwards to the facts of con- 
 sciousness ; and hence in Greece men had attained 
 to a high state of civilisation, and acquired a great 
 deal of knowledge regarding external objects, before 
 any attempt was made to examine and analyse the 
 phenomena of the mind. 
 
 Another cause of the difficulty of reflection is the 
 great complexity of the phenomena made known in 
 consciousness. This complexity is twofold. In the 
 first place, phenomena are complex from the fact of 
 a great many of them occurring simultaneously or in 
 
 CHAP. I. 
 SECT. II. 
 
i6 
 
 THE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. II, 
 
 Method of 
 studying 
 phenomena 
 of con- 
 sciousness. 
 
 Its general 
 character 
 and ele- 
 ments. 
 
 immediate succession ; and it is difficult to separate 
 tliem the one from the other, so as to ascertain their 
 mutual relations. And in the second place, certain 
 mental actions which seem at first view to be quite 
 simple are in reality very complex in their origin. 
 It is frequently a matter of great difficulty and 
 delicacy to analyse the history of the mind's ability 
 to perform such actions. We are apt to suppose 
 that, because we can perform them easily and readily 
 now, we were always able to do so ; and it is difficult 
 to conceive the condition of our minds when we had 
 not our present ability. 
 
 § 10. As consciousness is the original and only 
 reliable witness testifying to the facts of the human 
 mind, it is manifestly important that the student 
 should know how to examine this witness, and what 
 kind of facts it might be expected to bear witness 
 to. And in the next section we purpose introducing 
 the student in a general way to the character and 
 elements of consciousness, its legitimate sphere, and 
 the different methods by which its testimony may 
 be interpreted. 
 
 Section III. 
 
 CONSCIOUSNESS. 
 
 § 11. We give our first attention to the general 
 character and elements of this most important 
 source of knowledge regarding the mind. Con- 
 sciousness is the most general phenomenon of the 
 human mind, and all particular phenomena are 
 
PSYGEOLOGY OF COGNITION. 
 
 17 
 
 but its states or modifications. No mental phe- 
 nomenon can take place whicli is not, as it were, 
 a link in the general train of our conscious life, 
 a particular form of consciousness. Hence it is 
 impossible to define consciousness in the proper 
 sense of the term, that is, to refer it to a higher 
 class of phenomena of which it is a species. Every 
 particular mental phenomenon involves conscious- 
 ness; and, on the other hand, there can be no 
 general consciousness which is not some par/- 
 ticular phenomenon. Psychologists analyse 4fc^ 
 sciousness into the following elements : — A 
 cognising or knowing subject; a recognised o? 
 known modification ; and a recognition or know- 
 ledge by the subject of the modification. Thus 
 consciousness, or immediate knowledge is, in 
 reality, a relation between two things, — the knowing 
 subject and the known modification or phenomenon. 
 This relation and the terms of it are worthy of 
 very close examination. 
 
 The first term of this relation is the knowing 
 subject, the self or ego; the second term consists 
 of the presentations and representations which are 
 known. With reference to the first of these terms 
 it is manifest that it cannot be itself a phenomenon ; 
 we could never say that one sensation knows 
 another, or that a thought is aware of a volition, or 
 that any single mental phenomenon cognises any 
 other. It would seem equally absurd to say that 
 the whole collection of phenomena which constitutes 
 our consciousness at any one time knows any 
 
 
 
 .xs^ 
 
 ¥r^_ Ti^-^ 
 
 CHAP. I. 
 SECT. III. 
 
 The ego. 
 
i8 
 
 TEB ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. III. 
 
 particular phenomenon of the series; or that the 
 whole of our past and present conscious life con- 
 sisting of all past and all present phenomena 
 cognises any phenomenon now in consciousness. 
 Every single phenomenon is hnown, is an object of 
 knowledge ; and it is impossible to invest the whole 
 aggregate of phenomena with a power the elements 
 of which are not possessed by them separately. 
 Still further we cannot, by generalisation, from all 
 the past and present aggregate of mental pheno- 
 mena, obtain an element which can be considered 
 identical with the first term of the relation we are 
 examining. Suppose that, from all past and present 
 mental phenomena, we abstract and generalise 
 Feeling itself, we may have here the highest mental 
 abstraction we can reach, but it is not the self. 
 Thus we set aside three doctrines which may bo 
 held regarding the character of the first term of 
 the relation of knowledge, the knowing subject : — 
 (1) That the subject of consciousness is some 
 particular phenomenon of consciousness; (2) that 
 it is the whole aggregate of mental phenomena 
 past as well as present ; (3) that it is some element 
 or characteristic of the mental phenomena, ab- 
 stracted from particulars, such as Thought or 
 Feeling. All of these propositions we reject, be- 
 cause it is inherently absurd that a single phe- 
 nomenon, or an aggregate of phenomena, or an 
 abstraction from phenomena, should exercise the 
 function of Icnowing, which we are conscious of 
 possessing. There is an element in the relation of 
 
PSYCHOLOGY OF COGNITION. 
 
 19 
 
 immediate knowledge which makes it impossible to 
 explain that relation as existing between mental 
 phenomena simply, or between any combinations 
 of mental phenomena or any abstractions from 
 them. 
 
 § 12. A common man speaking of his mind or 
 feelings would say " my mind,' or *' my feelings J' 
 He would say ''I thought so-and-so/' or '^ J felt 
 such a sensation/' or " / was conscious of this smell 
 or that sound.'' In short, every one thinks and 
 speaks of himself as a person not to be identified 
 with his body ,11 or the series of phenomena which 
 make up what he calls his mind. This reference 
 of all one's feelings and thoughts to self is called self- 
 consciousness. The idea of self-hood involves the 
 belief that "I'' who am conscious of feelings at 
 the present moment am the same identical being 
 who was conscious at a past time of those feelings 
 which "I" remember. This permanence of self 
 in the midst of successive and diverse sensations is 
 the essential element of personality. The idea of self 
 is not that of the sum of the series of feelings which 
 constitute our general consciousness, because it is 
 absurd to speak of the aggregate of a series of 
 feelings being conscious of any one of themselves. 
 Nor is it that of Feeling in general abstracted from 
 particular feelings, because it is absurd to attribute 
 to this or any other abstraction the function of 
 conscious knowledge. In the relation of know- 
 ledge there is implied a kind of opposition be- 
 tween self and the sensations of which seK is 
 
 G 2 
 
 CHAP. I. 
 SECT. III. 
 
 A' 
 \ 
 
20 
 
 THE ELEMENTS OF TEE 
 
 CHAP. I. 
 SECT. III. 
 
 TinowaUe. 
 
 conscious. Sensations past, present, and expected 
 are all referred to self as tlieir possessor and subject. 
 Self is tliouglit to be the imity in tlie midst of diverse 
 kinds of sensations, tlie permanent element in the 
 midst of transient and successive sensations, the one 
 conscious subject in the midst of many Jcnown objects. 
 In " self therefore we have the subjective term 
 of the relation of knowledge ; but this term of the 
 relation is so peculiar and remarkable that we must 
 bestow some more attention upon it. We have 
 said that it is not a phenomenon, and it cannot, in 
 any way, be phenomenised so as to become Icnown. 
 The function of self is to hiow, and although, in 
 the very act of knowing, a phenomenon arises, yet 
 it is impossible for that which knows to set itself 
 over against itself as object and thus become known. 
 Self is the universal relative of all objects, — a 
 something separating itself, as it were, from the 
 phenomena of general consciousness and converting 
 them into objects, but incapable itself of becoming 
 an object. This peculiarity of self makes it the 
 most intractable and puzzling element of our 
 conscious existence. Unknown_, but all-knowing, 
 it emerges, as it were, from the midst of the endless 
 variety of phenomenal consciousness, asserting its 
 freedom from phenomenal law, and offering the 
 great miracle of the life with which we are endowed. 
 It is absurd to attempt a scientific definition or 
 exposition of the unknown ; but we have the power 
 of studying its function conscious activity^ and 
 through the study of this function alone can we 
 
PSYCEOLOGY OF COGNITION. 
 
 21 
 
 learn anything about tlie nature of that which is 
 conscious. 
 
 § 13. The function of the subject of knowledge is 
 really the same as the relation between the subject 
 and the objects of knowledge. And it is manifest 
 that this relation must be different from other rela- 
 tions with which we are acquainted, since the sub- 
 jective terra of it is different from any object of our 
 knowledge. Moreover the terms of the relation, 
 under present conditions, are insejparahle, because 
 the phenomena which we know are themselves 
 comprehended in and to a certain extent identical 
 with the act of knowing. When we feel a smell, 
 the act of feeling and the smell itself appear to be, 
 as it were, different sides of the same phenomenon. 
 When we attempt, therefore, an examination of 
 conscious activity as seen in cognition we cannot 
 very well separate that activity from its objects. 
 We describe the function of self in cognition as 
 conscious activity in order to distinguish it from 
 the objective or passive element in phenomena. 
 Knowledge is not the reception of images or 
 impressions from without; it is essentially an 
 activity of self in relation to things which are not 
 self. This activity is perhaps best described or 
 rather indicated by such terms as assertion, judgment^ 
 or predication. We are conscious of a loud noise ; 
 in the act of consciousness there is involved the 
 assertion of the existence of the sound. We are 
 conscious of two varying sensations ; we assert that 
 they differ from one another. We are conscious of 
 
 CHAP. I. 
 SECT. III. 
 
 Its 
 
 functions. 
 
22 
 
 THE ELEMENTS OF TEl 
 
 CHAP. I. 
 SECT. III. 
 
 Methods of 
 interpre- 
 ting con- 
 sciousness. 
 
 (1.) Psy. 
 cJiological 
 or induc- 
 tive. 
 
 a particular smell, colour, figure, aud taste ; we assert 
 — this is a rose. Now without this mental assertion 
 there is no knowledge; the mere appearance in 
 consciousness of some phenomenon which does not 
 call forth a responsive activity is not knowledge. 
 We have therefore in this assertion — this conscious 
 activity indicated by the term assertion — the 
 essential element of that relation existing between 
 subject and object in cognition. 
 
 There is a particular feature of this relation of 
 great importance which we may indicate by the 
 term ohjectification. It is essential to knowledge 
 that the object should be put over against the 
 subject, — that the phenomenal activity should be 
 discriminated into subjective and objective elements. 
 This creation of an opposition or antithesis between 
 subject and object, called ohjectification, is perhaps 
 a result of the conscious activity before described 
 as assertion, or is perhaps identical with it ; but it 
 is at least essential to every act of cognition. 
 
 § 14. There are three leading methods which 
 psychologists have employed in the interpretation 
 of consciousness, which inay be termed respectively 
 the psychological or inductive, the critical and the 
 psychogenetical. According to the first of these 
 methods, particular phenomena of consciousness 
 are subjected to study, and classified according to 
 their resemblances or differences, and from them 
 general laws of thought are derived. Many cases 
 of causal connectiorij for example, are observed, and 
 from them there is generalised the great principle 
 
PSYGEOLOGY OF COGNITION. 
 
 23 
 
 that every event has a cause. Similarly, many 
 material objects are perceived to be extended, and 
 it is concluded, by induction, that all material 
 things are extended, or are perceived as occupying 
 space. Against this method of interpreting con- 
 sciousness it is objected that it is incapable of 
 explaining the element of necessity which is in- 
 volved in many mental products or laws. Induction 
 alone can only lead to a principle which is generally 
 and probably true ; but there are principles in the 
 human mind which are universally and necessarily 
 true. For example, all men not only believe, but 
 must believe, that every event has a cause; all men 
 not only perceive, but must perceive, phenomena 
 under the relations of time and space. Now this 
 element of necessity, it is alleged, does not and 
 cannot arise from an induction from experience. 
 And it is urged by many psychologists, after Kant, 
 that induction alone cannot account for all the facts 
 of our conscious life. These psychologists employ 
 criticism J by which they discriminate the phenomena 
 of consciousness into two classes : those which are 
 contingent, the results of mere experience ; and 
 those which are necessary, and therefore not the 
 results of experience, but rather the d priori con- 
 ditions of experience. By this critical examination 
 of the simple facts of consciousness they are able 
 to account for the elements of necessity and uni- 
 versality in the more complex products of conscious 
 life, while they claim the right of employing the in- 
 ductive method also wherever it may be applicable. 
 
 CHAP. I. 
 SECT. III. 
 
 (2.) Criti- 
 cal. 
 
24 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. I. 
 SECT. III. 
 
 Necessity 
 from asso- 
 ciation. 
 
 § 15. The advocates of tlie psychological method 
 object to the critical, that necessity and universality 
 do not of themselves render it certain that a mental 
 fact is original; complex and derived facts, or 
 phenomena, may also be characterised by necessity. 
 Hence, before we accept any fact or phenomenon 
 as an original and simple datum of consciousness, 
 we must examine into the character and source of 
 its necessity. There is a necessity which results 
 from experience, and which consists simply of an 
 inseparable association; and, in fact, all necessity 
 may result from the application of the laws of 
 association to phenomena. And those who make 
 use of the psychological method try to show that 
 all mental products are the results of experience 
 and association. 
 
 Now there can be no doubt that the laws of 
 association play a most important part in the forma- 
 tion of the complex contents of our consciousness. 
 Phenomena do not appear in consciousness in an 
 accidental or random order, but there is a mutual 
 connection between them of such a nature that 
 they serve to bring one another before conscious- 
 ness. When two mental phenomena have been 
 experienced at or about the same time, a bond of 
 connection i"s formed between them, so that after- 
 wards if one of them is repeated the other is likely 
 to be represented. This link of association between 
 mental phenomena appears to be altogether inde- 
 pendent of volition ; the associated idea of any 
 particular phenomenon appears in consciousness 
 
I 
 
 PSYCHOLOGY OF COGNITION. 
 
 25 
 
 without any effort of ours, or even in spite of 
 efforts to avoid thinking about it. Illustrations of 
 this association of mental phenomena will readily 
 occur to any one. We have once visited a house, 
 and at the time of our visit something of particular 
 interest to us has occurred. If we ever again visit 
 the house, or even have our thoughts directed to 
 it, the idea of the interesting fact obtrudes itself 
 upon our attention. The various laws by which 
 phenomena are associated together have been suf- 
 ficiently investigated and are well known. We 
 need not therefore refer to them, but shall proceed 
 to point out a distinction of importance with refer- 
 ence to our present study. 
 
 § 16. We have to distinguish between what is 
 properly a mental association and an ohjedive con- 
 nection. When two or more phenomena have been 
 once or frequently presented together in conscious- 
 ness, they become connected in representation. But 
 there are two different cases to be considered. Two 
 different phenomena may be, upon one or more 
 occasions, connected together in presentation, but 
 may afterwards become objects of consciousness 
 separately. This we may call the case of the asso- 
 ciation of separable phenomena. On the other 
 hand, two or more phenomena may be so connected 
 together that the one is never presented except in 
 connection with the other, and the association in 
 this case is an association of inseparable phenomena. 
 And we must be careful to discriminate between 
 the distinction which we have here drawn between 
 
 CHAP. I. 
 SECT. III. 
 
 Lnportant 
 distinc- 
 tion. 
 
26 
 
 THE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. III. 
 
 separable and inseparable plienomena and another 
 distinction which is considered of great importance 
 by psychologists, — the distinction, viz., between 
 separable and inseparable associations. There may 
 be an inseparable association of separahle pheno- 
 mena; but as a matter of course, when the pheno- 
 mena are inseparable in presentation, the association 
 of the representations is inseparable also. There 
 are many familiar instances of an inseparable asso- 
 ciation of separable phenomena ; a book, a watch, a 
 trinket of any kind, which has been presented to us 
 by a dear friend becomes, in our mind, inseparably 
 associated with the idea of that friend. But quite 
 different from this is the inseparable association of 
 phenomena which are inseparable. Let us study a case. 
 In our experience we have never been conscious 
 of colour except in connection with extension. No 
 matter how far back in our lives we attempt to 
 reach by the aid of memory, we are incapable of 
 discovering the slightest trace of the possibility of 
 a separation between the two phenomena. We do 
 not remember ever to have seen a colour which 
 was not extended, or an extended figure which was 
 not in some way coloured. Nor is there any indi- 
 cation in history or in language of the existence of 
 any race o"f human beings in whose minds there 
 was ever conceived the possibility of such a separa- 
 tion. And since the presentation of colour is always 
 combined in our experience with that of extension, 
 it follows as a matter of course that the representa- 
 tions also are always combined. 
 
PSYCHOLOGY OF COGNITION. 
 
 27 
 
 § 17. This distinction between an inseparable sub- 
 jective association and an association of objectively 
 inseparable phenomena is one of great importance. 
 When phenomena which are only occasionally pre- 
 sented together have an affinity for one another so 
 as to cling together in representation, the associ- 
 ation is truly and only mental. The possibility of 
 their being separated in presentation shows that 
 their synthesis in association is only a mental one, 
 or at least that the objective union is only acci- 
 dental. But, on the other hand, when phenomena 
 are always united in presentation and can never by 
 any means be separated, their synthesis is not only 
 or even chiefly mental. The objective inseparable 
 connection is that upon which the subjective asso- 
 ciation depends. It constitutes a different kind of 
 connection from that which is simply subjective. 
 There is such a decided difference both in degree 
 and in kind between the mental synthesis which 
 we form between two phenomena which have acci- 
 dentally been brought into contiguity, and that 
 synthesis which exists between two such inseparable 
 phenomena as extension and colour, that no person 
 who has not a particular theory to support, would 
 ever place them in the same category. The inse- 
 parability of phenomena in presentation leads, no 
 doubt, to their inseparability in representation ; but 
 it also leads to something else, and that is, to the 
 conclusion that the synthesis which binds them 
 together is not a subjective one at all. 
 
 Another phase of the same distinction is found 
 
 CHAP. I. 
 SECT. III. 
 
28 
 
 THE ELEMENTS OF TEE 
 
 CHAP. I. 
 SECT. III. 
 
 Special 
 and uni- 
 versal as- 
 sociations. 
 
 in the distinction between associations wliicli are 
 peculiar to individuals and those which are common 
 to all mankind. All mental associations depend 
 upon the experience of the individual in whose 
 mind they have been formed. Peculiar experi- 
 ences will therefore produce peculiar associations. 
 Experiences common to all will result in associa- 
 tions common to all. In different zones of the 
 earth^s surface and in different countries there are 
 many differences of climate^ landscape, means of 
 living, habits and customs which give rise to very 
 varied mental associations. The character of the 
 seasons in India, in Britain^ and in Canada presents 
 striking differences, and^ in the minds of the 
 inhabitants of these countries respectively, there 
 are consequently very different ideas connected 
 with each of them. The word "water," for 
 example, in the torrid zone, is always asso- 
 ciated with fluidity as one of the characteristic 
 qualities constituting the denoted object. But in 
 the temperate and frigid zones, where water 
 frequently assumes a solid form, fluidity is nob 
 uniformly associated with the word. Many other 
 examples of variable associations might be given. 
 On the other hand, with the word "air^' there are 
 always asS"ociated the peculiar sensations or ideas 
 connected with respiration. "The air which we 
 breathe^' is a phrase which may be universally 
 employed to express the experience of mankind, the 
 reason of course being that, in our present state of 
 existence and with our present physical constitution, 
 
FSYCEOLOGY OF COGNITION. 
 
 29 
 
 the breathing of air is an essential condition of life. 
 This association of the word " air '^ with the idea of 
 breathing is quite as inseparable as any association 
 which we could name. It is, moreover, an association 
 formed in the minds of all men without exception; 
 but there are important differences which we 
 shall note between this and other inseparable 
 associations. 
 
 § 18. We have just considered two associations, 
 one of them variable and the other invariable and 
 universal, but both being associations connected 
 with particular objects of our knowledge. The 
 qualities or ideas associated are relative to or repre- 
 sentative of particular complex sensations depending 
 upon our present physical constitution. But if we 
 consider the connection between extension and 
 colour we shall be able to note an important 
 difference. The qualities to which we referred as 
 associated with air and water were simply a com- 
 bination of complex sensations objectified; but here 
 we have a sensation '' colour ^^ associated with some- 
 thing which is not a sensation. Extension is neither 
 a sensation nor any combination of sensations, but 
 a certain relation which is seen to exist between 
 objectified sensations, or a form which is perceived 
 in connection with a single sensation. And 
 although the mental association between azV and 
 breathing may be quite as inseparable and universal 
 to the human mind as that between colour and 
 extension^ yet we would never place the objective 
 connection between the first pair in the same 
 
 CHAP. I. 
 SECT. III. 
 
30 
 
 THE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. III. 
 
 category as that between the second pair. The 
 connection between air and breathing is determined 
 to our minds by the peculiar circumstances in which 
 we are placed as physical beings, and we can easily 
 imagine other circumstances in which this connec- 
 tion would not exist. But the relation between 
 extension and colour, although neither more 
 objective nor more necessary than the former is 
 determined by the constitution of our minds with 
 reference to external objects, or the constitution of 
 external objects with reference to our minds. Hence, 
 since we are unacquainted with any other forms or 
 laws of knowledge except our own, it is impossible 
 for us to conceive that any intelligence could be 
 cognisant of colour without extension ; or to state 
 the same thing more abstractly, it is impossible for 
 us to conceive that any intelligence could be 
 cognisant of phenomena except in the relation of 
 difference and co-existence. Thus the connection 
 between extension and colour is characterised by an 
 absolute universality with reference to all in- 
 telligence as far as intelligence can be understood 
 by us; while that between air and breathing has 
 only a contingent universality with reference to 
 beings who may possess bodies constituted as ours 
 are. 
 
 We have endeavoured to show that the connection 
 between extension and colour is not a case of mental 
 association and cannot be resolved into association. 
 Objectively the two things are absolutely inse- 
 parable ; and subjectively the relation of extension 
 
PSYCEOLOGY OF COGNITION. 
 
 31 
 
 depends upon the primary relation of co-existence 
 whicli we have seen is an a ^priori condition of our 
 constitution as capable of knowing. But if this 
 doctrine be correct, we have here an original fact of 
 our consciousness which the psychological method 
 of Mr. Mill fails to interpret. And until this 
 method explains satisfactorily the inseparability 
 of colour and extension both objectively and sub- 
 jectively, we cannot admit that it is adequate to the 
 interpretation of all the facts of our consciousness. 
 This case of inseparability is only one of those 
 which might be adduced as being insoluble by the 
 psychological method. We have chosen to examine 
 it thus fully because it is perhaps the most im- 
 portant. And as, until the above doctrines are 
 overthrown, the psychological method must be 
 considered unsatisfactory, we shall now proceed 
 to the consideration of another method, the Psijcho- 
 genetical. 
 
 § 19. Those who adopt this method admit that 
 there are mental facts and products which cannot 
 be explained by the principles of association. 
 Neither the form nor the matter of our knowledge 
 is the result of our individual experience merely. 
 We are born with a certain constitution, mental 
 and physical, and the nature and extent of our 
 subsequent acquirements in knowledge and practi- 
 cal ability depend upon our inherited constitution. 
 In other words, it is admitted that individuals 
 possess certain d priori principles and tendencies 
 by which the phenomena of their consciousness are 
 
 CHAP. I. 
 SECT. III. 
 
 ll^X-Q^ 
 
 5^ 
 
 Mm I 
 
 (3.) Psy. 
 
 chogeneti- 
 
 cal. 
 
32 
 
 THE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. III. 
 
 Objections. 
 
 determined and governed. This admission, made 
 by such psychologists as Herbert Spencer and 
 G. H. Lewes, is a tacit acknowledgment of the 
 essential truthfulness of the position held by those 
 who have adopted the critical method. But, while 
 admitting this, the psychogenetical method attempts 
 to trace the origin of the a priori conditions and 
 principles of our nature to a very remote source. 
 The accumulated experience of the past ages of 
 human history, as well as of the past ages, countless 
 in length and impenetrable to human knowledge, 
 of brute history, is called upon for an explanation 
 of the origin of that physical, intellectual, and 
 social nature with which we are born into the 
 world. It is assumed that lower living forms 
 develop themselves into the higher, that the ex- 
 perience of individuals and races gradually produces 
 organic changes which are transmitted to successors, 
 and that thus, by the natural transmission of organic 
 structures produced or modified by incessant ex- 
 perience, all the higher forms of life and mind have 
 been produced. An adequate examination of this 
 ambitious method would carry us far beyond our 
 allotted space and our object; but we offer the fol- 
 lowing observations with reference to it. 
 
 1. The "problem attempted by this method is 
 practically an impossible one. We are not able 
 to trace the series of changes asserted to have 
 taken place. It cannot be established that ex- 
 perience gives rise to the structural changes in the 
 organism said to be the result of it. The pheno- 
 
PSYCHOLOGY OF COGNITION. 
 
 33 
 
 mena requiring to be studied in a satisfactory 
 employment of the method are too remote from 
 possible observation to be used as the foundation 
 of a science. Even if we attempt to study the 
 organic changes produced by experience in human 
 beings now living we cannot succeed; and any 
 dogmatic assertions made regarding them must be 
 rash and vain. Much more must this be the case 
 with reference to races of men and animals which 
 existed in a remote past antiquity. Consequently 
 the researches carried on in accordance with this 
 method are nothing better than ambitious and 
 perfectly uncertain speculations. 
 
 2. Against the fundamental assumptions of this 
 method it may be alleged that mental phenomena 
 do not, in some cases at least, correspond to organic 
 structure. It is now universally admitted that the 
 brain and nervous system of the anthropoid ape is 
 exceedingly similar to that of man, whereas the 
 mental functions of the latter are almost infinitely 
 in advance of those of the former. This fact is 
 quite inconsistent with the fundamental assumption 
 of the psychogenetical method. 
 
 3. If experience in past ages has given rise to 
 necessary truths and a priori conditions of thought 
 and knowledge, we might reasonably expect that 
 these a priori principles should continue to be pro- 
 duced in our own age. While it may be admitted 
 that some particular tendencies and abilities may 
 be acquired and transmitted, it has not been shown 
 that the essential and universal laws of human 
 
 CHAP. I. 
 SECT. III. 
 
34 
 
 TEE ELEMENTS OF THE 
 
 CHAP. I. 
 SECT. III. 
 
 intelligence have suffered the slightest change since 
 man came into being. 
 
 From these considerations we should be inclined 
 to reject the psychogenetical method as imprac- 
 ticable, possibly false, and quite incompatible with 
 that desire to attain certain conclusions which ought 
 to characterise men of science. And we are now 
 driven back to the critical method of Kant and 
 Hamilton which we adopt as correct and adequate, 
 with the following reservations : 
 
 1. The adoption of this method does not commit 
 us to all the results of criticism which those who 
 have hitherto employed the method have reached. 
 It may be that mistakes have been made in dis- 
 criminating between facts of consciousness as 
 original and acquired, simple and complex, that 
 some phenomena have been regarded as original and 
 simple which are really derived and complex. But 
 this admission does not detract from the value of 
 the method. 
 
 2. The adoption of the critical method does not 
 prevent us from making use of the principles of 
 association as far as they are applicable. It is not 
 an essential principle of this method that anything 
 which is now found to be necessary must be an 
 original necessity of intelligence. And if any 
 necessity of thought or knowledge can be explained 
 by the laws of association or any other principles of 
 experience, it ought unquestionably so to be ex- 
 plained. But the critical method insists upon 
 distinguishing between such explicable necessities 
 
PSYCHOLOGY OF GOGNITION. 
 
 35 
 
 of thought, and an inexplicable residue of necessities 
 which^ from their nature, must be taken as d 
 ^priori and founded in the constitution of our intelli- 
 gence. 
 
 3. The critical method, while it looks principally 
 to the phenomena of consciousness as the materials 
 with which it has to deal, is not inconsistent with a 
 careful study of the organism and cosmic forces and 
 laws in so far as these may throw light upon the 
 problems to be solved. 
 
 In this section, for the sake of the completeness of 
 our study of the subject, we have been led into a 
 discussion, which at this stage of the student^s pro- 
 gress can scarcely be very intelligible to him, that 
 is, if he be new to the study of psychology. We 
 should recommend, therefore, a brief and general 
 study of the section, upon first reading, to be 
 followed by a more careful examination after- 
 wards. 
 
 CHAP, I. 
 SECT. III. 
 
 D 15 
 
36 
 
 THE ELEMENTS OE TEE 
 
 CHAP. II. 
 SECT. I. 
 
 Example 
 ofanalysis. 
 
 CHAPTER II. 
 
 TEE ACQUISITION OF PBE8ENTATIVE KNOWLEDGE. 
 
 Section I. 
 
 ANALYSIS OF PEECEPTION. 
 
 § 20. By way of introducing tlie problems con- 
 nected with this subject, let us begin with a par- 
 ticular example. Suppose that we see a flowering 
 tree in full bloom a short distance in front of us. 
 The cylindrical trunk, the branching stems, the 
 foliage, the numerous clusters of flowers form a 
 very beautiful object to the eye. The flowers are 
 odorous ; the wind is blowing from the direction of 
 the tree towards us ; and a pleasing perfume is 
 wafted into contact with our olfactory nerves, giving 
 us the sensation of an agreeable smell. The wind 
 which brings the perfume of the flowers causes 
 the innumerable leaves of the tree to flutter, and 
 thus produces that pleasant murmuring sound of 
 fluttering leaves with which every one is familiar. 
 The tree, we have supposed, is at a short distance 
 from us. This means, that if we walk a short 
 distance towards the object which we see, we shall 
 be able to touch it. Acting upon this hint, we 
 advance and touch one of the leaves of a branch 
 hanging near the ground. A slight sensation is 
 
PSYCHOLOGY OF COGNITION, 
 
 37 
 
 felt on tlie point of the finger. We touch the 
 trunk and press against it ; it resists our pressure; 
 it is hard. We move our hand over its surface, 
 pressing lightly against it, and discover that 
 there are inequalities in it, the tactual sensation 
 being here and there interrupted ; in other words, 
 the bark of the tree is rough. Our curiosity is 
 not yet satisfied, and so we pluck a cluster of the 
 flowers, put one of the coloured petals into the 
 mouth and chew it ; it is pleasant to the taste. All 
 our senses having been thus brought into exercise, 
 we take our seat upon a mossy hillock near by, and 
 reflect upon what we have been doing. 
 
 § 21. The complex activity which has given us a 
 more or less complete knowledge of the qualities of 
 the tree is called perception. And this perception 
 is, of course, most complete when, with each of our 
 senses, we have become directly acquainted with 
 that quality of the tree which is capable of being 
 perceived by it. Three of these qualities we have 
 seen are capable of affecting us at a distance — the 
 colour, the smell, and the sound. The remaining 
 two, the touch and the taste, require, as their con- 
 ditions, that we shall advance to the tree and bring 
 parts of it into immediate contact with our organs 
 of sensation. Thus, touch and taste of themselves 
 bring to our knowledge objects at no greater dis- 
 tance than we are able to reach our hands — the 
 latter, indeed, at no distance at all. Sight, smell, 
 and hearing give us a knowledge of colours, odours, 
 and sounds, and these qualities are perceived as at 
 
 CHAP. II. 
 SECT. I. 
 
 Analysis 
 explained. 
 
38 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. I. 
 
 a distance from us. But a little reflection will con- 
 vince us that tlie sensations whicli we experience 
 througli these senses are really felt within our own 
 bodies, although apparently the causes of those 
 sensations exist at a distance from us. The colour 
 which we perceive appears, as it were, spread over 
 that object whose different other qualities we smell, 
 hear, touch, and taste. But we observe that its 
 apparent colour varies according to the amount and 
 kind of light which is thrown upon it ; and scientific 
 men assure us that the white light of the sun is 
 compounded of three or seven elementary colours ; 
 that green leaves absorb all these colours except 
 green, which is reflected from their surface, and, 
 falling upon the retinae of our eyes, produces the 
 sensation of greenness ; so the sensation of any other 
 colour is produced by the light from that colour 
 falling upon our organ of sight. Thus we learn 
 from our own reflections, or from the discoveries of 
 scientific men regarding light, that all sensations of 
 colour are felt in and by means of our eyes. These 
 sensations are what we directly know, because we 
 are conscious of them. And as we have seen that 
 by consciousness we can only know what is imme- 
 diately present to our minds, it follows that the 
 perception of the tree as at a distance must be 
 accomplished by means of some other power than 
 consciousness. 
 
 A similar line of reflection or observation will lead 
 us to the conclusion that the sensations of smell and 
 sound also are felt within, and by means of, our 
 
PSYCEOLOGY OF COGNITION'. 
 
 39 
 
 organism. And the sensations of touch and taste are, 
 from their nature, seen at once to be organic, since 
 their objects must be in immediate contact with the 
 senses. 
 
 Thus we see that what we may call a complete 
 perception of the tree may be resolved into sensa- 
 tions of the several senses and the elements of 
 distance in space or the occupation of a certain part 
 of space without us. But we may say that we 
 perceive the tree, although all our senses are not 
 actually engaged ; if we simply look at it from a 
 distance we are said to perceive it. Although in this 
 case, we see only a certain coloured figure which we 
 believe to be at a distance, yet we know that if we 
 pass through the intervening distance we shall be 
 able to touch a hard and rough object and taste the 
 green leaves. And in the same way, if our eyes are 
 shut and we smell the perfume of the flowers, we 
 know that we are not far from some object which 
 we might see, and touch, and taste. So, likewise, 
 with all our senses. If by any one of our senses a 
 sensation is experienced, we immediately conclude 
 that there is some object outside of us which is 
 capable of affecting our other senses ; and our per- 
 ception of the object is more or less complete, 
 according as more or fewer of our other senses 
 have been affected by it. 
 
 Now, there is nothing more certain than that by 
 each sense we can have only that kind of sensation 
 which is proper to it. By sight we can only 
 know colour, by smell only odonr, by hearing | 
 
 CHAP, ir. 
 
 SECT. I. 
 
40 
 
 TEU ELE2IENT8 OF TEE 
 
 CHAP. II. 
 SECT. I. 
 
 Result. 
 
 Subjects 
 of inquiry 
 regarding 
 sensations. 
 
 only sound, and so on. Yet when the object 
 of sight or of any of the other senses is familiar 
 to us, the one sensation which we can obtain 
 by that sense calls up before our minds the 
 ideas of a number of other sensations which we do 
 not actually experience, but which we know we 
 may experience if we fulfil the necessary conditions. 
 These sensations, not actually experienced, but 
 simply imagined, we may call ideal sensations. 
 And so the result of our reflection upon the nature 
 of the process of perception may be summed up 
 thus : — In perception there is felt a sensation which 
 is objectified or referred to some external object ; it 
 also calls up ideal sensations of the other senses 
 which are referred to the same object, and these 
 ideal sensations are believed to be capable of 
 realisation if the proper steps be taken : the object 
 of perception is thus a collection of objectified 
 sensations united into a whole and believed to exist 
 in space. 
 
 § 22. From this analysis of the process of per- 
 ception and its object we may trace out a series of 
 investigations regarding the different parts of the 
 process. Sensations themselves are known to us 
 only in consciousness ; they are mental phenomena. 
 Our inquiries regarding them will have reference to 
 their nature, their relations to one another, and to 
 consciousness in which they are known. We must 
 endeavour to learn also the nature and mode of 
 their connection with the physical organism, the 
 nature of the process which we have called objecti- 
 
P8YCE0L0GY OF COGNITION. 
 
 41 
 
 fication which plays such an iniportant part in per- 
 ception, and the manner in which objectified 
 sensations become united together in the object 
 of perception. And since we have sensations suc- 
 ceeding one another in time and objectified into 
 space, the nature and origin of our ideas of time 
 and space must occupy a prominent position in our 
 investigations. 
 
 Section II. 
 
 ANALYSIS OF SENSATION. 
 
 § 23. As we have seen that our perception of 
 external objects may, by analysis, be reduced to 
 organic sensations,* along with a conception of 
 space, we must now give some attention to sensa- 
 tions themselves. By sensations we mean those 
 feelings or states of consciousness which, as we 
 learn from physiology, are connected with certain 
 nervous movements in our physical organism. 
 Light, for example, is reflected from some external 
 object and falls upon the retinae of our eyes. The 
 minute fibrils of the optic nerve spread over the 
 retina are sensitive to the light which falls upon 
 them, and a nervous current of some kind is pro- 
 pagated to the brain. The nervous action having 
 taken place, the sensation of light or colour is felt. 
 So there is reason to believe that all sensations are 
 connected in a similar manner with certain bodily 
 conditions. A fuller discussion of the circumstances 
 
 * Sensations felt in consciousness but localised in the organism. 
 
 CHAP. II. 
 SECT. II. 
 
 Sensations 
 described. 
 
42 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. II. 
 
 Classifica- 
 tion of sen- 
 sations. 
 
 of this connection will be attempted hereafter. But, 
 in the meantime, it must be borne in mind that this 
 reference to nervous activity as preceding sensation i^ 
 no explanation whatever of sensation in itself, hut 
 simply of the physical conditions upon which sensa- 
 tion is felt in consciousness. A sensation can be 
 known only in consciousness, and as sensations 
 are the simplest mental facts which consciousness- 
 affords, we cannot resolve them into any simpler 
 elements, although it is possible that some complex 
 sensations may be reducible to simpler ones. Our 
 analysis of sensation will therefore be completed 
 when we have — (1) arranged them into clearly- 
 defined classes; (2) resolved complex sensations into 
 their simpler elements as far as can be done ; 
 and (3) determined how far this resolution can be 
 effected, and especially if conscious sensations can 
 be legitimately analysed into elements of which 
 we are not conscious. 
 
 § 24. Everyone is familiar with the five senses, 
 or gateways of knowledge, as they have been called, 
 by which we know the qualities of the external 
 world. But, in addition to the sensations connected 
 with these senses, it has been found necessary to 
 form another class comprehending a variety of 
 sensations clearly distinguished from the former. 
 This class comprises all the sensations connected 
 with the different parts of the organism with 
 the exception of the five senses. This class and 
 the sensations comprehended in it have been 
 denominated variously, the vital sense, the organic 
 
PSYCHOLOGY OF COGNITION. 
 
 43 
 
 sense, the sensations of organic life, &c. A clear 
 view of the great variety of sensations of which we 
 are conscious may be obtained by the study of the 
 following table : — 
 
 '1. Connected with the bones, tendons, 
 &c. 
 
 2, Connected with the nervous system. 
 
 3. Connected with circulation and nu- 
 trition. 
 
 1 4. Connected with the general state of 
 
 organs, as heat, &c. 
 5, Connected with the respiration. 
 ^6. Connected with digestion. 
 
 a. Smell. 
 
 h. Taste. 
 
 I. Of Organic Life. 
 
 II. Of Intellectual 
 Life. 
 
 |l. 
 
 rsranico-Intellectual. 
 
 V 
 
 2. Intellectual. 
 
 c. Touch. 
 
 d. Hearing. 
 
 e. Sight. 
 
 I. From a glance at the parts of the organism 
 referred to in this class, it will be readily apparent 
 what sensations are indicated. The organs con- 
 cerned in muscular exertion give rise to different 
 sensations when in a state of repose, when active, 
 when fatigued, and when resting after labour. The 
 nervous system may suffer excitement or depression 
 in various degrees or manners, and give rise to a 
 variety of sensations. Hunger, thirst, and their 
 opposites, with the sensations connected with them, 
 depend upon certain states of nutrition and circula- 
 tion. From a general condition of the body, which 
 cannot be very clearly defined, there arise feelings 
 of languor or the opposite, and also heat and cold ; 
 the sensations of the latter kiod being, however, 
 chiefly felt in the skin. The respiratory system is 
 the seat of a class of sensations such as that of 
 
 CHAP. ir. 
 
 SECT. II. 
 
44 
 
 TEE ELEMENTS OF THE 
 
 CHAP. 11. 
 SECT. II. 
 
 Senses of 
 smell and 
 taste. 
 
 suffocation, and there are sensations also connected 
 with, the digestive organs. The general cha- 
 racteristics of these sensations are that they arise 
 in the organism itself as the concomitants of vital 
 operations, and that they are accompaniments, 
 results, or stimulants of action, not elements of 
 knowledge, ^.e., of knowledge regarding extra- 
 organic objects; but they are elements of our 
 knowledge of the organism. 
 
 II. The sensations of intellectual life are those 
 whose chief end appears to be the imparting of 
 knowledge regarding external things. 
 
 1. Two of these senses are so closely connected 
 with the respiratory and digestive systems, and give 
 us comparatively so little extra-organic knowledge, 
 that their sensations occupy a middle position 
 between those of the first class and those of the 
 more intellectual senses which we have placed last 
 in order. The sense of smell, placed at the portal 
 of the respiratory organs, gives notice of the 
 entrance of any noxious vapour into the lungs, and 
 occasions the sensation of smell when any odorous 
 emanations come into contact with the olfactory 
 nerves. '*" The sense of taste is that by which we 
 distinguish the sapid properties of bodies. The 
 term, as 'commonly understood, includes much 
 more than this ; being usually employed to desig- 
 nate the whole of that knowledge of the qualities 
 of a body (except such as is purely tactile) which 
 we derive through the sensory apparatus situated 
 within the mouth. But this is dependent upon the 
 
PSYCHOLOGY OF COGNITION. 
 
 45 
 
 assistance of the olf active sense, which, is affected 
 by the odorous emanations of all such bodies as are 
 capable of giving them off ; and the indications of 
 which are so combined with those of the true 
 gustative sense as to make an apparently single 
 impression upon the sensorium. Moreover, there 
 are certain sensorial impressions received through 
 the organ of taste, which are so nearly allied in 
 their character to those of touch, as to render it 
 difficult to specify any fundamental difference be- 
 tween them ; such are the pungent sensations pro- 
 duced by mustard, pepper, the essential oils, &c., 
 all of which substances, when applied for a suffi- 
 cient length of time to any part of the cutaneous 
 surface, produce a sensation which can scarcely be 
 distinguished from that excited through the organs 
 of taste, in any other way than by its inferior 
 intensity, and by the absence of the concurrent 
 odorous emanations. The taste of such substances 
 might, therefore, perhaps be considered as the com- 
 posite result of the impressions made upon the 
 sensorium through a refined and acute touch, and 
 by the effect of their odorous emanations upon the 
 organ of smell/'* 
 
 The sensations both of smell and taste may be 
 arranged in a loose popular way into subordinate 
 classes ; such as pungent, acrid, sweet, &c. But as 
 no classification having any pretence to scientific 
 accuracy and exhaustiveness has yet been offered, 
 the subject does not demand much of our attention. 
 
 * Carpenter, " Human Physiology," p. 177. 
 
 CHAP. II. 
 SECT. II. 
 
46 
 
 TEB ELmiENTS OF THE 
 
 CHAP. II. 
 SECT. 11. 
 
 Original 
 distin- 
 guished 
 from ac- 
 quired 
 Icnoiuledge 
 in sensa- 
 tion. 
 
 Sense of 
 touch. 
 
 It may be remarked by the way tiiat tbere are 
 certain well-defined classes, inasmucli as the sensa- 
 tions of one class, such as the bitter, cannot, by 
 any means of which we are aware, be transformed 
 into those of another. 
 
 2. We now come to the study of the sensations of 
 the more intellectual of the special senses — touch, 
 hearing, and sight. And it will be necessary to 
 distinguish carefully between those which are pro- 
 per and original to those senses and those which are 
 acquired. We have seen already that in the case of 
 two of these senses, hearing and sight, the sensation 
 undergoes a process of objectification, being referred 
 to a distance. In the case of touch this is not so 
 obvious, although it is still true to a certain extent. 
 The sensation of pressure, which is in itself purely 
 organic, is referred to something not at a distance, 
 it is true, but still external to the organism. Now, 
 in each of these cases the objectifi.cation of the 
 sensation, not being original, must be distinguished 
 from the sensation itself. 
 
 The sense of Touch has, as its proper organ, the 
 skin, which " is peculiarly adapted for this purpose, 
 not merely by the large amount of sensory nervous 
 fibres which are distributed in its substance, but 
 also by its possession of a papillary apparatus in 
 which these nerves for the most part terminate, or 
 rather commence." The tactual sensation proper is 
 that which is felt when any body slightly comes 
 into contact with the skin so as to make its presence 
 felt. But this tactual sensation is often combined 
 
PSYCHOLOGY OF COGNITION. 
 
 47 
 
 and confounded with, otliers of a different kind. 
 When, for example, the point of the finger is pressed 
 against the table, in addition to the tactual sensa- 
 tion, there is a feeling of resistance or hardness 
 which is manifestly the sensation of muscular exer- 
 tion objectified. Where the finger is rubbed over 
 the surface of a rough, body there is also a combi- 
 nation of the tactual sensation with that of muscular 
 exertion. 
 
 The skin is also the principal seat of the sensations 
 of heat and cold, and when an object which differs in 
 temperature from that of our body is brought into 
 contact with it these sensations are experienced. 
 But although the nerves of the tactual sensation are 
 susceptible also to heat and cold, the two kinds of 
 sensations are essentially unlike. 
 
 From descriptions of the organ of hearing given 
 by physiologists, we learn that it is a very delicate 
 organ of touch. The object of hearing is sound; 
 and the physical conditions of sound are vibrations 
 of some material body which affect the air, and are 
 propagated by it to the ear. The sensations of 
 sound may vary in many ways, according to the 
 nature of the sounds which are heard. The principal 
 characteristics of single sounds are pitch or tone, 
 clearness, volume or quantity. Two or more 
 simultaneous sounds are harmonious or discordant. 
 The pitch or tone of a sound is determined by the 
 number of vibrations of the air which strike upon 
 the ear in a second, and by many experiments this 
 has been accurately determined. The other qualities 
 
 CHAP. II. 
 SECT. II. 
 
 Sense of 
 liearing. 
 
48 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. II. 
 
 Sense of 
 sight. 
 
 of sound appear to depend to a great extent upon 
 the material and size of the vibrating body. 
 
 The knowledge of the distance and direction of 
 the body which causes the vibrations of the air is 
 obtained by experience,* and the ability to detect 
 slight differences between successive sounds and the 
 harmony or discord of simultaneous ones is also to 
 a certain extent an acquired power. We are con- 
 cerned at present only with the sensations in their 
 original simplicity which are marked by clear dif- 
 ferences from those of every other sense, and 
 discriminated from one another by many distinctions 
 of pitch, strength, clearness, volume, and quality. 
 
 The proper object of the sense of sight is light or 
 colour; and the physical conditions of sensation are 
 the emission or reflection of rays of light from 
 some external body, and the transmission of these 
 rays to the retina of the eye. Those who have 
 studied the laws of light tell us that the colour of 
 bodies depends upon the nature of their reflecting 
 power. Some bodies, such as mirrors, reflect light 
 without producing any change upon it ; others 
 absorb and partly re-emit the light which falls upon 
 them. Amongst this latter class, different bodies 
 possess different powers of absorption and reflection ; 
 and, in consequence of this difference, the white light 
 which falls upon them is variously modified before 
 reflection, and, falling upon the retina of the eye,, 
 gives rise to the sensation of colour. " We all know 
 
 * Of coarse we must postulate the possession of a suitable 
 organism to render this experience possible. 
 
PSYCEOLOGY OF COGNITION. 
 
 49 
 
 that a ray of wliite light may be divided with a 
 prism into several rays of different colours. It 
 spreads out into a spectrum, in which the colours 
 form a continuous scale. At the commencement of 
 the scale is red, then come orange and the different 
 yellows, then green, the different blues, indigo, and, 
 lastly, violet, and each of these tints passes, by 
 intermediate stages, into the one preceding it and 
 the one following it. The science of optics shows 
 us that the spectrum is formed by the different rays 
 which make up the white ray being inflected, some 
 more and some less, in passing through the prism ; 
 this inflection increases with the shortness and 
 rapidity of the waves ; therefore, if we follow, from 
 red to violet, the series of rays which form the 
 spectrum, we find the shortening and acceleration 
 of the waves go on increasing. Thus from red to 
 violet, each sensation corresponds to waves quicker 
 and shorter than those of the preceding sensation, 
 slower and longer than those of the succeeding sen- 
 sation. An increase of speed and diminution of 
 length in the waves are sufficient to determine the 
 variations which our sensation of colour undergoes 
 in passing from red to violet.''^ * 
 
 § 25. The resolution of sensations into simpler 
 elements is shown to be possible most clearly with 
 reference to the senses of hearing and sight. In 
 connection with the former, everyone is familiar 
 with what we call a musical sound. That this sound 
 is really a complex sensation is shown in several 
 * Taine, '' Ou Intelligence/' p. 117. 
 
 CHAP. II. 
 SECT. II. 
 
 Analysis of 
 sensation. 
 
50 
 
 THE ELEMENTS OF THE 
 
 CHAP. ir. 
 SECT. II. 
 
 ways, and amongst others by experiments with the 
 wheel of Savart. This wheel is a flat circular steel 
 plate, having its circular edge cut to some depth 
 into fine elastic teeth_, and made to revolve with great 
 rapidity upon an axle. " When this wheel is turned 
 at an uniform rate, its teeth_, which are at equal 
 distances, strike a bar in passing ; and this regular 
 succession of similar concussions excites a regular 
 succession of similar sensations of sound. Now, 
 while the wheel turns sufficiently slowly, the sensa- 
 . tions, being discontinuous, are distinct, and each of 
 them, being compound, is a sound. But when the 
 wheel is set to turn fast enough, a new sensation arises, 
 that of a musical note. It distinguishes itself from 
 the remains of the noises which still go on and con- 
 tinue distinct, and stands out as a fact of a different 
 kind; among the different elementary sensations 
 which make up each sound, there is one which the 
 operation has separated ; and this now ceases to be 
 distinct from the similar elementary sensation follow- 
 ing in each of the succeeding sounds. All these 
 similar sensations now combine in one long continuous 
 sensation — their mutual limits are effaced ; experi- 
 ence, just as in a chemical analysis, has extracted 
 an elementary sensation from the complex group in 
 which it was included, has joined it to an absolutely 
 similar elementary sensation and formed a new com- 
 pound — the sensation of musical sound.^^ * Thus it 
 is seen that a particular sensation, that of a 
 musical note, is capable of being resolved into more 
 •=' Taine, " On Intelligence," p. 108. 
 
PSYCHOLOGY OF COGNITION. 
 
 51 
 
 elementary sensations, each of wliich is distinctly 
 in consciousness. If we now examine a sensation of 
 light, we shall see that it also is resolvable into more 
 elementary sensations. The resolution of the sensa- 
 tion is effected by the resolution of its most impor- 
 tant condition, the ray of light. The prismatic 
 spectrum comprehends a variety of distinct sensa^ 
 tions which, previous to the analysis, must have been 
 contained in the complex sensation of white light. 
 A well-known optical toy, consisting of a disc of card- 
 paper with the spectral colours painted upon it, 
 made to revolve rapidly upon its axis, shows that 
 the separate sensations may by rapidity of succession 
 become blended together again and form one complex 
 sensation more or less closely resembling the original 
 one. The proper mixing of colours is an important 
 part of the oil-painter's art, and in this there is a 
 complex sensation produced by the mixing together 
 in proper proportions of the oils, which, taken 
 separately, would produce .? simple, or at least a less 
 complex, sensation. 
 
 We thus see that in many cases the sensations of 
 the two most noble senses may be shown to be com- 
 posed of more simple elements, being, however, still 
 sensations. A similar course of investigation, regard- 
 ing the sensations of taste, smell, and of organic life, 
 would probably show that in all these cases there 
 are many complex sensations which are capable of 
 resolution. But it is needless to continue the inves- 
 tigation farther, as we have already sufficiently esta- 
 blished our conclusion, which may be thus stated : — 
 
 CHAP. II. 
 SECT. II. 
 
 ^OfinS 
 
52 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. II. 
 
 Result of 
 Analysis. 
 
 Analysis 
 into un. 
 conscious 
 hut mental 
 elements 
 considered. 
 
 (1). There are in consciousness sensations of a 
 complex character, which, as far as consciousness is 
 concerned, appear to be simple. 
 
 (2). The resolution of these complex states of 
 consciousness cannot be effected by consciousness 
 alone, but by applying the methods of physical 
 science to the physical conditions of these states of 
 consciousness. 
 
 (3). Hence, we may conclude the possibility of 
 there being other complex states of consciousness, 
 which, by mere reflection, cannot be analysed into 
 their component elements. 
 
 § 26. We now consider the possibility and legiti- 
 macy of analysing sensations into elements which 
 are not, and cannot, be brought within the sphere of 
 consciousness.* 
 
 Suppose that the point of a needle has been made 
 so small, that when it is held in a clear light, di- 
 rectly before the eye, it is just visible, and no more. 
 Upon the principle of the infinite divisibility of 
 matter, this point may be divided into two halves, 
 each of which is invisible. Or, suppose that in the 
 wheel of Savart, referred to above, all the teeth ex- 
 cept two have been broken off, and the concussion 
 of two teeth upon the bar is necessary to produce an 
 audible sound. If one of these teeth be broken, the 
 vibration of the remaining one will be inaudible. In 
 
 * The doctrine of latent mental modification held by Sir W. 
 Hamilton and others, asserts that underlying the sphere of our 
 conscious activity there is a still more extensive sphere of mental 
 activity, of which we are never conscious, but the results of which 
 manifest themselves in consciousness. 
 
PSYCHOLOGY OF COGNITION. 
 
 53 
 
 both of these cases^ and in others which might be 
 mentioned, a certain amount of physical antecedent 
 is necessary as a condition of conscious sensation. And 
 the question is. May that conscious sensation be 
 resolved into mental elements of which we are not 
 conscious ? By some it is held that this resolution 
 is not only possible, but necessary to explain the 
 phenomenon. Against this view the following 
 objections may be urged : 
 
 (1). The essential character of a sensation is that 
 it is felt, and felt consciously. Therefore to analyse 
 sensations into elements of which we cannot be 
 conscious is not legitimate.* 
 
 (2). There are other possible explanations of the 
 difficulty. It may be that the object from which the 
 light is reflected, or from which the vibration of the 
 air proceeds, produces such a slight agitation of 
 the intervening medium that it is spent or dispersed 
 before it reaches the organ of sense. Or, suppose 
 the agitation of the ether or air to reach the nerve 
 of sense, it may be that the impression upon the 
 nerve is so slight, that no vibration is propagated to 
 the nerve centre in the brain, or that the vibration 
 is so exceedingly slight as not to be a sufficient 
 condition of sensation. And that either of these 
 suppositions is the true one, appears to be supported 
 by the fact, that certain artificial appliances, such 
 
 * This objection, however, does not hold good against the 
 possible latency of other forms of mental activity. There may 
 be an activity of the ego which has no physical antecedent, and 
 such activity may leave its trace not in the brain but in the 
 spiritual nature beyond the sphere of consciousness. 
 
 CHAP. II. 
 SECT. II. 
 
 Objections. 
 
54 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. III. 
 
 Revived 
 
 sensations 
 
 described. 
 
 as the microscope, collect or intensify tlie physical 
 conditions of sensation, so that what was before 
 invisible or inaudible, may be distinctly seen or 
 heard. The rays of light falling from a point 
 invisible to the naked eye, are collected and con- 
 densed by the microscope so as effectually to impress 
 the optic nerve, from which we naturally conclude 
 that previous to the use of the instrument the 
 vibrations 'of the ether were so slight as not at all, 
 or not sufficiently, to impress the nerve. It is 
 possible, also, that there may be an excitement of 
 nervous activity, either in the brain or the nervous 
 fibres, but which is not a sufficient condition of 
 sensation. In the meantime, we may conclude that 
 the most probable reason why, in certain cases, a 
 conscious sensation does not take place, is that the 
 physical conditions, whether here or there, whether 
 nervous or extra-organic, are inadequate. 
 
 Section III. 
 
 REPRESENTATION OF SENSATIONS. 
 
 § 27. The possibility of the revival of a sensation 
 once experienced is a fact familiar to everyone. But 
 the sensation as revived is not the same as when 
 actually experienced. It is idealised, it appears 
 more refined, farther removed from sense than it 
 was originally. Illustrations of this are numerous 
 and familiar. If we have once seen a fine building 
 
PSYCHOLOGY OF COGNITION. 
 
 55 
 
 which, has made a great impression upon us by its 
 architectural beauty^ a very slight effort will serve to 
 recall before our minds its colours and outlines. We 
 imagine that we almost see it. So of sounds. We 
 are familiar with the voice of a friend ; in his absence 
 it is quite easy to recall the tones and quality of his 
 voice ; we fancy that we hear him speakiug. Other 
 sensations of taste, smell and touch, are capable of 
 revival in a similar manner, some more vividly, more 
 approaching the original than others, but all to a 
 greater or less extent. In all these cases the pheno- 
 menon, the revived sensation, is recognised as related 
 to the original one — a repetition of it, but different 
 from it. Moreover, the sensation revived appears 
 always to be connected with the same organ as when 
 originally experienced. 
 
 § 28. The physical condition of the revival of 
 sensations is probably some agitation of the same 
 nerves as served for the physical condition of the 
 original sensation. The researches of physiologists, 
 however, appear to lead to the conclusion that a 
 particular part of the brain, the cerebral lobes, is de- 
 signed to prolong and repeat the action of the nerves 
 of the senses. And many philosophers, assuming 
 that they know the functions of the different parts 
 of the nervous system, have given minute elaborate 
 explanations of the nervous motions which take 
 place in correlation with the revival and varied 
 combination of our sensations. A distinguished 
 writer, who has made a great use of physiology in 
 the explanation of psychical phenomena, has well 
 
 CHAP. II. 
 SECT. III. 
 
 Fhysical 
 condition 
 of revival. 
 
56 
 
 TEE ELEMENTS OF THE 
 
 CHAP. 11. 
 SECT. III. 
 
 Correla- 
 tion of ner- 
 vous with 
 psychical 
 action in- 
 directly in- 
 ferred and 
 not more 
 than p7'o- 
 lahle. 
 
 expressed the indirectness and obscurity of our 
 knowledge of the relation of nervous action to 
 feeling in the following sentences : — 
 
 (1.) ''Each individual is absolutely incapable of 
 knowing any feelings but his own. That there 
 exist other sensations and emotions, is a conclusion 
 implying, in the first place, the reasoning through 
 which he identifies certain objects as bodies of like 
 naturewith his own body; and implying, in the second 
 place, the further reasonings which convince him 
 that along with the external actions of these bodies, 
 there go internal states of consciousness like those 
 accompanying such external actions of his own body. 
 (2.) This conclusion, that there exist beings like him- 
 self, and that under like conditions they experience 
 like feelings, even supposing it entirely true (and it 
 is not entirely true, for many facts unite to prove 
 that, under like conditions, both the quantities and 
 the qualities of sensations and emotions in different 
 individuals differ considerably), by no means implies 
 that what he knows under its subjective aspect as 
 feeling is, under its objective aspect, nervous action. 
 The average observer has not direct evidence that 
 these other like beings have nervous systems, any 
 more than that he himself has a nervous system, and 
 he has no direct evidence in the one case any more 
 than in the other, that nervous excitations are the 
 causes of feelings. Experimental physiologists and 
 pathologists only have proofs, and even their proofs 
 are mostly indirect. The experiments which yield 
 them are usually made on beings of another and 
 
PSYCHOLOGY OF COGNITION. 
 
 S7 
 
 much inferior order. The contractions of muscles 
 and arteries, caused by irritating nerve- trunks in 
 frogs, the convulsive movements, and sometimes the 
 sounds made by birds and mammals whose nerve 
 centres are variously injured — these are the pheno- 
 mena from which it is inferred that the human 
 nervous system is the seat of the human feelings, 
 and that these feelings are the correlations of its 
 excitations. The only important verifications of the 
 inference being those obtained during surgical opera- 
 tions where nerve-trunks are cut through, and those 
 furnished by post-mortem examinations of morbid 
 nervous structures in the bodies of those who, when 
 alive, displayed abnormal excesses or defects of 
 feeling. (8.) And then, having learnt at second- 
 hand, through the remotely inferential interpretation 
 of verbal signs^ that in now one and now another of 
 the bodies he recognises as like his own there has 
 been found a nervous system, and that the stimula- 
 tions of this produce those manifestations which, in 
 himself, accompany feelings, the reader imagines a 
 nervous system contained in his own body, and con- 
 cludes that his sensations and emotions are due to the 
 disturbances which the outer world sets up at its 
 periphery and arouses by indirect processes in its 
 centres."* Considering, then, the small number of 
 facts bearing upon the question which physiologists 
 have been able to observe, the indirectness of the ob- 
 servations which have been made, and the obscure, 
 infinitesimal character of the movements themselves, 
 * Herbert Spencer's " El. of Psjch.," i., pp. 99-100. 
 
 CHA.P. II. 
 SECT. III. 
 
ss 
 
 THE ELEMENTS OF THE 
 
 CHAP. ir. 
 SECT. III. 
 
 Nature 
 and rela- 
 tions of 
 idealised 
 sensations. 
 
 it appears impossible to determine with any degree 
 of scientific accuracy the precise physical antecedents 
 of those mental actions which are in a greater or less 
 degree removed from sense. The attempts which 
 have been made to do this are, and, from the nature 
 of the case, can be, little more than conjectures 
 founded upon uncertain analogies and few and crude 
 observations. And although the facts which are 
 known and admitted may warrant a general belief 
 that the lower forms of mental activity, such as re- 
 viving sensations, have special physical antecedents, 
 yet there does not appear to be a suflScient ground- 
 work of facts to justify us in constructing an elaborate 
 and detailed theory regarding their correlation. Con- 
 sciousness is the only direct and reliable revealer of 
 mental facts, and although we may sometimes be 
 assisted in our study of consciousness by the facts 
 and observations of physiology, an attempt to make 
 these the foundation of mental science is directly to 
 reverse the natural order of things. Leaving out of 
 account, then, the correlation, or inferred correlation, 
 between physical and mental events, as only of 
 secondary and occasional importance in the explica- 
 tion of our subject, we proceed to the study of the 
 revival and association of our sensations as revealed 
 in consciousness. 
 
 § 29. If a clear bright light be kept for a short 
 time before the eye, and then removed, the sensation 
 produced will persist for a time, and at intervals, per- 
 haps, be revived. The same is the case with tastes, 
 smells, and other sensations. But the sensation, as 
 
PSYCHOLOGY OF COGNITION. 
 
 59 
 
 persistent or revived, is not so clear and vivid as it 
 was originally — it lias become idealised. The appear- 
 ance before consciousness of idealised sensations is 
 not fortuitous, but takes place in certain regular and 
 connected series. Sensations of different quality, 
 that is of different senses, are connected together, so 
 that an actual sensation of one kind will serve to 
 introduce, before consciousness, idealised sensations 
 of other kinds. The sight of a particular kind of 
 fruit with which we are acquainted, at once makes 
 us think of its smell and taste. Thus, there are 
 certain fixed groups of sensations which we regu- 
 larly experience together, the different members of 
 the group differing in quality. We have a com- 
 plete knowledge of one of these groups, when we 
 have once become conscious of all the sensations 
 comprehended in it. And afterwards when any 
 one of these sensations is actually felt, we know 
 what the rest of the group are like. But it is not 
 necessary that one of the original group should be 
 actually felt in order that the whole may be ideally 
 recalled. If a particular sign, as, for example, the 
 
 word 
 
 orange, 
 
 have become attached to a certain 
 
 group of sensations, the repetition of the sign will 
 serve to recall the whole group quite as really as the 
 consciousness of any one of the sensations of the 
 group. Thus, a sign of a group of sensations be- 
 comes by association, as it were, a part of the 
 group, and our curiosity regarding a sensation is 
 satisfied when we are able to refer it to a certain 
 known group of sensations, and to attach to the 
 
 CHAP. II. 
 SECT. 111. 
 
6o 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. III. 
 
 Order of 
 sensa- 
 tions : 
 
 successive. 
 
 memory, 
 
 group the sign by whicli it is usually designated. 
 When a new sensation is experienced, our curiosity 
 is excited because we do not know the other sensa- 
 tions which are regularly connected with it, or the 
 sign, or name, by which the whole is denoted. 
 Thus our knowledge of a sensation resolves itself 
 into a knowledge of its quality, and a knowledge of 
 the position or relation which it holds amongst 
 other actual or idealised sensations. 
 
 § 30. There is a twofold order in which series 
 or groups of sensations may appear in conscious- 
 ness. They may be successive, or they may be 
 simultaneous. In the meantime we give our atten- 
 tion to the first of these orders. A single sensation 
 of any kind may persist or may be revived. An 
 actual or revived sensation may call up in succession 
 a series of other revived sensations of different 
 kinds which we distinctly recognise as having been 
 at one time actual. This successive order of sensa- 
 tions, or revived sensations, involves the conception 
 of time, and is the only means whicli we have of 
 determining time. When we experience one of 
 a group of sensations with which we are well 
 acquainted, we recognise it as something which we 
 have felt before, and we give it a position more or 
 less definite amongst other previously experienced 
 sensations ; in other words, we remember it. Thus, 
 memory, in this reference, is the ability to deter- 
 mine the position of a sensation in a successive past 
 series of sensations. But idealised sensations may 
 be referred also to a future time, that is, to some 
 
PSYCHOLOGY OF COGNITION. 
 
 6l 
 
 future succession of ideal sensation which we think 
 likely to be realised, and this is what we call expec- 
 tation. Thus with reference to this subject, memory 
 and expectation consist in the ability to place an 
 ideal sensation into that position in the series of 
 successive sensations which, in the one case, we 
 believe with certainty were actually experienced 
 during a time past, and in the other, we expect 
 with greater or less assurance will be experienced 
 during some future time. 
 
 § 31. We thus arrive at the conclusion that sensa- 
 tions become so connected together in groups, that 
 one of a group is capable of reviving before con- 
 sciousness all the others. But although we may 
 describe these sensations as being our mental phe- 
 nomena, we cannot determine what particular 
 sensations shall constitute particular groups. This 
 is done for us by nature ; or, in other words, there is 
 a natural grouping of sensations in which we can- 
 not, as a rule, produce any essential change. By 
 experience only can we come to know the con- 
 stituent elements of a group, and by frequently 
 experiencing naturally connected groups of sensa- 
 tions, a subjective association such as we have 
 described comes to be formed between them. The 
 succession of sensations before consciousness gives 
 us time. The positing of an ideal sensation in the 
 midst of a group recognised as having had a past 
 existence, or as likely to have a future existence, is 
 memory or expectation. This mental process, it 
 must be borne in mind, as referred to here, is sub- 
 
 CHAP. II. 
 SECT. III. 
 
 and expec- 
 tation. 
 
 Indepen- 
 dence of 
 the order of 
 sensations. 
 
62 
 
 TEE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. IV. 
 
 Meaning 
 0/ object. 
 
 sidiary to the acquisition of presentative knowledge, 
 as we shall presently see. In the meantime^ we are 
 not supposed to know anything except sensations^ 
 revived sensations, and the relations which they 
 bear to one another in kind, in time, and as 
 members of associated groups.* 
 
 Section IV. 
 
 SENSATIONS AS OBJECTS. 
 
 § 32. We have hitherto been considering sensa- 
 tions merely as differing from one another in kind, 
 and as succeeding one another in time, but in our 
 analysis of self-consciousness f we saw that they 
 are necessarily looked upon as being objects related 
 to and known by the subject, self. We must now 
 examine them more carefully in their character as 
 objects of consciousness, in order to see if anything 
 is involved in them which will help us in the 
 explication of the process of acquiring our presen- 
 tative knowledge. And the very word ohjectj contra- 
 distinguished as it is from suhject, appears to indicate 
 an element in our sensations which may be of great 
 
 * It is possible that there are some sensations which cannot be 
 revived except as parts of a group ; and, perhaps, there are few 
 which can be recalled by a merely mental effort without the aid of 
 some associated circumstances. But nevertheless it seems allow- 
 able for us, as we have done in this section, to treat sensations as 
 revived, excluding the conditions and accompanying circumstances 
 by the helps of which they usually appear before consciousness. 
 
 t Sect. III. chap. i. 
 
PSYCHOLOGY OF COGNITION: 
 
 63 
 
 importance. It indicates tliat sensations are pos- 
 sessed of an element /o?'ei^?i to tlie subject knowing; 
 tliey are regarded as being not-self. There are 
 besides,, other features of sensations which render 
 more complete their character of objectivity. In- 
 dividual sensations cannot be created or annihilated 
 at pleasure. We may, it is true, interfere with the 
 physical conditions of sensations ; we may shut our 
 eyes, get out of the reach of perfumes, or close our 
 ears. But as far as self- consciousness is concerned, 
 the conditions of sensations being fulfilled, the 
 conscious self cannot but be cognisant of the sensa- 
 tions which appear. And not only is the existence 
 of sensations beyond the control of self, but also the 
 grouping of sensations. The particular taste, smell, 
 colour, and tangible quality which we designate by 
 the name orange cannot, as far as consciousness is 
 concerned, be made to undergo any change. There 
 are natural combinations of sensations, not produced 
 by subjective association, but evidently governed by 
 some objective law, over which the conscious subject 
 has no control. Thus, when we consider either in- 
 dividual sensations, or natural groups of sensations, 
 as objects, we see that their objectivity arises not 
 merely from being opposed to the subject in con- 
 sciousness, but also from the laws of their existence. 
 They are known as objects in contradistinction to 
 the conscious subject ; but their character as objects 
 is not complete till they are considered as having 
 laws of existence and mutual relations of their own, 
 determined for them independently of any subjective 
 
 CHAP. II. 
 SECT. IV. 
 
64 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. IV. 
 
 Relations 
 of sensa- 
 tion-oh- 
 jects. 
 
 Intuitive 
 theory of 
 extension. 
 
 association. Henceforth, wlien we speak of objects 
 of consciousness, there will be implied the foreign * 
 elements which we have now indicated. 
 
 § 33. We now come to a question of great impor- 
 tance in psychology, and about which there is great 
 diversity of opinion. The objects of consciousness, 
 the sensations and revived sensations variously 
 grouped together according to their own laws, have 
 an existence in time — they succeed one another. But 
 their order in time is twofold ; they may be succes- 
 sive, or they may be contemporaneous. Several 
 objects may at the same time appear in conscious- 
 ness ; several sensations of different kinds may 
 be experienced at the same moment. And the 
 question is, — What is the relation in which these 
 contemporaneous objects of consciousness stand 
 to one another? The following are clearly dis- 
 tinguished answers to this question : — 
 
 (a.) The co-existence of sensations at the same 
 point of time implies their mutual externality, and 
 therefore involves the idea of extension or space. 
 Several sensations, as of smell, taste, colour, sound, 
 may exist altogether, and as they are distinguished 
 from one another in kind, they must appear to be 
 the one without the other. And this relation of 
 mutual outness is the simplest form in which we 
 perceive extension. According to this doctrine, 
 extension or space is a form of our sensations as well 
 
 * Of course by ohjects here we do not mean anything extra- 
 organic; but sensations as possessed of the foreign-to-the-ego cha- 
 racter which we have described. 
 
FSYCEOLOGY OF COGNITIOK. 
 
 65 
 
 as time, and equally original in reference to our 
 knowledge. There is a slight modification^ or per- 
 haps an integral part of this theory, in which it is 
 held that some single sensations, as colour and 
 touch, occupy space, or are diffused over an extended 
 space. Whether the one or the other, or both of these 
 opinions be held, it is manifest that their holders 
 look upon space as an original form of sensation, and 
 perceived intuitively in the same way as time.* 
 
 (b.) In opposition to the above theory it is held that 
 all mental phenomena are unextended, and that the 
 possession of extension is the essential characteristic 
 which distinguishes physical from mental objects. 
 A sensation, therefore, as an object of consciousness, 
 cannot possibly occupy extension or place. And 
 ^ since an individual sensation does not exist in space, 
 it is impossible that the relation between two or more 
 contemporaneous sensations can be a spatial relation. 
 To speak of the mutual externality of sensations is, 
 therefore, to attribute to sensations a mode of ex- 
 istence which they do not possess. Sensations differ 
 in kind, and they succeed or co-exist with one 
 another in time, and the attributing to them of any 
 other relation would destroy their character as 
 mental phenomena. 
 
 § 34. Those who hold the second of the preceding 
 views regarding sensation must in some way account 
 for the origin of our conception of extension. Sensa- 
 tions, the primary object of consciousness, are not 
 themselves extended, but we evidently possess a 
 * For a full exposition and defence of this theorj, see § 36. 
 
 F 
 
 CHAP. II. 
 SECT. IV. 
 
 Objection 
 
 consti. 
 
 tuting a 
 
 general 
 
 opposing 
 
 theory. 
 
66 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. IV. 
 
 A priori 
 theory of 
 extension. 
 
 Muscle- 
 
 and-tiirie- 
 
 tlieory. 
 
 notion of extension which we must have got in some 
 way. How has it been attained ? The answers to 
 this question divide themselves into two classes : — 
 
 (a.) Some maintain that extension is an original 
 principle of our constitution which springs into con- 
 sciousness upon the occasion of some sensation taking 
 place. The sensation, although not itself extended, 
 suggests extension by a law of our nature. Exten- 
 sion is thus an a priori but latent conception which 
 rises up into consciousness upon the occasion of a 
 certain experience, but is not the result of that ex- 
 perience. Now, it is evident that the placing of any 
 conception amongst d 'priori principles simply 
 amounts to a confession of inability to explain it 
 otherwise. Inexplicability is an important charac- 
 teristic of all conceptions believed to be a priori. 
 But before admitting any notion to be inexplicable, 
 we are in duty bound to examine any attempt which 
 has been made to explain it. The following attempt 
 is the most important. 
 
 (6.) It is held by J. S. Mill and others that the 
 notion of extension is the product of muscular sensa- 
 tions differing in intensity and duration. " Suppose," 
 says Mr. Mill, "two small bodies, A and B, suffi- 
 ciently near together to admit of their being touched 
 simultaneously, one with the right hand, the other 
 with the left, here are two tactual sensations which 
 are simultaneous, just as a sensation of colour and 
 one of odour might be ; and this makes us cognise 
 the two objects of touch as both existing at once. 
 The question then is, What have we in our minds 
 
PSYCSOLOGY OF COGNITION. 
 
 67 
 
 when we represent to ourselves the relation between 
 these two objects, already known to be simultaneous, 
 in the form of extension or intervening space — a 
 relation which we do not suppose to exist between 
 the colour and the odour ? Our answer to this is, 
 *' That whatever the notion of extension may be, we 
 acquire it by passing our hand or some other organ 
 of touch in a longitudinal direction from A to B ; 
 that this process, as far as we are conscious of it, 
 consists of a series of varied muscular sensations. 
 . . . When we say that there is a space between A 
 and B, we mean that some amount of these muscular 
 sensations must intervene ; and when we say that 
 the space is greater or less, we mean that the series 
 of sensation (amount of muscular effort being given) 
 is longer or shorter. If another object, C, is farther 
 off in the same line, we judge its distance to be 
 greater, because to reach it, the series of muscular 
 sensations must be further prolonged, or else there 
 must be the increase of effort which corresponds to 
 augmented velocity. Now this, which is unquestion- 
 ably the mode in which we become aivare of ex- 
 tension, is considered by the psychologists in question 
 to he extension. The idea of extended body, they 
 consider to be that of a variety of resisting points 
 existing simultaneously, but which can be perceived 
 by the same tactile organ only successively, at the 
 end of a series of muscular sensations which con- 
 stitutes their distance, and are said to be at different 
 distances from one another because the series of 
 intervening muscular sensations is longer in some 
 
 F 2 
 
 CUAP. II. 
 
 SECT. IV. 
 
6S 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. IV. 
 
 Refuted. 
 
 cases than in others. . . . An intervening series of 
 muscular sensations before the one object can be 
 reached from the other, is the only peculiarity which 
 (according to this theory) distinguishes simultaneity 
 in space from the simultaneity which may exist 
 between a taste and a colour, or a taste and a smell; 
 and we have no reason for believing that space or 
 extension in itself is anything different from that 
 which we recognise it by.^' * Here then is an 
 attempt to explain extension by one who does not 
 think extension is involved either in single sensa- 
 tions or in the relations of different but simultaneous 
 sensations. Let us examine the attempt : 
 
 1. It is assumed that extension is identical with 
 that by which it is recognised or measured, that is, 
 with a succession of muscular sensations occupying 
 time.t But this is by no means to be admitted. 
 
 * " Mill Ex." pp. 273-275. 
 
 t The Saturday Keviewer, commenting upon this sentence, 
 says : " Such is not the assumption. We do not answer for 
 Mill's expression of the theory at all points ; but the substance 
 of it is, not that extension is the same thing as muscular sensa- 
 tion, but that our notion of extension is an abstract mental 
 symbol of possible muscular sensations, which is the result of in- 
 numerable muscular sensations that have taken place in the actual 
 experience of ourselves or our ancestors." 
 
 We did not, assert that Mill's theory was " that extension is the 
 same thing as muscular sensation." The sentence commented 
 upon makes extension identical with a succession of muscular 
 sensations occupying time ; and this is exactly Mr. Mill's expla- 
 nation in brief. It is unfair to take a summarised statement of a 
 theory as a subject of criticism when a more or less full and 
 complete statement has been given ; and we submit that the full 
 statement is probably as accurate an account of Mr. Mill's theory 
 as could be given within our limits. Of course, the conception of 
 
FSYGROLOGY OF COGNITION. 
 
 69 
 
 The amount of force with wMcli a ball is expelled 
 from the mouth of a cannon is recognised and 
 measured loy its velocity, that is, by the number of 
 feet which it traverses in a second of time. But no 
 one ever maintains that force is identical with 
 velocity. In the same way, although extension is 
 measured by a succession of muscular sensations 
 occupying time, to say that the former is identical 
 with the latter is quite unwarranted. 
 
 2. Why is it that muscular sensations are chosen 
 to fill up the intervening space between one point 
 and another ? All sensations are ex hypothesi equally 
 destitute of extension. The two points, A and B, are 
 recognised by two sensations, and must be assumed 
 not as points in space, but as points in time, because 
 the idea of space is not supposed to be known. Let, 
 then, the point A be marked by a particular 
 sensation, say of smell; a number of intervening 
 sensations, muscular sensations, or any others dif- 
 fering in intensity and duration take place. Then 
 another point of time, B, is reached, marked by 
 
 extension, according to Mill, is an abstract mental symbol drawn 
 from actual experiences of muscular sensations succeeding one 
 another in time ; and we presume that the careful student would 
 gather as much from our statement. Where Mr. Mill teaches that 
 the actual experiences are either our own experiences, or the 
 experiences of our ancestors, we do not know and would be glad 
 to be informed. Some of Mill's successors in the same line of 
 psychological thought have been driven to feel the weakness of 
 his theory of the origin of our conception of extension, and have 
 imported ancestral experiences in order to help it out of the dif- 
 ficulty. It is illegitimate, however, for the critic to introduce 
 this as an element in his criticism of our statement of Mill's 
 theory, which we still maintain to be substantially correct. 
 
 CHAP. II. 
 SECT. IV. 
 
70 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. IV, 
 
 another sensation. Thus, here we have two points, A 
 and B, points in time, and recognised by two distinct 
 sensations, separated from one another by a number 
 of intervening sensations, say of sight, or hearing, or 
 smell, differing in intensity and duration. Is the 
 result of this an idea of extension or space? 
 Certainly not. The mere statement of the problem 
 substituting for '^ muscular sensations '^ any other 
 kind of sensations is sufficient to show the ab- 
 surdity of deducing the notion of extension from 
 that of sensations succeeding one another in time. 
 
 3. The reason why muscular sensations are 
 chosen to fill up the space between the points A and 
 B, instead of sensations of smell, or taste, or colour, 
 appears to be that the former kind of sensations is 
 conjoined with mo ^^o?2', which involves extension, and 
 the points A and B are tacitly assumed to be points 
 in space. For let us eliminate carefully from the 
 data all spatial elements, and see what follows. The 
 sensations by which they are marked are at first 
 supposed to be simultaneous. In this there is only 
 time. But the idea of space is said to be acquired 
 by passing the hand from A to B. Suppose the 
 hand is at A. Here is a sensation in time. B as 
 yet does not exist, because the existence of the 
 point must not be assumed till the sensation indi- 
 cating it has taken place. The hand leaves A ; the 
 point A ceases to exist, except in memory, because 
 the sensation indicating it has ceased. The hand 
 reaches B ; a new sensation takes place, a new point 
 in time has been reached. But where is A ? In 
 
PSYGEOLOGY OF GOGNITION. 
 
 71 
 
 memory. It is a point not now existing, except in 
 past time. To speak, therefore, of two points of 
 time existing simultaneously is altogether unmean- 
 ing. And Mr. Mill's explanation is quite unintel- 
 ligible unless the points are tacitly assumed to exist 
 in s]pace and the muscular sensations to result in 
 motion. Thus the very idea whose origin the theory 
 professes to explain is quietly assumed at the begin- 
 ning of the explanation.* 
 
 § 35. The preceding theory of extension, called 
 by Mr. Mill the psychological theory, being found 
 untenable, we are driven back to a reconsideration 
 of the view which makes the notion of extension an 
 a priori principle of the mind. According to this 
 theory, the mind possesses in its own structure, as 
 it were, a notion of space, but not a conscious one, 
 and upon a certain experience this notion becomes 
 conscious and is projected upon the object of ex- 
 perience. Now, with reference to this view, we 
 confess, in the first place, a strong prejudice against 
 the explanation of a difficulty by some latent or a 
 "priori mental principle. It simply amounts to a 
 confession that the difficulty cannot be explained, 
 and moreover it assumes the existence of a mental 
 
 * We do not know that anything would be gained by con- 
 sidering sensations as possible of being repeated in serial order, 
 and repeated as many times as we choose to fulfil the conditions 
 of feeling the sensations. This would indeed give us the idea of 
 some 'permanent object, independent of self, from which the pos- 
 sibility of the sensations arose. But we do not see how repeated 
 series of sensations, succeeding one another in time, could give us 
 any idea of extension which could not be obtained from a single 
 series of such sensations. 
 
 CHAP. II. 
 SECT. IV. 
 
 A priori 
 
 theory 
 
 rejected. 
 
72 
 
 TEE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. IV. 
 
 Extension 
 how first 
 given. 
 
 principle beyond the sphere of consciousness, which, 
 is, in philosophy, a very questionable procedure. 
 And still farther, our conception of extension is 
 not that of a subjective principle, but rather of an 
 objective condition of things. For these reasons 
 we decline to accept the view in question, although 
 probably there is a certain truth involved in it, and 
 go back to a more careful consideration of the first 
 answer to the question, '^What is the relation in 
 which these contemporaneous objects of conscious- 
 ness stand to one another ? " That answer was that 
 " the co-existence of sensations at the same point of 
 time implies their mutual externality; and therefore 
 involves the presentation of extension." 
 
 § 36. In considering this view it must be borne 
 in mind that sensations are considered as objects of 
 consciousness. They have been set over against 
 the subject into the position of the non-ego ; they 
 have laws of existence and mutual relations of their 
 own. They are found collected together in groups 
 or arranged in series, the different members of the 
 groups or series not being capable, by any voluntary 
 efforts of ours, of being separated from the other 
 members. Thus they are recognised as having an 
 element of foreignness-to-the-suhjed in them. The 
 grouping of'these objectified sensations is infinitely 
 varied. Sensations of touch, and sight, and hearing, 
 and taste, and smell, and muscular effort, are all 
 combined in wonderful variety ; and by the com- 
 binations and variations of these sensations the 
 infant mind, just beginning its experiences in a new 
 
PSYCHOLOGY OF COGNITION. 
 
 73 
 
 CHAP. II. 
 SECT. IV. 
 
 worldj becomes acquainted with, its organic sur- 
 roundings. The little hands take hold of a toy, 
 the eyes look at it, the mouth tastes it, the ears 
 hear its rattle; in a great variety of ways these 
 sensations are combined and modified. In the 
 course of infinitely varied experience these sen- 
 sations become localised in the midst of fixed 
 groups of actual or ideal sensations. A sen- 
 sation is localised when it becomes, in experi- 
 ence, inseparably connected with a group of 
 other sensations ; as, for example, when the taste 
 of sweetness, in the mouth of an infant, is found 
 connected with the peculiar feeling of a long 
 cylindrical stick of candy, with the colours that are 
 seen in it, and with the muscular sensations con- 
 cerned in carrying it to and from the mouth, and 
 so on. All these sensations become inseparably 
 grouped together, that is, they become localised 
 in an object, partly organic and partly extra-i ^X^^ S^ 
 organic. Now it is to be observed that these ob4 
 jectified sensations appear in consciousness not 
 merely in successive order as a temporal series; seve- 
 ral of them appear simultaneously in consciousness ; 
 they hold the same position in time, and they are 
 also external in reference to one another. This 
 externality is perceived immediately, an intuitive 
 act of consciousness. We can be conscious of more 
 than one object at the same moment of time, other- 
 wise all comparison would be impossible. And in 
 the early consciousness of objectified sensations 
 several of them may be and are comprehended in 
 
 L^/. 
 
 :^r 
 
 
74 
 
 TEE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. IV. 
 
 the same act of consciousness. These sensations^ 
 simultaneously intuited^ are not confounded with 
 one another; they are clearly distinguished as 
 being differenced the one from the other^ as the 
 one being outside of the other, and the one differing 
 in quality from the other. And this mutual ex- 
 ternality of objectified localised sensations, as per- 
 ceived in consciousness, is the first and essential 
 element of the perception of extension. 
 
 § 37. The preceding paragraph is concerned with 
 the question, How are the essential elements of 
 extension given in consciousness ? The answer to 
 this question may be thus summarised: — First, 
 sensations are objectified, set over against the 
 knowing subject as being known- secondly, they 
 are grouped together in a variety of combinations, 
 and when any one sensation becomes -inseparably 
 connected with a particular group it is said to be 
 localised in that group ; thirdly, these groups of 
 objectified and localised sensations may be either 
 successive, in which case we perceive that they hold 
 to one another a temporal relation ; or they may be 
 simultaneous and distinguished from one another by 
 difference in quality, in which case we perceive that 
 they hold to one another a spatial relation. The 
 first of these relations, the temporal, is admitted by 
 all psychologists to be given in an original intuition 
 of consciousness ; and we have here maintained that 
 the second of these relations is given in the same 
 way. It is to be understood of course that the 
 process of abstraction must be employed before the 
 
PSYCHOLOGY OF COGNITION. 
 
 7S 
 
 perceptions of sensations succeeding one another 
 and sensations being mutually external to one 
 another become developed into the conceptions of 
 time and space. With this inquiry we are not at 
 present concerned. There are two other subjects of 
 investigation intimately connected with our subject, 
 which must likewise be set aside for the present. 
 
 The first of these has reference to the grouping 
 and presentation of sensations in consciousness. 
 How comes it that such and such sensations are 
 presented in consciousness, that they are differenced 
 from one another in such and such ways, that they 
 are presented in such and such groups, that this 
 appearing and disappearing depend upon such and 
 such conditions ? This subject of investigation 
 would take us into a sphere beyond that df psycho- 
 logy proper, as it is concerned with the constitution, 
 origin and laws of that most important element of 
 the non-ego known as the organism. 
 
 The second has reference to our ability to per- 
 ceive sensations as succeeding one another in time 
 and co-existing in space. How is it that the 
 knowing subject can be conscious of its objects as 
 coming the one after the other or as existing side 
 by side in mutual wlthoutness? That this ability 
 of the conscious subject is an ability not derived 
 from the infinitely varied groups of sensations 
 which appear in and disappear from consciousness, 
 we feel certain ; that it implies a certain constitution 
 and origin of the knowing subject different from 
 the constitution and origin of the organism, we also 
 
 CHAP. II. 
 SECT. IV. 
 
76 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT.V. 
 
 B4sum4. 
 
 believe. But the determination of tlie mental consti- 
 tution which, makes possible the perception of succes- 
 sion and externality and the conception of time and 
 space is also beyond the sphere of psychology, and 
 would lead us into the profound depths of metaphysics, 
 which are not the subject of the present treatise. 
 
 We have now reached all the elements necessary 
 to complete our knowledge of that nearest and most 
 complex portion of the outer world, the organism. 
 And it will be our endeavour, in the next section, 
 to study that process of acquiring knowledge next 
 in order, the perception of external objects. 
 
 Section V. 
 
 PEECEPTION. 
 
 § 38. In our analysis of perception we saw that 
 our knowledge of external things may be resolved 
 into certain sensations of different kinds, supposed 
 to be at a distance from us, and united together in 
 objects. Perception thus consists of sensations 
 projected into space, and united together in a per- 
 manent group, supposed to have an existence 
 independent of the mind which perceives. In the 
 synthetical construction of our knowledge we have 
 already studied sensations as objects to conscious- 
 ness, and learned what is involved in them. We 
 have already attained the knowledge of extension as 
 the form of the non-ego immediately presented to 
 consciousness ; and we have seen that this non-ego 
 
FSYCHOLOGY OF COGNITION. 
 
 77 
 
 constitutes that complicated physical organism by 
 means of which more remote objects are brought to 
 our knowledge. We have now to trace the educa- 
 tion of this complicated sense, the process by which 
 it enables us to perceive distant objecis and their 
 qualities. 
 
 § 39. The sensations which chiefly make known 
 to us the existence of objects outside of our bodies 
 are doubtless that of touch and the muscular sensa- 
 tion. In the exercise of the muscles, portions of the 
 body are brought into contact with some objects 
 outside of them which excite sensations of touch and 
 resist muscular effort. The sensations of touch and 
 muscular effort appear to have one object^ and the 
 resistance which it offers reveals its externality to 
 the physical organ 'and independence of it. Thus 
 there is produced within us the belief of the exist- 
 ence of some object of touch without us ; and as 
 that object opposes a greater or less amount of 
 resistance to muscular pressure, we think of it as 
 having a power to resist pressure, that is as being 
 hard and solid. Thus hardness is the correlative 
 of muscular force, the sensation of muscular exer- 
 tion projected outside of our bodies and attributed 
 to some external objects. But that which, in the 
 organism, was a sensation, when thought of as with- 
 out, is called a quality. Sensation and quality are 
 thought of as having a twofold relation ; the one 
 with reference to knowledge, the other with reference 
 to existence. In the first reference, sensation is the 
 sign which suggests to us the quality ; in the second, 
 
 CHAP. II. 
 SECT. V. 
 
 Sensation 
 
 and 
 
 quality. 
 
7^ 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. V. 
 
 Projection 
 of colours. 
 
 the quality is thouglit of as the cause whicli produces 
 the sensation. The muscular sensation is connected 
 also with motion of the limbs of the body, and when 
 this motion is combined with the tactual sensation 
 there is made known to us the smoothness, rough- 
 ness, or other superficial qualities of the bodies which 
 we touch. And as a matter of course, the extension 
 which we saw was involved in the diffusion or the 
 mutual externality of localised sensations, accom- 
 panies those sensations when projected outside of 
 us. And thus we think of the hard or soft, rough 
 or smooth objects of touch as being extended and 
 figured. Hence we see that touch and its closely 
 connected muscular sensations are very important 
 means of augmenting our knowledge, carrying us 
 away beyond ourselves into surrounding space and 
 revealing a world of wonderful objects. But as far 
 as we have gone, these objects are known to us 
 only as correlatives of our tactual and muscular 
 sensations invested with extension. We must now 
 bring into requisition another sense, and see how 
 the revelations of sight are combined with those of 
 touch. 
 
 § 40. It must be borne in mind that the know- 
 ledge primarily given in sensations of sight has for 
 its object Only a certain organic condition, and the 
 colour which we see is really within us. , But it is 
 equally certain that colours appear to be at a dis- 
 tance from us, and consequently must have under- 
 gone a process of projection out into space. And 
 we are now to inquire how this process has taken 
 
PSYCHOLOGY OF COGNITION. 
 
 79 
 
 place^ or, in other words, liow the eye Las been 
 educated. We have already seen that touch brings 
 to our knowledge external resisting bodies ; and we 
 shall see that this sense is the great educator of the 
 eye, teaching it to clothe those bodies with the 
 colours which appear in consciousness through the 
 medium of the eye. It has been laid down as a 
 law, " That a sensation appears to us to be situated 
 at the spot in which we are accustomed to meet 
 with its usual cause or condition, and this spot is 
 the one at which tha explorations of touch are 
 capable, by acting there, of checking or modifying 
 the commenced sensation.^^ * A coloured object, 
 for example, is placed within easy reach of a child^s 
 hand. The colour is a sensation which the child 
 has not yet learned to project beyond its own eyes. 
 Its hand touches and partially covers the object; 
 the sensation of colour is at the same moment inter- 
 fered with and modified. Thus a sensation of touch, 
 by repeated experiments of a similar kind, becomes 
 intimately associated with sensations of colour. The 
 principal organs of touch, the hands, are themselves 
 objects of vision. By repeated and various com- 
 biuations of tactual and visual sensations, the object 
 of touch is believed to be the same as the object 
 of sight. But the movements of the hands serve 
 to measure distance, and as the visual sensations 
 soon become inseparably associated with everything 
 which the hands touch, these sensations are thus 
 projected to a distance from the eye. The power 
 * Taine "On Intelligence," p. 314. 
 
 CHAP. II. 
 SECT. V. 
 
 By associ- 
 ation with 
 touch. 
 
8o 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. V. 
 
 Other sen- 
 sations as- 
 sociated 
 and pro- 
 jected. 
 
 of projection having been once acquired, the pro- 
 cess by wbicli it was acquired is forgotten, and the 
 eye spontaneously and unconsciously refers sub- 
 jective sensations of colour to external and distant 
 objects. The estimation of particular distances is 
 soon acquired, depending upon clearness or ob- 
 scurity of colour, number of intervening objects, 
 magnitude, and other circumstances which will 
 readily occur to any one. 
 
 § 41. A connection between the object of touch 
 and the object of hearing, and between the objects 
 of hearing and the objects of sight, is formed by a 
 process similar to that described in thelast paragraph. 
 Hearing and sight are the only two senses in which 
 sensations are projected to any considerable distance, 
 and as the acquired powers of both are obtained 
 chiefly through the assistance of touch, there is an 
 intimate connection between all the three. A sensa- 
 tion of sound having taken place, it is immediately 
 transferred to a distance, and we attempt to conceive 
 or perceive what the sounding object looks like. In 
 other words we attempt to explain to our minds the 
 object of hearing by translating it, as it were, into an 
 object of sight. In the same way, a sensation of 
 colour having taken place, we at once project it to a 
 distance, greater or less according to circumstances, 
 and then connect it with sensations of touch and 
 muscular sensations, or think what it would feel like 
 if we were within reach of it. Thus we explain and 
 enlarge the knowledge communicated to us through 
 one sense, by connecting it with or translating it 
 
PSYCHOLOGY OF COGNITION: 
 
 8l 
 
 into tlie idealised sensations of tlie other senses. 
 And tlie objects of the material world around us, as 
 far as our knowledge of them is concerned, consist 
 of various sensations projected to a distance without 
 us, and united together in such a way that when 
 one of them occurs, the others are invariably believed 
 to be possible. But this objective union is not of 
 our creation; it is manifestly a condition of the 
 non-ego which we become aware of by the process 
 we have indicated, but which we did not produce 
 and cannot change. 
 
 § 42. We are now led to a more careful considera- 
 tion of this distant non-ego. As far as our knowledge 
 of it is concerned we have seen that it consists of sen- 
 sations projected into space and combined variously 
 into different unities called objects. These pro- 
 jected sensations we call qualities, and thus objects 
 are composed of a number of qualities. But objects 
 thus composed are manifestly the creation, to a great 
 extent, of our own minds. The sensations are mental 
 phenomena; the act of projection, and the combina- 
 tion of sensations of touch with those of sight, and 
 others, are mental processes. The foreignness and in- 
 dependence of these objects to the mind are revealed 
 only in the fact that the mind cannot create or 
 annihilate its sensations at will, and that the laws of 
 the combination of these sensations are evidently 
 not mental laws, but laws of the non-ego. In the 
 ohjectiveness of projected sensations and their laws 
 there is believed to be involved the existence of 
 some non-ego independent of our knowledge. A 
 
 CHAP. II. 
 SECT. V. 
 
 Extra, 
 organic 
 objects. 
 
82 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. V. 
 
 Phenome- 
 nal and 
 noumenal 
 elements. 
 
 Quality 
 ambirju- 
 ous, 
 
 sensation — for example, a colour — is something of 
 which we are conscious, and even after the process of 
 projection has taken place, after the eye has been 
 educated, and we perceive the colour as at a distance 
 from us, it is still a thing known to us. But besides 
 this colour as known, we think of some cause or 
 power existing beyond or behind the projected sen- 
 sation which, striking upon our eye, has produced 
 the sensation. This cause or power cannot be a 
 sensation ; it is supposed to exist anterior to and 
 independent of our sensation. It cannot be an 
 object of knowledge, because it can be known only 
 as a sensation ; but ex hypothesi, it has an existence 
 anterior to sensation. Thus, the non-ego appears to 
 consist of two elements; an element which is known, 
 and an element which is unknown, but supposed to 
 exist. The known element, we have seen, consists 
 simply of projected sensations ; the unknown element 
 is composed of something which, when brought into 
 relation with our senses, helps to produce sensations. 
 The term quality has unfortunately become am- 
 biguous by being applied to both of these elements. 
 When it is said that the quality of an object is one 
 of its characters by which it is known to us, it is 
 evidently a projected sensation, for all objects as 
 known consist of such. When it is said that the 
 quality of an object is that which produces a certain 
 sensation in us, it is applied to something which, 
 apart from the sensation, is unknown. The former 
 of the two applications of the word quality appears 
 to us the most natural, and by quality we shall. 
 
FSYCEOLOGY OF COGNITION. 
 
 83 
 
 therefore, hencefortli indicate those characteristics of 
 objects which constitute our actual knowledge of 
 them. There is^ however, a still farther restriction 
 to the term quality, or at least an important dis- 
 tinction between two kinds of qualities. The quali- 
 ties of colour, smell, hardness, &c., are simply sen- 
 sations of sight, smell, muscular effort, &c., ideally 
 transferred or projected into external space. But 
 the space into which these sensations are projected 
 or which they occupy is not a sensation of any kind. 
 Although in our knowledge it is inseparably con- 
 nected with sensation, it is essentially different from 
 sensation. To adopt scholastic distinctions, it is the 
 form of which sensation is the mattery the quantity 
 of which sensation is the quality. It is therefore 
 perhaps improper to speak of extension, figure, and 
 other forms of space as being qualities at all. They 
 are rather the spatial relations of qualities, the ob- 
 jective form into which sensations, being projected, 
 are known as qualities. This essential distinction 
 between the form of sensation and sensation itself 
 has given rise to the distinction between primary 
 and secondary qualities, the former comprising 
 different modes of space, and the latter qualities 
 properly so called, that is, projected sensations. 
 Taking quality in the latter, that is in its proper 
 sense, there is another distinction, although not an 
 essential one, which may be observed. The mode of 
 operation of the different senses is somewhat different. 
 In touch there is necessarily a contact between the 
 external object and the organism ; in sight, hearing, 
 
 G 2 
 
 CHAP. II. 
 SECT. y. 
 
 Quality 
 distin- 
 guished 
 from form 
 or quan- 
 tity. 
 
84 
 
 THE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. V. 
 
 non-ego. 
 
 and smell, the necessity of similar contact is not so 
 obvious. Consequently touch has been supposed by 
 some to bring us into contact with objects as they 
 really exist; other senses not. Hence the distinction 
 of some qualities being supposed to be more essen- 
 tial to the idea of body than others, or of some 
 being purely subjective while others are partly or 
 wholly objective. Perhaps such distinctions have 
 arisen also from the fact that in some of the senses— 
 for example, sight and hearing — there is obviously a 
 perception of distance, or a projection of the sensa- 
 tion, while in others, as smell, there is not so much 
 or so clearly so. Whatever may have given rise to 
 such distinctions, they are fallacious. All qualities 
 properly so called are originally sensations and 
 subjective. All sensations come to be objectified, 
 and involve elements belonging to the non-ego. 
 All sensations except purely organic ones are pro- 
 jected ideally beyond the organism and there known 
 as qualities, while purely organic sensations, that is, 
 sensations which are discovered not to depend upon 
 extra-organic conditions, are not thought of as 
 qualities at all. Consequently the only essential 
 difference between qualities of objects arises from 
 the difference between the hinds of sensations.* 
 Other differences are either fallacious or accidental. 
 § 43. Having considered the constituent elements 
 of objects as known to us, that is, as consisting of 
 real or ideal sensations projected into space and 
 forming there a unity, let us now give some 
 * For another distinction, see § 199. 
 
PSTCEOLOGY OF COGNITION. 
 
 85 
 
 attention to the supposed imJcnown non-ego. When 
 we perceive a colour, we think of some unknown 
 cause or power which, coming into contact with our 
 eye, gives rise to the sensation. So every other 
 quality of objects suggests to us the existence of 
 something behind it and beyond it which, in relation 
 to our organism, gives rise to different sensations. 
 Whatever this is, it is and must be in itself un- 
 known, because when it comes within the sphere of 
 our knowledge it is already transformed into some 
 sensation or other mode of consciousness, and when 
 we attempt even to conceive it, it must be conceived 
 under the form of some mode of consciousness. Let 
 us, for clearness, call this unknown something x. 
 There is then supposed to be an a? corresponding to 
 every different quality which we perceive. And we 
 may ask. What is the relation between the x of one 
 quality and that of another ? Is the x of light, for 
 example, or a particular colour, the same as the x 
 of heat ? Is the x of smell the same as the x of 
 taste ? Or is there only one x for all qualities, which 
 coming into relation with our organism, gives rise 
 to the different kinds of sensations of which we are 
 conscious ? These are some of the questions which 
 may be proposed in connection with this subject, 
 and we refer to them here chiefly for the purpose of 
 setting them aside. They are not questions which 
 it is the business of the psychologist to answer. In 
 so far as they can be answered, they belong to the 
 sphere of experimental physics or of metaphysics : 
 in so far as they are insoluble, they should be left 
 
 CHAP. II. 
 SECT. V. 
 
86 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. V. 
 
 Proper 
 tneaning 
 and object 
 of percep- 
 tion. 
 
 alone altogetlier. As far as psycliology is concerned^ 
 we are confined to tlie analysis and synthesis of our 
 conscious knowledge; and in perception tlie object 
 of our knowledge in the sensible world, that is, 
 the world revealed to us through our senses. Out- 
 side or behind this sensible world we cannot go, 
 either in perception or in imagination.* The un- 
 known X of sensible qualities is not only incapable 
 of being perceived, but also as x of being conceived. 
 As in psychology we are concerned only with what 
 can be known, questions regarding the unknown 
 are referred to only to point them, out as irrelevant. 
 § 44. We are now in a position to understand 
 clearly what we mean by the object of perception. 
 From what we have seen, it is manifest that 
 perception is the act only of educated senses. And 
 those who identify perception with consciousness must 
 mean by it something different from what is usually 
 meant by the word. The object of perception must 
 be at a greater or less distance from the sentient 
 organism. Its existence is made manifest by a 
 sensation of colour or some other. The sensation is, 
 as we have seen, transferred outwards, in a particular 
 direction and to some particular distance. We see 
 the object. But sight gives us nothing but colour 
 and figure ; these qualities are, however, connected 
 in our minds, in consequence of past experiences 
 with other qualities. And if we have before seen 
 the object, we are able to predict what other sensa- 
 
 * We may, however, as we shall afterwards see, hj inference. 
 See §§ 198-200 and 207-9. 
 
PSYCHOLOGY OF COGNITION. 
 
 87 
 
 tions it is capable of giving rise to. We can say 
 liow it will feel, smell, taste, &c., that is, we recog- 
 nise the object, and give it a name. Thus percep- 
 tion implies at least one actual sensation, and several 
 other ideal ones connected with it; implies also a 
 belief that these ideal sensations will become actual 
 if the necessary physical conditions are fulfilled. 
 Now the sensible world, in perception, is separated 
 from the mind, although in the analysis of the pro- 
 cess of perception we have seen that this separation 
 is not a real one. The sensible world is partly the 
 creation of the conscious mind; and in the study of 
 psychology it must ever be borne in mind that the 
 objects of that world combine in themselves both 
 subjective and objective elements, partake both of 
 the ego and the non-ego. In the study of the par- 
 ticular sciences, however, such as optics, acoustics, 
 mineralogy, botany, as well as in the ordinary affairs 
 of life, it is quite legitimate, and, indeed, necessary, to 
 bestow independent existence upon the objects of the 
 senses. This is done for us naturally in the education 
 which our senses receive. And the study of objec- 
 tive science does not require us to leave the stand- 
 point of practical life while the study of psychology 
 does. 
 
 Note on the Process of Perception. 
 
 The process of perception described in the fore- 
 going section is so important that, at the risk of 
 
 CHAP. II. 
 SECT. V. 
 
88 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. II. 
 SECT. V. 
 
 Elements 
 of ^perceip- 
 tion. 
 
 being charged with iteration, we subjoin a some- 
 what fuller description of it than the above. The 
 crude phenomena which appear in consciousness are 
 Feelings related to one another in point of difference, 
 resemblance, simultaneity ^ or succession. The most 
 primitive act of thought consists in the intuition of 
 one of these relations. And next in rank is the 
 synthetic act by which objects or elements thus 
 related are connected together into unity. These 
 primitive acts of thought, carried on involuntarily, 
 result in certain products which constitute the 
 simple objects of common knowledge ; and we now 
 propose to study these products. We consider first 
 the perception of difference and simultaneity. 
 
 We have already seen that there can be no cog- 
 nition of simultaneous objects without a perception 
 of difference. That which enables the child to 
 distinguish between colours, and sounds, and tastes 
 and smells, is a certain difference in the manner in 
 which his senses are affected. But along with this 
 difference of sensation there is a co-existence of 
 them. Sensations differing from one another in 
 quality are frequently experienced in regularly com- 
 bined groups. A connection is thus formed between 
 them, so that when one of the sensations is experi- 
 enced the ofhers are expected. This combination 
 of a real with expected sensations constitutes an 
 object. The formation of natural objects is there- 
 fore one of the most primitive products of thought. 
 
 All objects of knowledge are composed of a 
 certain uniform group of sensations and expected 
 
PSYCHOLOGY OF COGNITION. 
 
 89 
 
 sensations ; but it takes a considerable amount of 
 experience to determine accurately the exact con- 
 stituents of objects. A child, for example, has 
 been accustomed to take some disagreeable medicme 
 from a spoon ; this experience has been repeated so 
 frequently that a firm connection has been formed 
 between the appearance of the spoon in the hand of 
 the nurse and the disagreeable taste of the medicine. 
 To the mind of the child, the hand of the nurse 
 holding the spoon and the expected taste constitute 
 an object ; and the child's mistake is corrected only 
 when some pleasant food is given to it by the spoon. 
 Then it learns that the taste of the medicine is not 
 an invariable element of that cluster of sensations 
 introduced by the sight of the spoon. 
 
 The most important of the sensations connected 
 together in the formation of objects are those of 
 sight and touch. The sense of sight gives only 
 colours differing from one another in quality and 
 occupying a certain bounded space. The sense of 
 touch combined with the muscular sense of effort 
 leads to the inference of hard or soft, rough or 
 smooth, resisting bodies existing outside of us. The 
 motion of our limbs in contact with external bodies 
 gives us the idea of distance ; but it takes a con- 
 siderable time for the child to connect the figured 
 colour which it sees with the resisting body which 
 it touches. The same sensations of colour and the 
 same sensations of touch and muscular effort having 
 been frequently experienced together, the child 
 learns to beheve that the object which it sees is the 
 
 CHAP. II. 
 SECT. V. 
 
 Connec- 
 tion of the 
 objects of 
 sight and 
 touch. 
 
90 
 
 TEE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. V. 
 
 Distance 
 — how 
 measured. 
 
 same as the object which, it touches. Other sensa- 
 tions, as of smell, taste, or sound, are soon added 
 to the group, and thus is produced the full concep- 
 tion of a natural object. 
 
 The distance of an object from the body is first 
 measured by the motion of the hand towards it. 
 The greater time and effort required to reacli an 
 o jject the farther it is believed to be away from us. 
 Bat it is observed also that the greater time and 
 effort taken by the hand to reach an object, the 
 diuimer does the colour of the object appear to the 
 eye ; and the difference between clearness of colour- 
 ing is still more observable when the process of 
 walJcing is combined with the stretch of the arm. 
 Ouher differences of appearance also are observed 
 by the eye, as a greater or less size, a greater or less 
 clearness in the appearance of the minute parts of 
 objects and so on. These differences of appear- 
 ance become gradually connected with the longer 
 or shorter time and the greater or less effort 
 required to reach objects with the hand, and 
 thus we learn to see the distance of objects, or, 
 properly speaking, to infer from visible appear- 
 ances, what are the distances from us of the objects 
 of touch. Hence we see that the perception of 
 the objects of 'the external world is a combination 
 of intuition and inference. We perceive intuitively 
 actual sensations; we expect, by an involuntary 
 inference, the other sensations of the group. We 
 intuite sensations of muscular resistance; we infer 
 some resisting external object. We intuite par- 
 
PSYCHOLOGY OF COGNITION. 
 
 91 
 
 ticular sensations of colour; we infer the distance 
 to be passed over before particular sensations of 
 touch can be readied. 
 
 The products of thought just described are founded 
 mainly but not exclusively upon the relations of 
 difference and simultaneity ; other products of a 
 primitive kind are founded mainly but not ex- 
 clusively upon the relations of resemblance and 
 succession. The child is conscious of the same 
 sensation or the same group of sensations at succes- 
 sive times ; the regular recurrence of the group of 
 sensations leads to a belief in the identity of the 
 object. Thus our belief in the permanence and 
 independence of natural objects is the result of 
 seeing that a present group of sensations resembles 
 a group of sensations which we remember to have 
 experienced some time ago. This recognition of 
 similarity between present experienced sensations 
 and past represented sensations is of the greatest 
 importance as it is the foundation of our belief not 
 only in the permanence of objects but also in the 
 permanence and identity of ourselves. We have in 
 this also the only means we possess of comparing 
 all kinds of relations as well as objects with one 
 another. Past periods of time, figures and dimen- 
 sions of space, forthputtings of energy, experiences 
 of pleasure and pain, are recalled and compared 
 with present experiences ; and thus our lives are 
 enriched by being able to bring together the past 
 and the present. 
 
 When the present group of sensations does not 
 
 CHAP. II. 
 SECT. V. 
 
 Perma- 
 nence of 
 objects — 
 how 
 learned. 
 
92 
 
 THE ELEMENTS OF THE 
 
 CHAP. II. 
 SECT. V. 
 
 exactly resemble the representation of a past group, 
 we get the idea of sameness of kind but difference 
 of individual object. The child at first is unable to 
 distinguish between its mother and other ladies ; 
 but, soon differences are recognised and individuals 
 distinguished. The ability to perceive minute 
 differences in the midst of a general resemblance is 
 necessary in order to enable us to distinguish one 
 object from another ; as the ability to assert with 
 confidence the exact resemblance of a present 
 object and a representation is necessary to enable 
 us to identify an individual. 
 
 The uniform connection between succeeding 
 events constitutes what we know of the causal 
 relation. When a certain phenomenon is uniformly 
 followed by another phenomenon, the two become 
 so connected that when the one appears the other 
 is expected. Uniformity of succession is thus an 
 essential, though not the only essential element in 
 the causal relation. 
 
 We thus see that the objects and relations of our 
 common knowledge are produced by the exercise 
 of involuntary and to a great extent unconscious 
 thought. When we first waken up to conscious 
 life we find ourselves in the midst of a world of 
 objects regarding which we know a good deal. 
 This primitive knowledge is the result, no doubt, 
 of an almost unconscious process which has gone 
 on during the dreaming sleep of infancy, as our 
 bodies and minds were being gradually adapted to 
 our surroundings. 
 
PSYCHOLOGY OF COGNITION. 
 
 93 
 
 CHAPTER III. 
 
 THEORIES OF PEBCEPTION. 
 
 Section I. 
 
 GENERAL DESCKIPTION AND CLASSIFICATION. 
 
 § 45. In order to have a clear understanding of 
 any theory of perception, it is necessary to compare 
 it with and distinguish it from other theories from 
 which it to a greater or less extent may differ. And 
 in this chapter we purpose to bring together, for the 
 purpose of comparison, the most important theories 
 regarding this subject which have been held by 
 philosophers. In the early history of philosophy, the 
 different departments of study were not clearly 
 distinguished from one another. In the writings of 
 the Grecian philosophers, there were frequently 
 collected together, in a confused manner, discussions 
 on psychological, cosmological, theological, ethical 
 and logical questions ; and a greater or less confu- 
 sion of subjects that ought to be separately ex- 
 amined may be found throughout the whole history 
 of philosophy. It is natural that in the early stages 
 of human knowledge there should be this confusion; 
 but it is necessary to the progress of knowledge that 
 this confusion should be cleared away. It is chiefly 
 
 CHAP. III. 
 SECT. I. 
 
 Subject in- 
 troduced. 
 
 J 
 
94 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. I. 
 
 Twopoints 
 of view. 
 
 in modern times, and especially since the time of 
 Descartes^ that we find the original chaos of human 
 knowledge becoming separated into clearly defined 
 sciences. We shall therefore look for the theories 
 of perception which we wish to examine only in the 
 history of modern philosophy, from the time of 
 Descartes, as in that period we are likely to find the 
 clearest statements of the results of investigation 
 into the nature of our knowledge of external things. 
 
 Before proceeding to examine any of the parti- 
 cular theories which have been held regarding per- 
 ception, we purpose to take a general view of certain 
 fundamental differences between these theories, by 
 means of which we may arrange them into classes. 
 The possibility of making a classification assumes, of 
 course, a knowledge more or less complete of the 
 things to be classified, and the reader must there- 
 fore take for granted the accuracy of our general 
 descriptions until he is able to verify them by the 
 study of the special theories to which they may be 
 applied. 
 
 § 46. There are two distinct points of view from 
 which the student of the process of perception may 
 proceed in the examination of his knowledge. It is 
 difiicult to find any single unambiguous word which 
 indicates these points of view respectively, and 
 therefore, without in the meantime naming them, 
 we shall proceed to describe them at length. 
 
 (1) From the first stand-point the psychologist 
 regards the objects of the world of sense as having 
 an existence independent of the mind, and the 
 
PSYCHOLOGY OF COGNITION. 
 
 95 
 
 phenomena of the mind as having an existence inde- 
 pendent of material objects. The trees and stones 
 and other objects which we know, and as we know 
 them_, exist away outside of us, and the mind which 
 knows exists somewhere within the body; and these 
 two things, the external material bodies and the 
 mindj are totally different in nature and indepen- 
 dent in existence. And the problem of psychology 
 is to determine how it is that the mind knows the 
 objects of the material world, and what amount of 
 confidence is to be placed in this knowledge. This 
 is what we might call the stand-point of practical 
 common sense. The practical man, with his sensive 
 organism completely matured and educated, sees ob- 
 jects in the world around him apparently existing 
 independently of his mind ; and when he becomes 
 a philosopher his great question naturally is how 
 these objects which are extended, figured, and 
 distant can be perceived by his mind, which is an 
 unextended spiritual substance. Thus there is 
 assumed the existence of two worlds differing in 
 nature and independent in existence, and then the 
 question is asked how does the one come to know 
 the other, how does mind know matter ? For the 
 sake of distinctness, and for want of a better 
 name, we may call this the stand-point of practical 
 dualism. 
 
 (2.) Those who adopt th.e second point of view 
 assume nothing regarding the existence or nature 
 of an external world, but analyse all their know- 
 ledge into its original elements as found in con- 
 
 CHAP. III. 
 SECT. I. 
 
 Practical 
 dualism. 
 
96 
 
 THE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. I. 
 
 Philoso- 
 phical 
 stand- 
 point. 
 
 Origin of 
 represen- 
 tationism. 
 
 sciousness, and beginning with the simplest facts 
 given in consciousness, seek to discover the manner 
 in which the sphere of our knowledge and belief is 
 gradually filled up. As a preliminary to the adop- 
 tion of this method it is necessary that nearly all 
 our naturally acquired beliefs regarding the exist- 
 ence and nature of objects of sense should, for the 
 time, be given up. The object of the psychologist 
 is to determine the origin and process of the acqui- 
 sition of knowledge, and therefore it is not legiti- 
 mate to assume anything regarding the existence 
 and nature of the objects of knowledge until it is 
 seen how they have become objects. From this, 
 which we may call the philosophical point of view, 
 the student works his way from within outwards, 
 beginning with those facts of consciousness, which, 
 as far as he can discover, are elementary, endeavour- 
 ing to discover what they reveal of the non-ego, 
 and how they are combined or modified, and in no 
 case assuming anything which they do not give. 
 
 One or other of these points of departure has 
 been adopted and adhered to with greater or less 
 consistency by nearly all modern philosophers. We 
 shall not at present express any opinion as to their 
 respective merits, but proceed to examine the 
 theories of perception which may be classed under 
 them respectively. 
 
 § 47. We have said that the problem which the 
 psychologists who adopt the first method require to 
 solve is to determine how two independently existing 
 and heterogeneous substances can have communi- 
 
PSYCHOLOGY OF COGNITION. 
 
 97 
 
 cation, the one with the other. Given that there 
 exists a mind, spiritual and unextended ; that out- 
 side in space there exist material bodies possessing 
 various qualities ; how does the former come to 
 know or believe in the latter ? The answers to this 
 question have been various, and at present we shall 
 not attempt any exact classification of them, as, 
 indeed, perhaps no classification could be made 
 without in some way doing violence to the theories 
 concerned. Generally speaking it has been held 
 that mind can have no immediate knowledge of 
 matter, and that knowledge can only be effected 
 by the intermediation of some image or idea which 
 either represents or suggests the external object. 
 The fundamental principle which appears to under- 
 lie most of the theories of this kind is that the 
 mind cannot directly know anything but its own 
 ideas, and consequently these theories have been 
 classed together under such names as idealism, 
 representative idealism, cosmothetic idealism, &c. 
 But it is to be borne in mind that injustice may 
 easily be done to theories by forcing them into 
 some particular classification because some common 
 form of language is employed in them, without care- 
 ful consideration of the real meaning of the language 
 and of other essential principles which the theories 
 conprehend. 
 
 § 48. Amongst those who study the process of 
 perception from the second, which we called the 
 philosophical stand-point, there are important 
 differences. They all begin by giving up the posi- 
 
 CHAP. III. 
 SECT. I. 
 
 Philoso- 
 phical 
 method. 
 
98 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. I. 
 
 tion of practical dualism whicli is tlie result of the 
 ordinary education of tlie organism tlirougli which, 
 everyone passes. They analyse the objects of the 
 senses into materials given in consciousness, and 
 endeavour to ascertain those facts of consciousness 
 which are irreducible to others more simple. Taking 
 up their position thus at the origin of knowledge, 
 they work their way outwards, tracing the process 
 by which knowledge is gradually acquired. The 
 principal differences which exist between different 
 theories of this class arise from the different views 
 which are taken regarding the nature and signi- 
 ficance of the facts revealed in consciousness. As 
 in the previous class we hesitated to attempt giving 
 a more minute classification of the theories contained 
 in it for fear of doing injustice to some of them, so 
 now it will be as well to postpone minuter descrip- 
 tion until we have examined the important theories 
 which assume this stand-point. Our general division 
 of theories of perception into two great classes has 
 been instituted chiefly for the purpose of furnishing 
 a sort of key to the understanding of the theories 
 to be passed in review. We shall not examine all 
 the theories of each class in immediate succession, 
 but shall rather take them in the historical order of 
 their appearance, being thus better able to perceive 
 their relations to one another. 
 
PSYCHOLOGY OF COGNITION. 
 
 99 
 
 Section II. 
 
 DESCARTES. 
 
 § 49. Descartes began his pHlosopliising by 
 resolving to doubt tbe truth of all propositions 
 received at second-hand. He found himself able to 
 doubt the existence of the world, of God, of his own 
 body, of everything in short except doubt itself. 
 But doubt is only a form, of thought, and hence, 
 according to Descartes, the act of thinking itself, as 
 given in consciousness, was the one certain founda- 
 tion of all knowledge. But the assertion of thinking 
 involves the assertion of a thinking being; cogito 
 ergo sum. Thinking, in its widest sense, is the 
 essence of mind. 
 
 Having thus established a firm foundation on 
 which to build the superstructure of his system, 
 Descartes proceeded to prove the existence of God. 
 According to him, ^'^ When the mind reviews the 
 different ideas that are in it, it discovers what is by 
 far the chief among them — that of a Being omni- 
 scient, all-powerful, and absolutely perfect ; and it 
 observes that in this idea there is contained not 
 only possible and contingent existence, as in the 
 ideas of all other things which it clearly perceives, 
 but existence, absolutely necessary and eternal, 
 .... so from its perceiving necessary and eternal 
 existence to be comprised in the idea which it has 
 
 H 2 
 
 CHAP. III. 
 SECT. II. 
 
 Descartes^ 
 founda- 
 tion. 
 
 Proof of a 
 Deity. 
 
ICX) 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. II. 
 
 Psycho, 
 logy of per- 
 ception. 
 
 of an all-perfect Being, it ouglit manifestly to con- 
 clude that this all-perfect Being exists." * 
 
 We need not stop to criticise this demonstration 
 of God's existence. To Descartes' mind it was 
 satisfactory, and he employed his belief in God's 
 existence and veracity as a part of his psychology 
 of perception. He reasons thus : " It cannot be 
 doubted that every perception we have comes to us 
 from, some ^bj^ct different from ourjnind; for it is 
 not in our power to cause ourselves to experience 
 one perception rather than another, the perception 
 being entirely dependent on the object which 
 affects our senses. It may, indeed, be matter of 
 inquiry whether that object be God, or something 
 different from God; but because we perceive, or 
 rather, stimulated by sense, clearly and distinctly 
 apprehend^ certain matter extended in length, 
 breadth, and thickness, the various parts of which 
 have different figures and motions, and give rise to 
 the sensations we have of colours, smells, pain, . &c., 
 God would, without question, deserve to be regarded 
 as a deceiver, if he directly and of himself presented 
 to our mind the idea of this extended matter, or 
 merely caused it to be presented to us by some 
 object which possessed neither extension, figure, nor 
 motion. For- we clearly conceive this matter as 
 entirely distinct from God and from ourselves or 
 our mind ; and appeareyen clearly to discern that 
 the idea of it is fqi-med in us on occasion, of objects 
 existi ng out of our minds, to which it is in every 
 
 * "Principles," part i., si v. 
 
PSYCHOLOGY OF COGNITION. 
 
 lOI 
 
 respect similar. But since God cannot deceive us_, 
 for this is repugnant to His nature, as lias been 
 already remarked, we must unhesitatingly conclude 
 that there exists a certain object, extended in 
 lengthy breadth, and thickness, and possessing all 
 those properties which we clearly apprehend to 
 belong to what is extended. And this extended 
 substance is what we call body or matter."" * 
 
 § 50. From these extracts, and from other parts 
 of his writings which need not be cited, we may 
 draw out what appear to be the essential principles 
 of Descartes' psychology. 
 
 (a). He begins his investigations by starting 
 from what we have called the philosophical stand- 
 point, assuming nothing but the existence of think- 
 ing as his foundation. Then from the nature of 
 certain ideas which constitute his conscious think- 
 ing, he infers the existence of an all-perfect and 
 veracious Being. 
 
 (6). Consciousness reveals to us also certain other 
 ideas which are — (1) beyond our power to create or 
 annihilate ; (2) ideas of extended substance giving 
 rise to certain sensations ; and (3) occasioned by 
 objects different from God ajid existing outside of 
 our minds wMch they (the ide&fi)^7:£present . 
 
 (c). These ideas being beyond_jDjir_._CLsni._powQr 
 must be produced in us by„Sad. But since we 
 clearly apprehend the idea of extended substance, 
 and since God would not deceive us, it follows that 
 this ext_ejided-sttbstance must exist outside of us. 
 
 * "Principles," part ii., i. "^ 
 
 CHAP. Ill, 
 SECT. II. 
 
 Systematic 
 statement 
 of Des- 
 cartes' doc- 
 trines. 
 
102 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. II. 
 
 Criticism. 
 
 [d). As the essential quality of mind is thiiiking, 
 so the essential quality of material objects is exten- 
 sion; other qualities^ such as hardness^ colour, &c.^ 
 being variable, and therefore accidental. 
 
 § 51. It is admitted that the point of departure 
 of Descartes^ psychology is the true one ; and it is 
 more than could be expected that his subsequent 
 investigations as to the essential elements of our 
 knowledge and belief should, at the beginning of 
 the history of modern philosophy, be faultless « 
 Consequently we find in the principles which he 
 endeavoured to establish several weak points which 
 afterwards produced evil results. To these we shall 
 turn our attention. 
 
 (a). The demonstration which Descartes gives of the 
 existence of God assumes that whatever we clearly 
 and distinctly conceive to exist must therefore have 
 an objective existence. The nature of our subjective 
 concept of God is the datum from which is inferred 
 His objective existence. We believe in God^s exist- 
 ence, therefore, because we trust that our faculty 
 of conception will not deceive us. . We need not 
 criticise this so-called demonstration, as that would 
 be apart from our subject, but it will be necessary 
 for us to remember that, with Descartes, the exist- 
 ence of God depends upon the fidelity with which 
 his own conceptions of God correspond to the ob- 
 jective reality. And of fidelity, the only test which 
 he is able to apply is the clearness and distinctness 
 of the conceptions themselves. 
 
 (fe) . There is great confusion in Dgscartes'_descrip- 
 
PSYCHOLOGY OF COGNITION. 
 
 103 
 
 ■ tion of tlie ideas of material objects. From tlie 
 fact that thej are beyond bis power to create or 
 annihilate^ he very rightly concludes that__they 
 belong in some way to the non-ego. Bat when he 
 speaks of ideas of extended substance, confusion is 
 apparent. The idea^ if mental^ must^ according to 
 Descartes^ principles, be unextended ; how then can 
 it be "in every respect similar ^^ to that which is 
 extended ? And again, when he speaks of ideas 
 being occasioned by objects outside of us, he very 
 evidently passes away from the philosophical stand- 
 point to that of practical dualism. Objects are 
 believed in only by inference from the ideas ; and it 
 is illegitimate ^r5^ to assert the existence of objects 
 as an inference from ideas, and then to shift one's 
 ground and account for the existence of ideas by 
 the presence of objects. It is equally illegitimate ] 
 to affirm that the ideas represent or resemble the 
 objects. In order to say that one thing resembles 
 another we must have an independent knowledge of 
 both, and then, having compared them, we can 
 affirm their likeness or unlikeness. But ex hypothesi 
 we have no independent knowledge of objects, no 
 knowledge whatever of them except through their 
 ideas. Hence we cannot assert that the one re- 
 sembles the other. 
 
 (c) . It is, according to Descartes, by the power of 
 God that the idea of extended substance is produced 
 in our minds, and since we have confidence in God's 
 veracity, we believe that there is really extended 
 substance without us. But the existence of God 
 
 CHAP. III. 
 SECT. II. 
 
104 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. II. 
 
 depends upon tlie clearness and distinctness of our 
 ideas ; our idea of extended substance is also clear 
 and distinct. It is difficult, therefore, to see why 
 the inference from the clearness and distinctness of 
 one set of ideas should be made use of to establish 
 the inference which may be drawn with equal 
 certainty from the clearness and distinctness of 
 another set of ideas. Still farther, it is an un- 
 warranted assumption, that our ideas of material 
 bodies are produced in our minds by the power of 
 God. Of course, in one sense everything is done by 
 the power of God ; but, 5^ Descartes makes use of 
 the power of God in his psychology, he means by.it 
 some~ special interposition by which an extended 
 substance may be represented to a mind which is 
 unextended. The introduction of the power of God 
 is, at best, an unphilosophical hypothesis for ex- 
 plaining what, to the mind of Descartes, was an 
 otherwise inexplicable difficulty. We shall see that 
 this feature of Cartesianism afterwards became still 
 more prominent. 
 
 In consequence of Descartes' doctrine of divine 
 interposition, it was unnecessary for him to endow 
 matter with any active powers. And consequently 
 he makes bare extension the one essential quality 
 of material substance. As for other ideas, such as 
 colour, hardness, taste, etc., they proceed from this 
 extended substance, or rather result from the close 
 and intimate union between the mind and extended 
 substance. We do not at present criticise Descartes' 
 doctrine that simple extension, instead of some 
 
PSYCHOLOGY OF COGNITION. 
 
 105 
 
 dynamical principle, is tlie only essential quality of 
 tlie objective world. We call attention to it now in 
 consequence of the influence wliicli it exerted upon 
 subsequent speculation. 
 
 § 52. The most important of the followers of 
 Descartes was Malebranche (1638-1715). The doc- 
 trine by which he is best known is only a further 
 development of a principle belonging to Cartesiauism. 
 Mind and body are two absolutely distinct and 
 heterogeneous entities, and it is absolutely impossible 
 that there can be any natural connection between 
 them. Consequently Descartes said that our ideas of 
 material bodies must really be produced by Grod. In 
 the researches of Malebranche, this feature of Car- 
 tesiauism is brought out into still greater prominence. 
 He teaches that we, as spirits, exist in a manner in 
 God, who is the place of spirits, and, participating in 
 His knowledge, " we see all things in God." As God 
 is omniscient, the ideas of all things in the universe 
 must be in His mind ; and since we, as spirits, are 
 also in Him, we perceive the divine ideas of material 
 bodies. It is interesting and amusing to see what 
 wonderful contrivances are invented to overcome 
 the difficulty assumed to exist, that the mind, because 
 un extended, cannot directly perceive extended body. 
 And it is probable that most readers in modern 
 times will regard the explanation as still more in- 
 comprehensible than the original difficulty to be 
 explained. Waiving, therefore, any general criti- 
 cism of the doctrine as unnecessary, we shall 
 point out a certain characteristic of the ideas 
 
 CHAP. III. 
 SECT. II. 
 
 Male- 
 hranche. 
 
io6 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. II. 
 
 Cartesian 
 meaning of 
 idea. 
 
 O"' 
 
 y 
 
 of Descartes and Malebranclie whicb. must be 
 noticed. 
 
 § 53. Both, of tliese pHlosopliers use the word 
 idea to indicate some object of thought which, is dis- 
 tinct from the activity of the mind in perceiving or 
 thinking it, and which appears to have attributed to 
 it an independent existence. For example, Descartes 
 says :* " Further, I cannot doubt but that there is 
 in me a certain passive faculty of perception, that is,, 
 of receiving and tahing knowledge of the ideas of sen- 
 sible things j but this would be useless to me if there 
 did not also exist in me, or in some other thing, 
 another active faculty capable of forming and pro- 
 ducing those ideas.'' And he soon concludes that the 
 active power of producing these ideas is in corporeal 
 objectsL. "' ~— 
 
 The cardinal doctrine of Malebrancbe's psycho- 
 logy is that ideas of material objects can be directly 
 perceived only by the mind of God; but since we 
 exist in Him, we participate in His knowledge and 
 perceive His ideas. Thus, in Cartesianism the idea 
 is a distinct entity, contained in some mind either 
 Divine or human, and existing quite independently 
 of the mental activity involved in the perception of 
 it. But a careful analysis of consciousness might 
 have led these philosophers to the conclusion that the 
 distinction between th.e act of thinking andthat which 
 is thought, the act of perceiving and the percept, the 
 act of conceiving and the concept, is only a logical one. 
 Any conscious activity of the kind is on one side an 
 * Med. vi. 
 
PSYCHOLOGY OF COGNITION. 
 
 107 
 
 act, on the other side an object or idea ; the act is the 
 idea, the idea is the act, but viewed in another relation. 
 The greatest confusion in psychology has risen from 
 the use in different senses and for different purposes of 
 the word idea. And it is necessary now either to banish 
 the word altogether from use, or to employ it in a 
 clearly defined meaning. In the meantime it should 
 be noted that all mental phenomena are objects of 
 consciousness, and cannot exist apart from the conV 
 sciousness in which they are apprehended. And to 
 speak of ideas as if they could pass from objects to 
 the mind, or as if o^e mind could be conscious of 
 the ideas of another,'' is either an abuse of language 
 or the illegitimate attribution of independent exist- 
 ence to an abstraction. Th is error of Cartesianis m 
 long continued to cause confusion in psychology, 
 but it is now long since it was perceived and 
 abandoned. 
 
 § 54. The philosophy of Spinoza (1632-1677) 
 was, in a sense, the result of Cartesianism. The 
 chief differences between the doctrines of Spinoza 
 and Descartes had reference not to the psycho- 
 logical process of knowledge, with which only we 
 are now concerned, but to the nature of the real 
 existence which underlies all phenomena. Desca rtes 
 had postulated, the, exi stence j )f two substances, 
 thoughJL^^tnd^ extens ion, as the necessary constitu- 
 ents of, mind and_ matter^ But it~app eared to 
 Spinoza that thought and extension are both them- 
 selves phenomena, and cannot therefore be the 
 suhstances in which other phenomena inhere. 
 
 > 
 
 ■> 
 
 CHAP. III. 
 SECT. II. 
 
 Sjpinoza. 
 
io8 
 
 THE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. II. 
 
 Descartes' psycliological analysis had discovered 
 only those attributes which, were found to be essen- 
 tial to the mind and material body respectively. 
 But Spinoza thought that all attributes must have 
 a substance in which they inhere. And rejectiDg 
 the dualism which had hitherto prevailed, he 
 asserted that thought and extension are attributes 
 of OTi^co^moru-substajQce which underlies them 
 hoiL There is thus only one substance, self- 
 existent, infinite and eternal ; and that substance is 
 Gpd^ The qualities, however, of mind and matter 
 are phenomenally distinct, so that, as in Descartes, 
 there can be no direct causal or cognitive relation 
 between them. But both are phenomena of one 
 substance ; there is a correspondence between them. 
 The thought corresponds to the thing ; the idea to 
 the object. 
 
 To enter into any detailed examination of 
 Spinoza's pantheistic ontology would take us alto- 
 gether aside from our subject. The only important 
 correction which he made in the Cartesian psycho- 
 logy was the assertion that thought and extension, 
 being only essential attributes, cannot be considered 
 as substances. 
 
 We shall now leave Descartes and his followers 
 for the present, and give our attention to the 
 beginning of another philosophical movement in 
 England. 
 
\< 
 
 PSYCEOLOGT OF COGNITION 
 
 109 
 
 Section III. 
 Locke. 
 
 § 55. Locke, in his psycliology, begins with the 
 principle, that there is nothing in the mind except 
 what comes into it from without : it is like a sheet of 
 white paper upon which experience writes our ideas. 
 The experience which gives us . our ideas is of_two 
 kinds, sensation and reflection : by the former, we 
 perceive the qualities of bodies ; by the latter, the 
 ideas we have derived from sense are variously 
 modified, repeated, or combined. Our ideas are thus 
 either simple or complex. " But it is not in the 
 power of the most exalted wit, or enlarged under- 
 standing, by any quickness or variety of thought, to 
 invent or frame one new simple idea in the mind 
 not taken in by the ways before-mentioned ; nor can 
 any force of the understanding destroy those that are 
 there.''* 
 
 There are some ideas, such as those of colours or 
 sounds, which gain admittance to the mind through 
 one sense specially adapted for them. There are 
 other ideas, such as of space or extension, which con- 
 vey themselves into the. mind by more senses than 
 one ; whatever the mind perceives in itself, or is the 
 immediate object of perception, thought, or under- 
 standing, Locke calls idea ; and the power to produce 
 
 * Essav, bk. ii., cli. ii., § 2. 
 
 CHAP. III. 
 SECT. III. 
 
 Lockers 
 Ijrincijple 
 
no 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. III. 
 
 Primary 
 
 qualities. 
 
 Secondary 
 qualities. 
 
 LocTce's 
 doctrines 
 hriefiy 
 stated. 
 
 any idea in the mind lie calls quality of tlie subject 
 wherein that power is. Qualities are of two kinds : 
 First, those which are utterly inseparable from 
 the conception of body, such as solidity, extension, 
 j&gure, &c. ; and second, those which are nothing 
 in the objects themselves, but powers to produce 
 various sensations in us by their primary qualities. 
 Bodies produce ideas in us ; in the case of primary 
 qualities, by impulse, and in the case of secondary 
 qualities, by the operation of insensible particles on 
 our senses. The ideas of primary qualities of 
 bodies are resemblances of them, and their patterns 
 do really exist in the bodies themselves; but the 
 ideas produced in us by the secondary qualities, 
 have no resemblance of them at all. Perception is 
 the first and simplest idea we have from reflection 
 upqn_aegsations. Before perception can take place 
 there must be some idea imprinted by sense upon 
 the mind ; but in perception the ideas of sensations 
 are often changed by the judgment. 
 
 § 56. In the preceding paragraph we have given, 
 pretty much in Locke's own language, the most 
 important of his doctrines regarding perception. 
 We shall now endeavour to present in more 
 systematic form his solution of the chief psy- 
 chological problems, pointing out those which he 
 has not attempted. 
 
 (1 .) He appears to assume that the mind is nothing 
 but a capacity of receiving sensations or ideas from 
 experience. In this he differs from Descartes, who 
 cannot doubt the existence of his mind as a thinking 
 
PSYCHOLOGY OF COGNITION. 
 
 Ill 
 
 CHAP. III. 
 SECT. III. 
 
 being independent of everything material. The 
 principle of Locke and his school is : There is nothing 
 ill the intellect hut what comes into it through sense; 
 by Leibnitz, a distinguished follower of Descartes 
 and opponent of Locke, this principle is amended 
 by the addition, except intellect itself, 
 
 (2.) The psychological problem which Locke at- 
 tempts to solve is not how there arises in cpnsci(Mis- ^j^/ *- i>(>v^ ^ 
 ness the knowledge of an extended non-ego, hut\ I <'% *** * * '*^ 
 how the sensive organism assumed to exist conveys 
 to the mind ideas of more distant objects. Locke thus 
 begins from the stand-point of practical dualism. 
 
 (3.) The mind knows the external world by means 
 of ideas, some of which resemble the qualities which 
 exist in bodies, while others do not. And in this' 
 reference Locke is guilty of the same error which we 
 find amongst the Cartesians ; the idea is evidently 
 thought to be something different from the activity 
 of the_mindjn thinking it ; Locke's psychology 
 may therefore be described as one of representative 
 idealism of the crudest kind. 
 
 (4.) The primary qualities of bodies are the only 
 real qualities which they possess. The secondary 
 qualities are only poivers to produce certain ideas, as 
 of colour, sound, &c., in us, but these powers are 
 possessed and exercised hy the primary qualities. 
 
 § 57. With reference to the first position of 
 Locke, that there is nothing in the mind except 
 what comes into it through sense, we may remark 
 that it has occasioned an important and long- 
 continued controversy amongst philosophers. Leib- 
 
 Locke's 
 'principle 
 contested 
 hy Leih' 
 nitz. 
 
112 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 
 i^' 
 
 Locke 
 
 assumes 
 
 dualism. 
 
 nitz, the ablest contemporary critic of Locke's 
 philosophy^ pointed out that there must be a mind 
 possessing a certain structure or constitution in 
 order to render experience possible. And although 
 Locke may be correct in saying that there are no 
 innate ideas anterior to experience, yet the nature of 
 certain elements of our knowledge is such that they 
 could not be derived simply from experience. There 
 are certain propositions which are characterised by 
 self-evidence and necessity, that is, the truth of 
 which we perceive intuitively and cannot possibly 
 deny. As an example of these propositions we may 
 cite, " Things which are equal to the same thing 
 are equal to one another." This proposition is an 
 ultimate intuition ; it cannot be proved by anything 
 more simple; it cannot be denied, because its 
 opposite is inconceivable. It is argued, therefore, 
 by those who differ from Locke, that the necessity of 
 such a proposition could not originate in experience 
 since experience can only give what is, not what 
 must be; and consequently that there must be 
 something in the constitution of the mind which im- 
 parts the character of necessity to certain axiomatic 
 propositions. 
 
 § 58. Locke sets out with the resolution to trace 
 the origin of our knowledge, and supposes that the 
 mind at the beginning is destitute of all ideas. 
 The most simple ideas are introduced into the mind 
 through sensBj that is, through the *organs of our 
 physical bodies. And still further, the ingress of the 
 idea through sense is accounted for by some impulse 
 
PSYCHOLOGY OF COGNITION. 
 
 113 
 
 of the primary qualities of external bodies, ^hu^ 
 there is assumed the existence of organs of sense 
 and external bodies, and the problem is to show how 
 the latter, by means of the former, transmit ideas 
 of themselves into the vacant mind. Now there can 
 be no question that this position of Locke is the 
 one which the majority of men naturally occupy. 
 There is in children and savages a complete practical 
 knowledge of objects around them and of their own 
 bodies, although there is thorough ignorance of 
 what is meant by such words as mind, or sensation, 
 or consciousness. In ^tbe-iistorical. acquisition of 
 knowledge, objects are perceived before sensations are 
 known in consciousness. Mankind, without reflection 
 or conscious thought, assumes the stand-point of 
 crude or practical realism, and the great majority of 
 men never leave it. But when one attempts to 
 make a psychological analysis of his knowledge, it 
 is not legitimate to assume objects as existing until 
 it is shown how they become known. 
 
 § 59. Notwithstanding the implied assumption of 
 the existence of bodies, there is an attempt on the 
 part of Locke to show how the mind knows- external 
 objects. This is by means of ideas which come into 
 the mind through the senses. It is difficult fre- 
 quently to say what Locke means by the word idea, 
 on account of the many different senses in which 
 he uses it, and the inextricable confusion with which 
 different senses of the word are interchanged. There 
 is, however, reason to believe that he was what has 
 been since called a representative or hypothetical 
 
 CHAP. III. 
 SECT. III. 
 
 Locke's 
 theory of 
 ideas. 
 
114 
 
 TEE JELBMENTS OF THE 
 
 CHAP. III. 
 SECT. III. 
 
 realist ; that lie held ideas to be the only things 
 iinmediatfily known; that from the mind^s knowledge 
 of ideas it infers the existence of external qualities y 
 and that the ideas of primary qualities really resem- 
 ble those qualities^ which latter really constitute 
 bodies as they exist. Without undertaking a 
 criticism of some of these positions, which we shall 
 see afterwards is done by others^ we may at present 
 point out an important paralogism. The design of 
 the representative hypothesis is to explain how we 
 come to know external objects. These objects then 
 are assumed to be in themselves unknown ; and their 
 existence is inferred to account for the existence of 
 the ideas which are immediately known. Thus the 
 idiQQi,^jr^X£sent the primary qualities of external 
 objects .ta the mind. Now supposing ideas to exist, - 
 and supposing the inference to be admitted that they 
 have some external cause, we may ask how can it 
 be affirmed that the idea represents or resembles the 
 inferred quality ? In order to assert that one thing 
 resembles or does not resemble another^it is necessary 
 that there should be an independent knowledge of 
 the two things — a comparison between them, and a 
 recognition of their resemblance or non-resemblance» 
 But in this case there can be, ex hypothesi, no inde- 
 pendent knowledge of one of the terms of the com- 
 parison. The quality is known only as an inference 
 from the idea, and hence nothing can be asserted as 
 to its likeness or unlikeness to the idea. The fact is, 
 psychological analysis, in Locke's time, was only in 
 its infancy, and consequently in his writings there 1 
 
PSYCHOLOGY OF COGNITION. 
 
 115 
 
 was very great confusion in various respects — a 
 confusion wliicli has been to a very great extent 
 cleared away by subsequent writers. 
 
 § 60. It is to be noticed that, according to Locke, 
 it is the insensible particles of the primary qualities 
 of bodies wliicli produce in us the ideas of the 
 secondary qualities. The meaning of this appears 
 to be that the resisting substance of a body may 
 become so small as not to excite any sensible 
 tactual sensation, but that still it is capable of exci-. 
 ting sensations of sight, smell, or taste. Thus alV 
 ideas are produced by impulse from some extended 
 material substance, but in the case of the primary 
 qualities, the extension is perceived, and therefore 
 the idea resembles the quality, whereas when the 
 extension becomes so small as to be imperceptible, 
 it then gives rise to smells, tastes, and other non- 
 resembling ideas. If this be Locke's meaning, we 
 naturally ask, how is it that secondary qualities do 
 not exist in bodies ? If they are simply primary 
 qualities divided into particles so small as not to offer 
 resistance to pressure, there appears no reason for 
 saying that they have no objective existence at all. 
 This is another instance of Locke's confusion. We 
 must now see how Locke's principles were treated 
 by his successors in psychological research. 
 
 CHAP. III. 
 SECT. III. 
 
 Of second. 
 ary quali- 
 ties. 
 
 
 I 2 
 
ii6 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. IV. 
 
 Berkeley's 
 clearness. 
 
 New theory 
 of vision. 
 
 Section IV. 
 
 BEEKELEY (1684-1753). 
 
 § 61. When we compare tlie subtlety and clear- 
 ness of the mental analysis found in the writings of 
 Bishop Berkeley with the confusion perceptible in 
 Locke, we might fancy that we had advanced at 
 least a century onwards in the history of thought. 
 In Berkeley we have the first English philosopher 
 who obtained a clear insight into the problems of the 
 psychology of perception. And his solution of 
 some of these problems has not been improved 
 upon to the present day, except, perhaps, in the 
 manner of expression. We shall endeavour to give, 
 as briefly as possible, an outline of the psychological 
 doctrines of which he is the author. 
 
 Berkeley's Essay towards a New Theory of Vision 
 was his first published philosophical work, and may 
 serve us here as an introduction to his system. In 
 it we have Berkeley's_departure from th^ crude 
 dualismjaf _practical lif^^nd his theory -of the man- 
 ner in which that dualism is established. The fol- 
 lowing are the positions which he takes and defends : 
 
 " (1.) Distance, or the fact of an interval between 
 two points in the line of vision-^in other words, 
 externality in space, in itself invi_sible — is, in all 
 cases in which we appear to see it, only suggested 
 to our imagination- by certain visible phenomena 
 and visu^sensationSj- which are its arbitrary-signs. 
 
PSYCHOLOGY OF COGNITION. 
 
 117 
 
 " (2.) Magnitude, or the external space that ob- 
 jects occupy, is absolutely invisible ; all that we can 
 see is merely a greater or less quantity of colour, 
 and our apparently visual perceptions of real mag- 
 nitude are interpretations of the tactual meaning of 
 colours and other sensations in the visual organ. 
 
 '^ (3.) The situation of objects, or their relation to 
 one another in space, is invisible ; all that we can 
 see is variety in the relations of quantities of colour 
 to one another, our supposed pure vision of actual 
 locality being an interpretation of visual signs. 
 
 " (4.) There is no sensible object common to sight 
 and touch ; space or extension, which has the best 
 claim to this character, and which is nominally the 
 object of both, is specifically as well as numerically 
 different in each, externality in space or distance 
 being absolutely invisible, while size and situation 
 as visible have nothing in common with size and 
 situation as tangible. 
 
 *' (5.) The explanation of the unity which we attri- 
 bute to sensible things, as complements of visible 
 and tangible qualities of one and the same sub- 
 stance, is contained in the theory that visible ideas 
 and visual sensations, arbitrary signs in a Divine 
 Language, are significant of distances and of the 
 real sizes and situations of distant things; while 
 the constant association in nature of the two worlds 
 of vision and touch has so associated them in our 
 thoughts, that visible and tangible extension are 
 habitually regarded by us as specifically, and even 
 numerically one. 
 
 CHAP. III. 
 SECT. IV. 
 
Ii8 
 
 THE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. IV. 
 
 Suhstance 
 of theory. 
 
 5C 
 
 \/ 
 
 Objects of 
 knowledge. 
 
 " (6.) The proper object of geometry is the kind 
 of Extension given in our tactual experience, and 
 not the kind of Extension given in our visual ex- 
 perience, and neither real planes can be seen — 
 real extension in all its phases being invisible, and 
 colour in its modifications of quantity being the only 
 proper object of sight, while colour being a pure 
 sensation cannot exist extra-organically in space." * 
 
 § 62. The substance of the New Theory may be 
 thus expressed: The perception by sight of dis- 
 tance^ magnitude, and direction, or of bodies as 
 existing without us and being extended, is not an 
 original but an acquired power. In sight we are 
 conscious only of colour, but as this sensation and 
 various tactual sensations are frequently experi- 
 enced contemporaneously, we fancy the object of 
 sight is identical with the object of touch. And 
 since it is the tactual qualities of bodies in which 
 we have the greatest practical interest, visible 
 colour and extension soon, by association, become 
 simply signs to call up the tactual qualities of 
 bodies supposed to be more real. There are some 
 points in connection with this theory which may 
 offer matter for criticism hereafter, but in the mean- 
 time, we shall take a farther view of Berkeley's 
 psychology By quoting from his '^Principles of 
 Human Knowledge,'' part i. : 
 
 (1.) " It is evident to anyone who takes a survey 
 of the objects of human knowledge, that they are 
 either ideas actually imprinted on the senses; or 
 
 * Prof. Frazer's analysis in his edition of * ' Berkeley." 
 
PSTGHOLOGY OF COGNITION. 
 
 119 
 
 else suck as are perceived by attending to tlie 
 passions and^ operations of tlie mind; orjlastly, 
 ideas formed by help of memory and imagination — 
 either compounding, dividing, or barely represent- 
 ing those originally perceived in the aforesaid ways. 
 By sight, I have the ideas of light and colours, with 
 their several degrees and variations. By touch, I 
 perceive hard and soft, heat and cold, motion and 
 resistance, and of all these more or less either as to 
 quantity or degree. Smelling furnishes me with 
 odours, the palate with tastes ; and hearing conveys 
 sounds to the mind in all their variety of tone and 
 composition. And as several of these are observed 
 to accompany each other, they come to be marked 
 by^one_iiame. Thus, for example, a certain colour, 
 tastei^sniell, figure, and consistence having been 
 observed to go together, are accounted one distinct 
 thing, signified by^jthe name aj)ple 
 
 (2.) "But besides all that endless variety of ideas 
 or objects of knowledge, there is likewise something 
 which knows or perceives them, and exercises divers 
 operations, as willing, imagining, remembering, 
 about them. This perceiving, active being is what 
 I call mindy sj^irity soul or my sei?7'^B^y which words 
 I do not denote any one of my ideas, but a thing 
 entirely distinct from them, wherein they exist, or, 
 which is the same thing, whereby they are perceived 
 — for the existence of an idea consists in its beinof 
 perceived. 
 
 (3.) " That neither our thoughts, nor passions, nor 
 ideas formed by the imagination, exist without the 
 
 CHAP. III. 
 SECT. IV. 
 
 Knowing 
 mind. 
 
 \y 
 
 Objects 
 have men- 
 tal exist- 
 ence only. 
 
120 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. IV. 
 
 No matter. 
 
 mind, is what everybody will allow. And to me it 
 is no less evident that the various sensations or 
 ideas imprinted on the sense, however blended or 
 combined together (that is, whatever objects they 
 compose), cannot exist otherwise than in a mind 
 perceiving them. I think an intuitive knowledge 
 may be obtained of this by anyone that shall attend 
 to what is meant by the term exist when applied 
 to sensible things. The table I write on I say 
 exists, that is, I see and feel it; and if I were 
 out of my study I should say it existed, meaning 
 thereby that if I was in my study I might perceive 
 it, or that some other spirit actually does perceive 
 it 
 
 (7.) " From what has been said it is evident there 
 is not any other substance than spirit, or that which 
 
 perceives For an idea to exist in an unper- 
 
 ceiving thing is a manifest contradiction, for to have 
 an idea, is all one as to perceive ; that, therefore, 
 wherein colour, figure, &c., exist must perceive them, 
 hence it is clear there can be no unthinhing sub- 
 stance or substratum of those ideas. 
 
 (8.) " But, say you, though the ideas themselves 
 do not exist without the mind, yet there may be 
 things like them, whereof they are copies or re- 
 semblances, which things exist without the mind in 
 an unthinking substance. I answer, an idea can be 
 like nothing but an idea ; a colour or figure can be 
 
 like nothing but another colour or figure 
 
 Again I ask, whether those supposed original or ex- 
 ternal things, of which our ideas are the pictures or 
 
PSYCHOLOGY OF COGNITION. 
 
 121 
 
 representations, be themselves perceivable or no ? 
 If they are, then tliej are ideas, and we have gained 
 our point; but if you say they are not_, I appeal 
 to anyone whether it be sense to assert a colour is 
 like something which is invisible; hard or soft, 
 like something which is intangible ; and so of the 
 rest. 
 
 (9.) " Some there are who make a distinction 
 betwixt 'primary and secondary qualities. By the 
 former they mean extension, figure, motion, rest, 
 solidity or impenetrability, and number; by the 
 latter they denote all other sensible qualities, as 
 colours, sounds, tastes, and so forth. The ideas we 
 have of these we acknowledge not to be the re- 
 semblances of anything existing without the mind, 
 or unperceived, but they will have our ideas of the 
 primary qualities to be patterns or images of things 
 which exist without the mind, in an unthinking 
 substance which they call matter, therefore we are 
 to understand an inert, senseless substance, in which 
 extension, ngure, and motion do actually subsist, 
 /^ut jb is evident, from what we have already shown, 
 -tiiat extension, figure, and motion are only ideas 
 existing in the mind, and that an idea can be like 
 nothing but another idea, and that consequently 
 neither they nor their archetypes can exist in an 
 unperceiviug substance. Hence, it is plain that the 
 very notion of what is called matter or corporeal 
 snhstance involves a contradiction in it 
 
 (10.) " We perceive a continual succession of ideas, 
 some are anew excited, others are changed or 
 
 CHAP. III. 
 SECT. IV, 
 
 Distinc- 
 tion he- 
 tween 
 qualities 
 fallacioiis. 
 
 Spirit the 
 objective 
 cause of 
 ideas. 
 
122 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. IV. 
 
 Criticism. 
 
 Berlceley a 
 
 presenta- 
 
 tionist. 
 
 totally disappear. There is therefore some cause of 
 these ideas whereon they depend, and which pro- 
 duces and changes them. That this cause cannot be 
 any quality or idea is clear It must there- 
 fore be a substance; but it has been shown that 
 there is no corporeal or material substance; it 
 remains therefore the cause of ideas is an incorporeal 
 active substance or spirit.^' 
 
 § 63. We now proceed to point out some things in 
 Berkeleyanism worthy of remark. And, in the first 
 place, it must be admitted that Berkeley has not 
 carried his psychological analysis quite far enough. 
 When he says, " by sight we have ideas of colour, 
 &c./^ it is plain that he assumes the existence of our 
 sensive organism. And although, according to his 
 theory, the organism is composed, like all other 
 objects, of ideas, yet its existence should not be 
 assumed until it is shown how it is known. 
 
 There is another defect in Berkeley's analysis 
 which must be admitted. He was^not able to dis- 
 cover the error committed by Descartes and Locke 
 before him of supposing ideas to be distinct entities 
 coatained in a mind. He did not reach the dis- 
 covery that the mental object of consciousness is 
 identical with the mental activity. And con- 
 sequently there is a character of crudeness about his 
 theory which would have been avoided had he taken 
 a correct view of the relation between ideas and 
 mind. 
 
 § 64. Perhaps the greatest merit -of -Berkeley as 
 a psychologist is his complete overthrow of the 
 
PSYCHOLOGY OF COGNITION. 
 
 123 
 
 representative idealism found in Descartes and 
 Locke. The real objects whicli constitute tlie world 
 in whicli we live are ideas^ tliat is, are objects 
 known ; tbe ideas which are immediately known are 
 the real things which exist. The assumption of 
 some unknown, unthinking matter as the cause of 
 our ideas is unphilosophical and absurd. Ideas 
 cannot represent or resemble anything but ideas ; 
 qualities as known can have no resemblance to 
 matter unknown. The sensible objects which we 
 know are not representatives of any more real 
 matter underlying them ; they are the very things 
 which exist. 
 
 It cannot be objected to Berkeley's psychology 
 that because he denies the existence of insensible 
 matter he destroys the reality and permanence of 
 things. He believes that the things which he sees 
 and touches would exist whether he saw and touched 
 them or not; that they have a permanent existence 
 because they are always perceived, that is, they 
 always exist in the Divine Mind. The. problem is 
 to account for the permanent objective existence of 
 sensible things. Berkeley's predecessors did this by 
 postulating insensible matter ; Berkeley was success- 
 ful in his destructive arguments against the repre- 
 sentative idealism of his predecessors ; whether he 
 was equally successful in establishing his own posi- 
 tion remains to be seen. 
 
 § 65. There is probably to be seen in Berkeley's 
 reasoning an illustration of the tyranny of language 
 over thought. He sets out with the assumption 
 
 CHAP. III. 
 SECT. IV. 
 
 BerTcelet/s 
 thought 
 controlled 
 by Ian. 
 giULije. 
 
124 
 
 THE ELEMENTS OF THE 
 
 CHAP, III. 
 SECT. IV. 
 
 Confusion 
 in his use 
 of idea. 
 
 that everything we know is an idea ; and the very 
 word " idea" compels him to hold that it exists only 
 in a mind ; it is incongruous to think of ideas being 
 anywhere but in a mind. And since unknown, 
 insensible matter is seen by him to be inadequate 
 and contradictory as an hypothesis to account for 
 the permanence of sensible objects, he is driven by 
 his original view of the identity of ideas and things 
 to substitute for matter a mind in which ideas may 
 be contained when his or some other finite mind does 
 not perceive them. Had he commenced with a 
 different view of the nature of ideas ; had he seen 
 them to be not distinct entities capable of existence 
 in different minds, but identical with and insepara- 
 ble from the mental activity of his own consciousness, 
 he probably would have been led to a different con- 
 clusion. We observe also that there is in Berkeley 
 a trace of the confusion in the use of the word " idea" 
 which pervaded Locke. Colours, smells, tastes, are 
 ideas ; so are extension, figure, motion. Now after a 
 careful analysis, there can be nothing clearer than 
 that the sensation of smell or colour is quite different 
 from extension or any form of space. And to class 
 both under the common name " idea'' will almost 
 certainly lead to error. It has led Berkeley to the 
 conclusion tliat_ there is no eioternaUty of objects to 
 his mind except in the mind of some other being. 
 And objects generally have externality from finite 
 minds by virtue of their being contained in the 
 Infinite Mind. Now what is this but saying that 
 the Infinite Mind is practically identical with 
 
PSYCHOLOGY OF COGNITION. 
 
 125 
 
 space, in whicli all sensible objects are perceived ? 
 Thus Berkeley's most important conclusions, 
 regarding the non-existence of insensible matter, 
 regarding the existence of Infinite Mind, regarding 
 the nature of externality, and others, sprang from 
 an erroneous view regarding the nature of ideas, 
 and an indiscriminate application of the word " idea" 
 to things essentially different. But although in 
 the expression, and perhaps also in the meaning, 
 of his doctrines he is not free from error, it must 
 always be admitted that in his hands psychology 
 began to be characterised by that subtlety and 
 clearness of analysis which are so difficult of 
 attainment, and yet so essential to its taking a 
 position worthy of its importance in the circle of 
 the sciences. 
 
 Section V; 
 
 HUME (1711-1776). 
 
 § QQ. David Hume was the natural successor in 
 philosophy of Locke and Berkeley, and he carried 
 their principles to a logical conclusion. The same 
 clearness and acuteness of analytic power which we 
 observed in Berkeley are to be found in perhaps a 
 still greater degree in Hume. The publication of 
 his writings constituted a crisis in modern philosophy 
 which led his successors to go back to the considera- 
 tion of the premises from which modern philosophers 
 started, in order that they might avoid his conclu- 
 
 CHAP. III. 
 SECT. V. 
 
126 
 
 THE ELEMENTS OF THE 
 
 \ 
 
 CHAP. Ill, 
 SECT. V. 
 
 Hume's 
 doctrines. 
 
 Impres- 
 sions and 
 ideas. 
 
 Simple 
 and com- 
 plex per- 
 ception. 
 
 Character 
 and rela- 
 tions of 
 impres- 
 sions and 
 ideas. 
 
 sions. We shall give in his own words his most 
 important doctrines. 
 
 " All the perceptions of^the human mind resolve 
 themselves into two distinct lEinds^'wEch I shall 
 call impressions and ideas. The difference betwixt 
 these consists in the degrees of force and liveliness 
 with which they strike upon the mind, and make 
 their way into our thought and consciousness. 
 These perceptions which enter with most force and 
 violence, we may name impressions ; and under this 
 name, I comprehend all our sensations, passions, and 
 emotions, as they make their first appearance in the 
 soul. By ideas I mean the faint images of these in 
 thinking and reasoning.^^ * 
 
 "There is another division of our perceptions, 
 which it will be convenient to observe, and which 
 extends itself both to our impressions and ideas. 
 This division is into simple and complex. Simple 
 perceptions, or impressions and ideas, are such as 
 admit of no distinction or separation. The complex 
 are the contrary to these, and may be distinguished 
 into parts. Though a particular colour, taste, and 
 smell, are qualities all united together in this apple, 
 it is easy to perceive they are not the same, but 
 are at least distinguishable from each other/^ f 
 
 "All our simple ideas in their first appearance 
 are derived from simple impressions which are 
 correspondent to them, and which they exactly 
 represent.'-' J 
 
 "Impressions may be divided into two kinds, 
 
 * Works, i., p. 15. f lb. i., p. IG. % lb. i. p. 18. 
 
PSYCHOLOGY OF COGNITION. 
 
 127 
 
 those of sensation and those of reflection. Tlie_first 
 kind arises on tlie soul originally from unknown 
 causes. ^TEe second is derived, in a great measure, 
 from our ideas, and that in the following order. An 
 impression first strikes upon the senses and makes 
 us perceive heat or cold, thirst or hunger, pleasure 
 or pain, of some kind or other. Of this impression 
 there is a copy taken by the mind, which remains 
 after the impression ceases; and this we call an 
 idea. This idea of pleasure or pain, when it returns 
 upon the soul, produces the new impressions of 
 desire and aversion, hope and fear, which may 
 properly be called impressions of reflection, because 
 derived from it. These again are copied by the 
 memory and imagination and become ideas." * 
 
 With reference to the suhstratiim of bodies, Hume 
 a^ks " whetherthe id¥a of suhstance be derived 
 from the impressions of sensation or reflection ? If 
 it be conveyed to us by our senses, I ask which of 
 them, and after what manner ? If it be perceived 
 by the eyes, it must be a colour ; if by the ears, a 
 sound ; if by the palate a taste, and so of the other 
 senses. But I believe some will assert that sub- 
 stance is neither a colour, a sound, nor a taste. The 
 idea of substance must therefore be derived from 
 an impression of reflection if it really exist. But 
 the impressions of reflection resolve themselves into 
 our passions and emotions, none of which can pos- 
 sibly represent a substance. We have, therefore, 
 no idea of substance distinct from that of a collec- 
 "orfesii,, p. 22. 
 
 CHAP. III. 
 SECT. V. 
 
 Substance f 
 what. 
 
128 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. V. 
 
 Extension 
 
 tion of particular qualities, nor liave we any other 
 meaning when we either .talk or reason concerning 
 \i^. The idea of a substance, as well as that of a 
 mode, is nothing but a collection of simple ideas^ 
 that are united by the imagination and have a par- 
 ticular name assigned them, by which we are able 
 to recall, either to ourselves or others, that collec- 
 tion. But the difference betwixt these ideas consists 
 in this, that the particular qualities which form a 
 substance, are commonly referred to an unknown 
 something f in which they are supposed to inhere ; 
 or at least supposed to be closely and inseparably 
 connected by the relations of contiguity and causa- 
 tion/'* 
 
 '^Upon opening my eyes and turning them to 
 the surrounding objects, I perceive many visible 
 bodies; and upon shutting them again, and con- 
 sidering the distance betwixt these bodies, I acquire 
 the idea of extension. As every idea is derived 
 from some impression which is exactly similar to it, 
 the impressions similar to this idea of extension 
 must either be some sensations derived from the 
 sight, or some internal impressions arising from 
 these sensations." It is not the latter, therefore it 
 must be the former. '^ My senses convey to me 
 only the impressions of coloured points, disposed iu 
 a certain manner. Hence we may conclude with 
 certainty that the idea of extension is nothing but 
 a copy of these coloured points and of the manner 
 of their appearance."''t 
 
 * Works, i., p. 32. f lb. i., p. 53. 
 
PSYCHOLOGY OF COGNITION. 
 
 129 
 
 Thus Hume concludes that extension is an idea 
 abstracted from particular impressions of sense, the 
 peculiarities of colour, &c., being left out of view, 
 and attention paid only to the disposition of points. 
 
 "As it is from the disposition of visible and 
 tangible objects we receive the idea of space, so 
 from the succession of ideas and impressions we 
 form the idea of time; nor is it possible for time 
 alone ever to make its appearance, or be taken 
 notice of by the mind/^* 
 
 "We have no idea of space or extension but 
 when we regard it as an object of our sight or 
 feeling. So the indivisible movements of time 
 must be filled with some real object or existence, 
 whose succession forms the duration, and makes it 
 to be conceivable by the mind.^'^f 
 
 "As to those impressions which arise from the 
 senses, their ultimate cause is, in my opinion, per- 
 fectly inexplicable by human reason, and it will 
 always be impossible to decide with certainty, 
 whether they arise immediately from the object, or 
 are produced by the creative power of the mind, or 
 are derived from the Author of our being/^ J 
 
 " The opinion of the continued existence of body 
 depends on the coherence and constancy of certain 
 impressions.'^ § 
 
 § 67. Having given the important psychological 
 doctrines of Hume in his own language, we now 
 proceed to make such remarks upon them as seem 
 
 Works, i., p. 54. 
 
 + lb. i., p. 59. 
 § lb. i., p. 246. 
 
 X lb. i., p. 113. 
 K 
 
 CHAP, III. 
 SECT V. 
 
 \/ 
 
 Time. 
 
 Space. 
 
 Cause of 
 phenome' 
 na inex- 
 plicable. 
 
 Objectivity 
 explained. 
 
I30 
 
 THE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. V. 
 
 Doctrines 
 
 % 
 
 called for. But before doing so we shall arrange 
 more systematically tlie doctrines to whicli we pro- 
 pose to refer. 
 
 (1.) All our simple ideas are copies of some im- 
 pressions previously experienced. No idea, there- 
 fore, can be found in the mind which has not, more 
 or less proximately, been copied from some im- 
 pression. 
 
 (2.) There is no idea in the mind of suhstance, 
 either corporeal or spiritual, except in so far as 
 substance means a collection of qualities or of 
 impressions and ideas. This doctrine follows im- 
 mediately from the preceding, since substance is 
 admitted to be neither a sensation nor the copy of 
 a sensation. 
 
 (3.) Extension and duration, or space and time, 
 are ideas abstracted from sensations. The idea of 
 extension is a copy of the co-existent points of 
 visible or tactual impressions. The idea of duration 
 is a copy of the continuity of sensations. But as 
 abstract ideas have no existence independent of the 
 concrete impressions from which they are abstracted, 
 it follows that space and time have no existence 
 independently of extended or continuing impres- 
 sions. 
 
 (4.) It is impossible to infer with certainty the 
 cause of sensations. The metaphysical hypothesis of 
 an insensible substance as the cause of sensations, 
 has been shown to be contradictory. And it is like- 
 wise impossible to infer, with Berkeley, that the 
 Divine Mind is that cause. 
 
PSYCHOLOGY OF COGNITION. 
 
 131 
 
 (5.) If it be asked how objects, tbat is, collections 
 of impressions, appear to have a continued and in- 
 dependent existence, the only answer that can be 
 given is, that the impressions composing them are 
 seen to have a certain coherency and constancy of 
 recurrence which leads the mind to attribute to 
 them independent existence. 
 
 § 68. The first of these principles held by Hume 
 is only a re-statement in more definite form of what, 
 long before, had been held by Locke. But in 
 Hume's hands it became a powerful instrument of 
 destruction. We have no ideas except those that 
 are copies of some antecedent impressions. 
 
 But matter as a substratum is not given in any sen- 
 sation ; neither is mind as the subject of ideas ; neither 
 is causal efficiency, except merely that one impres- 
 sion or idea regularly precedes another ; neither is 
 God. Therefore we have no idea of matter, or mind, 
 or cause, or God. This ought to be Hume's con- 
 clusion ; but he actually concludes that we cannot 
 infer the existence of these unknown things. This 
 principle, drawing with it, as it did, such sceptical 
 conclusions, was most important in stimulating Reid 
 and Kant to inquire into its accuracy. "Vf e shall, 
 therefore, leave the criticism of it to them, merely 
 pointing it out now as the principle which, by its 
 consequences, led to the greatest revolution in the 
 history of philosophy. 
 
 § 69. We now consider one of Hume's sceptical 
 conclusions. He holds that we have no idea of 
 ■substance except as a collection of qualities or im- 
 
 K 2 
 
 CHAP. III. 
 SECT. V. 
 
 Criticism. 
 
 Sceptical 
 results. 
 
 Huyne's 
 doctrine of 
 substance. 
 
13- 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. V. 
 
 pressions; no idea of it as the unknown cause of our 
 known sensations. He holds, also, that it is impos- 
 sible to infer conclusively that our simple sensations 
 are caused by the Divine Mind. But_, at the same 
 time, there is an admission that sensations must have 
 an origin somehow and somewhere. Sensations, he 
 says, ''arise on the soul originally from unknown 
 causes. An impression first strikes upon the senses 
 and makes us perceive heat or cold," &c. There is 
 here, consciously or unconsciously, an admission that 
 there is something beyond, or behind our sensations, 
 which we cannot indeed hnoiu, but the existence of 
 which we cannot deny. Connected with the origin of 
 our sense-knowledge — that is, connected with the 
 real existence of things — there is, Hume admits, a 
 problem to be solved, which, however, he thinks in- 
 soluble. " An impression strikes upon our senses.^^ 
 Take almost any one of these words, and you cannot 
 understand its meaning without taking for granted 
 that very unhioivn which Hume wished to banish. 
 Impression implies some receptive thing upon which 
 some other thing presses, so as to leave its mark. 
 What is that other thing which makes the impres- 
 sion upon the senses ? Hume cannot answer ; but 
 he cannot employ ordinary language, he cannot 
 invent a language which does not imply that beyond 
 the sphere of our immediately known sensations there 
 is another sphere which we are bound to believe in 
 but may not completely know. Hume started with 
 the assumption that we have no ideas but what are 
 copies of sensations, and the sceptical conclusions to 
 
PSYCHOLOGY OF COGNITION. 
 
 133 
 
 whicli he was led are tlie reductio ad ahsurdum of his 
 principle. His principle landed him in a conflict 
 with beliefs of which he could not rid himself, and 
 he certainly showed great fortitude in throwing over- 
 board those beliefs for the sake of logical consistency. 
 But it is questionable if he was really sincere in 
 doing so, and there is some reason for supposing that 
 his design was simply to show the absurd conclusions 
 to which his predecessor's principles naturally led. 
 This at least he did, and did it with remarkable 
 effect. 
 
 § 70. Hume's view of the origin of the idea of ex- 
 tension must now be referred to. As he was not at 
 liberty to admit any idea which was not a copy of a 
 sensation, and as he could not deny that we have an 
 idea of extension, he was bound to show that it was a 
 copy of some sensation. He accordingly assumed 
 that sensations or impressions, as he called them, 
 were extended ; then abstracted his mind from the 
 quality of the sensation, as colour, &c.; then as the 
 result of the abstraction appears the idea of pure 
 extension. And as the idea is a copy of the sensation 
 omitting the particular colour or tactual quality, it 
 follows, of course, that the idea is extended. But as 
 it is an abstract idea, it can have no existence apart 
 from the concrete sensation from which it was 
 abstracted. One would have supposed that the in- 
 congruity of making an idea a copy of an extended 
 thing would have been sufficient to make Hume 
 abandon his principle altogether. But no ; with a 
 pertinacity worthy of a better cause he determines 
 
 CHAP. III. 
 SECT. V. 
 
 Extension. 
 
134 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. V. 
 
 General 
 view of 
 psycholo- 
 gical 'prol)- 
 lems. 
 
 that^ come wliat will, lie will adhere to liis principle. 
 His doctrines^ tliat tlie idea of extension is a copy 
 from a sensation^ tliat space and time are abstrac- 
 tions from concrete experiences, will be criticised 
 hereafter.* 
 
 § 71. As the scepticism of Hume formed such an 
 important crisis in the history of modern philosophy, 
 and as it is the natural conclusion of all that went 
 before, it may be as well to present in a brief form 
 a view of the important problems which had hitherto 
 occupied the attention of psychologists, and the ways 
 in which their solution was attempted. The diagram 
 on the next page is an attempt to illustrate, in a 
 rough way, the problems which psychologists have 
 set themselves to solve. Let the circle R, 0, H, T, S, 
 with I in the centre, represent the mind and its 
 sensations ; R, indicating resistance, C, colour, H, 
 hardness, T, taste, S, smell. I indicates the ego or 
 subject of consciousness. 
 
 The capital letters R, C, &c., indicate actual 
 sensations, and, since they are felt in the body, B, E, 
 the circumscribed circle, may represent the extension 
 of the organism. The small circle to the left hand, 
 r, c, h, t, s, indicates the mind in a state of reflection, 
 and each of these letters stands for the representative 
 or the idea of the sensation indicated by the corre- 
 sponding capital. The circle to the right hand, having 
 in the centre, indicates the object, supposed to 
 have independent existence, and consisting of the 
 qualities R^, C^, &c.,all comprehended in E^, ]E^, objec- 
 * See § 89. 
 
P8YCS0L0GY OF COGNITION. 
 
 135 
 
 tive extension. The small circle at the extreme 
 right may represent the unknown matter, consisting 
 of unknown powers, r^, c^, &c., corresponding to the 
 known qualities, R^, C^, &c., which constitute the 
 object of perception. 
 
 § 72. Now, in examining the problems connected 
 with the process of knowing and the objects of know- 
 ledge, there have been adopted, as we have pointed 
 out, two methods. According to the first of these, 
 the continuous and independent existence of the 
 object is assumed, and the problem is to explain 
 the relation between and I, between the extended 
 object and the perceiving mind. And as it is also 
 assumed that I and are so utterly different in 
 nature that the former cannot know the latter, it 
 becomes necessary to interpose between them some 
 intermediate and representative idea. Hence, the 
 sensations E, C, H, &c., or the revived sensations r, c, 
 h, &c., or some combinations of them, are thought 
 to be representatives of the object and its qualities. 
 But after a more careful analysis, it comes to be seen 
 that some of the qualities, such as C^, H^, T^, S^, are 
 really identical with sensations C, H, T, S, and when 
 this discovery is made, there must be a correction of 
 
 CHAP. III. 
 SECT. V. 
 
 Methods of 
 
 studying 
 
 them. 
 
 Represen- 
 tative 
 theory. 
 
136 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. V. 
 
 Modified. 
 
 Over, 
 thrown. 
 
 the representative theory. C, colour, is purely sub- 
 jective, and so are H, T, S, therefore there are no 
 qualities C^, H^, T^, S^, to be represented, nothing bub 
 certain unknown powers, c^, h^, t^, s^, consequently the 
 sensations C, &c., which are immediately known, are 
 made to represent these unknown powers. But here 
 another difficulty presents itself. How can you say 
 that something which is in itself utterly unknown is 
 represented by something that you know ? And, 
 especially, how can you maintain that ideas of your 
 mind are ideas of an unknown and unknowing 
 matter ? These are the questions that Berkeley asks, 
 and by them overturns the representative theory. 
 The sensations R, C, &c., are not representatives at 
 all ; they are the real things which exist. They are 
 identical with R^, C^, &c., the distance and externality 
 being only apparent not real. Scepticism regarding 
 matter and space, begun in Berkeley, is continued 
 and extended in Hume. All knowledge comes 
 through sensation. But matter is not a sensation, 
 neither is cause, neither is spirit, therefore these 
 things do not exist. There are only the two series 
 of sensations and ideas governed by certain laws. 
 Thus, psychology, beginning with the assumption of 
 practical dualism, is compelled to make use of a 
 theory of representation to explain its difficulties, 
 finds this theory unsatisfactory, and terminates in 
 scepticism. As the representative theory played 
 such an important part in psychology from Descartes 
 to Hume, it may be serviceable to us to give some 
 attention to the nature of representation and the 
 
PSYGEOLOGY OF GOGNITION. 
 
 137 
 
 use which has been properly or improperly made 
 of it. 
 
 § 73. Turning to the diagram in § 71 it is proper 
 to say that c represents C ; a revived sensation re- 
 presents correctly and more or less vividly the 
 original sensation of which it is a revival. But 
 suppose an object of perception, say an orange, lies 
 before us. A certain figured colour is seen, called 
 by Locke and others an idea. This idea represents 
 the object. Now 'this use of the word represent is 
 utterly confusing and inaccurate. For what does it 
 mean ? It means that the sensation C represents C^, 
 4- r + t + s ; or that the sensation of colour repre- 
 sents the quality of colour plus the other possible 
 and imagined sensations of resistance, smell, taste, &c. 
 which we believe we may experience from the orange. 
 Now it may be quite correct to say that the sen- 
 sation C calls up before consciousness by the power 
 of association certain other revived sensations which 
 have previously occurred in the same group with C ; 
 it is quite incorrect to say that C represents them. 
 A third use of the principle of representation makes 
 C represent C^, the sensation represent the quality. 
 But the truth is that the sensation is the quality as 
 far as we know it. Sensations associated together 
 and, by an organic process, projected into space are 
 the objects which we hnow. It may be said, in the 
 fourth place, that the sensation C represents the 
 unknown power c^, and this is quite as inaccurate a 
 use of the word as any of the rest, as has been 
 already shown. Thus in the first and only proper 
 
 CHAP. III. 
 SECT. V. 
 
 Different 
 meanings 
 of repre- 
 sentxition. 
 
138 
 
 TEB ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. V. 
 
 Ground of 
 reaction. 
 
 use of tlie word represent, it raeans both to stand 
 for and resemble; in tbe second it means to be 
 associated witb. so as to bring into consciousness ; in 
 the third it expresses the result of an organic illusion ; 
 and in the fourth it indicates an inference which we 
 make regarding the cause of our sensations. The 
 impropriety of regarding ideas as representatives 
 in any of these senses except the first was clearly 
 perceived by both Berkeley and Hume; and the 
 errors of these philosophers, if such there are, must 
 be looked for, therefore, in their views of the nature 
 or origin of ideas. The former thought that all 
 ideas, that is, objects of knowledge, must, as being 
 ideas, exist in some mind; the latter maintained 
 that all ideas are copies of some sense impression. 
 Hence the idealism of the former and scepticism of 
 the latter. 
 
 § 74. The conclusion of Berkeley and Hume may 
 be regarded as the reductio ad absurdum of represen- 
 tative idealism g,s found in Descartes and Locke. 
 But in these conclusions there was something un- 
 satisfying to the human mind. People can scarcely 
 bring themselves to think that the objects which 
 they perceive have or involve no reality except the 
 fact of their being perceived. Nor is it easy to 
 think that space, or the externality of objects with 
 reference to our minds, means simply the possibility 
 of being perceived by another mind. It was there- 
 fore to be expected that there would be a reaction 
 against the conclusions of Berkeley and Hume ; and 
 that that reaction would seek to establish — first, the 
 
PSYCHOLOGY OF COGNITION. 
 
 139 
 
 permanent and independent existence of a non-ego 
 other than a mental one ; and second, the existence 
 of ideas which are not merely copies of sensations. 
 By the efforts of Keid and Kant this was attempted. 
 
 Section YI. 
 EEiD (1710-1796). 
 
 § 75. Reid, like many other people of his time, 
 was greatly shocked at the sceptical conclusions 
 drawn by Berkeley and Hume, and he set himself 
 with great ardour to refute the system from which 
 he believed them to follow. The conclusions that 
 there is no matter and no mind, that all the objects 
 in the universe are nothing but floating impressions 
 and ideas, were so utterly repugnant to his practical 
 good sense, and so utterly repugnant to the ordi- 
 nary beliefs of mankind in general, that he resolved 
 to see whether some foundation for philosophy could 
 not be laid upon which it would be possible to build 
 more securely the structure of human knowledge 
 and belief. To this task Reid brought a great deal 
 of candour and honesty, a fair amount of learning, 
 and a great deal of good sense. 
 
 But unfortunately he did not understand either 
 Berkeley or Hume, and he was not at all clear as to 
 what position he ought to take up in order success- 
 fully to refute them. He resolved to appeal from 
 the philosophers to the common sense of mankind, 
 which is a more or less satisfactory appeal accord- 
 ing to what is meant to be included in the term 
 
 CHAP. III. 
 
 SECT. vr. 
 
 Reid 
 shocTced, 
 
140 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VI. 
 
 Reid 
 militant. 
 
 Reid 
 
 versus 
 
 ideas. 
 
 common sense. G-enerally speaking, he appears to 
 mean bj it that practical good sense which leads 
 men to trust to the testimony of their senses, and 
 to believe in the existence of the world and a variety 
 of other things. Sometimes, however, he gives it 
 a more scientific meaning, and describes the prin- 
 ciples of common sense as those beliefs which result 
 from the constitution of our nature, and which are 
 necessary and universal. Then taking his stand 
 upon these principles, he thought that he was able 
 to defy the most insidious attacks of the sceptic. 
 Like the good knight, FitzJames, he addressed his 
 foes, the idealistic philosophers : — 
 
 " Come one, come all, this rock shall fly 
 From its firm base as soon as I." 
 
 But, unfortunately, it was not long before he 
 went over to the camp of the enemy, cut his con- 
 nection with his first friends, the men of common 
 sense, and began to philosophise just as recklessly 
 as any that had gone before him. 
 
 § 76. We must now proceed to consider what it 
 was that he accomplished or attempted in the in- 
 terest of psychological science. And at the outset 
 we observe with satisfaction that he noticed the 
 improper use which his predecessors had made of 
 the word"idea.'' He saw that there was no mental 
 object numerically different from a mental activity ; 
 that the act of conceiving and the mental concept 
 were really identical, being the same thing looked 
 at from different sides. Consequently, when he 
 
PSYCHOLOGY OF COGNITION 
 
 141 
 
 speaks of ideas or any other mental objects, lie 
 considers them as equivalent to mental activities 
 or states. He brought into prominence also the 
 fact, wbicli Berkeley Lad clearly pointed out before 
 him, that the ideas or phenomena of the mind do 
 not at all resemble the qualities which he believed 
 to exist outside of him and to constitute the material 
 world. There can be no resemblance between the 
 sensation of colour and the objective quality which 
 causes it; nor between the sensation of touch or 
 pressure and the objective hard and extended 
 body which occasions it. Thus thought Eeid; 
 and in establishing this position he believed that 
 he had overthrown the idealistic hypothesis. If 
 there are no ideas in existence except mental 
 activities, and if these bear no resemblance to 
 qualities of matter, how can there be any pos- 
 sibility of reasoning from those mental pheno- 
 mena to either the existence or the non-exist- 
 ence of unknown material qualities ? Thus Reid 
 pronounced the demonstration of the existence of 
 a material world, upon principles of idealism, to 
 be impossible ; equally impossible was the demon- 
 stration of its non-existence. And having thus 
 shown the futility of the method of demonstration 
 as applied to the problems of the psychology of 
 perception, he took refuge in the instinctive beliefs 
 of mankind from that scepticism in which he 
 believed the principles of idealism terminated. 
 Thus far we have considered Reid as a destructive 
 thinker, overturning the false positions of his pre- 
 
 CHAP. III. 
 SECT. VI. 
 
142 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VI. 
 
 Percep- 
 tion. 
 
 Colour. 
 
 decessors ; we must now study his efforts towards 
 the establislimeiit of a true tlieory of perception. 
 
 § 77. '' If/' says Reid, ''we attend to that act of 
 our mind which we call the perception of an external 
 object of sense, we shall find in it these three 
 things: — First, some conception or notion of the 
 object perceived ; secondly, a strong and irresistible 
 conviction and belief of its present existence ; and 
 thirdly, that this conviction and belief are 
 immediate, and not the effect of reasoning.'^* And 
 again, when examining the sense of touch, he finds 
 that his conception of hardness is unlike any sensation 
 and therefore not an idea of sensation ; and also that 
 the belief of the existence of hardness cannot be the 
 result of any comparison of ideas or reasoning, he 
 concludes thus : — '' What shall we say, then, of this 
 conception and this belief, which are so unaccount- 
 able and so untractable? I see nothing left but 
 to conclude that, by an original principle of our 
 constitution, a certain sensation of touchboth suggests 
 to the mind the conception of hardness and creates 
 the belief of it : or in other words, that this sensation 
 is a natural sign of hardness.'^f In speaking of 
 colour, he says : — " The common language of man- 
 kind shows evidently that we ought to distinguish 
 between the colour of a body, which is conceived to be 
 a fixed and permanent quality in the body, and the 
 appearance of that colour to the eye, which may be 
 varied a thousand ways, by a variation of the light, 
 of the medium, or of the eye itself. The permanent 
 * Hamilton's "Reid," i., p. 258. t Hamilton's "Reid," i., p. 121. 
 
PSYCHOLOGY OF COGNITION. 
 
 143 
 
 colour of the body is tlie cause whicli, by the media- 
 tion of various kinds or degrees of light and of 
 various transparent bodies interposed, produces 
 
 all this variety of appearances The ideas 
 
 of sight come to be associated with and readily to 
 suggest thiugs external and altogether unlike them. 
 In particular, that idea which we have called the ap- 
 ^earance of colour , suggests the conception and belief 
 of some unlmown quality in the body which occasions 
 the idea, and it is to this quality, and not to the idea 
 that we give the name of colour/'* Eeid's account of 
 the perception of the primary qualities is substan- 
 tially the same as of the secondary. An impression 
 is made upon the retina of the eye, or a tactual 
 sensation is felt in the hand ; and these severally 
 suggest visible and tangible figure and extension by 
 some instinctive principle of our constitution which 
 we cannot explain and cannot resist. 
 
 § 78. Arranging the foregoing doctrines more 
 systematically, the following appear to be the 
 essential principles of his theory of perception : — 
 
 (1.) Qualities as they exist in bodies are, in them- 
 selves, absolutely unknown . This is true both of the 
 secondary and primary qualities, since no sensation 
 or idea of which we can be conscious has the slight- 
 est resemblance to either the one or the other. 
 
 (2.) The only objects which we can know are 
 sensations or ideas, but these are not to be distin- 
 guished from the mental acts which they constitute. 
 
 (3.) These sensations or ideas are of various kinds ; 
 
 I* Hamilton's " Reid," i., p. 137. 
 
 CHAP. III. 
 SECT. VI. 
 
 Primary 
 qualities. 
 
 Doctrines 
 arranged. 
 
144 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VI. 
 
 Beid's de- 
 parture 
 from, com- 
 mon belief. 
 
 and, by an original principle of our constitution 
 whicli we cannot explain^ suggest the conception of 
 some corresponding objective but in itself unknown 
 quality, and create in us a belief of its existence. 
 This suggestion of the conception and belief of th& 
 unknown quality is what Reid means by perception. 
 
 (4.) The suggestion, by the sensation, of the con- 
 ception and belief of the quality, is immediate, that 
 is, the mind passes from the " sensation to the con- 
 ception and belief of the quality without the 
 medium of any process of reasoning, but by an 
 instinctive and irresistible principle of our constitu- 
 tion. We have not been able to find in Reid a 
 single passage in which immediate means anythiog 
 but this. 
 
 § 79. We can now point out the differences between 
 Reid and his predecessors, and form an estimate of 
 the value of his attempt to advance psychological 
 science. We have already stated that he professed 
 to adhere to the generally-received beliefs of man- 
 kind, but that he soon departed from the stand- 
 point of men of common sense. The qualities of 
 bodies are, according to him, unknown ; the appear- 
 ance of colour, for example, the phenomenal colour, 
 is known to us, and suggests the existence of an 
 unknown c^use which exists permanently in bodies. 
 But ask any ordinary man of common sense, and he 
 will tell you that the colour which he sees exists in 
 bodies. All men who are not philosophers believe 
 that the greenness and the redness of which they 
 become aware through sight really exists in bodies 
 
PSYCHOLOGY OF COGNITION. 
 
 145 
 
 outside of them, and tliey do not know the meaning 
 of a colour which cannot be seen. Reid tells them, 
 *^ Oh no ! my friends, your principles of common 
 sense are generally correct, and what you cannot 
 help but believe is generally true; but in this case 
 there is a slight mistake. What you see, the blue- 
 ness or the redness, is not the colour of bodies at 
 all ; it is nothing but an idea in your mind. The 
 real colour of bodies is something that you cannot 
 see ; an unknown quality whose existence is sug- 
 gested to you by that delusive appearance of colour 
 which you incorrectly believe to be in bodies.'" 
 There is reason to fear that Reid's friends of common 
 sense would think his doctrine, that the colour of 
 bodies is something invisible, rather paradoxical. 
 
 § 80, The principal differences between ordinary 
 men, Reid, and the idealistic philosophers whom he 
 opposes may be resolved into an ambiguity in the 
 use of language. Turning again to the diagram in 
 § 71, all men who are not philosophers look upon C^ 
 as the only colour which they know; they see it and 
 believe it exists in bodies. Reid tells them that 0^ is 
 really C, an idea, and that it is incorrect to call it a 
 colour. The real colour is c^, an unknown quality. 
 Reid's opponents, the philosophers, agree with Reid 
 in identifying C^ with C, but they say that C is the 
 colour and not c^. Here is only a difference in the 
 application of a name. But there are other differ- 
 ences of greater importance. 
 
 According to Reid, the sensations of which we 
 become aware through the organism necessarily 
 
 L 
 
 CHAP. III. 
 SECT. VI. 
 
 Philoso- 
 phical Ian. 
 guage am. 
 higuous. 
 
 Suggestion 
 of qualities 
 necessary. 
 
146 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VI. 
 
 Extension 
 not derived 
 from sen- 
 sation. 
 
 suggest external and otherwise unknown qualities,, 
 and, by tlie constitution of our nature, we cannot hut 
 believe in the existence of those qualities. To 
 attempt, therefore, either to prove or to disprove 
 their existence is absurd ; they are given to us by 
 a law of our nature more fundamental than any 
 process of reasoning we might employ. And any 
 system of philosophy which results in the subversion 
 of this natural and necessary belief must bo 
 fallacious either in its original premises or in somo 
 of its intermediate processes. 
 
 Thus to the scepticism of Hume, Reid opposed his^ 
 doctrine of the necessary suggestion and belief of 
 objective qualities. What is necessarily believed 
 cannot possibly be doubted; the existence of the 
 qualities of bodies is, by a necessity of our nature, 
 believed ; therefore Hume's scepticism is impossible. 
 Such was the reasoning of Reid; and if he could 
 make out the alleged necessity, there can be no- 
 question but his reasoning was correct. But,, 
 unfortunately for his position, both Berkeley and 
 Hume found it possible to doubt that which Reid 
 pronounced to be necessary, and the possibility of 
 an honest doubt is a clear disproof of an alleged 
 necessity. 
 
 Another ' doctrine of Reid's, which he himself 
 thought to be of great importance, was directed 
 against one of the premises of idealism. Since the 
 time of Locke it was an accepted maxim amongst 
 English psychologists that all our ideas originate in 
 sense. Upon the principle that there can be no idea 
 
PSYCHOLOGY OF COGNITION. 
 
 H7 
 
 wHicli is not tlie copy of a sensation, Hume founded 
 Ms sceptical conclusions. And Reid, therefore, saw 
 tlie importance of endeavouring to show the falsity 
 of this principle. He took the idea of extension as 
 an exjperimentiim crucis ; showed that none of our 
 sensations can be extended, while at the same time 
 it cannot be denied that we have a knowledge of 
 extension ; and then triumphantly asked where this 
 knowledge could come from. Since it could not 
 possibly come through sense, no sensation being 
 extended, the idealists, Reid thought, must find it 
 utterly impossible to explain its origin upon their 
 princip]es, while he himself had his instinctive 
 beliefs to fall back upon. Extension is suggested, 
 necessarily and inexplicably, by non-extended sensa- 
 tions, and it has an objective existence as a primary 
 and essential quality of bodies. 
 
 These two points, the necessity of believing in 
 the existence of objective qualities, and the origin of 
 our knowledge of extension or space, are thought by 
 Reid to be the most important parts of his philo- 
 sophy. But perhaps if he and his opponents, the 
 idealists, had understood one another better, there 
 would not have appeared to be such great differences 
 between them. 
 
 Note on Reid's Doctrine of Peeception. 
 
 A distinguished modern psychologist. Sir W. 
 Hamilton, has attempted to show that Reid 
 held, in reference to perception, the doctrines of 
 Natural Realism, which Hamilton himself professes 
 
 L 2 
 
 CHAP. III. 
 SECT. VI. 
 
 ^ 
 
148 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VI. 
 
 Is Beid a 
 Natural 
 Realist ? 
 
 to hold, and whicli he regards as of first importance. 
 In his twenty- third lecture of the Metaphysical 
 Course Hamilton sums up his examination of Eeid's 
 doctrine by pointing out four suppositions upon 
 which Reid must be held to be a Natural Realist. 
 These are : — (1) If he maintain that his immediate 
 perception of external things is convertible with 
 their reality ; (2) if he assert that, in his doctrine of 
 perception, the external reality stands to the per- 
 cipient mind face to face, in the same immediacy of 
 relation which the idea holds in the representative 
 theory of the philosophers; (3) if he declare the 
 identity of his own opinion with the vulgar belief, 
 as thus expounded by himself and the philo- 
 sophers ; • or (4) if he declare that his perception 
 affords us equal evidence of the existence of 
 external phenomena, as his consciousness affords us 
 of the existence of internal. And Hamilton adduces 
 quotations, which we shall examine, to show that all 
 these suppositions are fulfilled in Reid^s doctrine. 
 In support of the first and second, he adduces the 
 following : — " We have before examined the reasons 
 given by philosophers to prove that ideas, and not 
 external objects, are the immediate objects of per- 
 ception. We shall only here observe, that if 
 external objects be perceived immediately we have 
 the same reason to believe their existence as philo- 
 sophers have to believe the existence of ideas, while 
 they hold them to be the immediate objects of per- 
 ception.^' (" Works,'' p. 446.) 
 
 From this quotation, according to Hamilton, we 
 are to conclude that Reid holds that to be perceived 
 means the same as to exist, and that, in perception, 
 the external reality stands face to face to the per- 
 cipient mind in the same immediacy of relation as 
 
PSYCHOLOGY OF COGNITION. 
 
 149 
 
 the ideas of the philosophers stand to conscious- 
 ness. 
 
 A fair reading of the quotation should lead us, we 
 think^ to this conclusion : — that the immediate per- 
 ception of external objects is as sure a guarantee of 
 their existence as the consciousness of ideas is of 
 their existence. It is one thing to say that percep- 
 tion is a guarantee of existence or reality ; it is 
 another thing to say that perception is convertible 
 with existence or reality. The latter was said by 
 Berkeley, but Reid did not understand the doctrine 
 and never expressed it. All that Reid meant to say 
 was that we should place as implicit confidence in 
 our perception of external objects as philosophers 
 do in their consciousness of ideas. And none but 
 madmen or fools have ever doubted this. But in 
 saying this he asserts nothing whatever regarding 
 the character of perception. He tells us, however, 
 that external objects are the immediate objects of 
 perception, and here we appear to have something 
 said regarding the nature of perception. But the 
 question arises, What does Reid mean by immediate ? 
 There are two meanings of this term which it is of 
 importance for us to discriminate. The first of 
 these may be called the psychological meaning, and 
 in this sense the term is used by Hamilton. In this 
 sense immediate knowledge means knowledge in 
 which the object is present to consciousness itself and 
 not through the medium of any representation. The 
 second of these may be called the logical meaning, 
 and in this sense immediate knowledge means 
 hioivledge which is obtained directly without the 
 intervention of a process of proof or inference. Now 
 when Reid says that the objects of the external world 
 are the immediate objects of perception, we cannot 
 
 CHAP. III. 
 SECT. VI. 
 
 Immediate 
 perception, 
 xohat ? 
 
 Two mean, 
 ings of im. 
 mediate. 
 
150 
 
 THE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. VI. 
 
 decide whether he is a Natural Realist, until we 
 have determined whether he uses the term in its 
 psychological or in its logical significance. He 
 might use the term in its latter sense without 
 having the most remote idea of the meaning of that 
 immediate knowledge which is asserted in Natural 
 Realism. A few quotations from his writings will 
 show in what sense he uses it. 
 
 " In the meantime, I beg leave to think with the 
 vulgar, that when I remember the smell of the 
 tuberose, that very sensation which I had yesterday 
 and which has now no more any existence^ is the 
 immediate object of my memory.-" ("Works," p. 
 106.) It is simply impossible that immediate can 
 be used here in the 'psychological sense, since the 
 so-called immediate object now no longer exists. 
 And immediately below this passage he explains 
 himself in such a way that we must conclude that 
 he had the logical meaning of the word in his mind. 
 " If you ask me,^^ he says, " why I believe that the 
 smell exists, I can give no other reason, nor shall 
 ever be able to give any other than that I smell it. 
 If you ask me why I believe that it existed yester- 
 day, I can give no other reason but that I remember 
 it.^^ Manifestly immediate y of the first quotation, 
 is identical in meaning with I can give no other 
 reason, of the second. That is, it is used in its 
 logical sense. Again, in his essays upon the Intel- 
 lectual Powers, Reid says : " If, therefore, we attend 
 to that act of our mind which we call the percep- 
 tion of an external object of sense, we shall find in 
 it these three things : — First, some conception or 
 notion of the object perceived ; Secondly, a strong 
 and irresistible conviction and belief of its present 
 existence; and, Thirdly, that this conviction and 
 
PSYCHOLOGY OF COGNITION. 
 
 151 
 
 belief are immediate and not the effect of reasoning .''^ 
 {" Works/' p. 258.) Here Keid himself indicates as 
 clearly as possible that tbe term immediate is used 
 in its logical sense. And in explaining tbe tbird of 
 the above points be enlarges upon tbe fact tbat no 
 process of reasoning is involved in perception. But 
 throughout his writings we have nowhere been ^fe 
 to discover the idea of psychological immedim 
 which is involved in the doctrine of Natural 
 E-ealism. 
 
 Hamilton's third point is that Reid declares the 
 identity of his own opinion with the vulgar belief. 
 What can be established by this it is difficult to 
 see. Berkeley declared the identity of his opinion 
 with the vulgar belief; and yet Reid is very far 
 away from the position of Berkeley. Reid declared 
 the identity of his opinion with the vulgar belief, 
 and yet he maintained, contrary to vulgar belief, 
 that the appearance or idea of colour is in the eye 
 ("Works," p. 137) and that the colour of an external 
 object is something unseen and unJcnown ("Works," 
 p. 138). Hamilton declared the identity of his 
 opinion with the vulgar belief, and yet he held that 
 the immediate object of perception is in all cases in 
 immediate contact with the organism, a proposition 
 which the vulgar can neither understand nor be- 
 lieve. An appeal to uncritical, unenlightened, vulgar 
 belief is surely unworthy of a philosopher. 
 
 In the fourth place, Hamilton tells us that if 
 Reid " declare that his Perception affords us equal 
 evidence of the existence of external phenomena, as 
 his consciousness affords us of the existence of 
 internal " he must be a Natural Realist. But surely 
 it is possible to hold that we can place implicit con- 
 fidence in the truth of perception without holding 
 
 CHAP. III. 
 SECT. VI. 
 
 £//»n, 
 
 
 Appeal to 
 
 vulgar 
 
 belief. 
 
 Certainty 
 of evi- 
 dence. 
 
152 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VI. 
 
 that the object of perception is immediately present 
 to the mind. The essential point of natural realism 
 is that the non-ego is immediately present to and 
 known hy the ego ; but this point is not involved in 
 the assertion that perception gives us certain evi- 
 dence of its object. The longest train of mathe- 
 matical reasoning gives us certain evidence of the 
 truth of its conclusion, but this fact vouches 
 nothing as to the character of the reasoning pro- 
 cess. Neither does the certainty of perception vouch 
 anything as to the character of perception. The 
 fact is that Reid knew no more about the doctrine 
 of natural realism than Berkeley knew about Kant's 
 doctrine of the subjectivity of space. Although 
 Berkeley came very close to the doctrine of natural 
 realism, Reid did not even understand him, and it 
 appears to be a foolish anachronism to attribute to 
 Reid a doctrine which had then scarcely dawned 
 upon the minds of psychologists. 
 
 Reid's doctrine of perception was a slight advance 
 upon that of preceding representationists. He held 
 that sensations, hy a natural and irresistible prin- 
 ciple of our constitution, suggest to our minds the 
 conception and create the belief of external objects, 
 and that this suggestion is immediate and not the 
 effect of reasoning. How this can possibly be inter- 
 preted as a form of natural realism, and ivhy the 
 attempt should be made thus to interpret it, tran- 
 scend the present writer's power of imagination to 
 conceive. 
 
 We must now see how the scepticism of Hume 
 was met by a German thinker far more profound 
 than Reid — Immanuel Kant. 
 
PSYCHOLOGY OF COGNITION. 
 
 153 
 
 Section VII. 
 KANT (1724-1804). 
 
 § 81. It was the negative scepticism of Hume 
 ^hich stimulated Kant to produce his great work, 
 le " Kritik of the pure Reason." He saw, as Eeid 
 dso did, that Locke's principle regarding the origin 
 )f knowledge naturally led to Hume's conclusion. 
 |If all our ideas are simply modified sensations, if all 
 >ur knowledge arises out of experience, many of our 
 lost cherished and valuable beliefs must be under- 
 mined. Hence, Kant set himself to show that, 
 although '' all our knowledge begins ivith experience," 
 yet " it by no means follows that all arises out of our 
 experience.'^ There are certain elements of our 
 knowledge which could not be derived from ex- 
 perience. " Experience, no doubt, teaches us that 
 this or that object is constituted in such and such a 
 manner, but not that it could not possibly exist 
 otherwise. Now, if we have a proposition which con- 
 tains the idea of necessity in its very conception, it 
 is a judgment a priori ; if, moreover, it is not derived 
 from any other proposition, unless from one equally 
 involving the idea of necessity, it is absolutely a 
 priori. An empirical judgment never exhibits strict 
 and absolute, but only assumed and comparative 
 universality."* 
 
 To show that there are such necessary and univer- 
 sal judgments Kant appeals to the sciences of mathe- 
 
 * Kant's "Introduction." 
 
 CHAP. III. 
 SECT. VII. 
 
 Kant*s 
 Kritik. 
 
 Origin of 
 knowledge. 
 
154 
 
 THE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. VII. 
 
 Sensation. 
 
 Matter and 
 Form. 
 
 Space. 
 
 matics and physics. We are not concerned with the 
 general use which he makes of this distinction 
 between the d priori and the empirical elements of 
 knowledge ; we have only to study its application to 
 the psychology of perception. And in this we shall 
 see a very important difference between the German 
 and the Scottish opponent of Hume. 
 
 § 82. According to Kant, sensation is the result of 
 objects affecting our sensibility or sensive faculties 
 in a particular way. Thus, by means of sensation, we 
 have an intuition of phenomenal objects. Tbat in 
 the phenomenon which corresponds to the sensation, 
 Kant calls its matter; but that which effects that 
 the content of the phenomenon can be arranged 
 under certain relations, he calls its form. But that 
 in which our sensations are merely arranged, and by 
 which they are susceptible of assuming a certain form, 
 cannot be itself sensation. It is, then, the matter of 
 all phenomena that is given to us d posteriori, the 
 form must be ready a priori for them in the mind. 
 By an easy analysis, Kant reaches the conclusion, 
 that the two forms of intuition, without which the 
 cognition of phenomena would be impossible, are 
 space and time. It is with the former that we are 
 now concerned. The following are the principal 
 elements of 'Kant's exposition of space: — 
 
 (1.) ^^ Space is not a conception which has been 
 derived from outward experiences. For in order 
 that certain sensations may relate to something 
 without me, and in order that I may represent them, 
 not merely as without of, and near to each other. 
 
PSYCHOLOGY OF COGNITION. 
 
 155 
 
 but also in separate places, the representation of 
 space must already exist as a foundation. 
 
 (2.) " Space, then, is a necessary representation 
 d 'priori, which serves for the foundation of all 
 external intuitions. 
 
 (3.) " Space is no discursive, or as we say, general 
 conception of the relations of things, but a pure 
 intuition. 
 
 (4.) " Space does not represent any property of 
 objects as things -in- themselves, nor does it represent 
 them in their relations to each other. 
 
 (5.) ^^ Space is nothing else than the form of all 
 phenomena of the external sense, that is, the 
 subjective condition of the sensibility under which 
 alone external intuition is possible." 
 
 The substance of Kant's doctrine of perception is 
 summed up by himself as follows : — 
 
 ' ^ All our intuition is nothing but the representa- 
 tion, of phenomena ; the things which we intuite are 
 not in themselves the same as our representations of 
 them in intuition, nor are their relations in them- 
 selves so constituted as they appear to us ; and if we 
 take away the subject, or even only the subjective 
 constitution of our senses in general, then not only 
 the nature and relations of objects in space and time, 
 but even space and time themselves disappear ; and 
 these as phenomena cannot exist in themselves, but 
 only in us. What may be the nature of objects 
 considered as things-in-themselves, and without re- 
 ference to the receptivity of our sensibility, is quite 
 unknown to us. We know nothing more than our 
 
 CHAP, III. 
 SECT. VII. 
 
 Summary 
 of Kant's 
 doctrine. 
 
156 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VII. 
 
 Criticism. 
 
 mode of perceiving them ; and with this alone we 
 have to do. Space and time are the pure forms 
 thereof; sensation the matter. The former alone 
 can we cognise a priori, that is, antecedent to all 
 actual perception ; and for this reason such cognition 
 is called pure intuition. The latter is that in our 
 cognition, which is called cognition a posteriori, that 
 is, empirical intuition. TJie former appertain abso- 
 lutely and necessarily to our'Sensibility, of whatsoever 
 kind our sensations may b^ ; the latter may be of 
 very diversified character. Su'pposing that we should 
 carry our empirical intuition even to the very highest 
 degree of clearness, we should not thereby advance 
 one step nearer to a knowledge of the constitution 
 of objects as things-in-themselves.^^ * 
 
 § 83. One great merit which we must ascribe to 
 Kant is the dismissal from his psychology of all 
 accidental side questions, and the clear presentation 
 of the fundamental problems which the psychologist 
 endeavours to solve. The process of perception is 
 reduced ultimately to a consciousness of sensations 
 varied in character, but all agreeing in having, as 
 a condition of their possibility, particular forms. 
 Through these sensations there is made known the 
 existence, although not the nature, of things-in- 
 themselves.' The essential problems of every system 
 of psychology must have reference to — (1) sensations, 
 or what Kant calls the matter of sensations; (2) space 
 and time, called the form of sensations ; and (3) the 
 
 * These quotations from Kant's " Kritik " are from Mr. Meikle- 
 john's translation, published in Bohn's series. 
 
PSYCHOLOGY OF COGNITION. 
 
 157 
 
 thing-in-itself, or whatever it may be called, sup- 
 posed to exist independently and as the cause of 
 sensations. There is a fourth problem not so funda- 
 mental, regarding the process by which sensations 
 form themselves or become transformed into distant 
 objects of perception. Here we have presented in 
 very small compass the subjects of all the disputed 
 questions of psychology, and if psychologists only 
 understood one another, the probability is that there 
 would not appear so great a difference between their 
 views as is now supposed. 
 
 With regard to the first of these problems, the 
 nature of the immediate objects of consciousness, 
 Kant makes no distinction between the sensations 
 and the mental acts which they constitute. But 
 still they are mental, purely mental, and called by 
 him representations of other and unknown objects of 
 .iintuition. We shall have to notice in a subsequent 
 )hilosopher an important difference regarding this 
 [uestion. The cardinal doctrine of Kant's psycho- 
 logy of perception is, however, the a ^priori and 
 )henomenal character of space and time. Space 
 and time are subjective in their origin, and are 
 conditions only of phenomena, not of things-in- 
 themselves. This problem also, we shall find,* gives 
 rise to a great deal of discussion. An investigation 
 into the nature of the so-called things-in- themselves 
 is not properly a psychological one, although psy- 
 chology has to do with the grounds of our belief 
 in them. Kant considered them beyond the sphere 
 §§ 88-90. 
 
 CHAP. III. 
 SECT. VII. 
 
 Immediate 
 oljects of 
 conscious- 
 ness. 
 
 Space and 
 Time. 
 
 Things-in- 
 
 them. 
 
 selves. 
 
158 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Study of 
 modern 
 psycho- 
 logy. 
 
 of human knowledge, but Kant's German successors 
 broke through the trammels which he had attempted 
 to impose upon the human intellect, and speculated 
 boldly regarding the nature of laws of what he 
 pronounced unknown. Into these speculations it 
 would be inconsistent with our subject to enter. 
 But the psychological doctrines of Kant have been 
 fruitful in stimulating and, to a certain extent, in 
 guiding subsequent researches into the perennial 
 problems of thought which he apprehended so 
 clearly. Any criticism of Kant's doctrines we shall 
 not now attempt, but leave it to be done by those of 
 the present generation, to whom we must now devote 
 some attention. Our historical review will, we trust, 
 have produced two good effects : it will have enabled 
 us to see the most important errors of the earlier 
 psychologists ; and will have given us a clear appre- 
 hension of what are the fundamental problems of 
 the psychology of perception. 
 
 Section YIII. 
 modeen english psychology. 
 
 § 84. Was Kant successful in his refutation of 
 Hume ? By the principle which Kant endeavoured 
 to establish, 'was philosophical scepticism rendered 
 impossible or absurd ? For an answer to these and 
 similar questions we must look to the history of 
 modern psychology. Hume and Kant are the 
 representatives of the two great schools of modern 
 English psychology, and it shall be our task in this 
 
PSYCHOLOGY OF COGNITION: 
 
 159 
 
 closing section to refer, as briefly as possible, to tbe 
 fundamental questions regarding wbicb tbese schools 
 are at issue. It would be impossible, within the 
 space to which we propose to confine ourselves, to 
 give anything like a fair account of even the most 
 important of the psychological works of the present 
 time; it would be equally impossible to do justice to 
 the philosophical ability and learning with which 
 the great problems of psychology have been treated. 
 All that we propose to do is to introduce the student 
 to a sphere of research of great interest and great 
 extent, and to furnish, perhaps, some stimulus and 
 some guidance in the pursuit of knowledge. "We 
 shall not, therefore, as heretofore, consider each 
 psychological system by itself, but shall give an 
 account of the manner in which psychological pro- 
 blems and difficulties have been treated by different 
 writers. For the sake of brevity, we shall endeavour 
 to avoid everything of secondary importance and of 
 merely historical interest. We shall restrict our- 
 selves to the consideration of the few essentially 
 important problems which must be solved in one 
 way or another by every psychological system ; pro- 
 blems which have already been pointed out in 
 connection with Kant. The attempt to ascertain or 
 accurately to state what a philosopher really means 
 is frequently attended with considerable difficulty ; 
 and we have prominent examples of the evils 
 arising from a disingenuous or a prejudiced read- 
 ing of the doctrines of another. This we shall 
 endeavour to avoid, and give as briefly and accu- 
 
 CHAP. III. 
 SECT. VIII. 
 
 Problems. 
 
i6o 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Objects of 
 conscious- 
 ness. 
 
 rately as possible the doctrines which we propose 
 to discuss. 
 
 § 85. Kant^s general doctrine that there are 
 certain a priori truths or principles which could not 
 originate in experience may be better discussed at a 
 future time. At present we are concerned chiefly 
 with the modern doctrines concerning : — 
 
 (i) Sensations, or the immediate objects of con- 
 sciousness ; (2) space and time, especially the 
 former; (3) the object and the process of percep- 
 tion; and (4) the believed objective cause which may 
 account for the existence and permanence of the 
 objects we perceive. 
 
 The question as to the nature of the immediate 
 objects of consciousness is one of great importance. 
 It has been almost universally held that the objects of 
 which we are immediately conscious are ideas purely 
 mental, either identical with the act of consciousness, 
 or numerically, but not in nature, different from it. 
 The names which have been given to these objects 
 are various : sensations, impressions, ideas, repre- 
 sentations, and so on. Whatever the name may be 
 by which they are designated there has been a re- 
 markable concurrence in considering the immediate 
 objects of consciousness simply modifications or 
 activities of the ego. Such is still the doctrine of 
 those who adhere to the Berkeleyan idealism ; such 
 is the doctrine of nearly all the Association-school 
 of psychologists represented by Hartley and the two 
 Mills. In opposition to this view we have the 
 doctrine to the establishment of which Sir W. 
 
PSYGHOLOGY OF GOGNITION. 
 
 i6l 
 
 Hamilton devoted his learning and abilities, the 
 doctrine that the immediate object of consciousness 
 is not merely a mental product, but that it is the non- 
 ego. There is frequently a great deal of difficulty 
 in reconciling Hamilton with himself, and in getting 
 a really intelligible view of his psychology. He 
 frequently speaks as if distant and material things 
 were objects of consciousness ; and as if the impres- 
 sions made upon our organs of sense were objects of 
 perception. 
 
 But laying aside both of these erroneous and un- 
 guarded statements, and interpreting him in a fair 
 and candid spirit, it appears to us that the essential 
 point of his doctrine as distinguished from that 
 which we have before referred to is as follows : In 
 conscious knowledge there is an ego and a non-ego, 
 a subject and an object known in contrast to one 
 another. The object is an affection of the sensorium, 
 a sensation of some kind, say of colour, resistance, or 
 sound. But although a sensation, it is or reveals a 
 veritable non-ego in immediate contrast with the 
 ego. Conscious knowledge is in fact impossible 
 which does not set over an object against the subject; 
 and in relation to perception that which is thus 
 objectified is a sensation. Thus sensations, although 
 immediately known in consciousness, are not there- 
 fore purely mental ; they contain a foreign element j 
 they belong to or constitute the non-ego of our 
 immediate knowledge. 
 ^^ § S^. This difference of view regarding the nature 
 ^Bf the immediate objects of consciousness is a funda- 
 
 CHAP. III. 
 SECT, VIII. 
 
 Associa- 
 tional and 
 intuitional 
 schools. 
 
1 62 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 mental distinction between wliat we may call the 
 Associational and tlie Intuitional schools of psy- 
 chology. It must be accepted as a fixed principle 
 of association that nothing can appear in the result 
 of the process of association which was not involved 
 in the original elements.* Now, according to most 
 of the members of the associational school the origi- 
 nal elements to be associated are sensations in cer- 
 tain relations. If these sensations are nothing but 
 activities of the ego, if they are purely mental 
 products, it is manifest that the objects into which 
 these sensations are clustered and bound together by 
 association can never become anything else but 
 mental. If they are at the beginning, they must 
 continue to be unto the end of the associational pro- 
 cess, simply mental states or activities. And in the 
 writings of the consistent association-psychologists, 
 as Hume and J. S. Mill, we find that this is actually 
 the case. Objects are clusters of sensations supposed 
 to have a permanent existence independent of the 
 individual mind, in consequence of their mutual co- 
 herence and regular recurrence. They are mental 
 products objectified, and called by Mr. Mill Per- 
 manent Possibilities of Sensation. He has been 
 censured for using such a negative term to indicate 
 what other people think to be a collection of positive 
 and non-mental powers. But the term is the very 
 best he could have used. Beginning his associative 
 process with purely mental elements, he could never 
 
 * That is, nothing different in kind. We have seen that asso- 
 ciation of sensations may give rise to new sensations, see § 25. 
 
FSYGEOLOGY OF COGNITION. 
 
 163 
 
 reach to that which, is non-mental. And if his 
 psychology may be condemned because it does not 
 recognise that which is essential in our knowledge 
 of a material world, it cannot, at least, be condemned 
 for its inconsistency. 
 
 § 87. The other view, which we consider the 
 correct one, regards sensations as being or involving 
 subject i^lus object ; there is in consciousness given 
 an ego and a non-ego; there is something in the 
 object of consciousness other than a merely mental 
 state or activity. The full significance of this we 
 shall not attempt to bring out at present. But in 
 the meantime, we can see that there is not the same 
 difficulty in attaining to a knowledge of a veritable 
 objective world as in the former case. We can see 
 that the association of elements already containing a 
 true non-ego could easily and consistently lead to 
 the ultimate result of the perceptive process, the 
 knowledge of objects constituting a real world. We 
 may now advance to the consideration of another 
 fundamental difference between the two psycho- 
 logical schools. This difference has reference to the 
 nature of our cognition of space or extension. 
 
 § 88. Kant, in order to withstand the scepticism 
 of Hume, gave to space and time an a priori origin 
 as the native form of our sense-intuition. The con- 
 ceptions of space and time are not derived from 
 experience, but they are the conditions by which 
 I experience is rendered possible. It is impossible to 
 I perceive any object or quality except in space, and 
 
 I his necessity at the very beginning of experience, 
 M 2 
 
 CHAP. III. 
 SECT. VIII. 
 
 Intui- 
 tional 
 stand- 
 point. 
 
 Extensiony 
 d priori 
 theory. 
 
164 
 
 THE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Extension 
 the result 
 of associa- 
 tion or ah- 
 atraction. 
 
 it is alleged, could not be the result of experience. 
 The necessity, however, is a subjective one; space 
 and time have only a phenomenal reality ; things in 
 themselves do not exist under spatial and temporal 
 conditions. Now, if by a priori, Kant meant only 
 to oppose Hume^s maxim that all our knowledge 
 consists of impressions or sensations, and ideas, which. 
 are the copies of sensations, he appears to have suc- 
 ceeded. That which is at first a necessary condition 
 of intuition cannot itself be the product of sense-ex- 
 perience. But the expression d priori appears to in- 
 volve a view which modern psychologists are anxious 
 to avoid. It appears to convey the idea that there is 
 in the mind some hidden receptacle of unconscious 
 forms or principles which are ready to start up into 
 conscious life whenever the first incipient experience 
 calls for them. This hidden limbo of d priori princi- 
 ples which cannot be examined by the light of con- 
 sciousness is most convenient for those psychologists 
 who think that it is a sufficient explanation of all their 
 beliefs, whether simple or complex, which they can- 
 not get rid of. But it appears at first sight un- 
 philosophical to attempt to explain a difficulty by a 
 mystery ; to account for some necessity by assuming 
 the antecedent existence of some form or principle 
 in some hidden mental labyrinth beyond the ken of 
 consciousness. 
 
 § 89. Leaving for the present Kant's d priori ex- 
 planation of space, we may examine the doctrines of 
 more modern psychologists regarding it. These 
 doctrines may be reduced to two. In the first place, 
 
PSYCHOLOGY OF COGNITION. 
 
 I6S 
 
 it is maintained that tlie idea of space is tlie product 
 of some process of abstraction or association ex- 
 ercised upon sensations; in tlie second place, it is 
 keld tliat space is given in intuition. With reference 
 to the first of these doctrines we have already 
 examined* one form of it as held by J. S. Mill, and 
 seen the impossibility of the attempt to evolve space 
 from time. And if we consider for a moment the 
 nature of the processes of association and abstraction, 
 we shall see that neither of them can account for 
 the origin of our knowledge of space. Association 
 unites together sensations or other objects of in- 
 tuition into a compound ; but the compound thus 
 formed cannot possibly contain anything which was 
 not in the original elements associated. Suppose that 
 our only original intuitions are unextended sensa- 
 tions and the relation between them of succession 
 or time, it will be impossible for any association 
 to convert either sensations or time, or any com- 
 bination of the two, into space. The most elaborate 
 attempt to do so is that of Mr. Mill, and it, we have 
 seen, is a failure. Equally impossible it is for 
 the process of abstraction to ijroduce anything not 
 involved in the original objects of intuition, or in the 
 perceived relation between them. Suppose that we 
 are conscious of redness, greenness, blueness, and 
 other particular sensations of colour. We are able 
 to compare them, perceive their resemblances and 
 differences, and form a general idea indicated by a 
 general name, colour. Now in the result of this 
 *§34. 
 
 CHAP. III. 
 SECT. VIII. 
 
1 66 
 
 THE ELEMENTS OF THE 
 
 CHAP, III. 
 SECT. VIII. 
 
 Extension, 
 an intui- 
 tion. 
 
 process there is notliing contained whicli was not 
 given in tlie original intuitions ; the result is just 
 the summing up^ as it were, of the original intuitions 
 of particular sensations and their relations. In this 
 case abstraction is employed for the purpose of 
 generalisation, for the formation of a general idea or 
 name. But space is not a general name ; it is not 
 predicable of any of the objects from which it is said 
 to be produced by abstraction.* Nor is it in any 
 way possible to know by abstraction /rom objects of 
 consciousness what was not known by intuition in> 
 them. Those who maintain the contrary have yet 
 to show its possibility. 
 
 § 90. The other modern view regarding the origin 
 of our knowledge of space we have already expounded 
 in Chapter II., and to that exposition now refer 
 the reader. Extension, a form of space, is, we be- 
 lieve, given in an intuition ; if not, we do not see 
 how it can be known at all, as it certainly has 
 hitherto proved incapable of resolution into any- 
 thing else. 
 
 At the same time, although the essential element 
 of extension is given in intuition, it must be admitted 
 that abstraction has something to do with the elabo- 
 ration of our notion of space. Abstraction must be 
 made from the particular sensations or qualities 
 which are given in intuition as extended, and there 
 remains the extension without the quality, the form 
 without the matter. But this abstraction manifestly 
 does not produce our idea of extension, it simply 
 * See Spencer, "Psy.," ii., 352. 
 
PSYCHOLOGY OF COGNITION. 
 
 167 
 
 disentangles it from the sensation or quality in wliicli 
 it is involved. 
 
 With reference to the nature of space and time, 
 there are many questions which have long exercised 
 the minds of thinking men. Are they real things, 
 having independent existence ; or are they only attri- 
 butes ? Can we conceive empty space or time ; or 
 are they always connected with sensible qualities or 
 objects ? What is the nature of our conception of 
 the whole of space and time; is it that of the infinite, 
 or only of the indefinite ? A reference to the 
 modern doctrines regarding these and other questions 
 would compel us to exceed our limits, and we must 
 therefore refer the student who wishes to pursue his 
 inquiries farther to the many able works upon these 
 subjects which have been produced in recent times.* 
 
 § 91 . We must now give some attention to modern 
 doctrines regarding the object and the process of 
 perception. And we remark at the outset that it 
 seems desirable for psychologists, when adopting 
 words that are in common use, to give them as 
 nearly as possible the meaning sanctioned by ordi- 
 nary usage. The word perception, when used, by 
 ordinary intelligent men, has a certain definite 
 meaning and object ; it means the knowledge which 
 we have of objects at a distance from us, believed to 
 have an independent and permanent existence, 
 whether they are perceived or not by us or any 
 other sentient being. But psychologists have con- 
 cluded, and rightly, that this knowledge is a very 
 
 * e. g., Hodgson on ** Space and Time." 
 
 CHAP. III. 
 SECT. VIII. 
 
 Perce'p- 
 tion. 
 
i68 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Mr. MilVs 
 explana- 
 tion of a 
 material 
 world. 
 
 complex product ; tliey have analysed it into wliat 
 they have believed to be its simplest elements ; but 
 instead of keeping the name perception to its proper 
 object, the complex product, they have applied it to 
 some of the more simple processes into which the 
 complex has been analysed. And as it has not been 
 applied uniformly, considerable confusion has been 
 caused. 
 
 We have next to refer to a false distinction be- 
 tween two opposing psychological' schools. One 
 school has been called the associational school, 
 another the intuitive. The distinction is not an 
 accurate one. All . psychologists agree that the 
 object of perception, as we understand and have just 
 explained that object, is not intuitively known. All 
 psychologists must assume at the beginning of the 
 construction of their acquired knowledge certain 
 objects which are intuitively known. All psycho- 
 logists make some use of the principle of association 
 in explaining the construction of their knowledge. 
 
 The only important differences which exist 
 between psychologists have reference — (1) to the 
 number and kind of the objects of intuitive know- 
 ledge; (2) to the extent of the use which may be 
 made of the principle of association ; and (3) to the 
 question whether association can explain everything, 
 or whether some other principle must be called in. 
 
 § 92. Mr. Mill, who is the representative of a 
 large class of psychologists, past as well as present, 
 assumes as the original contents of intuitive know- 
 ledge, certain sensations or states of consciousness. 
 
PSYCHOLOGY OF COGNITION. 
 
 169 
 
 and the relations of co-existence and sequence exist- 
 ing between them. Upon these original intuitions 
 he sets at work with his laws of association, and 
 attempts to explain our belief of the external world. 
 We have already seen with what success he has 
 attempted to account for the origin of our idea of 
 extension or space. We must now examine his 
 attempt to explain our knowledge or belief of a 
 permanent material world. 
 
 Beginning with the existence of sensations, he 
 maintains* "that there are associations naturally, and 
 even necessarily, generated by the order of our sen- 
 sations and of our reminiscences of sensations, which, 
 supposing no intuition of an external world to have 
 existed in consciousness, would inevitably generate 
 the belief, and would cause it to be regarded as an 
 intuition.''^ In support of this he shows that, in 
 certain circumstances, sensations which we have felt 
 recur to us regularly upon the fulfilment of certain 
 conditions ; that thus we think of the possibility of 
 the recurrence of these sensations as being per- 
 manent, whereas sensations themselves are fugitive ; 
 that it is not merely single sensations, but groups of 
 sensations, which are thus connected with permanent 
 possibilities of them ; and that the sensations of these 
 groups occur in a certain fixed order. " Hence,^' he 
 concludes, " we speedily learn to think of Nature as 
 made up solely of these groups of possibilities, and 
 the active force in Nature as manifested in the 
 modification of some of these by others. The sensa- 
 
 * " Examin.," p. 221. 
 
 CHAP. III. 
 SECT. VIII. 
 
I/O 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Criticism. 
 
 tionSj tliougli the original foundation of the whole, 
 come to be looked upon as a sort of accident depend- 
 ing on us, and the possibilities as much more real 
 than the actual sensations, nay, as the very realities 
 of which these are only the representations, appear- 
 ances, or effects. When this state of mind has been 
 arrived at, then, and from that time forward, we are 
 never conscious of a present sensation without in- 
 stantaneously referring it to some one of the groups 
 of possibilities into which a sensation of that parti- 
 cular description enters ; and if we do not yet know 
 to what group to refer it, we at least feel an irre- 
 sistible conviction that it must belong to some group 
 or other, i.e., that its presence proves the existence, 
 here and now, of a great number and variety of pos- 
 sibilities of sensation, without which it would not 
 have been. The whole set of sensations as possible, 
 form a permanent background to any one or more 
 of them that are, at a given moment, actual; and 
 the possibilities are conceived as standing to the 
 actual sensations in the relation of a cause to its 
 effects, or of canvas to the figures painted on it, 
 or of a root to the trunk, leaves, and flowers, or of 
 a substratum to that which is spread over it, or, 
 in transcendental language, of Matter to Form.'^ * 
 Here, then, we have the external world produced 
 by Mr. Mill from sensations variously associated 
 together. 
 
 § 93. Now, let us pass over the question, how 
 Mr. Mill gets his sensations projected into space, 
 
 *"Exainm.," p. 224-5. 
 
PSYCEOLOGY OF COGNITION. 
 
 171 
 
 whicli he does not explain, and refer to another 
 point of more vital importance. He speaks of " the 
 active force in Kature," but we may ask how he 
 comes to know anything about such a force ? Force 
 is not a sensation, nor is it any association of sensa- 
 tions. This, however, is not the main point of our 
 criticism. '^ The whole set of sensations," he says, 
 " as possible, form a permanent background to any 
 one or more of them that are, at a given moment, 
 actual ; and the possibilities are conceived as stand- 
 ing to the actual sensations in the relation of a cause 
 to its effects." Let us examine this statement. 
 
 The possibility of sensations is conceived as the 
 cause of actual sensations. We have, for example, 
 the sensation of a particular figured colour which is 
 associated with the name orange. Connected with 
 this sensation there are a number of possible sensa- 
 tions of smell, taste, touch, sound, &c. The possibility 
 of those sensations is the cause of the colour. What 
 does this mean? Is the possibility of a smell the 
 cause of a colour ? Is the possibility of a taste the 
 cause of a colour ? Or is the possibility of all the 
 other sensations of the group taken together the 
 cause of colour ? If we ask a scientific man what is 
 the cause of colour, he will answer that it is a ray of 
 light. If we inquire farther what he means by a 
 ray of light, he will tell us that it is the insensible 
 vibration of an ethereal fluid caused by some power 
 of a luminous body. This we can understand, but 
 when Mr. Mill tells us that the possibility of a smell, 
 or a taste, or a touch, or all put together, is the 
 
 CHAP. III. 
 SECT. YIII. 
 
1/2 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Mr. Mill's 
 
 method 
 
 criticised. 
 
 cause of a colour, we confess that we do not under- 
 stand what he means. There appears to be such an 
 utter incongruity between the antecedent and the 
 consequent, that we cannot think of them as form- 
 ing a sequence. And what is true of the sensation 
 of colour, is equally true with reference to all our 
 other sensations. The possibility, as Mr. Mill calls 
 it, of one or more sensations of a group, we cannot 
 think of as being the cause of the remaining different 
 sensation or sensations. But yet this is the only 
 kind of cause which could be reached from the 
 original elements with which he sets out by the help 
 of association. He begins with sensations ; he ends 
 with groups of actual and possible sensations having 
 a fictitious objectivity. 
 
 § 94. If, then, Mr. Mill's laws of association 
 operating upon the original sensations of conscious- 
 ness do not produce what we believe to be a veri- 
 table external world, we have now to inquire whether 
 there is in his method any fundamental defect. The 
 result of this inquiry will simply be an answer to 
 the question formerly referred to, — Whether some 
 other principle than the laws of association be not 
 necessary to explain our belief in an external world? 
 We believe that there is; and that the essential 
 defect of the psychology of which Mr. Mill is an 
 exponent, consists in the ignoring of this other 
 principle. In that psychology it is assumed that 
 sensations exist ; but no attempt is made to account 
 for their existence. Sensations exist in certain 
 relations of co-existence and sequence; in some 
 
PSYCEOLOGY OF COGNITION. 
 
 173 
 
 cases an invariable relation of antecedence and 
 consequence is observed; and by association tlie 
 antecedent conies to be looked upon as tbe cause 
 of tlie consequent. And from this association or 
 phenomenal theory of causation we are led to the 
 absurd conclusion that the possibility of a sensation 
 of resistance or smell is the cause of an actual sen- 
 sation of colour. Now, it is perhaps in the simple 
 original sensations of our consciousness that we 
 are able to see most clearly the fallacy of the 
 phenomenal view of causation which Mr. Mill 
 accepts. When we have a sensation, say of smell, or 
 colour, or taste, although they are most intimately 
 and inseparably associated together, we never look 
 upon the one as the cause of the other. And yet 
 we do give an account to ourselves of the cause of 
 these sensations. They are something beyond our 
 own control ; they come to us unbidden ; and our 
 very powerlessness with reference to them compels us 
 to refer them to some objective 'power. That power 
 is, as far as our consciousness is concerned, unknown; 
 it is not a phenomenoiij although it is manifested to 
 us in a phenomenon. Thus our conception of a 
 sensation as being a non-ego involves a belief of 
 some veritable objective cause of it ; and this intui- 
 tion of the causal relation, whether strictly original 
 or not, must be carried with us through the whole 
 subsequent process by which our perceptive know- 
 ledge is built up. By the introduction of the causal 
 judgment at this early stage we are able to account 
 for the objectifying of our sensations; and we are able 
 
 CHAP. III. 
 SECT. VIII. 
 
174 
 
 TEE ELEMENTS OF THE 
 
 CHAP. III. 
 SECT. VIII. 
 
 Inferred 
 causes of 
 pheno- 
 mena. 
 
 to account for a. belief in material body in which, 
 will not be involved the absurdity of one sensation, 
 or the possibility of one sensation being the cause 
 of another of a different kind. According to this 
 view, phenomenal body consists of objectified sensa- 
 tions collected together in a group by association ; 
 but to this body the educated intellect does not 
 attribute any causal efficiency. On the other hand, 
 non-pTienomenal body or matter, as it is called, is 
 simply a synthesis of inferred powers, each power 
 being inferred to account for the sensation or quality 
 corresponding to it which enters as a constituent 
 member into the group of qualities which we 
 perceive. 
 
 § 95. The statement of this latter view regarding 
 the nature of the perceptive process in which the 
 principle of causation is made use of in addition to 
 the laws of association brings us to the last important 
 point which we proposed to consider. The nature 
 of the inferred causes of our sensations and their 
 synthesis is a problem which the phenomenalism of 
 Mill and his school does not touch. And yet it is 
 with this problem that a great deal of modern 
 science has to do. Light, heat, electricity, force, as 
 studied by physicists, are non-phenomenal powers, 
 and the object of science is to ascertain their laws 
 and relations. With this subject we have nothing 
 to do, except to point out that a true psychology 
 must leave a place for it. The only place which 
 Mr. Mill, leaves for physical science is in that nega- 
 tive, utterly tantalising shadow of a thing which he 
 
PSYCHOLOGY OF COGNITION. 
 
 175 
 
 calls tlie permanent possibility of sensations. Ideal- 
 ism postulates an intelligent power as tlie cause of 
 the existence and objective synthesis of sensations; 
 and to this there is perhaps no serious objection, 
 except that the language which is used frequently 
 leads ordinary people to suppose that something 
 very absurd is meant. Realism, as found in Herbert 
 Spencer and the Scottish school of philosophers, 
 demands a belief in real objective non-phenomenal 
 forces, capable of correlation with and transmuta- 
 tion into one another. Into a discussion of this we 
 cannot enter ; sufficient that we have pointed out its 
 relation to the legitimate subjects of psychology. 
 
 We must now close our discussion of modern 
 theories of perception, although aware of many im- 
 portant omissions and imperfections in our sketch. 
 The necessity for brevity must be in part our 
 apology for these. The student who wishes to 
 pursue the subject farther will find valuable as- 
 sistance in the works of Hamilton, Ferrier, Pro- 
 fessor Grote, Bain, Mill, Spencer, Hodgson, Lewes 
 and others. 
 
 CHAP. III. 
 SECT. viir. 
 
176 
 
 TEE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. I. 
 
 Subject in- 
 troduced. 
 
 CHAPTER IV. 
 
 BEFBESENTATION. 
 
 Section I. 
 CONDrriON OP eepeesentation. 
 
 § 96. We jbave already seen that in the process of 
 the acquisition of presentative knowledge there is 
 found mixed up with it a great deal of what is only 
 representative. Our perception of any external 
 object is a complex of presentative and representative 
 elements^ of actual and ideal sensations. Thus^ in 
 the acquisition of knowledge, there is involved the 
 possibility of representing the elements of the know- 
 ledge already acquired. This power of representation 
 is of great importance, apart altogether from its being 
 subsidiary to the perceptive process, so that we must 
 devote special attention to it. By far the greatest 
 part of our knowledge can be brought before con- 
 sciousness only in a represented state ; and all the 
 higher operations of the mind depend upon represen- 
 tation as a condition of their possibility. Before 
 entering upon a consideration of the laws and kinds 
 of representative knowledge, we must first give heed 
 to the question, — How is representation possible ? 
 What are the conditions upon which the representing 
 
PSYCHOLOGY OF COGNITION. 
 
 i;7 
 
 in consciousness of forgotten knowledge depends ? 
 Sensations, once felt, disappear from consciousness ; 
 knowledge once obtained, whetker very simple or 
 very complex, drops into oblivion. After a long 
 time tke sensation may be more or less vividly 
 revived, tke knowledge more or less completely 
 restored. In tke interval, it kas been completely out 
 of tke spkere of consciousness. In its represented 
 state, its original cause, tke object of presentative 
 knowledge is not present. Tke question is, — How is 
 tke knowledge revived witkout tke assistance of its 
 original object ? How is tke sensation repeated 
 witkout tke concurrence of its original external 
 cause ? As tke objective cause of tke recurrence of 
 actual sensations in regular groups and order kas 
 been called tke permanent possibility of sensations, 
 so we migkt kere speak, and witk better reason, of 
 tke permanent possibility of pkantasms or ideas as 
 being tke condition of represented knowledge. But 
 tke trutk is tkat, in botk cases, tke permanent 
 possibility is tke very fact to be explained, and tke 
 mere statement of tke fact is not tke explanation of 
 it. Tke general fact, tken, wkick we know regarding 
 tkis subject, is tke permanent possibility of becoming 
 conscious of pkantasms or revived sensations. 
 
 § 97. Tke explanation of tkis fact is a problem 
 of very considerable difficulty. Tkere is no extra- 
 organic object necessary to aid in tke recall of for- 
 gotten knowledge. Sensations and perceptions, wken 
 forgotten, are altogetker beyond tke ken of con- 
 sciousness. Tkere are, tkerefore, no direct means of 
 
 CHAP. IV. 
 SECT, I. 
 
 Explana- 
 tion hypo- 
 thetical. 
 
178 
 
 TEE JEJLB31ENTS OF TEE 
 
 CHAP. IV. 
 SECT. I. 
 
 Two hypo- 
 theses. 
 
 Mental la- 
 tency. 
 
 observing tlie condition of the possibility of their 
 recall. Consequently, as far as psychology is con- 
 cerned, the explanation must be hypothetical. The 
 hypotheses which have been proposed in explanation 
 of the problem are two in number. The condition 
 of the permanent possibility of phantasms may be 
 mental, or it may be organic ; in the former case, we 
 have the hypothesis of latent mental modification ; 
 in the latter, that of unconscious cerebration. To 
 the respective claims and difficulties of these two 
 conflicting hypotheses we may give some attention. 
 § 98. The doctrine of latent mental modifications 
 has been already referred to* as an attempt to analyse 
 sensations into unconscious elements, and in that 
 connection we saw reason to reject it. As an expla- 
 nation of the permanent possibility of phantasms or 
 ideas, it is open to some of the same objections as 
 before. It postulates that the mind is capable of 
 retaining within itself certain latent activities which 
 are lying ready to spring up into conscious life when- 
 ever the occasion requires. But we have already 
 noticed the objection against calling anything mental 
 which cannot be observed by consciousness. If, how- 
 ever, we admitted the theory of idealism to be true, 
 this objection would fall to the ground. That theory 
 explains the actual sensations which are the elements 
 of perception as the result of an objective mental 
 cause. And consequently it would have no objection 
 to explain the permanent possibility of revived sensa- 
 tions by a mental cause. But if we wish to retain 
 
 * § 26. 
 
PSYCHOLOGY OF COGNITION. 
 
 179 
 
 the distinction between activities whicli are mental 
 and powers whicli are not mental^ and if we explain 
 the latter as powers which originate and operate 
 beyond the sphere of consciousness^ we must reject 
 the doctrine of mental latency. This distinction 
 and explanation which characterise philosophical 
 dualism as opposed to idealism appear to us to 
 correspond to the truth of things^ and therefore we 
 must seek elsewhere for an explanation of the per- 
 manent possibility of phantasms and ideas. 
 
 § 99. The mental hypothesis being rejected^ the 
 only other possible hypothesis must refer us to some 
 non-mental explanation of the difficulty; unless^ 
 indeed, we take refuge in some supernatural ex- 
 planation of it^ which, however, would in the pre- 
 sent day scarcely be thought scientific. And as all 
 realists or dualists admit a physical cause for their 
 actual sensations, they can consistently offer no 
 objections to the explanation of revived sensations 
 by a non-mental cause. But as ex hypothesi there 
 is no extra-organic object; the non-mental cause, 
 if such there be, must be an organic one. The 
 examination of this hypothesis is therefore trans- 
 ferred from the hands of the psychologist to those 
 of the physiologist, and the latter presents us with 
 his theory of unconscious cerebration. 
 
 In this hypothesis it is assumed that every sensa- 
 tion which has come into consciousness has been 
 preceded and caused by some molecular movement 
 in the substance of the brain; it is assumed that 
 the repetition or continuance of a cerebral activity 
 
 N 2 
 
 CHAP. IV. 
 SECT. I. 
 
 Cerebral 
 hypo- 
 thesis. 
 
i8o 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. I. 
 
 Difficulties 
 
 occasioned by continued attention to tlie conscious 
 feeling of which it is the antecedent, will have the 
 effect of making a permanent change upon the 
 nervous tissue, and thus of registering, as it were, 
 the original activity, so that it may be easily re- 
 peated. It is assumed, farther, that in the complex 
 network of nervous centres which constitute the 
 cerebrum, there is such a connection that any ac- 
 tivity propagates itself from one centre to another, 
 and to many others, and that this cerebral activity 
 may either excite conscious sensations or not, 
 according to circumstances. Here, then, we have 
 all the essential elements of the hypothesis. There 
 are, in the nervous tissue of the cerebrum, per- 
 manent registrations of forgotten feelings; per- 
 manent nerve-cells or clusters of cells produced or 
 modified by some past activity ; and these explain 
 the permanent possibility of forgotten sensations 
 being revived. Into the details of the hypothesis 
 we cannot at present enter, but offer the following 
 remarks regarding its difficulties and advantages.* 
 
 § 100. There is no possibility of observing 
 directly the correspondence between conscious 
 sensations and nervous activity. Neither is there 
 any possibility of observing any changes which 
 may take place in the nervous tissues of the 
 cerebrum; and if there were, it could not be 
 said that these changes are the result of sentient 
 
 * Those who wish to pursue the subject further are referred 
 to the writings of Herbert Spencer, Dr. W. B. Carpenter, and 
 Prof. Bain. 
 
PSYCHOLOGY OF COGNITION. 
 
 I8l 
 
 activity. The evidence upon which the hypothesis 
 is built is of a very indirect and obscure kind, 
 consisting of facts observed by the vivisection of 
 inferior animals, facts connected with diseased con- 
 ditions of the human brain, and a variety of facts 
 connected with peculiarities of memory and imagina- 
 tion. Thus the hypothesis is connected with many 
 difficulties and obscure problems which cannot as 
 yet be said to be finally solved. These difficulties, 
 however, should not lead to the rejection of the 
 hypothesis. The law of gravitation, which is now 
 so universally accepted, was originally only an 
 hypothesis founded upon very indirect evidence, 
 and relating to bodies apparently so remotely con- 
 nected with one another, that a man of ordinary 
 intelligence in the days of Newton would probably 
 have thought it absurd. Nearly all the great laws 
 of the operation of physical forces have been slowly 
 and laboriously established by the skilful guesses of 
 men of genius being applied to the explanation of 
 observed facts. The impossibility of directly observ- 
 ing unconscious cerebration, or cerebration of any 
 kind, therefore, ought not to be conclasive against 
 the acceptance of the hypothesis ; and yet more, if 
 this hypothesis be entertained, there is room for 
 further discovery, whereas in the mental hypothesis 
 there is none. What is beyond the reach of con- 
 sciousness the psychologist, as sach, can never 
 examine. But the method and the skill of the 
 physiologist are likely to improve as time goes on ; 
 and consequently we may hope that much additional 
 
 CHAP. IV. 
 SECT. I. 
 
 Should not 
 cause re- 
 jection of 
 hypo- 
 thesis. 
 
l82 
 
 THE ELEMENTS OF TEE 
 
 CHAP. IV. 
 SECT. II. 
 
 light may in future be thrown upon the obscure 
 problems concerning the condifcions of mental 
 activity. In the meantime we have nothing more 
 than an hypothesis; but no psychologist who is 
 uninfluenced by prejudice will deprecate the time 
 when the hypothesis may be recognised as an 
 established law. 
 
 Section II. 
 
 LAWS OF EEPEESENTATION. 
 
 § 101. Everyone is familiar with that condition of 
 mind which we call reverie. In moments of quiet 
 repose, when there is nothing to agitate or disturb 
 us, there appear before consciousness numberless 
 and varied images of sights and sounds, of persons 
 and things, of places and periods of life, of feelings 
 and thoughts, of events long since past, of possible 
 events still to come. These phantasms come and go 
 apparently altogether independent of any effort on 
 our part — they are spontaneous. But at other times 
 when we have some object to accomplish, something 
 to call forth our activity, we are able to control the 
 representations of the fancy, to banish certain 
 phantasms from consciousness and to call up others, 
 to give attent'ion to some and to disregard others. 
 In this case the representation of phantasms is under 
 the control of our will — it is voluntary » Now, in the 
 study of the spontaneous and voluntary representa- 
 tions of the mind, the first problem which presents 
 itself to the psychologist is to determine the laws 
 
PSYOEOLOGY OF COGNITION. 
 
 183 
 
 according to which phantasms either spontaneously 
 appear or, by an effort of will, are made to appear 
 before consciousness. And here it must be observed 
 that there is liability of confusion from not adhering 
 closely to the problem to be solved. The word laiu 
 should here indicate a general statement of the 
 order or relations observed amongst the facts given ; 
 whereas it has been taken to mean an exposition of 
 the nature or mode of operation of the cause by 
 which the facts are supposed to be produced. Adopt- 
 ing the former sense, we proceed to state the laws 
 of representation which have been formulated by 
 psychologists under the name of laws of association. 
 
 § 102. The special laws of association which have 
 been laid down are usually stated to be seven in 
 number : co-existence or consecutionin time; contiguity 
 in space ; dependence as cause and effect, means and 
 endj whole and part; resemblance or contrast; pro- 
 duced by the same power j or conversant about the same 
 object ; signified and signifying ; designated by the 
 same sound. 
 
 Illustrations of the connection between ideas thus 
 related to one another will readily occur to every one, 
 but the following may be taken as examples : — 
 
 In perception those sensations which are usually 
 felt together or in immediate succession have a bond 
 of association formed between them. Hence, an 
 actual sensation which has previously been felt at 
 the same time as a number of other actual sensations, 
 when it is again experienced, brings along with it 
 the phantasms or ideas of the other possible sensations 
 
 CHAP. IV. 
 SECT. II. 
 
 Meaning 
 of laivs. 
 
 Laws 
 stated, 
 
 Illus- 
 trated, 
 
1 84 
 
 TEE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. II. 
 
 of the group. So in more complex experience, per- 
 sons and places and events whicli have been once 
 conjoined together in our knowledge are always 
 likely to be thought of together at subsequent times. 
 
 From the process of perception also many illus- 
 trations of the influence of contiguity in space in 
 forming associated groups might be drawn. In 
 truth, co-existence in time and contiguity in space 
 are usually combined together ; those objects which 
 we have known at the same time have usually been 
 close together in space, and both might be combined 
 under one relation, that of contiguity in general. 
 
 In the next law, that of dependence, as of an effect 
 upon its cause, an end upon its means, we have also 
 a kind of contiguity. If we take the phenomenal 
 view of causation, considering the cause of one 
 phenomenon to be an immediately preceding phe- 
 nomenon, this law may be completely reduced to 
 the preceding one of contiguity in time and place. 
 We say, for example, that fire is the cause of heat. 
 If this means that the bright-coloured flame which 
 we see is the cause of the sensation of heat which we 
 feel, there is in the relation nothing but contiguity. 
 But if it means that there is some real objective 
 force which is at once the cause of the flame which 
 we see and of the heat which we feel, there is some- 
 thing more in the connection between a coloured 
 flame and a feeling of heat than mere contiguity in 
 time and place. Thus the possibility of reducing 
 the causal relation to one of contiguity depends 
 upon the view of the nature of the causal relation 
 
PSYCHOLOGY OF COGNITION: 
 
 185 
 
 which we take. If it is only a relation between phe- 
 nomena, it is nothing but a special form of the law 
 of contiguity in which an antecedent phenomenon 
 called a cause is joined in our thoughts with a 
 consequent phenomenon called an effect. If it is a 
 relation believed to exist between that which is a 
 phenomenon and that which is not a phenomenou, 
 although the former is always associated with the 
 latter, the connection of the two in thought exists, 
 not because of frequent experience, but because of 
 being given in an original or very primitive inference. 
 As this latter is the view which we have maintained,* 
 we cannot reduce the causal relation to that of 
 contiguity. 
 
 The relations of similarity and contrast have a very 
 powerful effect in recalling previous objects of in- 
 tuition to the mind. A single sensation of any kind 
 leads us to think of any similar sensation of the same 
 sense which we have previously experienced. So a 
 whole complex of sensations which we have formed 
 into an object leads us to think of other similar 
 objects. Illustrations of this are so numerous and 
 familiar that we need not specify. So when simi- 
 larity is made conspicuous by its absence, that is, 
 when objects are strikingly in contrast with one 
 another, the one has a strong tendency to recall the 
 other. 
 
 The other relations, of things produced by the 
 same power or conversant about the same object, of 
 signified and signifying, of things designated by the 
 * See § 94. 
 
 CHAP. IV. 
 SECT. II. 
 
1 86 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT, II. 
 
 Reduced to 
 more gene- 
 ral laws. 
 
 Redinte- 
 gration. 
 
 Integra- 
 tion. 
 
 same sound, are so obviously reducible to one or 
 other of tlie preceding tbat we need not give to 
 tbem special attention. In addition to tbose whicli 
 have been mentioned there are many other special 
 relations which may form a ground of association ; 
 but probably there are none which might not be 
 reduced to one or other of the three important rela- 
 tions to which we have referred — those of contiguity, 
 causation, and similarity. 
 
 § 103. Various attempts have been made by philo- 
 sophers to reduce those special relations which form 
 the basis of association into more general laws. 
 Prof. Bain reduces them to two, the Laws of Con- 
 tiguity and Similarity, Hamilton and others to the 
 Laws of Simultaneity and Affinity. A still higher 
 generalisation reduces these all to one, that of Eed- 
 integration, first enounced by Augustine, and after- 
 wards adopted by many subsequent philosophers. 
 It is thus stated : objects that have been previously 
 united as parts of a single mental state tend to recall 
 or suggest one another. This, however, is so ob- 
 viously open to the objection that it does not account 
 for the formation of new associations never before 
 perceived, that it has been modified into what has 
 been called the Law of Integration, "which may be 
 defined as that whereby the mind, in all its efforts, 
 completes a circle of thought — in other words, brings 
 a whole into all its representations. If we suppose, 
 for example, the case of one face, from some point of 
 likeness in it, suggesting another, let us see what is 
 the mental process which takes place. The mind, on 
 
PSYCHOLOGY OF COGNITION. 
 
 187 
 
 apprehending the particular point of resemblance in 
 the face before it, immediately begins to complete 
 the image thereby recalled. It feels that it has got 
 a part of a whole formerly familiar to it, and its 
 immediate aim is to bring into view that whole. In 
 ordinary instances the image completes itself in- 
 stantaneously, and we are not therefore conscious of 
 any such aim ; but in some instances, it is only after 
 frequent efforts that it does so (as when we see a face 
 resembling one that we cannot yet recall), and then 
 we become distinctly conscious of the reproductive 
 operation. The eye, or mouth, or whatever part of the 
 strange face is recognised as familiar, is fixed upon by 
 the mind, and becomes the centre of a representative 
 picture in which the mind has no satisfaction till 
 it is completed. In the case of the law of contrast, as 
 when night suggests day, good evil, a dwarf a giant, 
 the mental process is still more obviously of this 
 integrating character. For, in fact, the one mental 
 conception here directly involves the other, and is 
 only fully intelligible in relation to it. Each idea is 
 to us only what it is on account of its opposite. In 
 passing from the one to the other, therefore, the mind 
 is simply completing the complex image, one side of 
 which is always the necessary correlate of the other. 
 The same seems to hold equally true of the law of 
 co-adjacency, as when a certain house recalls the 
 friends we met — the conversation we had in it ; or 
 when one event recalls another which had happened 
 at the same time In speaking thus of the pro- 
 cess of reproduction as throughout of an integrating 
 
 CHAP. IV. 
 SECT. II. 
 
TEE ELEMENTS OF TEE 
 
 CHAP. IV, 
 SECT. II. 
 
 character, it may be necessary to guard against our 
 being supposed to say tbat tlie mind necessarily 
 impresses a whole upon all the successive train o£ its 
 ideas. This, on the contrary, we know it frequently 
 does not do, the last link in the train having often no 
 relation to the first as parts of a common whole. 
 Mental succession is not unfrequently, as in reverie, 
 a mere straggling array of scattered images. The 
 integration does not proceed, as it is not necessary 
 that it should, all along its course, but only from 
 step to step. The general train may thus present a 
 very incongruous mixture of ideas, while it has yet, 
 at every step, strictly obeyed the great law of mental 
 development. 
 
 We may further observe that it is not necessary, 
 as we might be apt to think from a first confused 
 conception of the law, that the facts of a train of 
 association should have previously co-existed in the 
 mind. In some cases they have co-existed, and to 
 this fact of their co-existence is owing their tendency 
 to reproduce one another ; but more frequently they 
 have had no such previous alliance in the mind. An 
 object never before perceived may suggest an old 
 familiar object; while again, an object frequently 
 perceived may suggest, in different moments, very 
 different and even quite opposite trains of thought. 
 Were it not for this characteristic of the principle of 
 association, the field of our knowledge would have 
 been comparatively narrow, confined, as it must 
 have been, to the relations which from actual obser- 
 vation, we had stored up in our minds. We would 
 
PSYCHOLOGY OF COGNITION. 
 
 never have been able to get out of the past wheel or 
 circle of our thoughts. As it is, the suggestive 
 capacity, continually started by everything around 
 us, is, in all active and cultivated minds, ever 
 entering on fresh fields of intellectual interest, and 
 acquiring fresh stores of knowledge/^ * 
 
 Section III. 
 
 KINDS OF EEPRESENTATION. 
 
 § 104. The simplest mode in which the repre- 
 sentative faculty operates is illustrated in reverie. 
 Objects are presented before consciousness singly or 
 in groups, without any particular order and without 
 any connection with a place or a time in which they 
 have previously been known. This mode of repre- 
 sentation, in which phantasms are isolated from 
 their determining circumstances, has been called 
 phantasy. Dreaming is a well-known example of 
 it. Images come spontaneously into the mind, and 
 are supposed to have a present reality. These 
 images may be complete in themselves, but they 
 are separated from the various relations in which 
 they may have been previously observed. This 
 phantasy, this simple bare representation of images, 
 is the least complex, and, at the same time, the least 
 perfect mode of representation. It usually takes 
 place in a state of mental inactivity, as in reverie or 
 dreaming, when there is no voluntary putting forth 
 of effort, or in some abnormal condition, as fever or 
 * Tulloch's " Theism," pp. 211-14. 
 
 CHAP. rv. 
 
 SECT. III. 
 
 Plumtasy. 
 
190 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. IV. 
 SECT. III. 
 
 Memory. 
 
 insanity, when the images of a period long past 
 come up vividly before consciousness, although 
 perhaps for years they had been dormant. Thus in 
 simple phantasy the mind appears to be, to a great 
 extent, passive ; there is no voluntary effort to fill 
 u]p the circle of knowledge connected with any 
 particular phantasm. Since this imperfect mode 
 of representation is usually found in quiescent, 
 abnormal, or diseased conditions of the organism^ 
 physiologists have given great attention to it for 
 the purpose of discovering the organic conditions 
 upon which the power of representation depends. 
 As, however, we are not at present interested in 
 this question, we shall proceed to the consideration 
 of a more perfect mode of representation, and one 
 with which we are more familiar. 
 
 § 105. Memory is not the simple representation 
 of phantasms or images before consciousness ; it 
 involves that, and something besides ; the additional 
 elements which it involves appear to be the 
 following : 
 
 (1.) There must be Recognition; that is, the 
 image at present before the mind is known to be 
 the same, although numerically different, as one 
 previously known. When we see the face of a 
 friend whom 'we have not seen for a long time 
 before, we recognise him, that is, we know that we 
 have seen him before ; and in the same way when 
 an image of an absent friend presents itself to the 
 mind, we recognise it. 
 
 (2.) Memory necessarily involves the element of 
 
PSYCHOLOGY OF COGNITION. 
 
 191 
 
 time. The very nature of recognition implies tliat 
 the present act of the mind has a reference to some 
 past time, and that the object recognised is believed 
 to have been previously known. 
 
 Although there may be many other circumstances 
 connected with an act of memory, yet these three 
 which we have mentioned — the simple phantasm, 
 the recognition, and the reference to a past time — 
 appear to be all the elements which are essential to 
 memory. 
 
 § 106. Memory, as a form of representation, we 
 have seen to be essentially an integrating process. 
 Some image presents itself before the mind, and we 
 recognise it, that is, we believe that we have known 
 it before in connection with a number of other 
 mental objects. The act of memory is not complete 
 until we are able to recall the other circumstances 
 with which the recognised phantasm was originally 
 connected in our knowledge. To remember a thing, 
 in short, is to posit the image of the thing in the 
 midst of a greater or less number and variety of 
 other images in connection with which we have 
 already known it. We must be able to posit it in 
 time, but as time is known to us only by a succes- 
 sion of events or images, the giving of a position in 
 time to the object of memory implies an ability to 
 say what events preceded, co-existed with, and 
 succeeded it. Hence, when we try to remember 
 an event, we are satisfied when we are able to say 
 that it occurred about the same time or soon after 
 another event with which we are more familiar. 
 
 CHAP. IV, 
 SECT. III. 
 
 Memory of 
 events in 
 time. 
 
192 
 
 THE ELEMENTS OF THE 
 
 CHAP, IV. 
 SECT. III. 
 
 Scientific 
 memwy 
 without 
 time. 
 
 And tlie greater the number of tlie circumstances 
 or events in tlie midst of whicli we are able to posit 
 the object of memory, the more complete is the act 
 of memory. These accompanying circumstances 
 may be of any kind; may be sensations of our own 
 minds, actions performed by us or others, objects 
 existing in space, even arbitrary artificial signs 
 indicating time, place, or circumstances. 
 
 § 107. There are, however, forms of memory in 
 which the reference to time does not appear to be 
 essential. A student wishes to demonstrate the 
 forty-seventh proposition of the First Book of 
 Euclid; but he has partially forgotten it. He 
 does not attempt to connect his partial knowledge 
 with anything past. He looks at the figure and 
 endeavours to recall the relations which exist be- 
 tween the different parts of which it is composed. 
 And a perfect memory of this proposition has pro- 
 bably no reference to past time at all, but is simply 
 a representation of the lines and angles of the 
 figure before the mind, with a clear perception of 
 the relations existing between them, and of the 
 conclusion which follows from the comparison of 
 these relations. Similar remarks might be made 
 with reference to our memory of other systems of 
 knowledge. . 
 
 There is also a form of memory which is involved 
 in the acquisition of practical habits, from which the 
 element of time appears to be eliminated. When 
 a musician remembers a piece of music, it is not 
 meant merely that the musical notes are represented 
 
PSYCHOLOGY OF COGNITIOK. 
 
 193 
 
 before the mind's eye in their proper order, but also 
 that he can, without hesitation or difficulty, strike 
 with his fingers upon the proper keys, and produce 
 in quick succession the sounds indicated by the 
 musical characters. And, in this case, the want of 
 memory consists in an inability to think of the par- 
 ticular series of musical notes which should follow 
 or precede some other remembered parts of the 
 piece. 
 
 Thus, perhaps, it would be more accurate to con- 
 sider recognition as the one essential characteristic 
 of memory by which it is distinguished from simple 
 representation ; and to add that when the object of 
 memory is a past event in our own lives, the act of 
 memory involves also the positing of its object 
 amongst a greater or less number of other objects 
 or events related to one another in a past time. 
 
 § 108. There is another mode of representation 
 differing from simple phantasy in having a reference 
 to time, and differing from memory in referring to 
 future instead of to past time. This we call expec- 
 tation or prevision. In the process of perception 
 this plays a very important part. The different qua- 
 lities of which an object of perception is composed 
 have been so constantly found in our experience 
 united together, that when we perceive any one of 
 them we expect to find the others. We have always 
 found that the coloured globular body which we call 
 an orange contains within it a pleasant acid juice 
 and several seeds. Whenever we see an orange we 
 expect to find within it what our past experience 
 
 o 
 
 CHAP. IV. 
 
 SECT. irr. 
 
 Expecta- 
 tion. 
 
194 
 
 TEE ELEMENTS OF TRE 
 
 CHAP. IV. 
 SECT. IIT. 
 
 tells us is likely to be there. Thus, expectation is 
 founded upon memory ; and, upon the constancy 
 and invariability of the experience with which 
 memory furnishes ns will depend the confidence of 
 our expectation. The perfection of expectation is 
 prevision. The astronomer can predict with certainty 
 when an eclipse of the moon will take place, because 
 his calculations are founded upon a long series of 
 accurately-observed and constantly and invariably- 
 recurring phenomena. The weather-casts of the 
 meteorologist do not give rise to the confident ex- 
 pectation produced by scientific prevision, because 
 the phenomena observed are exceedingly variable 
 and inconstant, and it is known that there may be 
 innumerable disturbing causes at work. In daily life 
 the principle of expectation is of the greatest practi- 
 cal importance in guiding our conduct. One of the 
 forms of superstition consists simply in founding an 
 expectation upon some sign or omen which is con- 
 nected by tradition with the event expected. The 
 slightest reflection might show the utter want of 
 connection between the sign and the object of expec- 
 tation; but the association has been formed in child- 
 hood through the instructions of parents or relatives, 
 and even after reflection has shown that it does not 
 conform to truth or reality, its power can scarcely 
 ever be completely overcome. A reasonable expec- 
 tation is founded upon the remembered or well- 
 attested experience of ourselves or others. We be- 
 come acquainted, for example, with persons, and have 
 opportunities of observing how they speak or act in 
 
FSYGHOLOGY OF COGNITION. 
 
 195 
 
 particular circumstances. We form an estimate of 
 their character, that is, we construct in our minds a 
 certain kind or class of ideal actions which we expect 
 them to perform in certain circumstances. The 
 better we know them, the greater confidence have we 
 in our expectations. Thus, in all the circumstances 
 of life, expectation, reasonable or unreasonable, is an 
 important guide of our actions ; and our success in 
 life to a great extent depends upon the carefulness 
 and ability with which our expectations are formed.* 
 
 Section IY. 
 
 kinds of representation — continued ; 
 imagination. 
 
 § 109. The power possessed by the human mind 
 of representation is exhibited in a still more import- 
 ant form than any which we have yet considered. 
 Hitherto we have studied the representing power in 
 its simpler operations, in simply recalling in their 
 natural order the objects of our previous knowledge. 
 We have now to study the power of representation as 
 combined with various other powers and exerted in 
 various interests. And in this form of the operation 
 of the representing power, we shall see that the 
 objects represented are modified and rearranged in 
 various ways to suit the design of the individual. 
 This form of representation is usually called the 
 
 * Although the most essential element of expectation is a mental 
 representation referred to a future time, yet it is in reality founded 
 upon inference, or a kind of implicit inference. 
 
 2 
 
 CHAP. ^^ 
 
 SECT. IY. 
 
 Represen- 
 tation com" 
 lined with 
 other 
 poivers. 
 
196 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. IV. 
 
 Modifica- 
 tions of 
 mental 
 pheno- 
 mena 
 caused hy 
 imagina- 
 tion. 
 
 constructive or plastic imagination, to distinguish it 
 from the simple representation of objects in phantasy 
 and memory. Before proceeding to consider the 
 most important special applications of the imagina- 
 tion, we may refer to certain general principles of 
 its operation. 
 
 § 110. The following are the most important 
 modes in which the constructive imagination is 
 found to operate : — 
 
 (1.) In imagination there may be a separation of 
 the parts or qualities of which any object is made up. 
 We can imagine a horse without its head ; a flower 
 without its colour or smell ; a bird without its wings ; 
 a human being without some quality or character 
 which he now possesses. 
 
 (2.) In imagination, parts or qualities thus 
 separated from their natural relations may be re- 
 combined so as to form new objects. Centaurs, 
 winged bulls, griflB.ns, &c., are illustrations of this 
 process. 
 
 (3.) In this reconstructive process, the elements of 
 the new object may be greatly and variously modified, 
 may be changed in shape, size, or excellence, either 
 for improvement or deterioration. Conformity to the 
 truth of nature is not at all an essential feature of 
 the products of imagination. 
 
 (4.) In imagination, when we wish to represent to 
 ourselves something unknown, we can do so only by 
 employing elements taken from things known. We 
 are frequently bound to believe in the existence 
 of things which we have not directly known, and 
 
PSYCHOLOGY OF COGNITION. 
 
 197 
 
 probably can never know. In this case tlie imagi- 
 nation clothes tlie unknown with forms taken from 
 tbe known. 
 
 (5.) In the object which the imagination constructs 
 there must be a certain congruity between the 
 elements of which it is made up in order to render 
 the imaginative act possible. To imagine a square 
 circle, for example, would be impossible. 
 
 § 111. We shall now study the operations of the 
 imagination as they are found in the most important 
 departments of human mental activity, — in science, 
 in art, in ethics, and in religion. It may perhaps be 
 thought somewhat incongruous to unite imagination 
 with science, as science is usually supposed to deal 
 only with known facts. But the truth is that nearly 
 all the great discoveries of science have been the 
 result of an effort of imagination ; and many of the 
 greatest men who have advanced scientific knowledge 
 have been men gifted with a strong constructive 
 imagination. Let us study the part which imagina- 
 tion plays in the progress of scientific discovery. 
 Some phenomenon, say the fall of rain from the 
 clouds, requires to be explained. It is observed 
 that dark clouds appear in the sky; the lightning 
 flashes, the thunder rolls ; the rain falls down in 
 torrents; the cause of all this is unknown, and 
 people set their imagination to work to think of 
 what the cause may be. In other words they frame 
 an hypothesis. Now in all cases, the nature of the 
 hypothesis framed will depend upon the nature and 
 amount of the knowledge or belief possessed by the 
 
 CHAP. IV. 
 SECT. IV. 
 
 Imagina- 
 tion in 
 science 
 illus- 
 trated. 
 
198 
 
 TEE ULmiENTS OF THE 
 
 CHAP. lY. 
 SECT. IV. 
 
 Further 
 described. 
 
 persons who frame it. The uneducated Hindu 
 peasant sees the dreadful commotion in the skies, 
 and imagines that the elephant of Indra is up there 
 throwing down the water which he has taken from 
 the sea with his trunk. If any difficulty presents 
 itself, it will soon be got over by the reflection that 
 Indra is great and can do all things. This is an 
 illustration of a very primitive kind of hypothesis 
 framed for the explanation of phenomena. But as 
 men advance, they observe more closely the phe- 
 nomena of nature. Vapour is frequently seen rising 
 from the surface of water ; especially when heat is 
 applied this takes place. At length some genius, by 
 an effort of imagination, sees the analogy between 
 the formation of clouds in the heavens and the 
 accumulation of steam in a room in which there is 
 heated water. This observation is a hint which may 
 assist in the formation of a new hypothesis. One 
 hint after another of a similar kind is taken advan- 
 tage of, until everything connected with the thunder- 
 storm is found to be analogous to some well-known 
 natural operation. Then the mind is satisfied and 
 the hypothesis becomes a theory. 
 
 § 112. The foregoing is an illustration of the 
 manner in which nearly all the most important 
 scientific discoVeries have been made. Some great 
 series of natural phenomena requires an explanation. 
 Its cause is unknown, or people are dissatisfied with 
 the explanation hitherto given. The imagination of 
 some Newton is brought to bear upon the problem. 
 His genius enables him to imagine that the unknown 
 
PSYCHOLOGY OF COGNITION. 
 
 199 
 
 cause of the phenomena in question is identical with 
 the cause of some familiar event ; he sees an analogy 
 between the phenomena, and he imagines an identity 
 of cause; the result is a new hypothesis. After the 
 formation of the hypothesis, its value requires to be 
 tested by ascertaining whether it is able to explain 
 all the phenomena. 
 
 § 113, There are hypothetical explanations of 
 phenomena which can 7iever be the objects of direct 
 observation, and in this case imagination may be 
 occupied in an endeavour to represent them before 
 the mind. The cause of the sensation of light or 
 colour, for example, is and always must be hypo- 
 thetical. The generally accepted hypothesis is that 
 the whole of space is pervaded by a very refined 
 ether, and in that ether vibrations of immense 
 minuteness and rapidity are being perpetually pro- 
 pagated in straight lines from luminous bodies. 
 These vibrations, striking upon the retina of the 
 eye, cause the sensation of light. Now in this 
 hypothesis the vibration is the essential element; 
 the ether is an hypothetical addition, invented for 
 the purpose of making the imagination of the 
 vibration possible. A vibration with nothing to 
 vibrate is inconceivable ; hence it was necessary to 
 invent an hypothetical ether in which the vibration 
 could take place. But in imagination, ether is 
 represented as simply a refined kind of atmosphere ; 
 and the vibrations are represented as analogous to 
 what we are able to observe when we look at a 
 distant object through a column of heated air. 
 
 CHAP. IV. 
 SECT. IV. 
 
 Imagina- 
 tion of hy- 
 pothetical 
 forces. 
 
200 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. IV. 
 
 Imagina- 
 tion in art. 
 
 Mechani- 
 cal. 
 
 Thus imagiDation represents the unknown cause of 
 our visual sensations by analogy from phenomena 
 which we know. We clothe the unknown with 
 forms taken from the known. But it mus.t be 
 remembered that this does not remove the hypothe- 
 tical character of the explanation. That which, from 
 its nature, can never be presented to consciousness, 
 can never be truthfully represented in imagination. 
 But yet it is necessary, when we think of hypothe- 
 tical causes which from their nature are unknown, 
 that we should imagine them as invested with a 
 phenomenal clothing in some respects analogous to 
 what we have known. Such is the limitation of the 
 human mind. 
 
 § 114 We now proceed to examine the opera- 
 tions of the imagination as found in the production 
 of works of art. 
 
 In the ordinary mechanical arts, the chief exercise 
 of the imagination is seen in the skilful adaptation 
 of means to ends. Some work requires to be done ; 
 the mechanical genius is able to see what particular 
 means, or what combination of means, will suffice to 
 do the work. The means at hand are, generally 
 speaking, of two kinds; artificial instruments, and 
 natural forces. A great deal of genius has been at 
 different timefe shown in devising plans for connect- 
 ing the latter with the former, for connecting the 
 natural forces of the world with the artificial instru- 
 ments of man's construction. The windmill, the water- 
 wheel, the steam-engine, the electrical machine, are all 
 I illustrations of this connection. And the imagina- 
 
PSYCHOLOGY OF COGNITION. 
 
 201 
 
 tion of meclianical inventors has been chiefly exerted 
 in devising scliemes for getting hold of^ governing, 
 guiding, or modifying the various forces of Nature. 
 
 § 115. In the fine arts we have a higher, 
 although perhaps not a more useful, exercise of the 
 imagination. Poetry, painting, sculpture, music, 
 and architecture are the usually recognised fine arts. 
 In the whole of these the imagination is exercised in 
 calling up and combining images in the mind fitted 
 to express or to excite some emotion. The artist 
 exerts his skill generally for the cesthetic purpose of 
 exciting pleasant emotions. But art is also frequently 
 employed to excite in the mind emotions of sub- 
 limity, fear, horror, or disgust. In all cases the imagi- 
 nation is exerted in the construction of an object or 
 the composition of a work which will be fitted to call 
 forth in the mind of the observer the particular 
 emotion, or combination of emotions, designed to be 
 produced. And generally speaking, it is by the 
 study of Nature and the construction of the work of 
 art after the analogy of Nature that the designed 
 effect can be successfully brought about. The artist 
 can only employ the materials which Nature gives 
 him, and whether he tries merely to imitate Nature 
 or to produce something better than Nature, his 
 imagination must be employed in moulding, re- 
 forming, or idealising natural things. 
 
 § 116. In poetry the physical material with which 
 the artist produces his effect is language. But the 
 words are only the signs of the mental objects of the 
 poet's imagination ; and it is in the calling up and 
 
 CHAP. IV. 
 SECT. IV. 
 
 Poetry. 
 
202 
 
 TEE ULBMENT8 OF TEE 
 
 CHAP. IV. 
 SECT. IV. 
 
 arrangement of these mental objects that the 
 poetical imagination consists. Hence versification, 
 rhyme, and other mechanical contrivances are not 
 essential to the poet's art. If the language employed 
 is fitted to call up the same ideas in the mind of the 
 hearer as in the mind of the poet, that is all that is 
 required of it. The aim of the poet then is, by 
 means of words, to conjure up before the mind of his 
 hearer or reader, images of such a nature as will 
 excite the special kind of emotion which he desires 
 to excite. There are various species of poetry in 
 which this is attempted, and perhaps it is difficult to 
 find amongst them a common characteristic. But 
 generally speaking it appears essential to the produc- 
 tion of the effect that there should be a certain illu- 
 sion produced on the mind of the hearer. He must be 
 made for the moment to believe in the reality of what 
 he only imagines. The true artist realises the pro- 
 ducts of his imagination. Hence a highly poetical ima- 
 gination is sometimes thought to be akin to madness. 
 
 Lovers and madmen have such seething brains, 
 
 Such shaping fantasies that apprehend 
 
 More than cool reason ever comprehends. 
 
 The lunatic, the lover, and the poet 
 
 Are of imagination all compact. 
 
 One sees more devils than vast hell can hold — 
 
 That is the madman ; the lover, all as frantic, 
 
 Sees Helen's beauty in a brow of Egypt. 
 
 The poet's eye, in a fine frenzy rolling, 
 
 Doth glance from heaven to earth, from earth to heaven, 
 
 And as imagination bodies forth 
 
 The forms of things unknown, the poet's pen 
 
 Turns them to shapes, and gives to airy nothing 
 
 A local habitation and a name. 
 
 M. N. D.~Act V. Sc. 1. 
 
PSYCHOLOGY OF COGNITION. 
 
 203 
 
 §117. The most important objects of the poet's 
 imagination are scenes in Nature, historical events, 
 facts of human life, different types of human 
 character, and the various objects of the unknown 
 spiritual world. All these classes afford innumerable 
 and infinitely varied objects suitable for tbe ex&f^ 
 ment of the most varied emotions in the human 
 mind. It would be impossible within our limited 
 space to enter into a full discussion of the quesUons 
 which suggest themselves in connection with, this 
 subject. But there are two types of the poetical 
 imagination to wbicb we must refer. One of these 
 we may call tbe descriptive ; the other, the dramatic. 
 In tbe former there is an ability to describe scenes 
 and events, it may be with great accuracy and great 
 beauty, as seen from the poet's own subjective stand- 
 point ; in the latter there is an ability to construct an 
 ideal character, quite distinct from the poet's own 
 character, and imagine the feelings, words, and 
 actions suitable to that character. Byron is an 
 illustration of the first ; Shakespeare of the second. 
 Byron's Childe Harold is admirable, because it is 
 descriptive, and he was able to describe with elegance, 
 and indulge in the most appropriate reflections 
 regarding the object of his description. Byron's 
 dramas are failures, because every character is simply 
 himself disguised. Shakespeare was able com- 
 pletely, in his dramatic efforts, to divest himself of 
 his own character, as it were, and assume that of the 
 person whom his imagination created. Thus he was 
 able to construct a wonderful variety of characters ; 
 
 CHAP. IV. 
 SECT. IV. 
 
 Suhjects of 
 poetry. 
 
 
 Types of 
 poetical 
 imagina- 
 tion. 
 
204 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. IV. 
 
 Fainting 
 and sculp- 
 ture. 
 
 and in every case he lias ascribed to them the 
 feelings^ words, and actions which everybody will 
 acknowledge as natural to these characters. In this 
 wonderful power of forgetting himself and being 
 able to imagine how all kinds and descriptions of 
 people felt and would naturally act in particular 
 circumstances lies the greatness of Shakespeare. 
 
 § 118. Painting and sculpture differ from poetry 
 in being more restricted as to the objects presented 
 to the imagination and in employing a different 
 material as the sign of those objects. The poet can 
 roam unrestrained in every field which his imagina- 
 tion can reach ; the painter and the sculptor can only 
 represent what were originally objects of sight. In 
 a very primitive period of the history of civilisation, 
 in Egypt, in Babylon, and in India, the sculptor's art 
 was usually employed in the representation of the 
 national ideas of the deity. The huge size and the 
 grotesque construction of the figures which have been 
 preserved to this day, reveal to us the nature of the 
 religious imagination of the people of these old days. 
 The different parts of human and animal bodies, 
 fearfully exaggerated in size and proportions, and 
 strangely combined together, are formed by the artist 
 into huge and uncouth figures, intended to express 
 the qualities' which the people attributed to their 
 deities. In Greece, the painter's and the sculptor's 
 art became more natural ; the imagination was 
 exercised to produce beautiful figures and features 
 which should imitate, or even emulate, Nature ; the 
 exaggeration and the grotesqueness of the old artists 
 
PSYCHOLOGY OF COGNITION. 
 
 20! 
 
 were discarded, and art was cultivated for the sake of 
 grace and beauty. The artist did not merely seek to 
 express with truthfulness the beauty of Nature, but 
 by combining the most beautiful forms which could 
 be discovered into one figure, or by idealising those 
 combinations of features or qualities which are 
 found in Nature, he sought to surpass the beauty of 
 Nature in his imaginary beau-ideal. 
 
 § 119. Music, like the other fine arts, was origin- 
 ally enlisted in the service of religion. Like poetry 
 it appeals to the sense of hearing instead of the eye ; 
 but its material consists of musical notes instead of 
 articulate words. The arts of the musician and the 
 poet were originally usually combined together ; the 
 bard chanted his own or other people's productions. 
 But in time a partial separation took place, and the 
 art was cultivated for the sake of the pleasing- 
 emotions excited by the melody and the harmony 
 of musical sounds. The power of music over the 
 emotional part of man's nature is illustrated in the 
 mythical legends of ancient times regarding Orpheus 
 and his lyre; we have a fine description of it in 
 Dry den's famous Ode on Alexander's Feast ; and in 
 the musical recitations by the Indian pandits of the 
 Kamayana and the Mahabharata in the present day 
 we have a survival of what was no doubt common in 
 Homeric and Yedic times. The effort of the imagi- 
 nation in music is exerted not merely to produce a 
 succession of pleasing sounds, but chiefly to produce 
 a succession of sounds which will harmonise with and 
 express certain emotions. It is this relation of the 
 
 CHAP. IV. 
 SECT. IV. 
 
206 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. IV. 
 
 musical sounds to our emotional nature wliicli gives 
 to music all its power. There is one style of music 
 suited to cheerful, social festivities ; another to the 
 mournful solemnities of the funeral procession, 
 another to the measured tread of armed men ad- 
 vancing to the field of battle. And the art of the 
 musician is exhibited in adapting his musical com- 
 positions to the nature of the emotions which he 
 wishes to excite, or with which he wishes his piece 
 to harmonise. 
 
 § 120. The art of architecture originated in an 
 attempt to beautify and adorn the temples of religion 
 or the houses of the wealthy. There is, therefore, in 
 this art a combination of beauty with utility. A 
 regard to usefulness and stability, therefore, ought to 
 govern the architect in deciding upon the principal 
 parts of the building ; these qualities being secured, 
 the imagination is at liberty to add such lines and 
 figures of beauty as may seem suitable. The art of 
 the architect at different times has invented a con- 
 siderable variety of style in the structure and orna- 
 mentation of buildings, for a description of which we 
 must refer the reader, who wishes to pursue the 
 subject, to the numerous works of professional men 
 who have devoted themselves to the subject. 
 
 We have* now concluded our brief account of the 
 different special modes in which the constructive 
 imagination of the artist operates, and with one 
 remark we dismiss the subject. The exercise of the 
 imagination in the study or in the construction of 
 works of art is fitted to have an ennobling and 
 
PSYCHOLOGY OF COGNITION. 
 
 207 
 
 refining effect upon the mind. It turns away tlie 
 attention from gross, vulgar, and merely sensuous 
 objects; and, if properly directed, cultivates those 
 liiglier and purer emotions which, give to human life 
 its best pleasures and to human character its greatest 
 excellences. 
 
 Section Y, 
 
 kinds op eepeesentation continued j imagination 
 
 in ethics and eeligion. 
 
 § 121. In practical life the activity of men is 
 directed to the attainment of some End. The Ends 
 which men propose to themselves are very various ; 
 pleasure, wealth, power, fame, and many others. 
 But in every case the End of a man's life is the 
 product of his constructive imagination; it is an 
 ideal composed of all the elements which, from his 
 nature, he is led to think desirable. The ethical 
 ideal must always be constructed out of materials 
 furnished by the actual. In our experience we 
 enjoy many pleasures ; but we think of pleasures 
 better and more lasting than those. In our expe- 
 rience we perform, or we witness performed by 
 others, actions which we approve of, which we con- 
 sider praiseworthy; but we are able to conceive 
 better, more generous, or more noble actions. In 
 short, we are able in our imagination to rise, as it 
 were, above our experience, and from what is to 
 construct the ideal of what ought to be. "We are 
 not here concerned with the nature of the power 
 
 CHAP. IV. 
 SECT. V. 
 
 The ethical 
 ideal. 
 
208 
 
 TEE ELEMENTS OF THE 
 
 CHAP. IV. 
 SKCT. V. 
 
 The ideal 
 
 introduces 
 
 conflict. 
 
 Formation 
 of ideal. 
 
 hj whicli we are able to perceive the ought or duty. 
 That is a question of ethics. But we may examine 
 briefly the nature of the process by which the 
 ethical ideal is constructed. 
 
 § 122. In all men there are certain primary dis- 
 tinctive impulses and springs of action — appetites, 
 desires, passions. A person who is completely under 
 the control of these, who is governed by them with- 
 out reference to the feelings or the interests of 
 others, is absolutely immoral. To be moral implies 
 that these natural impulses are controlled and regu- 
 lated by the voluntary power of the individual with 
 reference to some worthy end. But they will never 
 be controlled unless the individual sees that their 
 uncontrolled exercise leads to evil, that is, unless he 
 sees that there is some higher good to be attained 
 by controlling them. The conception of this higher 
 good is the ideal which he forms. The general 
 effect of the formation of an ethical ideal is to make 
 one dissatisfied with himself, to make him feel that 
 there is an excellence of character to which he has 
 not yet attained. There is thus a conflict produced 
 between the actual impulses and desires on the one 
 hand, and the ethical ideal on the other, as to which 
 of the two shall govern the conduct. The result of 
 this conflict' is of the most momentous importance 
 to the happiness and welfare of the individual. 
 
 § 123. With reference to the history of the for- 
 mation of the ethical ideal it is difficult to speak with 
 definiteness. The ideal of one person is often widely 
 different from that of another; of one nation from 
 
FSYCHOLOGY OF COGNITION. 
 
 209 
 
 that of another. There can be no doubt but an ideal 
 of some kind is usually formed by every one by 
 means of reflection upon the comparative worth of 
 different aims or objects in life. But the greatest 
 influence is exerted by people or nations coming 
 into contact with those who have higher moral 
 conceptions than themselves. The power which 
 a man of true moral worth sometimes possesses 
 in guiding the formation of an ethical ideal in 
 the minds of others is very great. Thus it is true 
 in the history of morals that it is very slowly and 
 with great difficulty, if at all, that an isolated race 
 can rise to a higher moral elevation; while the 
 influence of an individual or of a nation possessed 
 of high moral qualities upon a race not so favoured 
 is sometimes enormous. 
 
 § 124. The efforts of the imagination in religion 
 are chiefly exerted in constructing a representation 
 of the object of religious worship. Amongst lower 
 and uncivilised races the imagination is usually 
 assisted by the mechanical construction of actual 
 material idols or images. But the representation of 
 Deity under material forms degrades our conception 
 of a spiritual Being, and amongst all monotheistic 
 races the representations of the Deity are mental. 
 The idea of Deity which the human imagination 
 constructs has varied greatly at different times and 
 amongst different peoples. It is also a very complex 
 idea, perhaps the most complex which can be formed. 
 But the most important elements which have been 
 comprehended in it appear to be the following : The 
 
 CHAP. IV. 
 SECT. V. 
 
 Idea of 
 God. 
 
2IO 
 
 TEE ULEMENTS OF TEE' 
 
 CHAP. lY. 
 SECT. V. 
 
 Keiigious 
 ideal 
 founded, 
 on ana- 
 logy. 
 
 Deity is imagined as the all-powerful and all- 
 intelligent First Cause, the Moral Governor, and the 
 Universal Father. The first of these elements of the 
 conception identifies God as the source and the guide 
 of the various physical forces of Nature; the second 
 attributes to Him the moral control, that is, the 
 rewarding and punishing of human actions; the 
 third represents Him as having a direct and special 
 interest in the welfare of all His creatures. 
 
 § 125. Much might be said regarding the diflSculty 
 of uniting these various elements in one complex 
 representation, and regarding the many very im- 
 perfect and distorted conceptions which have been 
 formed. But we can at present only point out that 
 the imagination can construct the idea of God only 
 by analogy from things known. And as the qualities 
 of our own human nature, either known to ourselves 
 by consciousness or presented to ns in the lives of 
 others, are the most noble objects of our experience, 
 they are naturally the types from which our con- 
 ception of Deity is formed. The idea of God as our 
 moral Euler and our Father being constantly kept 
 before the mind, there can be no doubt but the 
 influence of this idea over conduct and life is greater 
 than that of any other. When, by an individual, 
 duty is performed and good is done '' as ever in his 
 great task-master's eye,^^ there is the highest 
 attainable guarantee that he is worthy of any trust 
 which may be reposed in him. 
 
PSYCHOLOGY OF COGNITION. 
 
 211 
 
 CHAP. IV. 
 SECT. VI. 
 
 Section VI. 
 
 PECULIAEITIES OF EEPEESENTATION. 
 
 § 126. There are great differences between dif- 
 ferent people with reference to their power of re- 
 calling particular classes of facts. Some people have 
 peculiar ability in remembering names; others in 
 remembering faces; others in remembering dates. 
 It may perhaps be assumed as a general principle 
 that when any event or circumstance has excited a 
 strong interest in an indi vidua? s mind, it will be 
 easily and readily recalled afterwards. The power 
 of memory may be very greatly cultivated by a 
 suitable kind of training. Generally speaking it 
 may be laid down as a rule, that the cultivation of 
 the habit of giving close attention to any subject 
 of study and obtaining a comprehensive and syste- 
 matic knowledge of it is the most important con- 
 dition of being able afterwards to recall it. There 
 are, however, many artificial systems of mnemonics 
 which chiefly depend upon some principle of associa- 
 tion. Particular names or particular dates are 
 associated in pronunciation with some arbitrary sign 
 which serves to recall that which is signified. Some 
 system of this kind is frequently resorted to for the 
 purpose of enabling students to pass examinations. 
 An artificial system of mnemonics of this kind is 
 about as useless as the system of examination which 
 renders it necessary. 
 
 p 2 
 
 Illustra- 
 tions of i^e- 
 culiarities, 
 
212 
 
 THE ELEMENTS OF THE 
 
 § 127. There are many peculiarities which, we 
 might mention in the series of representations which, 
 in the minds of different persons, are suggested by 
 particular objects. To different travellers going 
 along a road or visiting places of interest, the objects 
 presented to the eye will suggest to the mind 
 widely different lines of reflection. The artist, on 
 visiting the Falls of Niagara will admire the grandeur, 
 the sublimity of the scene ; the practical uncultured 
 American will think of the great loss of water- 
 power which might be utilised in driving number- 
 less mills. The followers of particular professions 
 have peculiar lines of reflection naturally suggested 
 to them by the objects of their knowledge. These 
 peculiarities in the series of representations depend 
 upon the circumstances of the individual, upon age, 
 sex, country, education, social position, prevailing 
 feature of character, and many other things which 
 might be specified. 
 
 That which gives to this subject its greatest im- 
 portance is the practical effect exerted upon one's 
 character and welfare by the spontaneous series of 
 representations which pass through the mind. The 
 mind is very injuriously affected by continually 
 indulging in thoughts of sensuous pleasures, by 
 cherishing feelings of anger or unworthy suspicions 
 towards others, by thinking always of difficulties and 
 hardships and thus taking a gloomy view of life. 
 And it should be remembered that there is a cer- 
 tain voluntary power which every one has to a 
 certain degree, and ought to cultivate, of regulating 
 
PSYCHOLOGY OF COGNITION. 
 
 213 
 
 and controlling the representations of his mind. By 
 a voluntary effort one is able to banish from his 
 mind evil and injurious reflections, and dwell upon 
 those of a better and more ennobling kind. And 
 the exercise of this voluntary power is perhaps the 
 most important element in self-culture. There is 
 scarcely any power which one can possess so valu- 
 able to him as that of self-control, and this not 
 merely the control of external expression and action, 
 but of the feelings and thoughts of the mind. 
 
 § 128. In the constructive imagination also there 
 are important differences to be noted between dif- 
 ferent individuals. And here, perhaps to a greater 
 extent than in any other department of the human 
 mind, we may observe inherited peculiarities. Poet a 
 nascitur, nonfit. The mechanical genius, the poet, 
 the musician, the painter, the sculptor, and the 
 architect, if they are not mere mechanics, but 'poets, 
 malcers, men of creative genius, are horn. They 
 bring with them into the world the capabiHties of 
 becoming what they afterwards become, and what 
 they could never become were it not for the inborn 
 genius which they have brought with them. Ee- 
 markable examples might be given of persons who, 
 at a very early age, have exhibited powers in mathe- 
 matics, in music, in poetry, in sculpture, which 
 could not possibly have been acquired by education, 
 and which must have been inherited. But from 
 whom the inheritance has been derived, and how it 
 has been transmitted, will probably always remain 
 insoluble problems. 
 
 CHAP. IV. 
 SECT. YI. 
 
 Peculiari- 
 ties in con. 
 structive 
 imagina' 
 Hon. 
 
214 
 
 THE ELEMENTS OF THE 
 
 Section VII. 
 
 repeesentation of abstractions. 
 
 § 129. It is frequently necessary to withdraw the 
 mind from some of the qualities of objects for the 
 purpose of giving undivided attention to others. 
 This process is called abstraction. The quality or 
 qualities to which attention is given are properly 
 said to be prescinded from the others ; the mind is 
 properly said to be abstracted from the qualities to 
 which attention is not given. In ordinary usage^ 
 however, this distinction is not attended to, and the 
 quality singled out for special attention is said to 
 be abstracted from the others, and is usually called 
 an abstraction. There may be abstraction from in- 
 dividual objects of perception, as where the colour 
 or the figure of an object is attended to apart from 
 its other qualities. And we have now to consider 
 how the representative faculty operates with refer- 
 ence to these abstractions. 
 
 § 130. Considering first the qualities of a body 
 which correspond to special sensations, we observe 
 that their presentation can be effected only by the 
 help of the special organ of sensation concerned in the 
 original intuition. A colour can only be represented 
 in connection with the eye ; a smell in connection 
 with the nose ; and so on. Thus by the aid of the 
 organs of sense a representation may be made of 
 particular qualities abstracted from an object. But 
 
PSYCHOLOGY OF COGNITION, 
 
 215 
 
 tliere is a series of so-called qualities, consisting of 
 extension, figure, position, and other modes of space 
 whicli must not be confounded with those qualities 
 that are the correlatives of sensations. Qualities 
 that are the correlatives of sensations are represented 
 by the aid of the one special sense-organ with 
 which they are peculiarly connected. Extension 
 may be represented in connection with any sensa- 
 tion located anywhere in the sensorium, but notably 
 in connection with the sensations of colour and the 
 tactual sensation. It is to be observed further that 
 the connection in representation between the 
 phantasms of colour and touch on the one hand, and 
 the idea of extension on the other, is inseparahle. It 
 is impossible to represent a colour or a tactual 
 sensation except as occupying some form of space. 
 And in so far as any sensation is specially located 
 in any part of the sensorium, the same inseparable 
 connection with some form of space is found to exist. 
 "We conclude then that we are able to represent the 
 qualities of bodies which correspond to our sensa- 
 tions apart from one another ; that we can make 
 abstraction of the colour, or the smell, or the hard- 
 ness, or the taste of an object, and represent any one 
 of them apart from the others. But when we 
 attempt to represent colour or hardness, we are com- 
 pelled to join some form of extension with them ; 
 there is such an inseparable connection between the 
 two that a separation, even in thought, is impossible. 
 § 131. Let us consider now the nature of our 
 representation of extension or space. Extension or 
 
 CHAP. IV. 
 SECT. VII. 
 
2l6 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. VII. 
 
 Of space or 
 extension. 
 
 space, coDsidered apart from theobjects whicli occupy 
 it, is undoubtedly an abstraction. Extension, we 
 liave seen, is the form of whicli the colour,hardness, 
 and other qualities of bodies are the matter. And 
 the question arises whether we can represent the 
 form apart from the matter; we have already seen that 
 we cannot represent the matter apart from the form, 
 and a little reflection will convince us that the reverse 
 is equally true. The representation of pure space or 
 pure empty extension is an impossibility. For when 
 we attempt to represent space, we invariably do so by 
 thinking of the possibility of moving through it. We 
 think that no matter how far we travel through space, 
 there is still a possibility of going farther. And if 
 we attempt to conceive a limited portion of space we 
 must do so by connecting it with some sensible boun- 
 dary, or some collections of qualities, or some pos- 
 sibilities of motion. This impossibility of representing 
 pure space, apart from the idea of some qualities 
 occupying it or some objects moving through it, 
 might be inferred from the nature of our conception 
 of space. It is an abstract formed from particular 
 relations of extension. But extension is the form of 
 intuition, the form in which objective phenomena are 
 perceived. But the form of phenomena is not itself 
 a phenomenon^ and we therefore need not expect it 
 to be capable of being represented as one. The 
 doctrine which we have maintained regarding 
 our representation of space does not affect the 
 question as to the nature of its actual objective ex- 
 istence. That is a question which belongs rather to 
 
PSYCHOLOGY OF COGNITION. 
 
 217 
 
 metapliysics than psychology, and which, therefore, 
 we shall not at present discuss. 
 
 § 132. In considering the possibility of represent- 
 ing logical abstractions we must anticipate a little, 
 and suppose the reader to be familiar with the nature 
 of the process to be afterwards described. The great 
 majority of the words in every language are the 
 names of classes of objects, as man, triangle, tree, 
 river ; and the question we have at present to con- 
 sider, is how, if at all, can we represent to our minds 
 the objects indicated by words such as these ? And 
 it must be remembered that there are in Nature no 
 things corresponding to these general names. There 
 are plenty of individual men, tall or short, black, 
 white, brown, or olive ; but there is no such thing as 
 man in general as distinguished from particular in- 
 dividuals. So there are triangles, equilateral, scalene, 
 right-angled, and so on; but triangle in general is 
 unknown. A little reflection will show not only that 
 such a thing as man in general does not exist in 
 Nature, but that it is incapable of being represented 
 in the imagination. For if we attempt to represent 
 what we mean by man to our mind, we shall find 
 the representation assuming some particular form 
 and colour, and other qualities. We cannot help it. 
 And in the same way of all other names which indi- 
 cate classes of objects. It is impossible to represent 
 the connotation of a general name, as for example, 
 triangularity, without bringing in along with it, more 
 or less definitely, the other qualities or parts belong- 
 ing to some particular objects of the class. 
 
 CHAP. IV. 
 SECT, VI r. 
 
 Logical 
 abstrac- 
 tions. 
 
2l8 
 
 THE ELEMENTS OF TEE 
 
 CHAP. IV. 
 SECT. VII. 
 
 Difficulty 
 stated and 
 obviated. 
 
 § 133. It may be asked, then, how are we able to 
 understand the definition of a class of objects, as, for 
 example^ a triangle is a figure bounded by three 
 lines ? Into the definition there are not introduced 
 any peculiarities belonging to particular triangles, 
 and yet we are able to understand its meaning. The 
 explanation of this is probably to be found in the 
 relation between language and the object of thought. 
 When a word has become attached to a particular 
 object or class of objects, it may frequently be used 
 without bringing into the mind the things denoted 
 by it. And especially when words have become very 
 familiar, they are joined together in propositions, and 
 the propositions are assented to, although there is in 
 the mind no attempt to realise their meaning. Thus 
 a familiar proposition such as, A triangle is a three- 
 sided figure, is listened to ; it has been thoroughly 
 understood long ago, and deposited in the memory 
 as something to be received without question; and 
 consequently when the proposition is pronounced it 
 excites no mental activity except a vague belief that 
 it is quite correct. But if an attempt be made to 
 realise a general name, or to understand a proposition 
 in which a general name is the subject, there must 
 be a representation of a more or less complete and 
 definite object. 
 
 § 134 The employment of words indicating 
 classes, or general qualities, or general modes of 
 action, as if they represented real things, has led to 
 many erroneous conclusions. And consequently it 
 is important that words and propositions should be 
 
PSYCHOLOGY OF COGNITION'. 
 
 219 
 
 frequently tested by attempting to realise their mean- 
 ing, that is, by attempting to form a representation in 
 the mind of the things which they denote. For ex- 
 ample, if such a collocation of words be formed as, a 
 square triangle, its illegitimacy would be at once 
 seen by an attempt at representation. The idea of 
 squareness and of triangularity are incongruous; they 
 cannot be joined together in the same representation. 
 Thus the possibility of representation is an important 
 test of truth. It must not, however, be accepted as a 
 test without certain limitations. There may be re- 
 presentations formed which have no corresponding 
 object in Nature. The formation of a centaur or any 
 other monstrosity is quite possible and quite common. 
 And thus the possibility of uniting in a representa- 
 tion any given number and kind of elements or 
 qualities is no guarantee whatever of objective truth. 
 But^ on the other hand, the impossibility of represen- 
 tation is, in certain circumstances and cases, the only 
 test of truth which we possess. For example, in the 
 proposition — Two straight lines cannot enclose a 
 space — the absolute incompatibility between the re- 
 presentation of two straight lines and that of an 
 enclosed space is to us the guarantee^ and the only 
 guarantee^ of the truth of the proposition. And we 
 might refer to certain other simple propositions 
 regarding primary objects of intuition in which 
 inconceivability is unquestionably the test of truth. 
 § 135. When, however, we take into consideration 
 highly complex objects of thought, it becomes much 
 more difficult to apply the test. An apparent im- 
 
 CHAP. IV. 
 SECT. vir. 
 
 Realising 
 of abstrac' 
 tion. 
 
 Test of 
 truth. 
 
 The test 
 applied to 
 complex 
 objects. 
 
220 
 
 TEE ELEMENTS OF THE 
 
 CHAP. IV. 
 SECT. VII. 
 
 General 
 idea has no 
 separate 
 existence. 
 
 possibility of representation frequently arises simply 
 from want of experience. For example, a prince of 
 Siam once found it impossible to conceive water 
 becoming solidified into ice. Ignorant rustics can- 
 not conceive the possibility of fish, flying through the 
 air. These and other examples show that there may 
 be an apparent impossibility of conception arising 
 from the want of having had the requisite experience, 
 and that the inconceivability must not be taken as a 
 test of truth until it has been criticised and its 
 nature discovered. 
 
 § 136. We have seen that it is impossible to 
 represent a general idea, as that of man, triangle, 
 except in connection with some particular individual 
 belonging to the class. And this impossibility is 
 taken as a sufficient guarantee that the general idea 
 has no objective existence except as found in indi- 
 viduals. This is true of all general ideas connoted 
 by general names, and formed by a process of logical 
 abstraction. For example, one of the most abstract 
 of all ideas is that of Being ; but it is impossible to 
 represent Being except as a predicate of particular 
 existing things, and consequently it is absurd to 
 speak of Being as having any objective reality^ 
 Similar remarks might be made regarding other 
 logical abstractions, such as The Absolute, The 
 Infinite. The same impossibility of representation 
 holds good with reference to them, and the same 
 absurdity is seen in attributing to them objective 
 reality. 
 
 § 137. There is another fallacy connected with 
 
PSYCHOLOGY OF COGNITION. 
 
 221 
 
 representation to whicli we must refer. There are 
 certain uniformities in tlie operations of Nature 
 which, being observed, are collected together and 
 expressed in what are called Laws of Nature. For 
 example, it is observed that material bodies always 
 show a tendency to move towards one another when 
 obstacles preventing them are removed. But 
 amongst the heavenly bodies, when there is no 
 apparent obstacle to prevent a general collision, it 
 is found that certain bodies, the planets, move in 
 elliptical orbits round central bodies of a larger size. 
 Now, by many careful observations the laws of the 
 motion of bodies in free space with reference to one 
 another have been discovered. But these laws are 
 merely expressions of the relations observed to exist 
 amongst phenomena. And when we attempt in 
 imagination to make a representation of a Law of 
 Nature, we cannot do so except by imagining a variety 
 of objects related to one another in such and such 
 ways. To attribute independent reality to a Law 
 of Nature, therefore, is illegitimate. And yet 
 we frequently hear Laws of Nature spoken of as 
 being causal agents, as producing the phenomena of 
 whose order and mutual relations they are simply 
 an expression. Generalisation from a number of 
 facts of falling bodies gives no force of gravitation, 
 but only the general truth that bodies fall when 
 unsupported, and this can never be a cause. 
 
 § 138. We have hitherto considered the possibility 
 or impossibility of representation as a test of truth 
 with reference to the actual or possible objects of our 
 
 CHAP. IV. 
 SECT. VII. 
 
 Laws of 
 Nature as 
 repre- 
 sented. 
 
 Represen- 
 tation of 
 non-phe- 
 nomenal 
 causes. 
 
222 
 
 THE ELEMENTS OF THE 
 
 CHAP. IV, 
 SECT. VII. 
 
 experience. But there are some things about which 
 we speak and reason which never have been, and 
 probably never can be objects of experience. These 
 are the hypothetical non-phenomenal causes which 
 we postulate to account for the existence of observed 
 phenomena. As an example we may give Force. 
 We are able to observe motion, that is, a relative 
 change of place amongst bodies. We ourselves 
 exert effort when we find some solid body in our way. 
 That which causes the change of motion and that 
 which resists our muscular effort is not observed 
 except in and through the motion and the effort. 
 The inference of an objective Force independent o£ 
 the motion and the effort is simply an hypothesis 
 which we make to satisfy our own minds by account- 
 ing for the existence of the phenomenon. Moreover, 
 this hypothetical Force can never be an object of 
 experience ; if it were to come within our experience, 
 it would be a phenomenon, and require itself to be 
 accounted for. The only way in which we can in- 
 crease our knowledge of this Force is by learning 
 how many kinds of phenomena it is capable of pro- 
 ducing. We might, for example, have reason to 
 conclude that the same Force which produced motion 
 and resistance, was also the cause of heat and light, 
 and the phenomena of electricity. The only way in 
 which we can represent this Force to the mind is 
 by investing it with some phenomena of which it is 
 regarded as the cause. And yet we know that this 
 is not a true representation. We know that that 
 which from the nature of the case can never be 
 
PSYCHOLOGY OF COGNITION. 
 
 223 
 
 presented to us as a phenomenon is not truly 
 represented as one. Now liere we liave a recog- 
 nised impossibility of representation which, is not 
 accompanied by a rejection from our belief of the 
 hypothetical entity. And the peculiarity of this 
 case appears to be that the entity in question is of 
 such a nature that it can never^ by any increase of 
 our knowledge^ become an object of our experience. 
 And yet we cannot in consequence of the impossi- 
 bility of representing it reject it from our belief, 
 since it is necessary to satisfy a want in our mental 
 nature, a desire to account for the existence of phe- 
 nomena which we know are neither produced by 
 ourselves nor self-existent. 
 
 CHAP. IV. 
 SECT. VII. 
 
224 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. I. 
 
 Process 
 illus- 
 trated. 
 
 CHAPTER V. 
 ELABORATION OF KNOWLEDGE. 
 
 Section I. 
 
 PEEDICATION. 
 
 § 139. We now advance to the study of the 
 highest psychological process which we propose to 
 consider, and which we have designated by the name 
 Elaboration. We have already studied many illus- 
 trations of this process in the preceding portions of 
 our essay; and we are now to examine into the 
 nature of the process itself. A few remarks will 
 make clear to us the general character of the prob- 
 lems which we must endeavour to solve. We see an 
 object before us; we affirm that it has four legs and 
 a head, and a mane and a tail; we call it a horse; 
 we say that it is an animal, or a vertebrated animal, 
 or a mammal. Now the question is. How or why do 
 we make all these assertions ? What mental pro- 
 cesses are expressed in these assertions ? Again we 
 assert that the exterior angle of every triangle is 
 equal to the two interior and remote angles; by 
 what mental process have we been able to make such 
 an assertion ? Or perhaps we affirm that the earth 
 is a spheroidal body revolving round the sun; or 
 
PSYCHOLOGY OF COGNITION: 
 
 225 
 
 that the sun and all its accompanying planets are 
 speeding rapidly through space. How are such 
 propositions as these reached by our minds ? Or 
 further we may assert that Alexander the Grreat was 
 the conqueror of Persia, or that Gautama Buddha 
 was the founder of a wide-spread form of religion ; 
 why do we make such affirmations ? In short, there 
 are a great many things which we know, although 
 they are not immediately under the observation of 
 our senses ; there are a great many things apparently 
 very different from one another which we connect 
 together in various ways in our minds ; there are a 
 great many things which we firmly believe, although 
 they have never been immediately known to us at all. 
 Knowledge and belief of these various kinds are the 
 result of a process which we have called Elaboration, 
 and which has been variously denominated. Thought, 
 Reasoning, Reflection, and so on. Our duty at pre- 
 sent is to examine the nature of our mental activity 
 in this process of enlarging and elaborating our 
 knowledge. 
 
 § 140. If we examine any part of our knowledge, 
 whether the simplest or the most elaborate, we shall 
 find that there is one manner in which it is uniformly 
 expressed. When we look at an object before us 
 we assert " That is white,'' or "That has four legs,'' 
 or '* That is a horse.'' When we compare different 
 classes of objects together we assert " A horse is 
 an animal," or " The sun is a luminous body." 
 The result of any process of elaboration is a men- 
 tal assertion of something or other. This result, 
 
 Q 
 
 CHAP. V. 
 SECT. I. 
 
 Predica- 
 tion ex- 
 plained. 
 
226 
 
 THE JELEME2TTS OF THE 
 
 CHAP. V. 
 SECT. I. 
 
 Further 
 explained. 
 
 expressed in language, we shall call Fredication. 
 In a certain sense, we have predication in the very 
 simplest act of consciousness ; as when there is a con- 
 sciousness of any simple sensation, there is a mental 
 assertion or acknowledgment of the existence of that 
 sensation. That a particular sensation, say of heat, 
 or colour, or smell, exists is the expression of the 
 conscious act in which it is known. But this implicit 
 assertion of existence regarding the simple objects of 
 consciousness can scarcely be called Predication as 
 we must understand Predication in its present con- I 
 nection. Another illustration will make clear what 
 we mean. An object of perception is before us ; it is 
 yellow, heavy, tasteless, and of a rounded irregular 
 figure ; the name gold has been associated with it ; l 
 by a little experimenting we discover that it yields 
 and changes its form by repeated strokes of the 
 hammer. We assert, ^' This piece of gold is malle- 
 able.^^ In other words, we predicate a certain quality, J 
 malleability, of the object, that is of the aggregate 
 collection of qualities which we called gold. And 
 our predication here means simply that the quality 
 malleability co-exists with a certain number of other 
 qualities to which there has been attached a certain 
 sound, gold. Predication in this case is the assertion 
 that one ohfect of our Imoivledge, a particular quality, 
 hears a certain relation, that of co-existence or co- 
 inclusion, to another object of our hnowledge, an 
 aggregate of qualities having a special name. 
 
 § 141. If we take any other case of predication 
 we shall find something similar. We see two sticks 
 
PSYGEOLOGY OF GOGNITION. 
 
 227 
 
 CHAP. V. 
 SECT. I. 
 
 or two lines placed side by side, and we perceive 
 them to be either equal in length or unequal. We 
 predicate that the one is equal or unequal to the 
 other ; or that the one object of our knowledge 
 bears a certain relation, that of equality or ine- 
 quality, to another. Similarly, there may be two 
 colours placed before us ; we predicate that the one 
 of them bears to the other a relation of similarity 
 or dissimilarity. So, when one object of conscious- 
 ness is observed to appear immediately before or 
 immediately after another, we predicate that the 
 one bears a certain relation, that of antecedence or 
 sequence to the other. Thus in all cases it will be 
 found that Predication consists in the affirmation that 
 one object of our thought hears or does not hear a certain 
 specified relation to another object of our thought. 
 
 § 142. We must now consider the ground or 
 grounds upon which predication rests. How is it 
 that we are able to make a predication regarding 
 the relation which two or more objects of our 
 thought bear to one another ? Is there any other 
 mental act of which predication is the result ? A 
 little examination will show that there is. When 
 we observe two colours and predicate that the one 
 is similar or dissimilar to the other, the act of pre- 
 dication is manifestly the result of seeing the simi- 
 larity or dissimilarity of the two objects. Before 
 we can predicate two lines to be equal or unequal, 
 we must ^perceive their equality or inequality. In 
 other words, predication is, in some cases at least, 
 founded upon Intuition ; we intuitively perceive j Intuition 
 
 Q 2 
 
 Basis of 
 predica- 
 tion. 
 
228 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. II. 
 
 Inference. 
 
 certain relations to exist between certain objects of 
 our knowledge, and as tlie result of that intuition 
 we predicate the relations. In other cases we must 
 admit a different ground for our predications. For 
 example, when we affirm, ^* The exterior angle of a 
 triangle is equal to the two interior and remote 
 angles/^ this is not the result of immediate in- 
 tuition. There are various comparisons to be made 
 before we can recognise the truth of the predica- 
 tion. So when we affirm that the earth bears a 
 certain regularly varying relation in space to the 
 sun, or in other words, that the earth revolves 
 around the sun in an elliptic orbit, this predication 
 is by no means the result of intuition, but of a 
 mental process of a very complex kind. The more 
 or less complex process by which we are enabled 
 to predicate relations between objects of our thought 
 which we do not intuitively perceive is called 
 Inference. But, as a general rule, intuition and 
 inference are combined in affording a ground for 
 our predications. We intuite certain relations to 
 exist, from which we infer certain other relations to 
 exist, and predicate accordingly. The nature of 
 inference will be explained hereafter ; in the mean- 
 time we must give some attention to our intuitions. 
 
 Section II. 
 
 INTUITION. 
 
 § 143. That act of the mind which we have called 
 Intuition is the immediate knowledge which we have 
 
PSYGEOLOGY OF COGNITION. 
 
 229 
 
 of any object of consciousness. Thus consciousness 
 is co-extensive with intuition, and therefore it might 
 appear that the term intuition was useless. But it 
 is convenient to have some word to distinguish the 
 knowledge given in consciousness from the know- 
 ledge which is the result of inference^ and the word 
 we have used appears the best suited for that 
 purpose. Moreover, consciousness is more properly 
 applied to our knowledge of objects or jphencmiena ; 
 whereas we have now to bring into prominence the 
 relations hetiveen objects. For these reasons we 
 employ the term intuition in this part of our work 
 to indicate the knowledge we have of objects given 
 in consciousness and the relations between them. 
 And manifestly, the simple objects of intuition are 
 identical with the objects of consciousness. A. 
 sensation, an idea, an emotion, any phenomenon of 
 the mind, is given to us in an iu tuition. In our study 
 of perception we have examined into the nature and 
 kinds of sensations, and now, leaving the considera- 
 tion of the individual phenomena of consciousness, 
 we must consider the relations between them as 
 given in intuition. 
 
 § 144. We have already seen that we have an 
 intuition of the relation of Sequence existing between 
 two phenomena, and that this intuition, when 
 generalised, gives rise to our conception of time. 
 But there is something else involved in this relation 
 which is of considerable importance. The phe- 
 nomena of consciousness are usually clustered 
 together in a very complicated way, and there are 
 
 CHAP. V. 
 SECT. II. 
 
 Intuition 
 is imme- 
 diate 
 knowledge. 
 
 Kinds of 
 sequence. 
 
230 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. II. 
 
 frequently sequences taking place in wliat we may 
 deem an accidental manner. For example, tlie 
 sound of a bell rings in our ears ; then we hear a 
 carriage going along the road; then we see the 
 postman coming to us with a letter. Now these 
 various events may occur in any order, and it does 
 not appear to be of any importance in what order 
 they come, or whether they form a sequence at alL 
 There is only an accidental sequence existing between 
 them. But take another example. We see a flash 
 of lightning ; a few seconds afterwards we hear a 
 peal of thunder; shortly after that rain falls. Now 
 the first two of these events cannot he reversed, at 
 least in our experience they never have been reversed. 
 We may have observed peals of thunder succeeding 
 flashes of lightning at a greater or less interval of 
 time, but we have never observed the former preced- 
 ing the latter. Thus there are sequences which, as 
 far as our experience goes, are irreversible. There is 
 another characteristic of certain sequences to which 
 we must refer. Sometimes we may see a flash of 
 lightning, but fail to hear the expected thunder : 
 sometimes we hear the thunder without having seen 
 the lightning. The antecedent of an irreversible 
 sequence sometimes takes place without the con- 
 sequent, or the consequent without the antecedent. 
 But in other cases the sequence is invariable. A 
 nugget of gold is suspended by a string ; we observe 
 the string cut with a knife ; the nugget falls to the 
 ground. Here is a sequence which our experience 
 tells us is not only irreversible but also invariable^ 
 
PSYCHOLOGY OF COGNITION. 
 
 231 
 
 The breaking or looseniDg of tlie thread never takes 
 place without the object falling to the ground ; the 
 heavy object never falls to the ground as long as the 
 thread remains fastened to it and entire. The full 
 significance of this we shall see afterwards ; in the 
 meantime we note the different kinds of sequences. 
 
 § 145. Another relation of which we have an 
 intuition is that of co-existence. We have already- 
 considered the part which this relation plays in 
 originating our conception of space, and we need not 
 recapitulate. We may here observe that our per- 
 ception of external objects usually comprehends a 
 complexity of relations of both sequence and co- 
 existence. And further we remark that a relation 
 of co-existence is a necessary condition of our being 
 able to intuite the relations to which we shall next 
 turn our attention. 
 
 § 146. The relation of Likeness and JJnliheness is 
 a most important object of our intuition. We are 
 able to compare two phenomena of consciousness or 
 two more complex objects of our knowledge, and to 
 know by an act of intuition whether they are like or 
 unlike to one another. We use the words like and 
 unlike in a comprehensive sense, including under 
 them various kinds of likeness or unlikeness, of 
 which the most important are the following : — 
 
 (1.) The likeness or unlikeness which exists be- 
 tween two bodies considered as occupying space we 
 call Equality or Inequality. Two lines being seen 
 side by side we intuite as equal or unequal ; and so 
 of two superficies or two solids. There is another 
 
 CHAP. V. 
 SECT. n. 
 
 Co-exist- 
 ence. 
 
 Likeness 
 and Un- 
 likeness. 
 
 Equality. 
 
232 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. II. 
 
 Likeness 
 in kind. 
 
 hi degree. 
 
 Derived 
 cmd com- 
 plex rela* 
 tions. 
 
 kind of likeness between superficial figures and solids 
 called by mathematicians Similarity , and constituted 
 by certain proportions existing between tlie different 
 parts of the figures. This, however, is not an object 
 of intuition, and with it we are not therefore at 
 present concerned. But there is an inferior and 
 vague kind of likeness which we intuite when we 
 compare objects which have a more or less re- 
 sembling figure or outline. As, for example, the 
 general figure of one horse is somewhat like that of 
 another, although there are many differences be- 
 tween them. 
 
 (2.) There is a likeness or unlikeness perceived in 
 the Nature or Kind of the objects of intuition or 
 knowledge. One red colour we intuite to be like 
 another, and to be unlike a blue colour. Any 
 sensation of colour we intuite to be unlike any 
 sensation of smell. And so of all objects of con- 
 sciousness. The same intuition takes place with 
 reference to complex objects of knowledge, and to 
 parts of which they are composed. 
 
 (3.) We are able also to compare in intuition the 
 Degree or Intensity of objects of consciousness. 
 There are many things agreeing in kind but differ- 
 ing in degree, and the perception of this agreement 
 or difference in degree is, in the case of simple 
 phenomena of consciousness, a matter of intuition. 
 
 § 147. The relations to which we have referred 
 in the preceding paragraphs appear to be those 
 which are primary; but there are many other 
 relations of which we usually speak which may be 
 
PSYCHOLOGY OF COGNITION. 
 
 233 
 
 reduced to one or ofher, or some combination of the 
 preceding. We speak, for example, of the relation 
 between the sign and the thing signified ; but this 
 upon examination will be found resolvable into that 
 of sequence. So also of the relation of cause and 
 effect, using cause in its phenomenal sense. Again, 
 when we say that an object comprehends certain 
 qualities, as that a horse is vertebrated, we mean that 
 there exist certain relations of co-existence or 
 immediate sequence between the quality vertebrated 
 and the other qualities which make up our concep- 
 tion or intuition of a horse. So of the relation of 
 parts to a whole, and various other relations which 
 might be specified. 
 
 § 148. We must be careful to distinguish the 
 use of intuition as described in this section from 
 another employment of the word which seems 
 not so appropriate. Some writers mean by in- 
 tuition the knowledge which we have of certain 
 first principles which are universally present in 
 the human mind, and the belief of which springs 
 up by a necessity of our nature, but in a way 
 which we cannot explain. The universality, 
 necessity, and inexplicability of a belief are the 
 marks by which it is known to be an intuition. 
 This use of the word appears to be objectionable. 
 An intuition ought naturally to mean the act 
 of seeing something directly, and therefore know- 
 ing it with certainty. Now there are many beliefs 
 which are necessary and universal, such as the 
 belief in some objective cause of the things which 
 
 CHAP. V. 
 SECT. II. 
 
234 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. III. 
 
 Predica- 
 tion not 
 arbitrary. 
 
 Law of 
 identity. 
 
 we know as constituting tlie natural world, wliicli 
 are tlie result of inference and not of intuition. 
 And the so-called intuitions of tlie mind spoken 
 of by some writers will probably be found in some 
 cases capable of analysis into simpler elements. 
 
 Section III. 
 
 DEPENDENCE OF PEEDICATION UPON INTUITION. 
 
 § 149. The connection of Predication with Intui- 
 tion, is not an arbitrary or fortuitous connection. A 
 certain intuition having taken place, the predication 
 which follows from it may not be this or that or 
 something else according to choice ; but there are 
 certain laws which govern us in founding mental 
 assertions upon intuition. These laws may be very 
 briefly stated and illustrated. We have before us 
 various objects of intuition ; they may be sensations, 
 they may be objects of perception, they may be rela- 
 tions, or anything else immediately before conscious- 
 ness. Let us indicate them by the first letters of the 
 alphabet. We intuite the object A ; it is necessary 
 for us to predicate " this is A; " it is impossible for us 
 to predicate " this is not A." This law of thought is 
 usually known as the Axiom of Identity , and thus 
 expressed : A is A, i.e., everything is what it is. 
 Again, we intuite a certain relation existing between 
 A and B. Upon this intuition is founded the predi- 
 
PSYCHOLOGY OF COGNITION. 
 
 235 
 
 cation "A is B;^^ and it is impossible for us to 
 predicate ^^ A is not B." This is usually called the 
 Axiom of Contradiction ; and its formula is^ Predica- 
 tions opposed contradictorily to each other cannot both 
 be true. The one or the other must be false, and 
 from the truth of the one follows the falsehood o; 
 other. These two axioms express the natur 
 dependence of predication upon intuition, 
 simply an analytic statement of the princi 
 predication must in all cases be conformable £" 
 intuition on which it is founded. Whatever is giverb 
 in intuition must be asserted in predication ; and it 
 is a mental impossibility to assert the opposite of 
 what is given in intuition. Or if the assertion be 
 made in words^ the mind refuses to acknowledge its 
 truth. 
 
 § 150. These two laws of the dependence of 
 predication upon intuition furnish us with the 
 ultimate test of truth. That predication which is 
 exactly conformable to the intuition of which it is 
 an expression must be true. Intuition is to us the 
 only perfectly reliable source of truth. If we are 
 immediately conscious of any object, it is impossible 
 for us to doubt the existence of that object, because 
 there is no more authoritative or reliable source of 
 information than consciousness. When, therefore, 
 we intuite any of these objects which, we have seen, 
 are given in intuition, we are compelled to recognise 
 them as existing as they are known ; there is no 
 room or no reason whatever for doubting. And 
 •when, from this intuition^ the predication has been 
 
 CHAP. T. 
 SECT. III. 
 
 Contradic- 
 tion. 
 
 Test of 
 truth. 
 
236 
 
 TEE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. III. 
 
 Errors in 
 
 applying 
 
 test. 
 
 made according to tlie above-mentioned laws, we 
 accept it as true ; we cannot help it. 
 
 § 151. Notwithstanding the absolute certainty of 
 this test of truth, if properly applied, a great deal of 
 error has crept into human belief. Arising from 
 the application of these laws, the error may have 
 two sources; it may arise from supposing some 
 mental act to be an intuition which is not really so ; 
 or it may arise from forming some predication 
 which does not exactly express what is given in the 
 intuition. As an example of the former we may 
 take the metaphysical doctrine of substance or sub- 
 stratum. 
 
 It has been thought by many that the substance 
 in which phenomenal qualities are supposed 
 to inhere is made known to us in an act of in- 
 tuition. But nothing can be farther from the 
 truth ; in itself it is admittedly absolutely unhnown ; 
 and, in fact, it is only one of several hypotheses which 
 have been invented for the purpose of explaining 
 the existence and objective unity of phenomena. 
 To connect substance with intuition is therefore to 
 give to intuition an entirely different meaning from 
 what we consider to be the correct one. Generally 
 speaking, both of the sources of error to which we 
 have referred 'are most prolific in connection with 
 acts of knowledge of a complex kind. Where the 
 object of knowledge is very complex, or where the 
 mental act is the result of some acquired power, it is 
 not easy to discover what are the simple original 
 intuitions, and consequently there is abundant room 
 
P8YCE0L0GY OF COGNITION. 
 
 2?^7 
 
 for error. But when we have before us an object 
 wliicb we know is directly given to us in an intui- 
 tion, and when the predication is made in accordance 
 with the laws of truth, there is, to our minds, no 
 possibility of doubt. 
 
 Section IV. 
 
 IMPLIED PEEDICATIONS. 
 
 § 152. There is such a connection and complication 
 between truths that, generally speaking, when we 
 know and express one truth there are many other 
 truths implicitly known and ready to be expressed. 
 In the predications which we make regarding the 
 objects of our knowledge we give prominence to 
 some particular feature which it suits our purpose to 
 express, but there may be many other relations 
 connected with the same objects which we know, 
 which we imply in our predications, but which we 
 do not care to state explicitly. Almost every 
 explicit predication is connected with other implicit 
 predications; in being distinctly conscious of the 
 former we know the latter also, although they may 
 not be so distinctly before consciousness. The 
 explicit predication stands out clearly from amidst 
 the surrounding implicit ones, but they are in the 
 immediate neighbourhood and simply require the 
 attention to be directed to them in order to make 
 
 CHAP. V. 
 SECT. IV. 
 
 Explicit 
 and im- 
 plied truth 
 
238 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. IV. 
 
 Predica- 
 tions im,' 
 ^lied and 
 excluded. 
 
 them as distinct as that whidi we have chosen to 
 express. And it is frequently as important to 
 know what is impHed in our predications as to 
 have a clear apprehension of what we distinctly 
 state. 
 
 § 153. A few illustrations will bring the subject 
 more clearly before us. 
 
 When we make the general predication — All men 
 are mortal — we have in our minds the class of men 
 as a whole wherever they are to be found, and we 
 predicate regarding them that they are, without 
 exception^ liable to death. But in the very act of 
 making this assertion there is involved the know- 
 ledge or belief that some particular men will die. In 
 asserting a universal predication we imply its truth 
 with reference to any particular number. The same 
 kind of implication is involved of course in negative 
 predications. 
 
 The Law of Contradiction is the expression 
 of another fact regarding the relations of pre- 
 dications. An explicit predication not only 
 implies other predications, but may also exclude 
 other predications. The proposition above referred 
 to excludes the corresponding negative — All men, 
 or some men, are not mortal. And in the same way 
 the predicatio'n of a universal or particular negative 
 excludes the corresponding affirmatives. To know 
 what a particular predication implies and what it 
 excludes is the most important condition of con- 
 sistency in our knowledge. 
 
 An important class of implicit predications is in- 
 
PSYCHOLOGY OF COGNITION. 
 
 239 
 
 volved in tlie predication of tlie internal relations of 
 an object or class of objects and its constituent 
 qualities. Whenever we predicate a quality of 
 any object we thereby implicitly classify that 
 object with others possessing the same quality. 
 When we say, for example, that birds are oviparous, 
 we do not satj anything about other oviparous 
 things and we do not even mean anything about 
 them, but if we examine the thoughts which cluster 
 about the explicit predication we shall find amongst 
 them that birds may be classified with other ovi- 
 parous beings, if such exist. Were we to examine 
 all other cases of internal predication we should 
 find that each of them implies an external predica- 
 tion ; whenever we predicate a quality of any object 
 or class of objects we implicitly predicate that that 
 object or class of objects may be included in a 
 larger class, all of whose members are marked 
 by the possession of that quality. This implied 
 predication has also its corresponding excluded 
 predication. 
 
 If we can assert that objects, in consequence 
 of possessing a certain quality, may be classified 
 with all other objects possessing the same quality, 
 we are precluded from making this predication 
 with reference to objects which do not possess the 
 quality. And, generally speaking, where two pre- 
 dications are inconsistent with one another, if the 
 one is either explicitly stated or implied, the other 
 is thereby excluded. 
 
 § 154. For the sake of illustration we offer the 
 
 CHAP. T. 
 SECT. IV. 
 
 Illustrated 
 
!40 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. IV. 
 
 following examples of explicit, implied, and excluded 
 predications : — 
 
 EXPLICIT 
 
 Predications. 
 
 All fishes oxi- 
 dise their blood 
 from water. 
 
 All planets 
 move in elliptic 
 orbits. 
 
 Whales be- 
 long to the class 
 mammals. 
 
 Alfred Ten- 
 nyson is a poet. 
 
 The angles of 
 a plane triangle 
 are either equal 
 to two right an- 
 gles or unequal. 
 
 John Smith is 
 a drunkard. 
 
 The line A is 
 double of B. 
 
 The sun illu- 
 minates the 
 earth. 
 
 IMPLIED 
 
 Predications. 
 
 Some fishes, or these 
 fishes, oxidise, &c. Fishes 
 belong to the class of ani- 
 mals oxidising, &c. 
 
 Any particular planet 
 moves in an elliptic orbit. 
 
 The class of bodies 
 moving in elliptic orbits 
 comprehends planets. 
 
 Some mammals are 
 whales. 
 
 Some of the qualities 
 possessed by all mammals 
 are possessed by whales. 
 
 Alfred Tennyson pos- 
 sesses the genius and other 
 qualities which constitute 
 a poet. 
 
 If they are equal to two 
 right angles they cannot 
 be unequal, and vice versa. 
 
 John Smith cannot con- 
 trol his appetite for strong 
 drink. 
 
 The line B is half of A. 
 
 The sun is luminous. 
 The sun and earth are so 
 related in space that light 
 from the former can fall 
 upon the latter. 
 
 EXCLUDED 
 
 Predications. 
 
 No fishes oxidise, &e. 
 Animals which do not 
 oxidise, &c. are fishes. 
 
 All or some planets 
 move in an orbit not 
 elliptic. 
 
 Bodies moving in a 
 parabolic or other 
 non-elliptic orbit are 
 planets. 
 
 No mammals are 
 whales. 
 
 Mammals possess 
 no qualities in com- 
 mon with whales. 
 
 Alfred Tennyson is 
 wanting in poetical 
 genius. 
 
 They may be both 
 equal and unequal. 
 
 John Smith can 
 choose either to drink 
 or not to drink strong 
 liquorwhen he pleases. 
 
 The lines A and B 
 are equal. 
 
 The lineB is greater 
 than half of A. 
 
 The sun is neither a 
 self-luminous nor a 
 light-reflecting body. 
 The earth is so situa- 
 ted that rays of light 
 from the sun cannot 
 fall upon it. 
 
PSYCHOLOGY OF COGNITION. 
 
 241 
 
 Having illustrated the relations between explicit 
 and implied and excluded predications, we may sum 
 up our results in the following canons : — 
 
 (1.) Whatever relation is predicated of a class of 
 objects may be predicated of any individuals be- 
 longing to the class ; the denial of this relation 
 with reference to any or all of these individuals is 
 excluded. 
 
 (2.) The predication of an internal relation of any 
 class of objects implies an external relation, viz., 
 that these objects belong to a larger class of things 
 possessing the quality predicated. The denial of 
 this and the assertion that objects not possessing 
 the quality belong to the class are excluded. 
 
 (3.) The predication that an individual belongs to 
 a class implies the possession of the qualities con- 
 stituting the class. The contrary is excluded. 
 
 (4.) The predication of any external relation be- 
 tween two or more objects implies the existence 
 of all the conditions which render that relation pos- 
 sible. The denial of these conditions is excluded. 
 
 (5.) Generally, the predication of any relation 
 excludes the predication of all other relations which 
 are inconsistent with it, and implies the predication 
 of all relations which are its necessary conditions or 
 consequences. 
 
 § 155. Notwithstanding the fact that these 
 principles regulating the implication and exclusion 
 of predications are clear and certain, there are 
 actually found many inconsistencies and inaccuracies 
 amongst the thoughts of men. Predications are 
 
 R 
 
 CHAP. V. 
 SECT. IV. 
 
 Canons of 
 'predica- 
 tion. 
 
 Errors in 
 predica- 
 tion. 
 
242 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. IV. 
 
 frequently thouglit to be implied whicli are not 
 really implied^ and thouglit to be excluded which 
 are not really inconsistent with admitted truth. 
 And it is the great duty of the instructors of man- 
 kind to spread abroad accurate and consistent 
 knowledge, that is, knowledge in which established 
 principles and facts are accompanied by everything 
 implied in them and from which all inconsistent 
 opinions are excluded. We may refer, by way of 
 illustration, to some mistakes which are frequently 
 made or have been made in determining the im- 
 plication or exclusion of predications. 
 
 In judging of the national characteristics 
 of foreign peoples, striking features are often 
 erroneously supposed to be universal, and false 
 judgments are consequently pronounced in par- 
 ticular cases. Englishmen are of the opinion that 
 the G-ermans are a musical people, and it might 
 be supposed that every particular German is a 
 musician either actually or potentially. But such 
 would be doubtless a mistake. 
 
 Europeans are of opinion that Bengalis are an 
 untruthful people, and many of them in Bengal 
 act upon the belief that the word of no Bengali is 
 to be trusted. This is unquestionably an error. 
 Bengalis, oil the other hand, are of opinion 
 that Englishmen are harsh and overbearing, and 
 frequently apply this judgment indiscriminately. 
 This is equally erroneous. 
 
 Defenders of the Jewish and Christian Scriptures 
 maintain their accuracy and truth, and many of 
 
PSYCHOLOGY OF COGNITION. 
 
 243 
 
 them think that it is implied that every statement 
 must be accepted as literally true, and they will 
 not admit any hostile criticism which results 
 in disclosing any inaccuracies or inconsistencies. 
 Believing that the Scriptures are true they think 
 that if anything in them is shown to be inaccurate 
 there is nothing worth preserving. They do not 
 see that the presence of most important religious 
 truth in the Scriptures is quite consistent with 
 the presence of many scientific and historical inac- 
 curacies and many inconsistencies amongst details. 
 Consequently when they learn that inaccuracies or 
 inconsistencies have been pointed out they fear that 
 the citadel of their faith has been taken and that 
 they can have no confidence in any religious truth 
 whatever. The same foolish position is frequently 
 assumed by the enemies of Christianity. Some of 
 them appear to think that_, if they have shown 
 statements in the Scriptures to be scientifically 
 or historically inaccurate or mutually inconsistent, 
 they have demonstrated the falsity of Christianity, 
 whereas in reality they have not approached the 
 foundations of the Christian faith in their attacks. 
 
 Similarly, in former times, it was usual for the 
 followers of rival creeds to attack with virulence 
 subordinate details in the religious systems or 
 Scriptures of their antagonists, thinking by so 
 doing they were aiding their overthrow. And 
 generally speaking, sectarians are those who are 
 unable to see that there may be possessed great 
 and important religious truth quite consistently 
 
 R 2 
 
 CHAP. V. 
 SECT. IV. 
 
244 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. IV. 
 
 Apparent 
 inconsis- 
 tency of 
 predica. 
 tions. 
 
 along with many minor points of form or doctrine 
 which they cannot agree with. 
 
 § 156. In philosophical doctrines there may 
 often be an appearance of inconsistence between 
 two predications when in reality they are quite 
 consistent. For example, Mr. J. S. Mill has 
 endeavoured to show that Sir W. Hamilton's 
 Doctrine of the Kelativity of Knowledge is incon- 
 sistent with his Doctrine of Immediate Percep- 
 tion. In the former doctrine Hamilton maintains 
 that we do not know things-in-themselves ; in 
 the latter doctrine, that we have an immediate 
 knowledge of real things. Mr. Mill assumes 
 that the things spoken of in the former doctrine 
 are the same as the things said to be known in the 
 latter, and upon that assumption rightly concludes 
 that the one statement is inconsistent with the 
 other. Now it appears to us that a careful examina- 
 tion of Hamilton's writings will show that Mr. Mill 
 is incorrect in his criticisms, and that Hamilton in 
 the two doctrines is speaking of two quite different 
 things : in the Doctrine of the Relativity of Know- 
 ledge he teaches that the cause or substratum which 
 underlies the objects of our senses is unknown ; in 
 the Doctrine of Immediate Perception he teaches 
 that the objects of our senses are directly known ; 
 and between these statements there is certainly no 
 inconsistency. 
 
 Again, there are many in the world who believe 
 that God's will is sovereign, or that all events in 
 their lives are controlled by Fate ; and frequently 
 
PSYCHOLOGY OF COGNITION. 
 
 245 
 
 they think that this implies that their own efforts in 
 adverse circumstances are unavailing. They cannot 
 reconcile the sovereignty of God with the importance 
 of exercising all their own power and wisdom at all 
 times as if they were sovereigns of their own lives. 
 In consequence of permitting the idea of an over- 
 ruling sovereignty to fill their minds to the exclusion 
 of the idea of their own personal responsibility, 
 when temptation or adverse circumstances come 
 upon them, they yield without an effort and prove 
 how helpless and worthless man is if he have not 
 a lively sense of his own dignity and responsibility. 
 Sophistical reasoners in their attempts to mislead 
 the people usually endeavour to show that opposing 
 statements are quite consistent, or that really con- 
 sistent statements are incongruous. And generally 
 speaking it is of the greatest importance for seekers 
 after truth to watch carefully appearances of incon- 
 gruity; falsehood frequently comes veiled under 
 the one, and truth is frequently concealed by the 
 other. Doctrines apparently conflicting may 
 frequently be comprehended harmoniously under a 
 higher truth; and doctrines joined together in some 
 human system may be as inconsistent as light and 
 darkness. 
 
 Section Y. 
 THE class; the concept; the name. 
 
 § 157. We have hitherto been concerned with 
 individual objects of knowledge and the relations 
 
 CHAP. V. 
 SECT. V, 
 
 Objects, 
 
 how 
 
 known. 
 
246 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. V. 
 
 existing between them. We must now consider a 
 mental process in wHcli tlie individual objects tbat 
 we know are variously joined together into classes. 
 And it must be borne in mind that, in this connec- 
 tion, when we speak of objects, we mean not merely 
 objects of simple intuition, but also objects or 
 results of more complex mental processes, such as 
 perception. Our knowledge of any object is made 
 up of all the predications which we can form 
 regarding it. Having perceived any object, we 
 express our knowledge of it by predicating that it 
 possesses such and such various qualities. And in 
 the case of each predication we mean that the 
 quality referred to in it exists in a certain relation 
 to the aggregate of the other qualities contained in 
 the other predications. Now, in considering any 
 object of thought, we are able to restrict our atten- 
 tion to a limited number of the qualities of which it 
 is an aggregate, to separate them in imagination 
 from the rest and consider them by themselves. 
 The qualities to which attention is thus ex- 
 clusively given are said to be abstracted from the 
 others. 
 
 § 158. The power of restricted attention being 
 admitted, we further postulate an ability to compare 
 different objects of knowledge with reference to the 
 possession of abstracted qualities. Having a number 
 of objects before us we can, by observation, ascertain 
 whether they all possess or do not possess a certain 
 quality or qualities to which we have given atten- 
 tion. If we find that they all actually possess this 
 
PSYCHOLOGY OF COGNITION'. 
 
 247 
 
 quality or these qualities we naturally attribute to 
 tliem a kind of unity ; we tHnk of tliem as forming 
 a class ; we apply to tliem some common name- 
 Thus the reason why we collect individual objects 
 into classes and designate them by a common name 
 is that we are able to predicate concerning them all 
 some specified quality or qualities. Now, in this 
 process there are three things to which we must 
 give attention : first, the abstracted qualities ; 
 second, the class which has been constituted by 
 virtue of the possession of these qualities; and 
 third, the use and meaning of the name. 
 
 § 159. In order that the process of generalisation 
 may be possible, it is absolutely necessary that our 
 attention should be restricted to some of the quali- 
 ties of bodies ; because amongst the bodies with 
 which we are acquainted variety is uniformly to be 
 found, and in order to reduce them to unity we must 
 disregard the qualities in which they differ. Having, 
 therefore, by observation abstracted certain specified 
 qualities in the possession of which a number of 
 objects agree, these qualities taken together form a 
 kind of mental object ; in the act of representation, 
 although we may not be able to banish altogether all 
 the other qualities of the bodies, yet we give to them 
 peculiar prominence ; we attribute to them a kind of 
 separate existence, which, although no doubt ob- 
 jectively fictitious, is mentally real. These ab- 
 stracted qualities thus mentally unified we call a 
 Concept. Now the question arises, Upon what 
 principle is it that we choose certain qualities 
 
 CHAP. V. 
 
 ConcejpU. 
 
248 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. V. 
 
 Formation 
 of a con- 
 cept. 
 
 Common 
 qualities. 
 
 Peculiar 
 qualities. 
 
 of objects for abstraction and unite tbem into a 
 Concept ? 
 
 § 160. In answer to tlie question proposed, it is in 
 tbe first place manifest that no qualities need be 
 cliosen except such as are possessed by all the objects 
 concerned. If we can at all unite objects into a class 
 it must be by means of something which they possess 
 in common ; some quality or qualities in which they 
 all agree. Thus we have one principle at least to 
 guide us in the formation of a concept. Nothing can 
 form a part of the concept which is not possessed hy all 
 the objects. This principle excludes all those qualities 
 with reference to which the individual objects differ 
 from one another. Here again another question 
 presents itself — Are all the qualities in which objects 
 agree to be included in the concept ? In order to 
 answer this question we must consider the end for 
 which generalisation is undertaken. 
 
 § 161. The reason why we collect objects into 
 classes is that we may know them better. But in 
 this connection, more complete knowledge does not 
 mean a more perfect knowledge of the qualities 
 possessed by each individual. Our knowledge of 
 classes is made complete by our being able to 
 compare them with other classes, and know in what 
 respects they agree and in what respects they differ 
 from them. Hence, when we wish to have an 
 accurate knowledge of a class, it is not sufficient 
 merely to collect into a mental unity all the qualities 
 in which the objects of the class agree with one 
 another ; we must also consider in what qualities 
 
PSYCHOLOGY OF COGNITION. 
 
 249 
 
 this class differs from other co-ordinate classes. The 
 points of difference are manifestly of great import- 
 ance^ because it is only by these that there can be 
 a distinction made between the class in hand and 
 other classes. Thus we have two collections of 
 qualities to be considered ; those in which all the 
 objects of one class agree, and those in which this 
 class differs from other classes. 
 
 For the sake of clearness let us suppose. 
 
 a \ 
 
 h i to be qualities pos- 
 c f sessed in common 
 d ^hj all the objects 
 e \ of the class 
 
 f 1 
 
 A, and 
 
 to be qualities pos- 
 sessed by all the 
 objects of the class 
 
 Now if we formed our concept of the class A 
 without comparing it with other classes, we should 
 include in it all the agreeing qualities a, h, c, &c. 
 But when we compare the two classes A and B, we 
 find that they agree in the possession of the qualities 
 hj d, fj and they differ in that A possesses a, c, e, 
 which are absent from B ; whereas B possesses li, Ij 
 which are absent from A. Consequently /or the 
 
 m 
 
 puiyose of distinguishing A from B we must reject 
 from the concept of A those qualities in which A 
 agrees with B, viz., 5, d,f] and we must include in the 
 concept of A the qualities a, c, e, in which A differs 
 from B. Thus for the purpose of distinguishing one 
 class from other classes, special attention must be 
 given in the formation of the concept to those 
 qualities which constitute the differentia between it 
 and other co-ordinate classes. 
 
 § 162. Are, then, all the points of agreement 
 
 CHAP. V. 
 SECT. V. 
 
 Formation 
 of higher 
 classes. 
 
250 
 
 THE ELE3IENTS OF THE 
 
 CHAP, V. 
 SECT. V. 
 
 How to 
 assign an 
 object toils 
 class. 
 
 between tlie class A and the class B to be rejected 
 from tbe concept of A? If our object were merely to 
 distinguish A from B we should reject them. But 
 as we wish to systematise our knowledge, to bring all 
 the classes of objects into relation with one another, 
 the points of agreement between classes are mani- 
 festly of great importance. For if we consider as 
 objects the lowest classes which we have formed, 
 and observe the points of agreement between them, 
 we shall be able to form a higher class, comprehend- 
 ing all these lower classes in the same way as they 
 comprehend individual objects. And this process 
 of classification may evidently go on until all the 
 objects with which we are acquainted have been 
 combined together by virtue of their possessing some- 
 thing in common. Kow, in order to connect any 
 particular class with this system of classes, it is 
 necessary to know not merely in what respects it 
 differs from other co-ordinate classes, but also by 
 virtue of what qualities it is comprehended under a 
 more general class. And these qualities, called 
 generic, must therefore be united in the concept to 
 the differentia before spoken of. Thus the concept 
 of any class must comprehend the generic qualities, 
 or those in which the class resembles other co-ordinate 
 classes, and fhe differentige, or those qualities which 
 distinguish it from these classes. 
 
 § 163. Having explained and illustrated the 
 general principles of classification, we now proceed 
 to study the process of assigning any particular 
 object of our knowledge or thought to its appropriate 
 
PSYCHOLOGY OF COGNITION. 
 
 251 
 
 ■class. To be able to do this correctly is a matter 
 of great importance, as we do not know an object 
 accurately until we know what class it belongs to. 
 Before we can classify any individual it is manifestly 
 necessary for us to know that it possesses the 
 essential qualities of some class ; having ascertained 
 this we immediately assign it to that class. We 
 see, for example, an object rooted to the soil, 
 evidently organic, and having a stem, branches, 
 and leaves. Knowing that these qualities are 
 possessed by many vegetables, we assign our 
 individual to that class. A further examination 
 reveals the fact that the object has flowers growing 
 upon it, that the leaves are netted instead of 
 parallel veined, that it has a woody stem composed 
 of a number of circular layers around a central 
 pith. Knowing something of botanical classifica- 
 tion we call our plant an exogenous flowering plant. 
 Pursuing our examination into minute characteris- 
 tics of the flower and the leaves and the seeds we 
 succeed in determining the Order, the Genus, and 
 the Species of the plant. 
 
 Thus it appears that all that is necessary in 
 classifying an object is a knowledge of the charac- 
 teristics of the class to which it is problematically 
 to be referred, and a knowledge derived from 
 examination that the object in hand presents these 
 characteristic qualities. Having discovered the 
 important qualities of an object we look about, 
 unless we already know, for some class whose 
 concept comprehends these qualities ; and having 
 
 CHAP. V. 
 SECT. V. 
 
252 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. V. 
 
 Difficulties 
 in classifi- 
 cation. 
 
 found it we unite by a syntlietic act tlie individual 
 with the other individuals of the class. 
 
 § 164. As long as we are dealing with inorganic 
 elements or organic material bodies there are no 
 great difficulties in the way of classifying individuals. 
 We are now able to apply chemical tests with 
 definite and precise results to all inorganic ele- 
 ments ; and the microscope and dissecting knife 
 enable us to examine the minute parts of organised 
 objects with great accuracy. And consequently it 
 only requires a certain amount of practical training 
 and skill to refer any object with precision to its 
 proper class. But when we come to the more com- 
 plex relations of human life and action much greater 
 difficulties present themselves. These difficulties 
 arise from the greater complexity of the phenomena 
 with which we are dealing, from the want of such a 
 precise system of classification as we have with 
 reference to material objects, from the impossibility 
 of observing such clear distinctions as are seen 
 between organic things, and from other causes. 
 The following are some of the objects of thought 
 in connection with human life and action which 
 present themselves for study and classification : — 
 The phenomena of consciousness ; mental modes of 
 action constituting character; bodily habits; lan- 
 guages ; general forms of body and countenance ; 
 national customs and superstitions ; family institu- 
 tions ; tribal habits and laws ; forms and charac- 
 teristics of governments; and other features con- 
 nected with social life which will readily suggest 
 
PSYCHOLOGY OF COGNITION. 
 
 253 
 
 themselves. A few illustrations will show the 
 difficulty of reducing these things to scientific 
 system. 
 
 § 165. When we observe an action done by 
 some person, we often experience a feeling of 
 pleasure or displeasure, of approbation or disappro- 
 bation, and we judge that the action is either 
 right or wrong. Now students of the human 
 mind cannot agree as to what is the true nature 
 of this moral feeling or judgment, as to whether 
 it is primarily a feeling or primarily a cognition, 
 as to whether it is a simple and original pheno- 
 menon of human consciousness, or a complex 
 and derived phenomenon found only in human 
 minds which have attained a certain degree of 
 advancement. 
 
 Again, when we try to estimate the charac- 
 ter of the men whom we meet there is room 
 for great doubt and uncertainty. We some- 
 times observe men giving large sums in charity 
 to the poor, or otherwise trying to ameliorate 
 their condition; and we should probably think 
 that these were henevolent men. But it is possible, 
 and many times true, that men perform apparently 
 benevolent actions from some selfish motive, and 
 the discovery of this fact makes it impossible for us 
 to classify them as benevolent. The motive by 
 which an action is inspired constitutes the most 
 essential element of the action, and the difficulty 
 of ascertaining its character renders it difficult to 
 characterise the action. 
 
 CHAP. V. 
 SECT. V. 
 
 Illustrated, 
 
254 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. V. 
 
 Comnnon 
 errors in 
 claasifica- 
 tion. 
 
 Suppose, again, that we wish to determine whether 
 a certain writer is a poet or a philosopher^ it is not 
 in all cases easy to do so. There are versifiers who 
 are not poets ; and there are many who write about 
 philosophy but are not philosophers. And critics 
 are not by any means agreed as to what it is that 
 constitutes a man a poet or a philosopher. Thus we 
 have here a twofold difiiculty ; the essential qualities 
 of the classes are not determined with precision ; 
 and even if they were determined it is no easy 
 matter to say in any particular case whether a 
 person possesses them. It requires a certain 
 amount of poetical or philosophical genius to esti- 
 mate the quality of poetic or philosophical writings. 
 Students of language also find great difficulty in 
 classifying the different languages of mankind. 
 Leading distinctions have no doubt been observed 
 and form the basis of a provisional classification, 
 but the science is yet in its infancy, and much 
 has to be done in the way of determining the 
 characteristics of different languages and arranging 
 them into a system. Similar remarks might be 
 made with reference to most of the problems of 
 classification which arise in connection with the 
 intellectual, moral, and social life of man. And we 
 may now point out a few leading errors which we 
 are apt to make in our study of the phenomena in 
 question. 
 
 (1 .) Errors are often made in failing to distinguish 
 the essential or predominating character of that 
 which we are examining. A man may conceal 
 
PSYCEOLOGY OF COGNITION. 
 
 255 
 
 under a harsh and forbidding exterior a really kind 
 and generous heart ; the manner of a man is most 
 frequently that by which he is at first judged ; and 
 thus people frequently form an erroneous judgment 
 by not looking through the manner at the more 
 essential qualities of mind and conscience. 
 
 (2.) Errors in classification arise from supposing 
 things to differ which in reality are the same or 
 similar. For example, Sir W. Hamilton supposed 
 that Dr. Reid's theory of perception was quite 
 different from and inconsistent with the representa- 
 tive theory held by Dr. Thos. Brown and others of 
 Eeid^s predecessors. In truth, although there were 
 minor differences, the essential doctrines of Reid^s 
 theory are not what Hamilton supposed, and are not 
 so different from the doctrines of Brown as to 
 entitle them to be put into a different class. Real 
 resemblances are often concealed under a difference 
 of phraseology, and it is an important function of 
 thought to penetrate beneath the verbal expression 
 of doctrines to the ideas taught. 
 
 (3.) Errors in classification arise from supposing 
 things to resemble one another which are in reality 
 different. Things indicated by the same word, for 
 example, especially if the things indicated are 
 mental in their character, are at first sight supposed 
 to be the same, but in reality they are frequently 
 found to be very different. Names, in the course 
 of time, often change their meaning, and it is 
 frequently very difficult to observe and discriminate 
 the different meanings which, at successive times 
 
 CHAP. V. 
 SECT. V. 
 
256 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT, V. 
 
 Essential 
 and acci- 
 dental 
 qualities. 
 
 and as used by different persons, tliey carry witli 
 them. Tlie philosophical name idea presents us 
 with a good example of a word which means very 
 different things as used by different writers or even 
 by the same writer. Not only may single words 
 mean different things, but also similar forms of 
 expression may be very ambignous in meaning ; of 
 this, good specimens are given in many of the 
 ancient oracles which were usually susceptible of 
 quite different interpretations. And the writings 
 of sophistical reasoners are usually filled with forms 
 of expression which convey one meaning to the 
 mind of the reader, but are used to express quite a 
 different idea of the writer^s mind. 
 
 § 166. There is a question of importance con- 
 nected with the nature of classes now to be 
 considered. Have classes only a mental existence ? 
 Have they an existence only in the concept 
 by which the mind binds them together ? If 
 they have not, then one concept, provided it be 
 constituted as we have shown it should be, will be 
 just as good as another. If the differentias of a 
 class are all duly observed, and included along with 
 the accurately known generic qualities in the con- 
 cept, these differentiae and generic qualities being 
 discovered only by the test of difference and agree- 
 ment, the concept thus formed must be unex- 
 ceptionable. But it is actually found that men of 
 science, in constructing a classification, select from 
 amongst all the points of difference and agreement 
 certain qualities which they think to be of greater 
 
PSYCHOLOGY OF COGNITION. 
 
 257 
 
 importance than others. They frequently reject 
 from their definition of classes some qualities which 
 by reason of agreement and some which by reason of 
 difference should be included. 
 
 An illustration will make plain what we mean : 
 
 Fishes ( 
 
 a. live in water. 
 6. are vertebrated. 
 
 c. obtain oxygen for 
 
 their blood from 
 the water. 
 
 d. propel themselves 
 
 by fins. 
 
 e. are oviparous. 
 
 /. have a long round- 
 ed figure fitting 
 them for easy 
 motion in water. 
 
 Whales 
 
 ^ a. live in water. 
 &. are vertebrated. 
 
 c. obtain oxygen for 
 
 blood by breath- 
 ing air. 
 
 d. move by organs 
 
 like fins. 
 
 e. are viviparous. 
 
 /. have a fish-like 
 figure. 
 
 Now comparing the lists of qualities possessed by 
 fishes and whales we see that the qualities marked 
 a, h, d, and / are identical or very similar ; while 
 the qualities c and e are different. And the ques- 
 tion isj Are we to include whales in the class Fish ? 
 The points of agreement are numerous. And if one 
 quality were just as essential as another, we should 
 probably come to the conclusion that a whale is a 
 fish, as it was long believed to be. But men of 
 science tell us that the points of difference to which 
 we have attached the letters c and e are of vastly 
 greater importance than such qualities as a and /; 
 and they make these points of difference essential, 
 and some of the points of agreement accidental, and 
 consequently conclude that a whale is not a fish. 
 Now upon what principle is it that the qualities c 
 and e are considered essential and included in the 
 
 CHAP. V. 
 SECT. V. 
 
2t^8 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT, V. 
 
 What con- 
 stitutes 
 essential 
 qualities ? 
 
 concept of a whale, while the qualities a and / are 
 not ? How do you know the essential attributes o£ 
 any class ? 
 
 § 167. A great variety of answers have been given 
 to this question, and it -would take us beyond our 
 limits to enter upon a description or criticism of the 
 different theories which have been held upon the 
 subject. The determination of what are the essential 
 qualities of classes is no doubt to be accomplished by 
 a comparison of many objects and an extended obser- 
 vation of the relations existing between the qualities 
 of objects. Those qualities of objects which from their 
 nature or uniform presence appear to determine a great 
 many other qualities, are naturally looked upon as 
 being essential. The possession of vertehra by an 
 animal, for example, must be considered an essential 
 quality, because we observe that it is the ground upon 
 which depend a great many qualities that distinguish 
 a vertebrated from an invertebrated animal. The 
 principles upon which the selection of essential 
 qualities depends are, however, a matter of science 
 rather than of psychology. But it is of importance 
 to observe here that we have established the fact of 
 the objective existence of natural classes of things. 
 There is a reason in the nature of things them- 
 selves for their being brought together in classes. 
 There are essential qualities comprehended in ob- 
 jects; and it is only when we make our concepts 
 to comprehend the same essential qualities that 
 we have an accurate knowledge of the objects. 
 A concept is true only whea it comprehends the 
 
PSYCHOLOGY OF COGNITION. 
 
 259 
 
 essential qualities of the class from wliicli it is 
 derived. 
 
 § 168. We now give some attention to tlie names 
 which we give to the various classes of objects that 
 we know. The study of the science of language has 
 brought to light many interesting and important 
 facts connected with the application of names to 
 objects. The simple names which primitive peoples 
 give to the objects of their knowledge are usually 
 expressive of some striking quality possessed by the 
 objects. A river, for example, may be called the 
 running thing ; the sun is named from its shining 
 quality ; the stars from twinMing, or perhaps shining. 
 A name which is at first significant of some striking 
 quality or action possessed or performed by an indi- 
 vidual object is afterwards applied to other objects 
 possessing a similar quality; and thus arises the first 
 rude classification. Now, it must be observed that 
 the name is attached to the objects individually ; be- 
 comes so associated with them as to form, as it were^ 
 one of their qualities. And upon its first application 
 the name expresses the concept which the name-giver 
 had in his mind when he invented the name ; that 
 is, expresses the quality which, to his mind, was most 
 striking, and therefore most important. But as know- 
 ledge increases the nature of the concept changes ; 
 other qualities of the object are discovered which 
 are found to be of greater importance than those first 
 observed ; but no corresponding change takes place 
 in the name. Thus the natural class and the name 
 are constant^ while the concept is variable. And 
 
 s 2 
 
 CHAP. Y, 
 SECT, Y. 
 
 Names, 
 
26o 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. V. 
 
 Denota- 
 tion and 
 connota- 
 tion. 
 
 the question arises^ What is the psychological 
 significance of the name ? 
 
 § 169. It is usual to say that a name denotes objects 
 and connotes attributes ; and it is usual to assume 
 that the objects denoted are the objects of the class 
 of which the attributes connoted are the essential 
 attributes, that is, the concept. Now it is quite 
 correct to say that the name denotes to all minds the 
 objects of the class with which it has become asso- 
 ciated ; but it is not correct to say that the name 
 connotes the attributes of the scientifically-formed 
 concept. We have seen that the concept is a 
 very variable mental object depending upon the 
 knowledge and mental habits of the individual in 
 whose mind it is formed. And, moreover, the 
 concept is never represented in the mind without 
 bringing along with it other accidental attributes 
 forming no part of itself. And unless we arbitrarily 
 restrict the connotation or meaning of a name, we 
 shall hold that it connotes all the attributes essential 
 or accidental which it is the means of bringing before 
 consciousness. Thus it would be very difficult for 
 any one to pronounce or hear the word fish without 
 thinking of the quality swimming in the water , 
 which is an accidental one. And it is in only a small 
 number of minds that the sound of the word " fish " 
 would suggest the quality of water-hreathing j which 
 is a constituent element of the concept. Thus we 
 should say that while the denotation of a class- 
 name is invariable, or varies only in consequence 
 of some change in the class, its meaning is, in 
 
PSYCHOLOGY OF COGNITION. 
 
 261 
 
 different minds, exceedingly variable, depending 
 not only upon the variation of tlie concept, but also 
 upon tlie introduction into the mental image of a 
 variety of accidental qualities. In consequence of 
 this variability of the meaning of names, scientific 
 men have, to a great extent, ignored the ordinary 
 names of common language, and invented a scientific 
 vocabulary whose words should connote only scien- 
 tifically-formed concepts. Thus the principle is re- 
 cognised that, in a scientific interest, the names of 
 classes ought not only to denote the classes, but also 
 to connote exclusively the attributes of the concept. 
 But it remains equally true that in the ordinary 
 affairs of life the names which we use have a very 
 variable meaning, but are used to denote something 
 which is practically invariable, a really existing 
 •class. 
 
 § 170. A great deal of confusion has been caused 
 by the application of the epithet general to the 
 names which have become associated with classes 
 and to the ideas, as they are called, which we form 
 of classes. It appears to be assumed that the 
 result of the process of generalisation must be 
 itself general; and the question has long been 
 discussed, Where is the assumed generality to be 
 found ? Realists have held that there is a general 
 idea existing in Nature; conceptualists maintain 
 that generality is to be found only in the mental 
 concept ; nominalists contend that nothing but the 
 name is general. The truth is, we might as well 
 speak of a square circle or a green smell as of a 
 
 CHAP. V. 
 SECT. V. 
 
 General 
 names and 
 ideas. 
 
262 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. V. 
 
 Defini- 
 tion. 
 
 general idea or a general name. Every concept 
 whicli we form is an individual collection of quali- 
 ties ; every name which, we utter is an individual 
 sound. The name has become associated in our 
 minds with certain similar objects which, in conse- 
 quence of their similarity, we think of as forming a 
 class. The concept consists of a number of quali- 
 ties which we have observed to exist in all the 
 objects belonging to the class. The name is pre- 
 dicable of all the objects of the class, and therefore, 
 if we insist upon using the word general, we may 
 say that the application of the name is general. 
 The qualities of the concept are predicable of all 
 the objects of the class, and therefore we may say 
 that the qualities represented in the concept are 
 generally or universally found in the class. And in 
 fact it is the universal presence of the essential 
 qualities in all the objects of the class which is the 
 ground both of the general application of the name 
 and of the formation of the concept. And, conse- 
 quently, that which we mean by a name and that 
 which we represent in a concept has a real existence 
 only in the particular objects of Nature. 
 
 § 171. The exposition in language of the quali- 
 ties of a concept is called Definition ; the arrange- 
 ment in subordinate groups of the objects denoted 
 by a name is called Division. But it must be 
 remembered that the definition is accurate only 
 when the concept is true. For a definition to be 
 correct it is necessary that the concept of which it 
 is an expression should comprehend the essential 
 
PSYCHOLOGY OF COGNITION. 
 
 263 
 
 qualities of tlie class ; if the essential qualities are 
 not known, if the class is recognised only by certain 
 accidental superficial attributes, a correct definition 
 is impossible, and we must be satisfied with such an 
 indefinite description of the class as may be within 
 our reach. The important point which we wish to 
 bring out here is that a definition^ to be correct, 
 must conform to objective existence ; that this con- 
 formity is brought about through the medium of a 
 true concept; and that unless the concept corre- 
 spond to real existence, a correct definition is 
 unattainable. Division is a process the reverse of 
 classification. As by the perception of mutual 
 agreements we unite objects into classes, so by 
 the perception of mutual differences we separate 
 classes into subordinate groups. 
 
 The rules of both definition and division are given 
 in logical works, and these rules assume that we are 
 always able to test the accuracy of a definition or a 
 division by means of intuition. By intuition, that 
 is, by direct observation, the concept is formed and 
 the class is determined, and when we attempt to 
 elaborate concepts and classes into systems, it is only 
 by reverting to intuition that we are able from time 
 to time to test the correctness of our systems. The 
 limitation of the sphere of logic, therefore, simply to 
 the exposition of the nature and relations of concepts, 
 without any reference to the truth of those concepts, 
 is, judged from the pyschologist's point of view, a 
 blunder. We are not satisfied with consistency 
 amongst concepts which may be crude or erroneous 
 
 CHAP. V. 
 SECT. V. 
 
 Division. 
 
264 
 
 THE ELEMENTS OF THE 
 
 or baseless ; we must have our systems of science 
 continually tested by a comparison with, tlie truth of 
 Nature^ otherwise they are simply castles in the air. 
 Consequently it is unwise to separate the sphere of 
 logical thought from that connection with the real 
 world which is afforded to it in the continually 
 possible exercise of intuition. 
 
 ' Section YI. 
 peedication again. 
 
 § 172. We have seen that Predication is the 
 mental assertion, expressed in language, that one 
 object of thought stands or does not stand in a 
 certain relation to another object of thought. We 
 have seen the dependence of predication upon 
 intuition, and the part which it plays in the forma- 
 tion of the concept. And before proceeding to 
 consider the more complex processes of thought, it 
 will be desirable to understand more fully the nature 
 and kinds of predication in itself. Predication is 
 founded upon a union in consciousness of the two 
 objects of thought of which the one is predicated 
 of the other. The union in consciousness may 
 correspond to an external objective union, or it may 
 not ; but a subjective union there must be in order 
 to render predication possible. The terms of the 
 predication, the things between which the relation 
 is affirmed to exist, are called Subject and Predicate 
 respectively. Since a union in consciousness is a 
 necessary condition of predication, it follows that 
 
PSYCHOLOGY OF COGNITION. 
 
 265 
 
 any proposition wliose subject and predicate cannot 
 be tbus united must be unmeaning or false. If we 
 assert in words, " A circle is a triangle/' and attempt 
 to think together in consciousness the subject and 
 predicate, we shall at once see that although a pro- 
 position has been constructed no intelligible predica- 
 tion has been made. There are, then, what we may 
 call i'mpom^Ze predications ; which are such that the 
 mind is incapable of bringing together the subject 
 and predicate into the relation which is asserted to 
 exist between them. 
 
 § 173. Again, there maybe objects of knowledge 
 united together in consciousness, of which the one 
 cannot properly be predicated of the other. For 
 example, we may have in consciousness together the 
 sweet smell and the red colour of a rose ; but it 
 would be absurd to predicate the latter of the former. 
 The only way in which we can form a predication is 
 to make one of these qualities a predicate of which 
 the whole aggregrate of qualities, along with the 
 name rose, is the subject. Thus, when we speak of 
 objects of perception,we invariably make the complex 
 objectified group of qualities the subject, and some 
 one or other of the qualities the predicate. Now if 
 we have in the same moment of consciousness a 
 sweet smell and a red colour, it might appear just as 
 reasonable that we should predicate the co-existence 
 of these two qualities as the co-existence of one of 
 them with the aggregate of qualities constituting the 
 rose. But this is not so, and the reason appears to 
 be that the aggregate of qualities has come to be 
 
 CHAP. V. 
 SECT. VI. 
 
 Some 
 
 unions im- 
 ^possible. 
 
 Accidental 
 co-exist- 
 ences not 
 joined in 
 'predica- 
 tion. 
 
266 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT, VI. 
 
 Classifica- 
 tion of 
 relations. 
 
 looked upon as having more tlian a relation of 
 co-existence with, the single quality which is 
 predicated of it. The aggregate of qualities is 
 regarded as an object, a united- whole, of which the 
 single quality is a constituent part. There is a 
 permanent and indissoluble connection between the 
 qualities which is not truly expressed when it is 
 predicated of them merely that they co-exist with 
 one another. And this permanent objective connec- 
 tion is the reason why the whole aggregate is usually 
 made the subject of predication. 
 
 § 174. From a careful examination of the nature 
 of predication we have seen reason to conclude that 
 it is the assertion that some relation or other exists 
 or does not exist between certain objects of our 
 thought. There are four great relations in one or 
 more of which the phenomena of our consciousness 
 must stand towards one another : — the relations 
 of Difference, Eesemblance, Simultaneity, and 
 Succession. 
 
 If now, we consider the objects of our knowledge 
 we shall reach another division of relations subor- 
 dinate to the above. All objects which are related 
 to one another may be distinguished into quantities 
 and qualities. The latter correspond to the sensa- 
 tions of which we are or may be conscious; the 
 former consist of the Form of sensations or objects, 
 namely, the space, time, motion and so on, by which 
 sense objects are conditioned. Again, the relations 
 of all objects or classes which may be predicated 
 are either internal or external; the former being 
 
P8YGE0L0GY OF COGNITION: 
 
 267 
 
 the relations of objects or classes to internal con- 
 stituent qualities or parts, the latter to other ex- 
 ternal objects or classes. Internal and external 
 relations may be both quantitative and qualitative, 
 and thus we have a fourfold division of relations 
 into : — I., Internal Quantitative; II., Internal Quali- 
 tative ; III., External Quantitative ; lY., External 
 Qualitative. This classification is founded upon 
 and not exclusive of our former division of the 
 four primary relations, as will be seen from the 
 following table : — 
 
 I. Internal 
 Quantitative 
 Relations com- 
 prehend : — 
 
 Eolations of 
 figure, size, 
 shape, motion, 
 number, and so 
 on, of the con- 
 stituent parts 
 or elements of 
 objects, classes 
 or systems. 
 These relations 
 may be any of 
 the four pri- 
 mary relations 
 or any combina- 
 tions of them. 
 
 II. Internal 
 Qualitative Re- 
 lations compre- 
 hend : — 
 
 Relations be- 
 tween the qua- 
 lities of objects 
 of our know- 
 ledge, or classes 
 of objects,these 
 qualities being 
 made known to 
 us by the sen- 
 sations or ideas 
 which they pro- 
 duce in our 
 minds. 
 
 III. External 
 Quantitative 
 Relations com- 
 prehend : — 
 
 Relations of 
 any of the four 
 primary kinds 
 or any combina- 
 tions of them 
 between the 
 figure, size, 
 shape, motion, 
 duration, num- 
 ber, and so on, 
 of objects, 
 classes or sys- 
 tems which are 
 external to one 
 another. 
 
 IV. External 
 Qualitative Re- 
 lations compre- 
 hend : — 
 
 Relations be- 
 tween external 
 objects or sys- 
 tems with re- 
 ference to 
 qualities made 
 known by sense, 
 moral or sosthe- 
 tical qualities, 
 characters, 
 habits, condi- 
 tions and any 
 other charac- 
 teristics of ob- 
 jects of know- 
 ledge which 
 may be appro- 
 priately called 
 qualitative. 
 
 § 175. We shall give illustrations of these great 
 classes of relations. 
 
 I. Internal Quantitative Relations. 
 
 When we construct a geometrical figure, as that 
 
 CHAP. V. 
 SECT. VI. 
 
 Illustrated 
 
268 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VI. 
 
 of the fifth, or the forty-seventh proposition of the 
 First Book of Euclid, we constitute a unity, and the 
 subsequent demonstration is a comparison of the 
 different internal parts in respect of their magnitude, 
 and the inferences which result from that com- 
 parison. Similarly, many of the propositions of 
 geometry consist of a combination of predications 
 regarding the internal quantitative relations of 
 different kinds of figures. 
 
 The astronomer who studies the motions of the 
 different bodies belonging to the solar system is 
 engaged with internal quantitative relations. The 
 solar system as a whole constitutes a unity, the 
 elements of which are the sizes, masses, distances, 
 orbits, velocities, and so on, of the various bodies 
 which revolve around the sun or the primary 
 planets, and of the central luminary. 
 
 The mechanical engineer is similarly occupied 
 when he arranges the figure, strength, motion, 
 position, and so on, of mechanical structures, as 
 houses, bridges, or machines. Comparative ana- 
 tomists are able to complete the skeletons of 
 animals, having given them certain of the bones. 
 This ability is the result of careful study of the 
 internal quantitative relations of the bodies of 
 animals. 
 
 11. Internal Qualitative Relations, 
 
 The qualities of single objects of sense often 
 require to be studied and compared in the interests 
 of science. The chemist in his analysis of the 
 various organic and inorganic substances which 
 
PSYCHOLOGY OF COGNITION. 
 
 269 
 
 come under liis notice is engaged in the study 
 of internal qualitative relations. The process of 
 classification involves a careful examination and 
 comparison of the internal qualities of bodies or 
 things classified. The composition and criticism of 
 the productions of the poet, musician, statuary, and 
 painter, consist chiefly of the arrangement and 
 examination of internal qualitative relations. The 
 same relations are the objects of study when we 
 examine the characteristics of a man, of a nation, 
 of a government, of a religious system, of a 
 systematic body of doctrine of any kind, of an 
 oration, in short of any of the vast variety of 
 things known to us which are characterised by 
 internal differences of quality or powers of exciting 
 ideas. 
 
 III. External Quantitative Relations, 
 
 In classification, when the extension or quantity 
 of one class is compared with that of another, we 
 are dealing with external quantitative relations. 
 Many geometrical propositions are concerned with 
 these relations. Comparisons of the weights, 
 masses, figures, proportions, velocities, numbers, 
 and so on, of distinct bodies not forming parts of a 
 connected system, have for their objects external 
 quantitative relations. 
 
 IV, External Qualitative Relations. 
 
 The botanist, zoologist, and chemist, in com- 
 paring the different specimens of objects which 
 come within their respective spheres of study are 
 concerned about external qualitative relations. So 
 
 CHAP. V. 
 SECT. VI. 
 
270 
 
 TUB ELEMENTS OF THE 
 
 CHAP. V. 
 SECT, VI. 
 
 Predica- 
 tion de- 
 fined and 
 illustrated 
 
 is the ethnologist in comparing the characteristics 
 of different races of men ; the philologist in com- 
 paring the principles of different languages; the 
 mythologist in bringing together the myths, legends, 
 and folk-lore of different countries; and the com- 
 parative economist in studying together the different 
 social and political institutions which have sprung 
 up in different countries at different times. This 
 study of the qualitative relations of things and 
 systems has sprung into importance chiefly in 
 modern times, and is a very powerful method of 
 scientific discovery. In the comparative study of 
 physical characteristics, of moral and social habits, 
 of myths, of religious beliefs, of languages, of 
 institutions, of laws, and of historical events, 
 consists the only available effectual method of 
 discovering the beginning and the principles of 
 human progress. 
 
 § 176. Now all thought is concerned about some, 
 or all or various combinations of the relations which 
 we have just now classified; and the result of every 
 comparison, as well as the expression of every 
 relation, is a predication or a proposition. In the 
 exposition of our own views, we shall use the former 
 term ; in the criticism of current logical doctrine 
 we shall use 'the latter. Predication, we may thus 
 define as the assertion that one object or element 
 of our knowledge or conception stands, or does not 
 stand, in some relation to one or more other objects 
 or elements of knowledge or conception. In order 
 that we may clearly understand the nature and 
 
PSYCHOLOGY OF COGNITION. 
 
 271 
 
 forms of predication we shall study a few examples 
 of it. And we shall begin with, the study of 
 examples of the predication of internal relations. 
 
 When we say, this rose is red, we affirm an internal 
 relation of simultaneity or co- existence. The red- 
 ness is a quality found co-existing with all the other 
 qualities which make up our knowledge of the 
 flower. The uniform and inseparable co-existence 
 of these qualities causes us to think of them all 
 as making one object ; and when we say this rose, 
 we mean by it the 07ie object made up of all the 
 qualities. The first term of the above predication 
 calls up .an image before consciousness ; the second 
 term is one of the elements of the image singled 
 out for the moment for particular attention; the 
 predication affirms that the element forms a part 
 of the whole object^ or co-exists with the other 
 elements of it uniformly and inseparably. 
 
 The horse has four legs. This predication also 
 affirms a certain internal relation of the object 
 horse. The first term of the relation denotes a 
 particular object composed of many parts and 
 qualities. The second term of the relation ex- 
 presses particular elements or parts of the whole 
 object. The predication affirms a relation of co- 
 existence of that regular and inseparable kind 
 which constitutes the co-existing qualities into an 
 individual. 
 
 All predications which we make regarding the 
 internal constitution of objects are of the same 
 nature as the abovOj and have about the same 
 
 CHAP. V. 
 SECT. VI. 
 
272 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. VI. 
 
 significance. The form of tlie predication is a 
 matter of comparative indifference, as we are now- 
 engaged in the study of thoughts j not of words. 
 The same relation is expressed by all the following 
 forms : — The rose is red ; the horse has four legs ; 
 the house consists of six rooms ; England contains 
 Middlesex; the lion is possessed of a shaggy mane ; 
 the solar system comprehends the sun, planets, and 
 satellites. And in all these cases the first term of 
 the predication denotes a whole object, and the 
 second term expresses some quality, part, or element 
 of the object. 
 
 § 177. Not only may we predicate internal re- 
 lations of material objects and systems of objects, 
 but also of mental and social phenomena. The 
 following are examples of such predications : — A 
 moral judgment consists of intellectual and senti- 
 mental elements; the family is composed of a 
 husband, wife, and children ; the Government of 
 England includes the Sovereign, the House of Lords, 
 and the House of Commons. The meaning of the 
 predication in all these cases is the same as before. 
 
 There are other predications of relations which 
 may, perhaps, be called internal, but which should 
 be distinguished from the above. These are predi- 
 cations of intransitive actions. We may give as 
 examples of these: — The dog barks; the fire burns; 
 the sun shines ; the river runs ; the wheels turn ; 
 and so on. In all these predications, and such as 
 these, there is involved the idea of something pro- 
 ceeding from the first term of the relation. The dog 
 
PSYCHOLOGY OF COGNITION. 
 
 273 
 
 harksj means a certain sound proceeds from the 
 dos:. Fire hums, means tliat a certain sensation is 
 experienced after contact with fire. The river runs, 
 means that a body of water occupies different places 
 at successive times. The wheel turns , means that 
 the different parts of the wheel successively occupy 
 different positions. The first term of each of these 
 predications denotes some object ; the second term 
 implies some sensation or action; and the predi- 
 cation affirms a relation of succession between the 
 co-existing qualities of the object and the sen- 
 sation or action predicated. 
 
 § 178. We now proceed to the examination of 
 external relations of objects as affirmed or denied 
 in predications, and, for the sake of convenience, 
 shall consider indiscriminately quantitative and 
 qualitative relations. And first amongst these we 
 have relations of difference. A relation of differ- 
 ence, we have seen, is absolutely necessary to enable 
 us to distinguish one object from another. If 
 two objects are exactly alihe in quality they 
 must, at least, have different spatial positions to 
 be distinguishable. Relations of difference are 
 usually expressed by the comparative degree of 
 the adjective which expresses the quality with 
 reference to which two objects are compared. The 
 following are exaniples : — Bed is brighter than 
 green. Lead is heavier than wood. The sun is 
 larger than any of its planets. The conceptions 
 of '' Paradise Lost ^^ are more sublime than those of 
 '' The Deserted Village.''^ A child is not so strong 
 
 CHAP. V. 
 SECT. VI. 
 
 Predica- 
 tion of exw 
 ternal 
 relations. 
 
274 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. VI. 
 
 as a man. A greyhound can rim faster than a 
 bulldog. The scenes of heaven are more glorioiis 
 than can be expressed by language. The fruit of 
 the pine-apple is not the same as that of the orangQ 
 tree. In all these cases^ and in others which might 
 be adduced, we see that the two terms of the predi- 
 cation are the two objects compared ; and the pre- 
 dication asserts that a relation of difference,, in 
 some particular respect, exists between them. The 
 words which we have italicised in the abovo 
 examples express the relation jpredieated between 
 the two terms ; and it is manifest that it is of no- 
 consequence which term of the relation comes first 
 in the predication. The substitution of the second 
 term for the first would simply involve a slight 
 change in the expression j but no change in the 
 thought. Bed is brighter than green, is in thought 
 the same as green is not so bright as red. And so- 
 of all the others. Frequently we have to express a 
 difference between two objects which consists in 
 the fact that, along with a certain resemblance, the 
 one possesses qualities which the other does not. 
 For example, the bat differs from the mouse in that 
 the former has membranous appendages answering 
 the purpose of wings, while the latter has not. 
 The zebra differs from the horse in having a regu- 
 larly striped skin. The whale differs from the most 
 of the mammals in being an aquatic animal. In 
 such comparisons as these it is not easy to adopt 
 such an expression as will show the difference pre- 
 dicated so clearly as in the former cases ; but the 
 
PSYCHOLOGY OF COGNITION. 
 
 275 
 
 thought is equally simple. There are two objects 
 compared ; they are found to differ in a certain 
 respect ; and the predication affirms that they do 
 thus differ. And, as before, it is of no consequence 
 which term of the relation comes first in the predi- 
 cation ; the thought is the same, whatever be the 
 particular mode of expression. 
 
 § 179. Amongst the external relations of objects, 
 both in respect of quantity and quality, that of 
 resemblance is of great importance. It is in con- 
 sequence of resemblance in certain respects that 
 we classify objects together and constitute them a 
 unity. It is in consequence of resemblance between 
 objects that we draw inferences regarding them. 
 We are not now concerned, however, with these 
 uses of resemblance, but only with the nature and 
 expression of the predication of resemblance. Let 
 us study some examples : — 
 
 This line is of the same length as that. These 
 triangles are all equal -sided. This piece of lead 
 loeighs two pounds. In the first and third of these 
 examples there is a comparison of two objects, and 
 a predication that they resemble one another; in 
 the second the predication of resemblance has 
 reference to several objects. When the terms 
 related to one another in a predication of resem- 
 blance are common names, there is always involved 
 a comparison of several objects. For example, 
 when we say, horses have four feet, we mean that 
 all objects known by the term horse resemble one 
 another in having four feet; here we predicate a 
 
 T 2 
 
 CHAP. V. 
 SECT. VI. 
 
 External 
 relation of 
 resem- 
 blance. 
 
276 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VI. 
 
 relation of resemblance between all known or con- 
 ceived individuals. And, as we said before, we 
 imply that each borse bas four feet — an internal 
 relation of co-existence. 
 
 We often predicate resemblance between tbings 
 wbicb are not exactly alike, but yet sufficiently 
 alike to be classified together. Wben we say 
 crimson is Wke scarlet, we mean not tbat tbey are 
 exactly alike, but tbat tbey are the same hind of 
 colour, and tbus distinguisbable from blue or green. 
 Wben we say tbat the sheep resembles the deer, 
 we mean to predicate resemblance only in certain 
 respects, and if we state our meaning fully we will 
 particularise tbe points of resemblance. The most 
 of tbe resemblances wbicb are affirmed in predica- 
 tion are only partial ; wben we affirm a complete 
 resemblance we call it an identity, an equality, or 
 some sucb name. 
 
 Altbougb mental phenomena and material pheno- 
 mena are thought to be entirely different in kind, 
 yet they are frequently employed to illustrate one 
 another. We speak of a lofty thought, thus implying 
 a resemblance between the excellence of the thought 
 and the altitude of some material object. We use 
 light as a symbol of truth, or we say that light 
 resembles tfuth, although there is in reality no 
 resemblance whatever between them in themselves ; 
 but in their results there is a resemblance since the 
 appearance of light and the imparting of truth are 
 both productive of knowledge in the mind. The 
 relation between a symbol and that which is 
 
PSYCHOLOGY OF COGNITION. 
 
 277 
 
 symbolised, between a sign and that which is 
 signified, is usually either a direct resemblance 
 between the two things, or is accompanied by a 
 resemblance amongst some of the circumstances or 
 results connected with the two things. Sometimes, 
 of course, this is not so, as in the case of the relation 
 of a word to that which is denoted by it, where 
 there is now often no resemblance, although there 
 is reason to believe that originally the application 
 of names was founded upon resemblance. 
 
 § 180. The relations of simultaneity and suc- 
 cession between mutually external objects are often 
 the subjects of predication. As when we say : 
 Milton was a contemporary of Cromwell ; John and 
 James were class-fellows ; soldiers on parade keep 
 step with one another. Or when we say : Chaucer 
 preceded Spenser; after the flash of lightning a 
 loud peal of thunder was heard ; a cause is always 
 followed by its effect. It will be observed that the 
 same relation of simultaneity or succession may be 
 expressed in many different ways; and so far as 
 thought is concerned, it is of no consequence by 
 what words the relation is indicated, provided only 
 it be indicated clearly. It will be observed, too, 
 that the order in which the objects said to be related 
 occur in the predication is immaterial. The sentence, 
 Chaucer preceded Spenser, is the same as Spenser 
 followed Chancer. The predication consists in assert- 
 ing that a relation of succession exists between the 
 two individuals, specifying which comes first. And, 
 with reference to all the other examples, it will be 
 
 CHA.P. V. 
 SECT. VI. 
 
 And of 
 simulta- 
 neity and 
 succession. 
 
 I 
 
78 
 
 TEE ELEMENTS OF TEE 
 
 CHAP. V. 
 
 SECT. vr. 
 
 Complex 
 relations. 
 
 admitted that tlie form of predication is unim- 
 portant, provided only that it be clearly expressed 
 what objects are related to one another and what is 
 the relation between them. 
 
 § 181. "We have hitherto confined ourselves as 
 closely as possible to simple relations of difference, 
 resemblance, simultaneity, and succession ; but in 
 the great majority of predications the relations 
 predicated are more or less complex ; and' often the 
 relations implied in a predication are more numerous 
 than those which are expressed. We may give 
 examples of such complex relations. 
 
 The judges in session, having tried the prisoner, 
 agreed to find him guilty. In this complex predi- 
 cation many relations are expressed and implied. 
 The judges sit simultaneously upon the bench — a 
 double relation of simultaneity — (1) amongst the 
 judges; (2) between the judges and the bench. 
 Having tried the prisoner, expresses a continuous 
 process and implies a multitude of relations ; it also 
 indicates that the action next Q,&serted followed the 
 trial. Agreed to find him guilty j here is expressed 
 a relation of agreement amongst the legal opinions 
 of the judges, and a relation of difference between 
 the action of the prisoner and some law. 
 
 John struck the table. In this short sentence there 
 are implied several relations. John and the table 
 are in point of time simultaneous, in point of space 
 contiguous ; and contiguity is itself the result of the 
 combination of several relations. The stroke of 
 John is an action, and therefore involves succession, 
 
f 
 
 PSYCHOLOGY OF COGNITION. 
 
 279 
 
 viz., first the arm is raised; then it is gradually 
 lowered, occupying successively different positions ; 
 and then it comes into contact with the table pro- 
 ducing, probably, a sensation of sound and certainly 
 one of touch. Thus this simple sentence predicates 
 a complex series of relations between two objects, 
 John and the table. 
 
 Many other examples might be given of complex 
 relations being predicated between two or more 
 objects; and it would be a useful exercise in the 
 analysis of thought for the student to examine and 
 separate the relations expressed or implied in the 
 sentences which he reads. We think it will be 
 found that all relations may ultimately be reduced 
 to the four simple ones which we have described ; 
 and that all predications may be shown to consist 
 of an assertion or denial, that one or more of these 
 relations exists between two or more objects or 
 elements of knowledge or conception. 
 
 § 182. We have given and illustrated what we 
 believe is a correct exposition of that most impor- 
 tant act of thought which we call predication. It 
 now remains for us, from the stand-point which we 
 have endeavoured to establish, to take a view of the 
 current logical doctrines regarding the proposition. 
 These doctrines are found in all the smaller text- 
 books of logic ; and they find a place also in many 
 of the more elaborate expositions of logical science. 
 Not, however, in all, for we observe decided ten- 
 dencies towards a departure from the traditional 
 doctrine of the proposition in some modern writers 1 
 
 CHAP. V. 
 SECT. VI. 
 
 Logical 
 doctrine 
 of the pro- 
 position. 
 
28o 
 
 TEE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VI. 
 
 of distinction. The leading features of the tradi- 
 tional doctrine are the following : — 
 
 Every proposition consists of two terms and the 
 copula. The terms represent either concepts, 
 classes or individual things ; and the copula serves 
 as the connecting link between them. The words 
 which constitute the copula are is and is notj 
 according as the one term is to be affirmed or 
 denied of the other. The first of the two terms, 
 that about which the assertion is made, is called the 
 subject ; the second, that which is asserted or 
 denied of the first, is called the predicate. The 
 subject of universal propositions is said to be 
 distributed, or applied to all the things denoted 
 by it ; that of particular propositions is not. The 
 predicate of negative propositions, being altogether 
 denied of all the individuals denoted by the subject, 
 is distributed ; that of affirmative propositions is 
 not. The copula is simply the sign of the relation 
 of the two terms to one another ; it must not in- 
 dicate the actual objective existence of the relation 
 or the things related, nor the time when the rela- 
 tion existed, nor the degree of certainty with 
 which the assertion is made. All these accidental 
 things must be included in the predicate. It is 
 always possible, after limitations and changes in 
 the predicate or copula, to convert propositions, 
 that is, to put the predicate in place of the subject, 
 and the subject in place of the predicate ; and this 
 conversion, being rendered necessary by the laws 
 of the syllogism, is an essential part of the doctrine 
 
PSYCHOLOGY OF COGNITION: 
 
 281 
 
 of the proposition. These are the principal points 
 in the doctrine of the proposition regarding which 
 writers upon logic are agreed ; but there are some 
 points about which they are not agreed. They 
 are not agreed as to the character of the predicate, 
 some maintaining that it may be either denotative 
 or connotative, others that it is connotative only. 
 Those who believe that it may be denotative are 
 not agreed as to its quantificatio7i, some holding 
 that its extent should be explicitly stated in the 
 proposition, others that its quantity should be 
 determined by the ordinary rules. They are not 
 agreed as to the meaning of the predication, some 
 holding that the subject and predicate are simply 
 asserted to be two different names of the same 
 thing ; some that the predicate consists of attributes 
 asserted of the subject ; and some that a relation 
 of mutual co-existence or mutual inclusion or 
 exclusion or congruence or confliction between 
 the two terms is asserted. These differing views 
 may be referred to in the following criticism ; but 
 we shall give the most of our attention to the fore- 
 going doctrines which are generally agreed upon. 
 
 § 183. For the sake .of clearness we divide the 
 subject of our criticism into the following parts : — 
 (1) the terms of the proposition; (2) the rela- 
 tion between these terms as expressed by the 
 copula ; (3) the doctrine of distribution ; (4) the 
 doctrine of conversion. 
 
 (1.) In examining the terms of the proposi- 
 tion our principal aim will be to ascertain whether 
 
 CHAP. V. 
 SECT. VI. 
 
 Criticised. 
 
 Terms. 
 
282 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VI. 
 
 they correspond with the terms of predication. 
 All predications_, we have already shown, con- 
 sist of the assertion or denial that one or more 
 objects or elements of knowledge or conception 
 holds some specified relation to one or more other 
 objects or elements of knowledge or conception. 
 All predications have, therefore, two terms related 
 to one another, and the assertion of some relation 
 existing between them. And we have to inquire 
 whether the terms of the proposition, as described 
 by logicians, are the same as the terms of the 
 predications which we consciously make. In every 
 proposition, put into logical form, the predicate 
 must comprehend all the elements of time, mode, 
 and action, which are usually expressed by verbs 
 and adjectives or adverbs. A few examples 
 of propositions may form a good basis for our 
 criticism. 
 
 Horses are vertehrated. In this predication we 
 affirm that each of a class of individual things 
 possesses a certain quality or rather a certain part 
 called a vertebra. Two objects of thought are 
 before consciousness^ the image of a horse or horses 
 and that of a vertebra; and. we affirm that the latter 
 constitutes a part of the former. Thus we here 
 assert an internal relation between the two terms ; 
 and this internal relation is correctly expressed by 
 the word are, Neither can there be any doubt 
 that the terms of the proposition correspond to the 
 terms of the conscious predication. But, suppose 
 we modify the proposition, and assert that horses 
 
PSYCHOLOGY OF COGNITION. 
 
 283 
 
 helong to the class of vertehrata, it appears manifest 
 that the predication which we make is quite different 
 from the former one. Instead of predicating an 
 internal relation we now predicate an external one; 
 we assert that the class of horses are included in a 
 much larger class of vertebrated animals. In the 
 former proposition we do not think of any other 
 animals except horses ; in this proposition we must 
 think of other animals constituting a large class 
 which includes horses. Now the scholastic doctrine 
 of the proposition teaches that the predicate 
 vertebrated is either connotative or denotative, and 
 thus fails to distinguish between the two important 
 kinds of predications above illustrated. This 
 ambiguity in the meaning of the predicate in such 
 propositions should not be recognised either in 
 psychology or logic ; a predicate should mean 
 either one thing or another, and the mode of 
 expressing it should indicate which meaning is 
 intended to be conveyed. 
 
 Again, the sun illuminates the earth. In this 
 predication we have in thought two objects which 
 are the terms of the predication, and a certain 
 relation existing between them, namely, that light 
 proceeds from the first to the second and thus 
 makes its surface visible to our eyes. This pro- 
 position when put into logical form becomes, the 
 sun is a-body-which-illuminates-the-earth. There 
 the subject is the sun, and the predicate is a-body- 
 which-illuminates-the-earthj i.e., the sun again, 
 along with its relation to the earth. Now we 
 
 CHAP. T. 
 SECT. YI. 
 
284 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. VI. 
 
 think that an appeal to consciousness will show 
 clearly that the terms of this proposition, after beings 
 put into the logical mould, do not correspond to 
 the terms of the predication which we consciously 
 make. The two objects which we think of as 
 related are, plainly, the sun and the earth, not the 
 sun and a-body-which-illuminates-the-earth. And 
 it should, therefore, appear that the so-called 
 logical form of this proposition has no foundation 
 in the facts of consciousness. Gold is heavier than 
 iron. Here we have the image of two substances 
 before consciousness, and we assert a certain 
 relation between them, namely^ that the one sub- 
 stance is heavier than the other. But according 
 to scholastic doctrine, the predicate of the pro- 
 position is not irorij but heavier-than-iron. In this 
 case also an appeal to consciousness will show that 
 the second term of the predication, said to be in 
 a certain relation to the first, does not correspond 
 to the predicate of the logical proposition. 
 
 Many other propositions might be adduced 
 which would show that in the majority of cases 
 the terms of the logically-formed proposition 
 do not correspond to the terms of predication 
 which are thought of in consciousness as related 
 to one another. We have seen and admitted that, 
 when a proposition expresses an internal relation 
 of an object or class to some of its constituent parts 
 or elements, the scholastic proposition may be 
 correct and adequate. But, when external relations 
 are predicated between objects, the logical propo- 
 
PSYCHOLOGY OF OOGmTION. 
 
 285 
 
 sition is quite inadequate to their expression ; the 
 terms of the proposition do not correspond to the 
 terras of the predication. 
 
 § 184. (2.) We now consider the relation itself 
 predicated between the objects or elements compared. 
 Is this relation accurately expressed by the logical 
 copula ? According to logical doctrine the relations 
 expressed by the copula are those of genus, species, 
 difference, property, and accident ; the predicate of 
 a proposition may stand to the subject in any one of 
 these relations. The two first of these are external 
 relations ; the remaining three are internal. Now 
 it is manifest that these relations have all reference 
 to the process of classification; and it appears 
 equally manifest that there are a multitude of other 
 relations which form the subjects of predication 
 that have no reference to classification whatever. 
 When we say, for example, lightning precedes 
 thunder J we do not mean to classify either lightning 
 or thunder with any other phenomena whatever, 
 nor have we in our mind any fact or process in- 
 volved in classification. We do not mean that the 
 fact of lightning preceding thunder is a differentia 
 or a property or an accident of lightning, or that 
 that fact distinguishes lightning from any other 
 phenomenon. We mean simply to assert that a 
 certain phenomenon, lightning, usually or always, 
 is observed, before another phenomenon, thunder, 
 heard. And this relation of antecedence or 
 
 IS 
 
 succession is certainly not expressed by the copula. 
 Again, when we say, elephants are quadrupeds, 
 
 CHAP. v. 
 SECT. VI. 
 
 The rela- 
 tion predi- 
 cated. 
 
286 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VI. 
 
 these words properly express an internal relation 
 between tlie animals spoken of^ and the quality- 
 indicated by the predicate, the possession of four 
 feet. But if this proposition is made to mean, 
 elephants belong to the class of four-footed animals^ 
 we have an external relation asserted, and the 
 copula is not adequate to its unambiguous expression. 
 In the same way it might be shown that all the 
 other external relations of difference, resemblance, 
 co-existence, and succession, and their various 
 combinations, cannot be expressed by the copula. 
 In fact, logicians do not pretend that they can, 
 because they always consign the expression of these 
 relations to the predicate, thus playing false with 
 the phenomena of consciousness and producing 
 monstrous forms of language. It appears then, 
 that psychology offers no foundation for the doctrine 
 that the copula is the only proper expression of 
 the relation between the terms of predication ; and 
 it might also be shown that there is no foundation 
 in language. In many languages which are 
 unquestionably expressive of thought there is found 
 no such abstract verb as our is. And, even in our 
 language, the substantive verb requires to be 
 divested of all its meaning before it is fitted for 
 logical use. ' Thus, it comes to be but an empty 
 symbol, which differs from the symbols of mathe- 
 matics, in that while each one of them has a 
 definite meaning and represents a relation in thought, 
 it is introduced for the purpose of putting aside the 
 relations thought of which it cannot express. 
 
PSYCHOLOGY OF COGNITION. 
 
 287 
 
 CHAP. V. 
 SECT. VI. 
 
 DistrihU' 
 tion of 
 terms 
 
 § 185. (3.) The doctrine of distribution is mani- 
 festly founded upon facts connected with, classifi- 
 cation. In the classes which we construct of 
 organised individuals there are some qualities which 
 are found in all the individuals denoted bj the 
 class-name; there are other qualities, called acci- 
 dental,, which are found in some individuals but not 
 in others. We are able^ then, to predicate that all 
 the individuals of the class possess the former kind 
 of qualities, but only that some of them possess the 
 latter kind of qualities. Again, when we predicate 
 an external relation of certain objects, as when we 
 say " birds belong to the class of oviparous animals," 
 it is evident that we speak of all birds, but only 
 of some oviparous animals ; and in this case the 
 first term of the predication is distributed, the 
 
 second not. But if we say " birds do not 
 belong to the class of quadrupeds,^^ we speak 
 of all birds and all quadrupeds, and assert that the 
 one class is altogether excluded from the other. In 
 this case both the terms of predication are distri- 
 buted. Thus, when the first term of the relation de- 
 notes a class, we indicate its distribution by prefixing 
 the words all or some. When the second term denotes 
 a class of greater extent than the first, we naturally 
 indicate by the form of the predication whether we 
 speak of all or some of the individuals belonging to 
 it ; and at least the accurate expression of thought 
 demands that the distribution of both the terms of 
 the relation should be unambiguously expressed. 
 These principles of distribution, properly applic- 
 
288 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. VI. 
 
 M ot always 
 thought of, 
 
 and its 
 laws not 
 always 
 a^ppUcahle. 
 
 able only to terms wliicli denote classes^ are applied 
 by logicians to all kinds of terms and all kinds of 
 propositions. All universal propositions distribute 
 their subject, while particulars do not. All negative 
 propositions distribute their predicate^ while affirm- 
 atives do not. Now if we had not a particular 
 system to maintain, it might appear plain to us that 
 the principles of distribution cannot be, without 
 absurdity, applied to anything which does not admit 
 of distribution or non-distribution. If we say, for 
 example, '^the Duke of Wellington is a man,^' 
 neither the first nor the second term of the predi- 
 cation is a class-name as here used ; and were it not 
 that we import from the process of classification, 
 ideas foreign to the subject in hand, we should 
 never think of the distribution either of '^ the Duke 
 of Wellington'' or '*aman.'' Logicians, however, 
 must reduce every proposition to the normal form, 
 and so they make this a universal affirmation and 
 write it '^ all of the Duke of Wellington is one of the 
 class — man." 
 
 Again, if we take a proposition expressive of an 
 internal relation, we shall see that the rules of 
 distribution are not applicable. In the proposition 
 "roses are sweet-smelling,'' the first term of the 
 predication -may denote either all or some roses 
 according to our opinion of their odour. But the 
 second term " sweet-smelling " expresses a quality 
 possessed by roses, and when we speak of a quality, we 
 surely mean the whole of the quality, and it seems 
 absurd to say that the name of the quality is either 
 
PSYCHOLOGY OF GOGNITIOK. 
 
 distributed or not distributed ; if we do so, we apply 
 a distinction to it which is plainly not applicable. 
 
 This objection, however, is got over by changing 
 the predicate and thus forming another j^roposition, 
 thus : — '^ Hoses are sweet-smelling flowers," meaning 
 "roses belong to the class of sweet-smelling flowers." 
 But it is surely objectionable, in order to get a 
 proposition into such a form that the rules 
 
 CHAP. V. 
 SECT. VI. 
 
 riiiX:^-- 
 
 distribution may be applied to it, to change/ihp: Off,^^^^^ 
 
 relation predicated in it. This proposition ill its' 
 first form asserts an internal relation to the secon^ , ^4, >'*. 
 
 term of which the principles of distribution do nok; S^O^ I. * 
 
 apply ; and in order to bring it into such a form that ^Si;^^^ iPTI .O. 
 the second term may be tested by the laws of dis- 
 tribution, it is changed so as to express an external 
 relation. Surely a correct psychology offers no 
 foundation for such a procedure. 
 
 It could be easily shown that the laws of dis- 
 tribution are inapplicable to many other kinds of 
 propositions, of which we may give the following as 
 examples : — The line A is equal to B ; the sun is 
 brighter than the moon ; the dawn precedes the day ; 
 silver is not so valuable as gold ; the Prince of Wales 
 shot an elephant ; stars bespangle the sky. In all 
 these propositions relations are predicated between 
 two or more objects, the relation being expressed 
 with perfect clearness, and in none of them can we 
 say, with any degree of appropriateness, that either 
 term of the relation is distributed or non-distributed ; 
 the distinction is inapplicable and foreign to the 
 subject. 
 
 
590 
 
 TEE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VI. 
 
 Conver- 
 sion. 
 
 Our conclusion, founded upon an examination of 
 the meaning of propositions, may be tlius stated. 
 Only tliose terms wliicli denote classes of things 
 can be properly spoken of as being totally or 
 partially distributed ; the names of single qualities 
 or objects should not be quantified ; but wherever 
 a class-name admitting of quantification should, 
 for the sake of clearness, have its quantity made 
 known, we have a right to insist that its quantity 
 should be explicitly stated. This conclusion is 
 founded upon the great law of expression, — what- 
 ever is contained in thought should be accurately 
 expressed in words ; whatever is not contained in 
 thought should not be expressed in words. We do 
 not thinh of the quality affirmed in the predicate of 
 a proposition as being applicable to many or few 
 objects; we should not therefore quantify it. But 
 where the subject or predicate is a class-name, 
 wholly or partially distributed in tliouglity its dis- 
 tribution should be expressed in language. 
 
 § 186. (4.) We now come to the doctrine of 
 conversion. For the sake of the transposition of 
 terms required by the syllogism, it is considered by 
 logicians of importance, that all propositions should 
 be convertible ; and there are certain well-known 
 laws laid down for their conversion. The laws of 
 distribution receive their full importance only in 
 connection with conversion ; as the importance of 
 the laws of conversion is seen only in relation to 
 the syllogism. The great law of conversion is, — 
 that no term should be distributed in the converted 
 
PSYCHOLOGY OF COGNITION. 
 
 291 
 
 proposition, which, was undistributed in the original 
 one. And by the application of this law it is found 
 that universal negative and particular negative pro- 
 positions may be converted without any change of 
 quantity or quality, that the universal affirmative 
 can be converted by limiting the quantity of the 
 predicate, and that the particular negative may be 
 simply converted after changing its quality, that is, 
 changing it into a particular affirmative by trans- 
 ferring the sign of negation from the copula to the 
 predicate. 
 
 Now, if we examine predications as they are 
 naturally expressed, there does not seem to be any 
 objection to the order of the terms being changed 
 provided there is a sufficient reason for the change. 
 If we say "whales are included in the class 
 mammals,^' we mean the same as "the class 
 mammals includes whales.''^ If we say "thunder 
 succeeds lightning,^' we are understood no better 
 than if we say " lightning precedes thunder.^' The 
 predication " gold is heavier than silver,'^ expresses 
 the same relation as '^ silver is lighter than gold.'' 
 The sentence " John strikes the table,'' is, as far as 
 thought is concerned, exactly the same as "the 
 table is struck by John." In short, if we express 
 any relation in a predication, the laws of thought 
 and language require nothing more than clear- 
 ness and accuracy in the expression; and it is a 
 matter of indifference which term of the relation 
 .comes first. 
 
 But, if we examine the conversions of logically 
 
 u 2 
 
 CHAP. V. 
 SECT. VI. 
 
292 
 
 THE ELEMENTS OF THE 
 
 CHAP. y. 
 SECT. VI. 
 
 Consii't' 
 ency of 
 predica- 
 tions. 
 
 formed propositions , we cannot so easily admit their 
 legitimacy. The proposition "roses are red/' 
 becomes, in the haads of logicians, when converted, 
 " some red things are roses/' The simple sentence 
 "thunder succeeds lightning'' is metamorphosed 
 into "a class of things succeeding lightning is 
 thunder." The monstrous forms of language which 
 require to be introduced for the purpose of convert- 
 ing the majority of logically moulded propositions 
 appear to afford a strong reason for doubting the 
 legitimacy of the process. But, as we have seen, 
 the principal objection does not lie against trans- 
 posing the terms of a predication, but rather against 
 the changes to which naturally expressed predica- 
 tions must be subjected, in order to bring them into 
 the so-called logical form. 
 
 § 187. There are certain things connected with 
 the mutual consistency of predications to which we 
 now turn attention. Predications having the same 
 subject may be related to one another in a variety 
 of ways. The subject may be taken in its whole 
 extent or only in part of its extent ; the predicate 
 may be affirmed or may be denied of the subject. 
 Conabining these different forms we get the con- 
 trary, contradictory, and subaltern relations of pre- 
 dications pointed out in works of logic. And it is 
 necessary in combining predications together in a 
 course of reasoning that consistency between the 
 different predications made must be maintained. 
 To be consistent is to avoid contradiction, and a 
 simple inspection of two simple propositions will 
 
FSYGHOLOGY OF COGNITION. 
 
 293 
 
 show whether they are contradictory or consistent. 
 If we can predicate either of the whole or of some 
 of the class A that they are B, it would be incon- 
 sistent to predicate that all are not B. If we can 
 predicate of the whole or of some of the class A 
 that they are not B, it would be inconsistent to 
 predicate that all are B. But we may consistently 
 predicate of some of the class A that they are B, 
 and of others that they are not B, provided that B 
 is not an essential quality. Further, inconsistency 
 may arise from attaching predicates which are in 
 their nature inconsistent with one another to the 
 same subject ; as, for example : The figure A is a 
 square. The figure A is a triangle. But there 
 may often be an apparent inconsistency arising 
 from the attachment of incongruous predicates to 
 the same subject, which is found to be not real. 
 The incongruous predications may be truly made of 
 different parts of the thing denoted by the subject. 
 Inconsistencies between propositions are usually 
 concealed by placing them wide apart in the dis- 
 course, by complicating them with many other pro- 
 positions not clearly arranged, by the use of am- 
 biguous terms, and in other ways. The avoidance 
 and the detection of inconsistencies cannot be 
 assisted to any great extent by special rules, but 
 depends chiefly upon the clearness of intellectual 
 perception, the correct and un-ambiguous use of 
 language, and the avoidance of complexities and 
 confusion, both in the individual parts and the 
 general arrangement of the discourse in hand. 
 
 CHAP. V. 
 SECT. VI. 
 
294 
 
 TBE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VII. 
 
 Law of 
 
 excluded 
 
 middle. 
 
 Import- 
 ance of 
 systematic 
 knowledge. 
 
 § 188. Witli reference to the mutual relations of 
 predications it is frequently of importance to place 
 a doubtful question in sucli a form that either one 
 or the other of two answers must be accepted as 
 true. This is done by means of contradictory 
 opposition. If " all A is B/^ it is perfectly certain 
 that the predication '^ some A is not B " is false. 
 If the latter is true, the former must be false. And 
 there is no middle predication possible. The prin- 
 ciple according to which we affirm that of two 
 contradictory propositions the one must be true 
 and the other false,, is called the " Law of Excluded 
 Middle.''^ In the application of this Law we are, 
 as a rule, not supposed to know which of the con- 
 tradictory extremes is true, because if we knew, the 
 proposal of the alternative would be useless. The 
 law is frequently very useful in controversial argu- 
 ment, enabling one to place before an opponent 
 two contradictory propositions, the one or the other 
 of which he must admit to be true, and thus involve 
 him in what is called a dilemma. 
 
 Section VII. 
 
 seasoning simulating infeeence. 
 
 § 189. It is of great importance to human wel- 
 fare that the knowledge which men possess should be 
 clearly arranged in their minds, that the different 
 elements of that knowledge which have a natural 
 relation to one another should be brought together, 
 and that ignorance and confusion should give place 
 
PSYCHOLOGY OF GOGNITIOK. 
 
 295 
 
 to systematic science. There may be possessed by a 
 man a great deal of knowledge wliicli can be of no 
 use whatever in consequence of inability to bring 
 together into one view related facts, to see their 
 significance, and to give them their proper place in 
 the system of knowledge. Thus the knowledge 
 which many possess, although very extensive, is a 
 perfect chaos, a jumble of confusion, and of no prac- 
 tical use in the guidance of life. To reason with a 
 man frequently means nothing more than to point 
 out the relation between different things which he 
 already knows, and thus bring into order what was 
 before confusion. There are to every man hundreds 
 of ^^ open secrets,^^ facts related in particular ways 
 which relations he cannot see, and it is the function 
 of what is commonly called reasoning to convert this 
 chaos of confused facts into a cosmos of order and 
 harmony, so that men may see clearly what has 
 always been under their eyes, and understand clearly 
 the relations and significance of what they have 
 blindly perceived. This discovery or pointing out of 
 the true relations between things already known is 
 not what we mean by Inference, although it very of ten 
 assumes the form in which true inference is naturally 
 expressed. It is made also still more closely to 
 resemble inference by being frequently forced by 
 logicians into the artificial forms of the syllogism, 
 which is assumed to be the universal type of reason- 
 ing. To make clear the true psychological nature of 
 the process which we are describing we shall examine 
 some typical examples of it. 
 
 CHAP. V. 
 SECT. VII. 
 
296 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. VII. 
 
 Erroneous 
 classifica- 
 tions. 
 
 § 190. We observe, in the first place, that mistakes 
 
 are very apt to be made in the classifying of the 
 
 objects with which we are acquainted, and a great 
 
 I deal of what passes for reasoning is simply an 
 
 I attempt to assign objects to their proper classes. 
 
 There are many popular classifications which are 
 
 erroneous in themselves and lead to other errors, and 
 
 an important duty of scientific men is to correct these 
 
 \ erroneous classifications. From our study of the 
 
 i formation of classes we can understand the manner 
 
 I in which a correct classification is to be effected and 
 
 I an erroneous one is to be avoided. It is only by the 
 
 ! possession of the Essentia of a class, or at least of 
 
 j some universal characteristic of a class, that any 
 
 I object is to be referred to that class. Suppose, for 
 
 I example, that a person ignorant of natural history 
 
 I were to assert that whales belong to the class fish, 
 
 his mistake would be corrected by informing him 
 
 that whales do not possess the essential qualities of 
 
 the class, fish, — they are not water-breathing or 
 
 j oviparous. Supposing him to know the principle 
 
 I of classification, he would immediately see that his 
 
 j predication regarding whales was incorrect. And 
 
 i upon discovering or being informed further that 
 
 whales are viviparous and suckle their young, and 
 
 i that these are the essential qualities of a class called 
 
 mammal y he would at once refer them to that class. 
 
 Thus in order to effect a correct classification it is 
 
 necessary to know by observation or instruction (1) 
 
 what are the essential or characteristic qualities of 
 
 j some class in question ; and (2) whether the object in 
 
PSYCHOLOGY OF COGNITION. 
 
 297 
 
 question possesses or does not possess these qualities 
 
 or characteristics. Knowing these two things^ the 
 
 mind at once refers or does not refer the object in 
 
 question to the specified class, 
 
 § 191. The preceding example which illustrates 
 
 the process of classification, when put by logicians 
 
 into their favourite form of the syllogism, appears as 
 
 follows : — 
 
 All fishes are oviparous animals : 
 Whales are not oviparous animals, 
 .'. Whales are not fishes. 
 
 We have already pointed out that the predicates of 
 propositions, as a rule, are connotative,* and that, 
 therefore, it is psychologically incorrect to give 
 them extensive quantity. The first two of these 
 propositions therefore ought to be : — 
 
 All fishes are oviparous : 
 Whales are not oviparous. 
 
 But these two propositions being taken together, it 
 becomes impossible to classify whales with fishes, 
 and consequently the mind asserts, — Whales are not 
 contained in the class, fish . Now it must be observed 
 that this is not an inference in the proper sense of 
 that term. The so-called conclusion is directly seen 
 the moment that the essential qualities of whales 
 and fishes become known. If a boy have before him 
 a number of marbles, and mixed up with them a 
 number of hazel-nuts, he sees at a glance that the 
 latter should not be classified with the former. The 
 
 * i.e. When the propositions relate to some facts of classifi- 
 cation. 
 
 CHAP. V. 
 SECT. VII. 
 
 The syllO' 
 ijism not 
 the best 
 form for 
 collecting 
 false clas- 
 sifications. 
 
298 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. vir. 
 
 Incon- 
 gruous 
 predicates. 
 
 only difference between this case and the previous 
 one is, that the qualities which make it impossible 
 to classify the two sets of objects together are more 
 obvious. 
 
 § 192. Again, it is a principle of consistency be- 
 tween predications that two incongruous predicates 
 cannot be attached to the same subject. To assert 
 '^ the figure A is a square/^ and " the figure A is a 
 circle," is a mental impossibility; and in practice 
 the only difficulty is to see what predicates are 
 incongruous, many predicates being- frequently sup- 
 posed to be incongruous which are not really so, and 
 vice-versa. Now much of so-called reasoning is 
 nothing more than an attempt to show the congruity 
 or incongruity of predicates. Suppose, for example, 
 we take the proposition, "the sensualist, being 
 enslaved by his appetites, cannot be free.^' When 
 placed before our minds in this form there appears 
 no difficulty in seeing immediately that " slavery to 
 appetites " and " freedom " are incongruous, and can- 
 not be predicated of the same individual. Logicians, 
 however, must express it in the form of a syllogism, 
 
 No one is free who is enslaved by his appetites : 
 The sensualist is enslaved by his appetites, 
 .'. No sensualist is free. 
 
 We leave it to the reader to decide which is the most 
 intelligible form. 
 
 Sometimes predicates are thought to be incon- 
 gruous which are not really so, and the way in which 
 this error can be most easily corrected is to point 
 out an instance in which the apparently incongruous- 
 
PSYCHOLOGY OF COGNITION. 
 
 299 
 
 predicates are plainly seen to be consistent. It 
 might, for example, be supposed that certain modes 
 of conduct which are consistent with holiness cannot 
 at the same time be inexpedient. This hasty judg- 
 ment would at once be seen to be incorrect by point- 
 ing out some special circumstances in which it would 
 be highly inexpedient to do some things which, after 
 all, were quite consistent with holiness. But logicians 
 would think that the simple pointing out of an 
 instance to the contrary would not be enough to 
 correct the error, and they would probably express 
 themselves in some such way as this : — 
 
 Some practices which the Divine Law allows are in some 
 
 circumstances inexpedient ; 
 All such practices are in themselves consistent with holiness : 
 . • . Some things in themselves consistent with holiness are 
 
 in some circumstances inexpedient. 
 
 § 193. Many other examples might be given of 
 the manner in which erroneous classifications are 
 corrected, and the consistency or inconsistency of 
 attributes or predicates determined. In popular 
 language these processes are called reasoning, and 
 logicians, basing much of their science upon this 
 popular phraseology, do violence to psychology as 
 well as to grammar by forcing them into the form of 
 syllogisms. But in truth they are nothing more than 
 the bringing together of related facts, and the percep- 
 tion of the relations between them. This being done, 
 the so-called conclusion is not an unknown thing ; 
 it is directly seen. And the preliminary process is 
 only the bringing of facts together so that it may be 
 
 CHAP. V. 
 SECT. VII. 
 
 Popular 
 reasoning 
 often not 
 inference. 
 
30O 
 
 TEE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VIII. 
 
 Character 
 of in- 
 ference. 
 
 seen. Notwithstanding that this arrangement and 
 harmonising of things known does not partake of the 
 nature of inference, it is most important to human 
 advancement and welfare that it should be well done. 
 But the details of its accomplishment cannot be con- 
 trolled by any rules more special than those general 
 principles of classification and consistency to which 
 we have referred. The work must depend chiefly 
 upon the practical good sense and insight of the 
 individuals who devote themselves to it. 
 
 Section VIII. 
 
 INFERENCE. 
 
 § 194. We have already seen that Inference is one 
 of the two grounds upon which predication rests, the 
 other being Intuition. And the difference between 
 the two is this, that whereas in intuition we see 
 directly the relation which is asserted in the predi- 
 cation, as well as the objects between which the 
 relation exists, an inference asserts a relation which 
 is not directly known, but which follows more or less 
 immediately from what is so known. In our study 
 of perception we have had under our notice many 
 instances of inference. When we see an orange 
 before us, we infer, or at least we may do so, that if 
 we cut open the skin we shall see and touch certain 
 small rounded elongated bodies called seeds. The 
 reason why we infer this is that all the oranges 
 which we have previously opened have had seeds of 
 this description within them. And, judging from 
 
PSYCHOLOGY OF COGNITION. 
 
 301 
 
 our past experience, we infer that this particular 
 orange which we see before us has seeds within it. 
 Now the nature of this simple inference is essentially 
 the same as of that wonderful illustration of the 
 power of reason exhibited in the discovery of 
 Neptune. An inference is a mental assertion j 
 regarding the existence and relations of something | 
 not directly known, or, it maybe, of something which 
 we cannot directly know. And on the other hand, 
 all inferences must be founded upon something which 
 we do know, either directly or indirectly. 
 
 § 195. The Law of Sufficient Eeason gives an 
 important caution regarding the drawing of infer- 
 ences. " Infer nothing/^ it tells us, '^ without a 
 Sufficient Reason.^' The statement of this law 
 implies that inferences cannot be made arbitrarily, 
 that before the mind can draw an inference there 
 must be some antecedent reason to justify it. This 
 principle is a universally binding one. But when 
 the law tells us that the reason must be Sufficient, 
 there is left a very wide margin for doubt and differ- 
 ence. All who draw inferences, and they include 
 the whole human race, think that they have reasons 
 sufficient for the inferences which they draw. But 
 subsequent reflection, or the judgment of othei-s, 
 frequently pronounces the reasons to be insufficient. 
 There are, therefore, valid and invalid grounds of an 
 inference. The ground alleged may not be sufficient 
 to support it; or, looking at it from the other side, 
 the inference may be drawn by the mind when there 
 is no reason sufficient to make it legitimate. Thus, 
 
 CHAP. V. 
 SECT. VII f. 
 
 SujUcient 
 Reason. 
 
502 
 
 THE ELEMENTS OF THE 
 
 Intuitive 
 basis of 
 inference. 
 
 CHAP. V. altliougli this Law expresses a most important caution 
 against hasty and baseless inferences, it must be 
 further defined and explained before it can be prac- 
 tically useful in enabling us to determine what 
 inferences are legitimate. 
 
 § 196. As Intuition is the original source of our 
 knowledge, we naturally look to it for the first 
 grounds upon which inferences may be built. 
 Knowledge which is given to us in intuition must 
 lie at the foundation of all knowledge and belief ; and 
 if in the superstructure errors are found, their source 
 is probably to be found in some of the false inferences 
 which have been drawn. Now we have seen that in 
 intuition there are made known to us either indivi- 
 dual objects or the relations between them. And 
 we have seen that these relations may be of sequence 
 in its various forms, of co-existence, and of likeness 
 and unlikeness in their various forms and degrees. 
 But all inferences are expressed in predications; 
 and all predications are the assertion that two 
 objects of thought exist in some relation to one 
 another. Hence it is primarily to the relations 
 given to us in intuition that we are to look as the 
 ground of our assertion of those other relations 
 which are predicated in our inferences. 
 
 From certain relations which we know, we infer 
 the existence of certain relations not directly intuited. 
 Thus, having known that a certain relation exists 
 between the objects of thought, A and B, and between 
 B and C, we infer that a certain relation exists 
 between A and C. In this case the objects A and C 
 
 Chiefly in- 
 tuited re- 
 lations. 
 
PSYCHOLOGY OF COGNITION, 
 
 303 
 
 are directly known, but the relation is not. Again, 
 having known that a certain relation exists between 
 A and B, there comes within our knowledge an 
 object like B : we infer that there exists in relation 
 to this second B an object like A. Thus we have 
 apparently two forms of inference : we infer the 
 existence of a relation between two objects both of 
 which are known ; and we infer the existence of the 
 unknown term of a relation, together with its relation, 
 to some object which we know. 
 
 § 197. A few particular illustrations will make 
 more clear the abstract statements of the last para- 
 graph. We have before us three straight ABC 
 lines. A, B, C. We are able to compare 
 A with B, and B with C, and find that A 
 is equal to B, and B to C. We infer, 
 without directly perceiving, that A is 
 equal to C. The relations compared are in this case 
 so simple, and the inference presents itself to the 
 mind with such force, that it is usually expressed in 
 mathematical works in the form of an d A B C 
 axiom, or self-evident proposition. | 
 
 *' Things which are equal to the same 
 thing are equal to one another/' But 
 it is none the less truly an inference, 
 although one regarding which there 
 cannot be in the mind the slightest 
 doubt. If, again, we take four lines, 
 A, B, C, D, of which A is equal to B, 
 D is double of A, and C is double of B, we infer 
 without hesitation that C is equal to D. Here the 
 
 CHAP. V. 
 SECT. VIII. 
 
 Tivo forms 
 of in- 
 ference. 
 
 Illustra- 
 tions of in- 
 ference of 
 first form. 
 
304 
 
 THE ELEMENTS OF THE 
 
 CHAP, Y. 
 SECT. VIII. 
 
 Illustra- 
 tion of in- 
 ference of 
 second 
 form. 
 
 relations between A. and D, B and C are known, a 
 certain ratio of length, A being one-half of B, and B 
 of C. Thus A and B being equal, and the relation 
 between A and D being equal to the relation 
 between B and C, we infer a relation of equality 
 between D and C. This inference is expressed in 
 the mathematical axiom, "Doubles of equals are 
 equal/^ Similar remarks might be made with 
 reference to the majority of the mathematical 
 axioms. They are inferences immediately based 
 upon intuitions ; their objects are simple and per- 
 fectly free from variable conditions, and there con- 
 sequently is not the slightest room for doubt as to 
 the legitimacy of the inferences. Inferences of this 
 simple kind have all the certainty of intuitions; but 
 yet they are not intuitions, unless we assume some 
 other distinction between inferences and intuitions 
 than that which we have given. They have been 
 called axioms, or principles of mathematical thought^ 
 but this is perfectly incorrect; they are particular 
 examples of inferences, so simple and unavoidable 
 that the mind can never fail to draw them when 
 occasion requires. The mind universally recognises 
 the respective equality of two lines or figures to a 
 third as a sufficient reason for the inference that the 
 two are equal to one another. 
 
 § 198. We now study an example of an inference 
 in which the existence of an unknown term of a re- 
 lation is inferred. By a long course of investigation 
 scientific men had come to the conclusion that all 
 material bodies in the universe exert upon one 
 
PSYCHOLOGY OF COGNITION. 
 
 305 
 
 another an influence resulting in motion, and called 
 the Force of Attraction. Illustrations of this force 
 are seen in the falling of bodies to the earth, the 
 motions of the moon and planets, and many other 
 phenomena. By means of many accurate observa- 
 tions, the laws of force, and of the consequent 
 motion of bodies, had been calculated ; and so pre- 
 cisely had this been done that astronomers could 
 predict exactly the position of any of the planetary 
 bodies amongst the stars at any given moment. 
 Now it had been observed that the positions of 
 Jupiter and Saturn at certain times were not 
 exactly what they ought to be ; there was a certain 
 variation in their motions which could not be 
 accounted for by the attraction of any of the known 
 heavenly bodies. This variation, therefore, was a 
 phenomenon to be accounted for ; it might be the 
 result of a mistake in the statement of the laws of 
 motion ; it might be the result of inaccurate obser- 
 vations j or it might be the result of the attraction 
 of some unknown body beyond the orbits of Jupiter 
 and Saturn. The first of these possibilities could 
 not be admitted, because the laws of motion had 
 been tested in innumerable instances and had never 
 before failed. The second was rejected, because 
 the observations had been taken with the utmost 
 precision by skilled observers and accurate instru- 
 ments. The only inference, therefore, which ap- 
 peared to have a sufficient reason was the third, 
 that there was some hitherto unknown body 
 beyond Saturn which caused the variation. And 
 
 CHAP. V. 
 SECT. VIII. 
 
3o6 
 
 THE JELmiENTS OF THE 
 
 CHAP. V. 
 SECT. VIII. 
 
 Another 
 illustra- 
 tion. 
 
 the success of astronomers in discovering this bodj 
 proved the accuracy of the inference. Now here 
 the process of reasoning appears capable of analysis 
 into the following elements : A great bodj^, the 
 sun, exerts a powerful influence over a number of 
 smaller bodies, the planets ; these also exert a 
 similar, but, in degree, a less influence over one 
 another ; the result of this is that certain compli- 
 cated relations in space exist between the sun and 
 surrounding planets. Here we have — (1) a number 
 of bodies; and (2) a certain regularity of their 
 motion in space. But a new phenomenon appears ; 
 this regularity is in a particular case interrupted : 
 a cause of this interruption there must be, and, so 
 far, no cause is known ; the only inference which 
 can be drawn is, that there is some hitherto un- 
 known cause, and that the unknown cause is similar 
 to the causes of motion already known — the forces 
 of the sun and planetary bodies. Thus we have 
 here — (1) a known relation between certain known 
 bodies and their motions ; (2) a motion, or variation 
 of motion, not related to, that is, not caused by, 
 these known bodies; and (3) the inference of the 
 other term of relation, the unknown planet, to 
 account for the variation. 
 
 § 199. Again, in our consciousness, we are aware 
 of two great classes of phenomena, described as 
 voluntary activities and passive states. The former 
 we are conscious of producing by our own effort ; 
 the latter we are powerless to produce or to anni- 
 hilate. As an example of the former we may 
 
PSYCHOLOGY OF COGNITION. 
 
 307 
 
 instance muscular sensations and the sounds of our 
 own voice ; as an example of the latter, sounds 
 heard, but not produced, by ourselves, and colours 
 which we see. Now, with reference to our voluntary 
 activities, we are conscious of a certain forth-putting 
 of energy in their production ; it makes no difference 
 whether we are aware of the different links which 
 connect the conscious effort with the result or not ; 
 we perceive an invariable relation of sequence 
 between — (1) the conscious effort ; and (2) the com- 
 plex of sensations which we regard as its result. 
 But, in the case of passive states, as, say colours, we 
 are conscious of sensations, but the other term of 
 the relation is wanting ; these sensations we know 
 that we have not produced ; we therefore infer the 
 other term of the relation, a cause not ourselves the 
 productive efficiency of which accounts for the 
 sensations. Analysing this process we have — (1) a 
 perceived relation between A {conscious effort), and 
 B {sensations) ; (2) a knowledge of B^ {similar 
 sensations) ; (3) the inference of A^ {a7i objective cause 
 more or less similar to A). And, be it remembered, 
 the objective A, is not an aggregate of other sensa- 
 tions collected somehow together in a group, because 
 every one of these sensations requires to be accounted 
 for in the way that we have now indicated. The 
 objective inferred term of the relation is therefore 
 unknown ; we think of it as a cause adequate to the 
 production of the perceived effect, and its nature 
 can be learned, and only learned imperfectly by the 
 aid of hypothesis, 
 
 X 2 
 
 CHAP. V. 
 SECT. VIII. 
 
3o8 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. VIII. 
 
 Inferred 
 
 relation 
 
 between 
 
 unTcnown 
 
 ipowers. 
 
 § 200. We take still anotlier illustration of 
 inference, in which there is inferred to exist a cer- 
 tain relation between unknown hypothetical powers. 
 Many years ago Count Kumford made experiments 
 regarding the connection between motion and heat.* 
 He found that the friction of two bodies always 
 produced a certain amount of heat; and that the 
 motion of any body, whenever it was arrested or 
 hindered, resulted in heat. Hence he concluded 
 that heat, as it exists in bodies, is a form of motion. 
 Since his time many experiments and observations 
 have been made regarding the relations of motion, 
 heat, light, electricity, and other natural forces, and 
 it has been clearly established that they are all 
 convertible into one another. But by inference like 
 that which we have examined in the last paragraph, 
 there is some objective Force or cause which has a 
 relation to each one of these phenomena, and the 
 discovery of the correlation of motion, heat, light, 
 &c., does not result in the inference that the one 
 phenomenon is the cause of the other. Intimate 
 relations are perceived to exist between motion, heat 
 and light ; the inference is that the unknown causes 
 of these phenomena, hitherto supposed different, are 
 in reality identical. 
 
 The accompanying diagram illustrates the dif- 
 ference of views produced by the experiments referred 
 to. Originally a different cause, F Cal L, is inferred 
 to account for each of the phenomena m, h, c ; 
 
 * This discovery is described in a paper published in the 
 " Transactions of the Royal Society for 1798." 
 
PSYCHOLOGY OF COGNITIOK 
 
 309 
 
 but observation sbows certain nu- 
 merous and intimate relations 
 between m, h, c ; it is consequently 
 inferred tbat F Cal L^ are really 
 one, as represented in tbe united lines 
 of the second diagram. And tbus 
 also the relations between m, h, c 
 are inferred to depend upon the 
 community of the Force F with 
 reference to them all.* 
 
 §201. There are many inferences 
 which have a close relation to classification. We 
 have observed, for example, that all vertebrated 
 animals which fly through the air by means of true 
 wings are oviparous as far as we have been able 
 to discover. These observations collected together 
 in a proposition, are thus expressed, " Birds are 
 oviparous." Having formulated our observations 
 in this proposition, and having come across a class 
 of animals agreeing in essential particulars with 
 the known class birds, we infer regarding the 
 newly-discovered class that they are oviparous. 
 We do this, although we have not seen the eggs 
 or the nest ; and a naturalist would not be satisfied 
 with his observations of a new species of bird 
 until he was able to verify his inference by the 
 examination of the nest and the habits of the bird 
 in the rearing of its young. Now an analysis of 
 this process gives us the following elements : (1) A 
 class of animals grouped together by the possession 
 
 * F, force; cal, caloric; L, light; m, motion; h, heat ; c, colour. 
 
 CHAP. V. 
 SECT. VIII. 
 
310 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. VIII. 
 
 Classifica- 
 tion of ob- 
 jects of 
 inference. 
 
 of certain characteristics^ this class, as far as we 
 have observed, having in particular a certain 
 predicable attribute, oviparous ; (2) a certain 
 number of animals observed to possess some of 
 the essential qualities of the preceding class ; and 
 (3) the inference that the attribute, oviparous, may- 
 be predicated of them. 
 
 § 202. The preceding illustrations of inference 
 will enable us to advance to the discussion of some 
 important questions regarding it. But, before doing 
 so, we shall offer and explain a classification of the 
 spheres of thought in respect to which inferences 
 are drawn. 
 
 (I.) We have, in the first place, inferences regard- 
 ing the relations of particular parts of Space and 
 Time, and also regarding that which is a result of 
 a combination of Space and Time^ Motion. Space 
 and time, we have seen, are the forms of external 
 intuition, and motion is known to us as in terms 
 of space and time. And when the lines, figures, 
 and other dimensions of space, time, and motion 
 are made the subjects of inference, abstraction is 
 made from all particular content of intuition; the 
 inference has reference only to the elements of the 
 forms. 
 
 (II.) Inferences are drawn, in the second place, 
 regarding certain Forces or powers which are not 
 known to us directly as phenomena, and which, 
 indeed, cannot be so known. The inferences have 
 reference to the nature, relations, and laws of these 
 powers, as well as to their connection with the 
 
PSYCHOLOGY OF COGNITION. 
 
 ir 
 
 phenomena througli wliich they manifest them- 
 selves. 
 
 (III.) There is a third class of inferences_, having 
 reference to the existence and relations of Phe- 
 nomena. These inferences determine our belief of 
 the existence of phenomena not directly known in 
 relation to certain other phenomena which we do 
 know. But they have not reference merely to the 
 present time ; they extend to the occurrence of past 
 events,, in which case they depend upon historical 
 evidence ; they reach forward also to the future, 
 constituting prevision, expectation, or probability, 
 according to their degree of certainty. 
 
 Before, however, we consider these classes of 
 inferences, we must give more minute attention 
 to the determining reasons upon which inference 
 rests. 
 
 Section IX. 
 
 DETEEMINING GEOUND OP INPEKENCE. 
 
 § 202. In the preceding section we analysed certain 
 particular examples of inference for the purpose of 
 gaining a general knowledge of the process. We saw 
 that inference is a mental assertion made, without 
 immediate knowledge, regarding some relation be- 
 tween known objects; or, regarding the existence 
 and relation to known objects, of some object or power 
 not directly known. We have seen that in certain 
 cases the same inferences are uniformly drawn by all 
 men, whereas, in other cases there is room for doubt 
 
 CHAP. V. 
 SECT. IX. 
 
 Question 
 proposed. 
 
312 
 
 TRE ELEMENTS OF THE 
 
 and difference ; and tliat in all cases there is some 
 ground upon wMch. tlie inference is based. Our 
 task, now, is to examine into tlie nature of this ground. 
 It is admitted that all inferences form a part of our 
 conscious experience ; and the question is, What is it 
 that determines this experience ? In any given case 
 of inference, why is it that we infer so-and-so, and 
 not otherwise ? When, for example, we see two lines 
 each equal to a third line, why do we infer that they 
 are equal to one another ? When we seethe motion 
 of any body without us taking place, why do we infer 
 that there is some force impelling it ? When we see 
 any seed, in germinating, putting forth a pair of leaves 
 instead of a single one, why do we infer that the 
 future plant or tree will grow by the addition of 
 annual layers of woody tissue upon the oufcside sur- 
 face ? In other words, what is the sufficient reason of 
 any inference which makes that inference necessary 
 or legitimate ? 
 
 § 203. The question of the preceding paragraph 
 may be discussed with reference to the three classes 
 of inferences described in the last section. We make 
 inferences regarding the forms of the objects of 
 knowledge, space, time and motion ; the /o?res which 
 operate in nature around us; and the phenomena 
 which present themselves, or are capable of doing so, 
 to oursenses or consciousness. In connection with the 
 first of these classes of inference, a great deal of dis- 
 cussion has arisen regarding the nature of the basis 
 upon which demonstration rests. Certain axioms, 
 such as, '' Things which are equal to the same thing 
 
PSYGHOLOGY OF COGNITION. 
 
 313 
 
 pare equal to one another," are generally placed at 
 the beginning of mathematical works, and assumed 
 to be self-evident. And we have now to consider the 
 nature of those axioms. One class of thinkers tells 
 us that they are a priori judgments, not founded upon 
 anything more simple and original than themselves. 
 Being self-evident, and necessary, and universal they 
 must be original intuitions of the mind. But to this 
 opinion, as it is generally expressed, there is a prima 
 facie objection. The axiom quoted above is general 
 in its application ; it applies to all things, of whatever 
 nature they may be, which are equal to one another. 
 And we may assume it for certain, that a proposition 
 of this kind is not formed until after one or more 
 particular examples of it have been known. This 
 axiom as well as all the others, has been generalised, 
 and the question is, What is the nature of the parti- 
 cular mental acts from which it has been drawn ? 
 Now, taking the particular axiom referred to, it is 
 manifest that the single mental act from which it is 
 generalised must be either an intuition or an infer- 
 ence. A is equal to B ; C is equal to B ; therefore 
 A is equal to C. This is the particular form of the 
 general axiom, and must have |9recec?e(^ the general 
 axiom in historical order. In this form the mental 
 act appears to be an inference. A is not directly 
 seen to be equal to C, but both A and C are seen to 
 be equal to B ; and the inference is drawn. But it 
 has been held that this apparent inference is ori- 
 ginally an intuition ; that we are not able to predicate 
 that A is equal to C until after we have compared 
 
 CHAP. V. 
 SECT. IX. 
 
 A priori 
 theory. 
 
 Empirical 
 theory. 
 
314 
 
 THU ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. IX. 
 
 Axiom 
 general- 
 ised from a 
 particular 
 necessary 
 inference. 
 
 them directly together ; and that having seen several 
 instances in which A and 0^ being each equal to a 
 third thing, B, they are found to be equal to one 
 another^ we generalise the axiom as above. Accord- 
 ing to this view, the axiom is generalised from ex- 
 perience, and the particular experiences from which 
 it is generalised are experiences,, not of inference^ but 
 of intuitions brought about by voluntary and artificial 
 means. This explanation is not satisfactory. It has 
 the appearance of being simply invented without any 
 other reason than that it is capable of partially ex- 
 plaining the axiom. There is no evidence whatever 
 that such artificial trials of equality as those postu- 
 lated are ever made for the purpose indicated. And 
 if they were actually made, the generalised axiom 
 resulting could not have that degree of certainty 
 which it has, unless this certainty had some other 
 ground than the alleged experience. 
 
 § 204. We must therefore examine the view which 
 considers the particular act from which the general 
 axiom is generalised as an act of inference. There 
 is a comparison of two things with a third thing, and 
 the inference that the two things, being equal to the 
 third, are equal to one another. But we must remem- 
 ber that the third thing, which is the medium of 
 comparison between the two others, may not be an 
 external object, but may be a part of our own organ- 
 ism. And we know, from the evidence of language, 
 that the original medium of comparison between the 
 lengths or other spatial relations of external objects 
 is some part of our organism. In many languages, 
 
PSYGEOLOGY OF GOGNITION. 
 
 315 
 
 and perhaps in every language, the original standards 
 of measure are particular parts of the body. A foot, 
 a hand^s breadth, a span, a cubit, a fathom, are 
 terms of measurement which, from being so uni- 
 versally used in English, and having so many 
 analogues amongst other nations, lead to the con- 
 clusion that the parts of the body implied in them 
 afford to men the primary standards of comparison 
 with respect to the relative extension of objects. 
 Now, if we analyze this primary mode of comparison 
 into its psychological elements, we appear to get 
 the following : The eye and the hand of a primitive 
 man having been trained to work together, he 
 applies the hand, outstretched to its farthest limits, 
 to a short object ; he sees that the tip of the finger 
 and the point of the thumb coincide with the ends 
 of the thing to be measured ; he has, in other words, 
 a certain complex act of perception, the result of 
 which is that he pronounces the object examined a 
 span in length. At another place and time, he 
 applies the same test to another object, with the 
 same result ; he remembers that the preceding 
 complex act of perception was essentially similar 
 to this one ; and he infers that the length of the 
 two objects is the same. Now, be it observed, this 
 inference is not one which he might make or not, 
 as he pleased. He is compelled to make it; he 
 cannot draw any different inference ; and it is this 
 necessity of the particular inference in hand which 
 gives the manifest universality to the axiom gene- 
 ralised from it. And as we see what is the nature 
 
 CHAP. V. 
 SECT. IX. 
 
3i6 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT, IX. 
 
 Artificial 
 standard 
 of com- 
 parison. 
 
 of the mental act whicli precedes the inference, we 
 can see also how the inference is necessary. A 
 complex act of perception is compared with a 
 remembered act_, and seen to be similar ; the fidelity 
 of each act of perception to the reality of nature 
 being assumed, it follows at once that the objects 
 are equal. Thus, a perception of similarity in the 
 mental acts by which two objects are known to us 
 is the ground of our inferring their equality. But 
 in making this inference it is assumed (1) that each 
 of the acts gives us a true knowledge of the spatial 
 relations of each object, and (2) that these spatial 
 relations have a true, and to our minds, independent 
 existence. 
 
 § 205. If we were to examine the other axioms 
 which deal with the relations of equality, inequality 
 or proportion of extended bodies, we should find 
 that the psychological basis of them all is a percep- 
 tion of likeness or unlikeness between the sensations 
 of eye and muscle, by the combination of which the 
 relative dimensions of the bodies become known to 
 But it is soon found that by a comparison of 
 
 us. 
 
 these sensations without any artificial assistance 
 correct results are not obtained ; and moreover, the 
 natural measures of length, the hand or the foot, are 
 not exactly th'e same in different individuals. Hence, 
 for the sake of greater accuracy, and of having a 
 common standard, artificial measures made of wood 
 or metal are invented. But even after this has been 
 done, the psychological basis of inference is not 
 changed. We apply a foot-rule to a body to dis- 
 
PSYCHOLOGY OF COGNITION. 
 
 317 
 
 cover its dimensions ; but this is only an artificial 
 contrivance to enable us more accurately to compare 
 our perception of its spatial relations with that of 
 another body, or to compare our measurement with 
 that of other individuals. There is thus recognised 
 the fact that objective standards of spatial dimensions 
 are more reliable than subjective or organic ones. 
 
 § 206. The axioms of equality and inequality 
 which are usually applied to space may be applied 
 to time also. The natural measures of time are — 
 (1) our sensations considered as succeeding one 
 another; and (2) our perception of certain bodies 
 which are found to recur at regular intervals. In- 
 ferences regarding the temporal relations of events 
 must be founded upon comparison of the psychologi- 
 cal acts by which these relations are estimated. But, 
 as a rule, inferences regarding time are combined with 
 the relations of space, as when we infer regarding 
 the time which it will take a certain body to pass 
 through a certain space. But before any inference 
 can be drawn it must be shown or assumed that the 
 motion of the body is either uniform or varies ac- 
 cording to certain known laws. This being granted, 
 inferences can be drawn with perfect certainty. 
 
 With reference to all reasonings regarding rela- 
 tions of space and time, either separately or com- 
 bined, it has been noticed that there is a remarkable 
 degree of certainty and precision connected with 
 them. It is also found that in simple cases no other 
 inference is possible than that which is drawn. This 
 precision and necessity of inference are to be 
 
 CHAP. V. 
 SECT. IX. 
 
 Axioms 
 applied to 
 time and 
 motion. 
 
 Certainty 
 of in- 
 ference 
 accounted 
 for. 
 
3i8 
 
 THB JELEMENT8 OF THE 
 
 CHAP. V. 
 SECT. IX. 
 
 accounted for by tlie nature of tlie circumstances in 
 wMcli tlie inference is made ; A and B are two di- 
 mensions of space or time, eack made known to us 
 in the acts of perception a and b. In consciousness 
 we compare a and b together, 
 O the one being actual, the other 
 remembered ; we see their 
 likeness, and we believe that 
 each mental act is a true tran- 
 O script of the objective quantity. 
 This being so, the inference 
 of the equality of A and B follows of necessity, 
 simply because there is no other inference which 
 has any foundation whatever. And even if, by 
 direct comparison, we found that A and B were 
 not exactly equal ; we would not conclude that our 
 inference was erroneous, but that some element of 
 error had entered into a- or 5 or the comparison of 
 them. Thus although it may be quite true that the 
 generalised axioms regarding space, time, and 
 motion are founded upon experience of particular 
 inferences; it is also true that there is something 
 which determines that this experience must be thus 
 and not otherwise. There are certain relations 
 between our conscious intuitions and the quantities 
 of space and time given in them, which afford a 
 basis for the inferences which we draw, and afford 
 no basis for any other inference. No other inference 
 is possible to us, and hence we call these inferences 
 necessary. 
 
 § 207. "We now pass on to consider the ground of 
 
PSYGHOLOGY OF GOGNITION. 
 
 319 
 
 inferences regarding forces not directly known. We 
 liave already in §§ 198-99 given a description of the 
 kind of inferences to which we refer. There is a 
 certain conscious effort exerted which is followed by 
 a certain result ; an event similar to this result occurs, 
 but without any effort on our part ; we infer an 
 objective power of which it is the result. And the 
 question is, upon what ground do we make this 
 inference ? Before considering this question, we 
 must, in the first place, postulate that there is given 
 to us in consciousness a knowledge of power. 
 Muscular sensations are the subjective side of that 
 of which muscular effort is the objective. And 
 muscular power is not known to us as a relation 
 between muscular sensations and some result. 
 Neither is power known to us as a relation between 
 any mental events and their consequents. Simple 
 succession can never give us the idea of power. 
 But in the consciousness of muscular sensation, the 
 objective side of which is muscular effort, we have a 
 direct knowledge of power, and when the organism 
 is in a healthy state, we are able, by means of other 
 sensations, to know the results of the forth-putting 
 of this power. Thus our knowledge of causal effi- 
 ciency is intuitive, although it no doubt takes a 
 little time and experience to connect muscular 
 efforts with their proper results. 
 
 § 208. Having now got the two terms of the first 
 relation, conscious effort and ifcs result^ another 
 object, a passive sensation, comes before conscious- 
 ness. We know that it is not caused by us, because 
 
 CHAP. V. 
 SECT. IX. 
 
 Inferences 
 regarding 
 unknown 
 forces. 
 
 Knowledge 
 of -power 
 intuitive. 
 
 Analysis of 
 inferential 
 process. 
 
320 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. IX. 
 
 we have been conscious of no forth-putting of effort 
 in its production. But why do we seek for its cause 
 at all ? Some people would answer that it is 
 because we know d priori that every event must 
 have a cause. Perhaps this statement may be 
 resolved into the simple fact that we are reasoning 
 animals, that by our birth as human beings we 
 inherit a tendency to search after the relations of 
 things, and that by the same birth-right we are never 
 satisfied until we have discovered the relations and 
 the causes of the things we know. If this is a correct 
 interpretation of the law we admit its truth. Now 
 comes the final question — what is the ground of our 
 inference that the known passive sensation is caused 
 oA^ by an unknown objective power ? The 
 relation between A and B is known ; 
 B^ is similar to B, in as far as it is an 
 
 BO oB^ object of consciousness ; the inference 
 
 of a subjective cause is excluded by 
 the conditions of the case ; the only 
 possible inference, therefore, is that of 
 an objective cause, A^ holding the same relation to 
 B^ which A holds to B. It must be admitted, 
 however, that this inference is usually accompanied 
 by other circumstances which give it form. A^ is 
 usually connected with a group of qualities consti- 
 tuting an external object. But into this group of 
 qualities the subjective idea of power is invariably 
 projected from which it can never be eliminated 
 except by the unnatural attempts of a phenomenal 
 psychology. The child attributes personality and 
 
PSYCHOLOGY OF COGNITION. 
 
 321 
 
 power to the stick whicli has given it pain, and 
 begins to beat it. The untutored savage thinks a 
 spiritual power into every object of Nature. 
 
 § 209. The inference of some objective power for 
 the events which we ourselves do not produce is 
 compulsory ; but there is a great room for doubt and 
 difference as to the nature of that power. Men 
 primarily inferred the existence of innumerable 
 spirits; others have postulated a common substratum, 
 matter ; others infer a universal mind ; others again 
 conclude that there are various powers mutually 
 correlated, which are but forms of a universal Force. 
 As this is not a work upon metaphysics, we do not 
 feel called upon to discuss these conflicting theories. 
 But we may point out that inferences regarding the 
 nature and laws of the unknown cause or causes of 
 phenomena must, from the nature of the case, be 
 hypothetical. And the best that we can do is to 
 adopt that hypothesis which, to our minds, most fully 
 explains the phenomena. It is therefore upon a 
 careful study of phenomena and their mutual rela- 
 tions that we should build our hypothetical inferences, 
 taking care that no phenomena be overlooked or 
 placed out of their proper relations. It would take 
 us far beyond our limits to discuss this subject as it 
 should be discussed. Some have held that because 
 in these matters the absolute certainty of mathe- 
 matical demonstration or of intuition is unattainable, 
 they ought to be excluded from the sphere of science 
 altogether. This, however, would be an arbitrary 
 limitation o£ the sphere of science against which the 
 
 CHAP. V. 
 SECT. IX. 
 
 Hypo- 
 thetical 
 nature of 
 inferred 
 causes. 
 
322 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. IX. 
 
 Inferences 
 as to 
 existence 
 and rela- 
 tions of 
 pheno- 
 mena. 
 
 actual practice of scientific men is a standing protest. 
 Hypothesis fingo, Newton to the contrary notwith- 
 standing, is the practical language of the man of 
 science, even in cases when there appears to be no 
 hope of his hypothesis ever being directly verified.* 
 § 210. We now come to the consideration of in- 
 ferences regarding the existence and relations of 
 phenomenal objects. Illustrations of these inferences 
 have already been given in § 200. . . . We have 
 seen also that they may be generally divided into 
 two classes, in the first of which we infer some 
 relation to exist between phenomena which we 
 know ; and in the second we infer the existence of 
 a phenomenon not directly known, and holding a 
 certain relation to another phenomenon, or set of 
 phenomena, known to exist. And the question to be 
 decided is, what is the ground of the inferences we 
 draw in each of these cases ? Now it must be 
 observed that in drawing these inferences there is a 
 great room for error. Thousands of instances might 
 be pointed out in which false relations have been 
 supposed to exist between phenomena. It must be 
 admitted, then, that inferences may be drawn which 
 are not in conformity with the truth of nature. And 
 therefore we must consider, not the ground of infer- 
 ence in general, but the ground of correct inference. 
 But in this it is implied that amongst phenomena 
 there exist certain objective relations which may be 
 known by us or not, and if our inferences are not the 
 
 * It maybe fairly maintained, however, that the sphere indicated. 
 above belongs rather to metaphysical than to physical science. 
 
PSYCHOLOGY OF COGNITION. 
 
 323 
 
 true expression of these objective relations they are 
 not correct. We observe, for example, tbat night 
 always precedes day, but if we were to infer from this 
 uniformity of sequence that a causal relation exists 
 between them, our inference would be erroneous, 
 as there are various reasons for our concluding 
 that this is not the true relation. In drawing 
 inferences, therefore, it is necessary to disting 
 between those relations of things which are 
 dental and those which are essential. In order 
 this properly, we must have recourse to those 
 of induction which Bacon and his followers have 
 formulated. The object of these laws is to enable 
 us to distinguish between accidental and essential 
 co-existences and sequences. Those relations which 
 are of the latter class are thought to have some 
 connection with the cause of the phenomena. And 
 those inferences are thought to be correct which 
 connect together phenomena between which there 
 is objectively a causal relation, or a relation de- 
 pending upon identity of causation. The relation, 
 for example, between the lowering of the tempera- 
 ture of the atmosphere and the deposition of dew 
 is an essential one, and the inference which con- 
 nected the one with the other was correct, although, 
 perhaps, it is not proper to call this the causal 
 relation. It is correct also to infer that animals 
 which we have discovered to have some of the 
 essential characteristics of birds are oviparous, 
 because we have learned that there is an essential 
 objective connection between these characteristics 
 
 Y 2 
 
 CHAP. V. 
 SECT. IX. 
 
 
324 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. X. 
 
 Contro- 
 versy re- 
 gardingthe 
 syllogism. 
 
 and that quality which we infer. Thus it appears 
 that before we can be satisfied with inferences 
 regarding phenomena, the subjective connection 
 which we form must be recognised as being the 
 counterpart of essential objective relations between 
 things. Inferences are not concerned merely with 
 the relations of ideas, but also, and principally, with 
 the objective connections of real things. 
 
 Section X. 
 
 THE fOEM OF INFEEENCE. 
 
 § 211. Is there any general form according to 
 which the mind acts in the drawing of inferences^ 
 and, if so, what is that form ? This question has 
 given rise to a good deal of controversy, especially 
 with reference to the claims of the syllogism to be 
 considered the universal type of reasoning. It has 
 been asserted, on the one hand, that, if all the mental 
 acts and principles which are involved in the 
 drawing of inferences be explicitly stated in lan- 
 guage, the statement will assume the form of a 
 syllogism. It has been held, on the other, that there 
 are many instances of reasoning in which the mental 
 process cannot, without the greatest violence, be put 
 into the form of a syllogism, although it is admitted 
 that many kinds of reasoning do naturally assume 
 that form. Before discussing this question we must 
 examine the nature of the syllogism. According to 
 the accounts of the syllogism, which we find in 
 logical treatises, syllogism is inference which is 
 
PSYCHOLOGY OF COGNITION. 
 
 325 
 
 drawn from the general, from some proposition or 
 judgment whicli is generally true. There are three 
 terms in every syllogism, two of which, the minor 
 and major terms, are the subject and predicate of the 
 conclusion; while the third, the middle term, is 
 found in each of the premises, and is the medium by 
 which the terms of the conclusion are compared 
 together. All these terms are held to be the names 
 of concepts having a greater or less denotation and 
 connotation. And in the syllogism there is a com- 
 parison of the denotation or the connotation of the 
 minor or major terms, with the denotation or con- 
 notation of the middle term. This comparison has 
 for its object to determine whether the one term 
 contains the other, either wholly or partially, that 
 is whether the denotation or the connotation of the 
 one term includes, wholly or partially, that of the 
 other. Now, in order to determine the character 
 of the claims of the syllogism to be considered the 
 only type of reasoning, we shall have to consider — 
 (1) whether inference proceeds only from the 
 general; (2) whether nothing but concepts are the 
 elements of inference; and (3) whether the rela- 
 tion of containing and contained is the only relation 
 regarding which we infer. 
 
 § 212. The first of these points has been prac- 
 tically decided by us already. We have seen that 
 some of the so-called mathematical axioms are 
 generalised from particulars, and consequently that 
 particular inferences are drawn before the gene- 
 ralised axioms are formed. We have seen, also. 
 
 CHAP. 
 SECT. 
 
 Inferences 
 may he 
 drawn 
 from par- 
 ticulars. 
 
326 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. X. 
 
 Inference 
 does not 
 regard con- 
 cepts hut 
 objects. 
 
 that in perception an objective cause of our passive 
 states is inferred to exist from the consciousness of 
 some particular sensation uncaused by our conscious 
 effort. Now, the only ground upon which inferences 
 of this kind can be expressed in the form of a 
 syllogism is, that there is an d priori principle 
 latent in the mind which serves for the major 
 premiss of the syllogism. Against this theory we 
 have already adduced objections.* And the over- 
 throw of this theory renders it impossible to put 
 into syllogistic form the inferences referred to. 
 There are, then, particular kinds of inference which 
 do not proceed from general judgments, but from 
 particular objects of knowledge. 
 
 § 213. With reference to the second point, it is 
 maintained by some that inference has to do pri- 
 marily with concepts and the relations of concepts. 
 But, as individual objects undoubtedly form sub- 
 jects of reasoning, concepts are taken to be not 
 merely the representations of the qualities of a class, 
 but also of an individual. To this doctrine, that 
 reasoning refers exclusively, or even principally, to 
 mental representations, we must take exception. 
 Every mental representation which we make, either 
 of an individual object or of a class, has significance 
 to us only as related to the real objects of which it 
 is a concept. When we make use of the term ma7i, 
 we mean not our mental representation of human 
 attributes, but the real external objects possessing 
 human qualities which we denote by that name. 
 * § 203.. 
 
P8YGE0L0GY OF COGNITION. 
 
 327 
 
 And when we say "man is mortal/' we mean fhat the 
 real beings whom we call men will all die. Thus, if 
 we are to depend upon what consciousness reveals 
 to us, inference has reference primarily not to con- 
 cepts, but to the real objects or classes of which the 
 concepts are more or less complete representations. 
 And the predication of the inference asserts or 
 denies a certain relation to exist between these 
 objects. 
 
 § 214 What is this relation ? Is it only that of 
 the container and the contained, the mutual inclusion 
 or exclusion, in whole or in part, of two objects of 
 thought ? A reference to particular cases of in- 
 ference will soon decide the question. From a 
 comparison of certain angles and triangles we infer 
 — " The angles at the base of an isosceles triangle 
 are equal to one another/' This is certainly not a 
 relation of inclusion, either total or partial. From a 
 variety of considerations we infer that the rapid 
 cooling of the atmosphere is the cause of the depo- 
 sition of dew. It would be difficult to put this 
 inference into the stereotyped form. From many 
 experiences we infer, when we see smoke, that com- 
 bustion is going on somewhere near at hand. The 
 relation expressed in this inference is certainly not 
 one of inclusion. In short, since inferences consist 
 of predications, and since predications assert any of 
 the relations which may be perceived in intuition as 
 existing between two objects of thought, it is manifest 
 that reasoning must occupy itself with all these 
 relations. This the syllogism, in its present form. 
 
 CHAP. V. 
 SECT. X. 
 
 Relations 
 predicated 
 in in- 
 ference. 
 
328 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. X. 
 
 as to form 
 of reason- 
 ing post- 
 poned. 
 
 does not do; and hence, in its present form, we 
 maintain that it is the type of only a particular, 
 although important^ variety of the reasoning process. 
 § 215. Having decided against the claims of the 
 syllogism to be the universal form of reasoning, we 
 might inquire if there is any other form which can 
 legitimately make similar claims. But we shall be 
 better able to consider this question after we have 
 studied more fully different reasoning processes with 
 which we are familiar. We have already divided 
 the sphere of inference into the subordinate sphere 
 concerned about (1) space and time, with their 
 various divisions and combinations, (2) the non- 
 phenomenal causes of things sensible, and (3) the 
 existence and relations of phenomena. But in these 
 different spheres the grounds upon which the infer- 
 ences rest may vary greatly in their nature and 
 extent, and the inferences themselves may have 
 every variety of probability attached to them. 
 Upon the principle of advancing from the more 
 concrete and particular to the more abstract and 
 general varieties of inference, the following appears 
 to be a suitable division : (1) Inferences regarding 
 the occurrence of particular events, depending upon 
 evidence or testimony ; (2) Inference founded upon 
 analogy and induction, either particular or expressed 
 in a less or more certain general law ; (3) Deductive 
 inferences from general principles. 
 
PSYCHOLOGY OF COGNITION. 
 
 329 
 
 Section XI. 
 evidence; induction; deduction. 
 
 § 216. It is frequently necessary, in the common 
 affairs of life, to form opinions regarding the occur- 
 rence or non-occurrence of events, or the nature of 
 alleged facts which have not come under our own 
 observation. These opinions are of the nature of 
 inference depending upon what is called Evidence. 
 We may divide the facts or events regarding which 
 evidence is taken into two general classes : (1) con- 
 temporary facts or events alleged to exist or occur 
 in our own time, within the memory of persons now 
 living ; and (2) historical facts or events alleged to 
 exist or occur in some past generation. The evi- 
 dence on which inferences regarding the first of 
 these classes of facts are based is most frequently 
 human testimony, although, in the absence of that^ 
 or when it is not thought completely trustworthy, a 
 great variety of circumstantial evidence may be 
 resorted to. Inferences regarding historical facts or 
 events depend upon tradition, historical records, the 
 existence of commemorative monuments and other 
 things. We shall refer to certain principles by 
 which we are guided in drawing inferences in each 
 of these cases. 
 
 § 217. The most direct evidence of contemporary 
 occurrences which we have not ourselves observed is 
 the testimony of others. But in receiving the testi- 
 mony of others there are various things which must 
 
 CHAP. V. 
 SECT. XI. 
 
 Inference 
 depending 
 upon evi- 
 dence. 
 
 Regarding 
 contempo- 
 rary facts. 
 
330 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. XI. 
 
 Testimony. 
 
 Circum- 
 stantial 
 evidence. 
 
 be considered before placing implicit reliance upon 
 it. We have found by experience that some persons 
 are not truthful in relating what they have seen or 
 heard ; that some persons are incapable of accurate 
 observation^ mixing up their own fancies or pre- 
 judices with the facts which they are observing ; that 
 some persons are very liable to be governed by 
 interested motives so as deliberately to misrepresent 
 in their own favour the facts which they relate. 
 These and other considerations have led to the 
 establishment of various legal customs connected 
 with the taking of evidence, such as the imposition 
 of an oath, cross- questioning, and others. For the 
 purpose of correcting human testimony it is found 
 also that a variety of circumstantial evidence is of 
 very great importance. The majority of the alleged 
 occurrences regarding which inferences a-re to be 
 drawn leave some permanent marks or traces behind 
 them which may be afterwards observed, and these, 
 in the hands of a skilful interpreter, frequently 
 form the basis of important and true conclusions. 
 There is, however, great difference in the skill 
 of different persons in discovering the significance 
 of permanent marks or signs. The barbarous 
 tribes of an uncultivated country usually show 
 remarkable acuteness in reading the meaning of the 
 traces of past events ; while the natural or acquired 
 skill of the professional detective is often equally 
 wonderful.* 
 
 * For a specimen of this acuteness and skill the reader is 
 referred to Edgar A. Poe's remarkable description, " The Murders 
 in the Rue Morgue." 
 
PSYCHOLOGY OF COGNITION. 
 
 331 
 
 § 218. In determining the value of evidence, tliere 
 are, generally speaking, two things to be considered ; 
 the nature of the evidence itself, and especially the 
 character of the persons by whom it is given, and 
 the nature of the fact testified to. The mind fre- 
 quently refuses assent to alleged facts in consequence 
 of the improbability of these facts occurring. When 
 a person is well acquainted with a particular class of 
 facts, he knows pretty accurately what phenomena 
 of that kind are likely in given circumstances to 
 occur, and he refuses to accept the testimony of 
 ignorant observers if their testimony contradicts his 
 expectations. The antecedent probability or impro- 
 bability of particular occurrences taking place exerts 
 a great influence upon our estimate of the value of 
 the evidence adduced in their favour. This predis- 
 position to believe or to disbelieve alleged occurrences 
 varies greatly in different minds, and depends greatly 
 upon the kinds of experience with which the mind 
 has been familiar. If, for example, an expert in 
 physical science is informed of the occurrence of 
 certain phenomena, such as table-rapping and other 
 things said to be performed by spiritual agents, he 
 feels a strong predisposition to attribute the pheno- 
 mena either to deliberate deception on the part of 
 some one concerned, or to the operation of some of the 
 natural forces with which he has already become 
 acquainted. This predisposition, although a valuable 
 safeguard against indiscriminate credulity, often 
 proves a hindrance to the discovery of truth by pre- 
 venting competent men from undertaking a careful 
 
 CHAP. V. 
 SECT. yi. 
 
 Value of 
 evidence. 
 
 Predis- 
 position to 
 receive or 
 reject ew- 
 dence. 
 
332 
 
 TUB ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. XI. 
 
 Regarding 
 historical 
 events. 
 
 examination of tlie evidence upon whicli alleged 
 occurrences rest. With reference to every human 
 being it may be said^ " There are more things in 
 heaven and earth than are dreamt of in your philo- 
 sophy," and consequently in the mind of every human 
 being there is likely to be a predisposition to reject 
 the evidence of some things which are actually 
 true. 
 
 § 219. We now proceed to the consideration of 
 the nature of the evidence upon which inferences 
 regarding the occurrence of historical events are 
 based. And it is manifest that, as a rule, this 
 evidence cannot be so satisfactory as that 
 of contemporary occurrences. The witnesses of 
 historical events are dead ; they cannot be put 
 upon their oath ; they cannot be cross-questioned ; 
 the whole of that searching process of eliciting 
 from unwilling, or stupid, or inconsistent witnesses 
 the true state of the case, with which we are 
 familiar in modern courts of law, must be 
 foregone or, at best, very imperfectly performed. 
 The evidence upon which our inferences are built 
 consists chiefly of written documtents containing 
 either descriptions of or allusions to the events 
 concerning which we are inquiring. The accounts 
 of these wHtten documents may be confirmed or 
 modified by the discovery of monumental figures or 
 inscriptions, or other remains, and by the perpetua- 
 tion amongst the people of traditions or customs 
 apparently depending upon the alleged events. In 
 examining the written documents, the most important 
 
PSYCHOLOGY OF COGNITION. 
 
 333 
 
 points whicli should be ascertained are : the persons 
 by whom these documents were first written ; the 
 time when they wrote and the opportunities which 
 they enjoyed of becoming accurately acquainted 
 with the events which they describe; the cha- 
 racter of the writers for intelligence and truthfulness, 
 and especially the feelings by which they might be 
 influenced in writing their accounts. These points 
 having been determined, either with certainty or 
 with a greater or less degree of probability, there 
 will remain to subject the documents themselves 
 to a criticism something analogous to the cross- 
 questioning of legal courts. This criticism will have 
 for its object the obtaining of a true and complete 
 view of the occurrences described, by bringing 
 together disjointed accounts, harmonising, where 
 possible, apparent inconsistencies or incongruities, 
 and, in short, bringing into a consistent unity the 
 great variety of unsystematically-arranged details 
 of events, and character, and life which the docu- 
 ments present ; but it may possibly result in the con- 
 clusion that such a unity is unattainable. Examples 
 of this historical criticism are to be found in modern 
 inquiries regarding the lives and labours of 
 Homer, and Plato, and other ancient worthies, and 
 especially in the modern criticism of the Christian 
 Scriptures. 
 
 § 220. Asinthetreatmentof the evidence adduced 
 in favour of the occurrence of contemporary alleged 
 events people are under the influence of a predispo- 
 sition to believe or disbelieve, according to the view 
 
 CHAP. V. 
 SECT. XI. 
 
 Prejudices 
 hoiv to he 
 treated. 
 
334 
 
 TEE ELmiENTS OF THE 
 
 CHAP. V. 
 SECT. XI. 
 
 Analogy. 
 
 which thev are likely to take of the probability of 
 the events occurring, so there is a similar predisposi- 
 tion with reference to historical events. From our 
 own experience and from the recorded experience of 
 others, we form opinions as to what may reasonably 
 be expected to take place in particular circumstances, 
 and these opinions influence our minds very strongly 
 in our treatment of historical evidence. These pre- 
 formed opinions, or prejudices, as they are called, it 
 is impossible to get rid of, simply because it is 
 impossible to annihilate our own past mental history 
 and the influence which it has had in forming our 
 present character. But it is possible for us to 
 understand that our prejudices may prevent us from 
 attaining to a knowledge of the truth concerning 
 which we inquire, and it is possible for us so far to 
 overcome our prejudices as to admit in particular 
 cases that what appears antecedently improbable to 
 us may nevertheless be true. The antecedent im- 
 probability, therefore, of any event which is not 
 merely ridiculous and absurd, should not prevent 
 any one from carefully examining the evidence 
 upon which it rests. 
 
 § 221. We now proceed to the consideration of 
 those inferences which are drawn from particular 
 facts or relations, and which are usually called 
 inductive. One of the commonest forms of this 
 is analogy. Two objects agree in certain particulars, 
 and it is inferred or expected that they will agree 
 in others. A child sees a tin rattle and hears the 
 rattling noise which it makes when shaken ; when 
 
PSYCHOLOGY OF COGNITION. 
 
 335 
 
 he sees sometliing afterwards at all resembling tlie 
 rattle lie expects from analogy that it will rattle 
 when shaken. In this case the expectation or 
 inference appears to be founded upon the principle 
 of association ; when two or more qualities have 
 appeared once or repeatedly in connection with one 
 another, the subsequent appearance of one of them 
 or of a similar one, leads to the expectation that the 
 others are capable of realisation. This rudimentary 
 example of analogy assumes a higher type as 
 knowledge increases and we begin to learn essential 
 resemblances and differences of things. In physical 
 science inferences founded upon analogy have led to 
 most important conclusions or discoveries. It was 
 by analogy that Newton drew his inference regarding 
 the cause of the motions of the heavenly bodies. It 
 was an apparent analogy which led Franklin first to 
 infer, and afterwards directly to ascertain the identity 
 of lightning and electricity. Innumerable examples 
 of inference founded upon analogy are presented in 
 the science of language. The philologist finds in 
 Latin or Greek a word the original root of which he 
 cannot discover in these languages; a word analogous 
 in form and meaning is found in some other Arian 
 language, as the Gothic or Sanskrit ; and in these 
 latter languages the root, perhaps, is found, and 
 thence inferred to be the original form of the Latin 
 or Greek word in question. 
 
 § 222. It is manifest that the analogy between two 
 objects which may form the basis of a reliable 
 inference cannot be a simple resemblance of some 
 
 CHAP. V. 
 SECT. XI. 
 
 Analogy of 
 accidental 
 qualities 
 not the 
 ground of 
 inference. 
 
z?>^ 
 
 THE ELEMENTS OF TEE 
 
 CHAP. V. 
 SECT. XI. 
 
 Induction. 
 
 Syllogistic 
 theory. 
 
 accidental qualities. There must be a resemblance 
 between qualities whicli are found to be essential 
 before the inference from analogy can be drawn. 
 A shark swims in the sea, and so does a whale ; but 
 this accidental resemblance would never form the 
 basis of analogical inference to any reasonable mind. 
 The qualities of two bodies which are to form the 
 ground-work of analogical inference must be 
 essential^ or be connected with essential qualities of 
 the bodies in question ; and also the quality which 
 is inferred must have some essential connection 
 with the other qualities from whose resemblance 
 the inference is drawn. Unless there is a recognised 
 objective connection the inference is baseless. 
 
 § 223. Induction proper has for its basis an 
 observed relation of phenomena, or the elements of 
 phenomena, in a greater or less number of cases ; and 
 the inference asserts what will take place in all 
 similar cases. Inductive inference affirms regarding 
 all instances of a particular kind what is observed to 
 be true of a certain number of instances of that kind. 
 As far as has been observed, all animals of the bovine 
 kind chew their cud; but naturalists assert that 
 this is true universally. As far as has been observed, 
 all material bodies have weight ; but physicists admit 
 no exception to the universality of the quality. 
 Thus in Induction the inference goes beyond the 
 observed facts, and in order that this extension of 
 the inference may be valid, there must be some 
 foundation for it. Let us see what this foundation 
 is. Those who are not satisfied until they have put 
 
PSYCHOLOGY OF COGNITION. 
 
 337 
 
 every kind of reasoning into the form of a syllogism 
 tell us that inductive inference is a syllogism with 
 the major premises suppressed; and further, that the 
 suppressed major is the principle that '^Nature is 
 uniform in her operations." Newton's induction 
 then would appear as follows : — 
 
 "What nature does sometimes she does always; 
 Xatnre makes this, that, and the other body to gravitate. 
 . ■ . Nature makes all bodies to gravitate." 
 
 Even although we allowed that all inductive infer- 
 ences are naturally expressed in the form of a 
 syllogism^ it seems inconceivable that such a crude, 
 indefinite, and practically worthless major premiss 
 as the one cited should have retained its position so 
 long. As an example of its uselessness we give the 
 following : — 
 
 "Nature is uniform in her operations ; 
 
 This, that, and the other animal of the class mammalia live 
 
 on dry land. 
 . • . All mammalia live on dry land." 
 
 Of course it will be at once answered that this is an 
 accidental quality. Very good; then let a prin- 
 ciple be adopted which will recognise the distinction 
 between essential and accidental qualities, which the 
 principle above named does not pretend to do. 
 
 § 224. What, then, is the foundation upon which 
 inductive inference rests ? It is certainly not a mere 
 subjective association, because that is quite as inca- 
 pable of distinguishing between the essential and the 
 accidental as the principle above referred to. There 
 must, therefore, be some recognised objective con- 
 
 CHAP. V. 
 SECT. XI. 
 
 Founda- 
 tion of 
 inducticn. 
 
338 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. XI. 
 
 The per- 
 manence 
 of species. 
 
 nection in things wliich. forms the basis of induction 
 regarding them. We have ah-eady seen* that in 
 the formation of a class or species to which we 
 apply a common name, we separate by abstraction 
 some of the qualities from the others, according as 
 we think them essential or not to the constitution 
 of the species. The Essentia of the species com- 
 prises all these qualities without which the species 
 would not be what it is ; this essentia, although 
 formed by abstraction, and therefore determined by 
 us, has a permanent objective existence in the 
 various individuals from which abstraction has been 
 made. Now, as we have determined such and such 
 qualities to constitute the species, it is manifest 
 that wherever any individuals of the species exist, 
 these qualities must be found ; if any other indi- 
 viduals are found destitute of one or more of these 
 qualities, we simply say that they do not belong to 
 that species, or we constitute them into a sub- 
 ordinate variety of the species, or we enlarge the 
 definition of the species so as to include them, as 
 the case may be. Thus, in drawing the inferences 
 which result in classification, we assume the per- 
 manence and immutability of natural species, and 
 having determined by careful examination and 
 comparison ' what are the essential qualities which 
 constitute the species, we infer with confidence that 
 all individuals belonging to the species possess 
 these qualities. And if any individuals, apparently 
 members of the species, are found destitute of its 
 * §§ 157-163. 
 
i 
 
 PSYCHOLOGY OF COGNITION-. 
 
 339 
 
 essential qualities, we either relax tlie terms of 
 admission into the species, or treat the refractory 
 individuals to scientific excommunication. 
 
 § 225. There are some cases in which a single 
 instance may lead to a universal induction. For 
 example, when, having applied a common measure 
 to two lines, we infer their equality, the mind 
 advances at once to the general maxim, — ^things 
 which are equal to the same thing are equal to one 
 another. 
 
 The nature of the original inference accounts for 
 the immediacy and universality of the induced pro- 
 position. The mind cannot help but draw the 
 inference in any particular case, as we have seen ;* 
 neither can it conceive any circumstances in which, 
 from the same basis, a different inference could be 
 reached; hence the universal axiom is accepted 
 without hesitation. There are other inferences of 
 induction which appear to be made with equal 
 readiness. Two ivory balls of equal size are sus- 
 pended by strings of equal length ; they are made 
 to fall down equal arcs of a circle at the same time 
 and strike against one another ; the force of the one 
 counteracts that of the other. Hence the generalised 
 principle, '^ Action and re-action are equal and oppo- 
 site.^^ Now, the particular mental act from which 
 this law is generalised is manifestly an inference. 
 We see two bodies of equal sizes moving through 
 equal spaces in equal times ; and we observe that the 
 motion of each is equally arrested by the concussion. 
 * § 206. 
 
 CHAP. V. 
 SECT. XI. 
 
 Axioms 
 general- 
 ised from 
 a single 
 inference. 
 
340 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. XI. 
 
 Differen t 
 kinds of 
 induction. 
 
 The inference pronounces that the force which each 
 ball exerts is exactly met and counteracted by that 
 of the other ball. As we know nothing about ob- 
 jective force, except as an inference to account for 
 otherwise unaccountable phenomena, so we know 
 nothing about the laws of forces, except as inferred 
 from the relations of observed phenomena. But the 
 inference is one which cannot be avoided, simply 
 because there is no foundation for any other inference. 
 And since the particular inference is an unavoidable 
 one, the induced principle is seen, without doubt, to 
 be of universal application. 
 
 § 226. Thus we see that all general laws are the 
 result of induction, as well as those general proposi- 
 tions which express the characteristics of classes of 
 objects. But there are inductions and inductions. 
 Some inductions, as those regarding the relations of 
 mathematical magnitudes, and the laws of forces, are 
 founded upon particular inferences, these inferences 
 being unavoidable in the present condition of things. 
 Other inductions are founded upon the perceived re- 
 lations of certain qualities which we have determined, 
 by observation and comparison, to be essential to the 
 constitution of particular classes. Thus, in all cases 
 of induction there must be recognised the existence 
 of a certain' established objective order of things, 
 and our inductions are only an expression in language 
 of what we believe to be essential relations of this 
 objective order. If our inductions accurately cor- 
 respond to the objective order, we say that they are 
 true ; if not, not. 
 
PSYOEOLOGY OF COGNITION. 
 
 341 
 
 § 227. We are now brought to tlie study of the 
 last form of inference, the deductive. Here the mind 
 passes ia reasoning from the general or universal to 
 the particular. Having already known something 
 to be true of a whole class of things, we are able to 
 affirm it to be true of every individual of the class. 
 Familiar illustrations of the deductive process are 
 seen in the application of the general laws of natural 
 forces to particular cases, and in inferences regardi 
 the qualities of particular individuals of a class f: 
 our knowledge of the essential constituents of 
 class. The astronomer, having determined the la 
 of the motion of some particular planet, is able to 
 infer with precision the particular point in the hea- 
 vens which it Avill occupy at any particular moment. 
 The chemist, having determined the laws of the com- 
 bination of particular elements, is able to predict the 
 result in any special case. The naturalist, having 
 discovered the universal characteristics of some 
 species of animals or plants, expects with certainty 
 to find these characteristics in every new specimen. 
 The natural form in which inference of this kind is 
 thrown is, no doubt, the syllogism. And the princi- 
 pal value of the syllogism is to state in an explicit 
 methodical form those deductive inferences at which 
 the mind arrives, frequently without any conscious 
 reference to the major premiss at all. 
 
 § 228. In order that the deductive inference may 
 be thoroughly reliable, the major premiss must be an 
 expression of some essential objective order or law of 
 things. If, for example, the maj or premiss of a syllo- 
 
 
 CHAP. V. 
 SECT. XI. 
 
 Deduction. 
 
 r/y 
 
 ^iriK. 
 
 Certainty 
 of infer- 
 ence de- 
 pends up- 
 on major 
 premiss. 
 
THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. XII. 
 
 Hypo- 
 thetical 
 Inference. 
 
 gism be *' All swans are white/' an inference from, 
 that, with reference to the colour of any particular 
 swans, hitherto unseen, could not be made with 
 perfect certainty. We could never feel certain 
 but that birds might be found possessing all the 
 essential characteristics of swans, but which were 
 of some other colour. Whereas, if we have for our 
 major premiss, "All cows ruminate,^' the inference 
 with reference to particular animals of the species 
 is certain, because the predication of the major 
 premiss expresses an essential condition of the 
 class. Deductive inferences which have for their 
 object some accidental quality or state of things 
 can never amount to more than a probability. The 
 probability of the inference is the consequence of 
 the want of certainty which characterises the major 
 premiss. And that want of certainty arises either 
 from the accidental nature of the relation which 
 is predicated in the premiss, or from our partial 
 ignorance regarding it. 
 
 Section XII. 
 
 CONCLUSION, 
 
 § 229. By way of summing up the conclusions at 
 which we have arrived in the preceding sections, we 
 may first point out the different kinds of inferences 
 which we draw. One of the most important of these 
 is the Hypothetical Inference,^ by the object of which 
 
 * This, of course, is altogether different from the hypothetical 
 form of the syllogism. 
 
PSYGHOLOGY OF COGNITION. 
 
 343 
 
 we account for the existence of known phenomena. 
 The existence of any particular sensation is accounted 
 for by inferring some objective hypothetical power. 
 The existence of a foot-print upon the sand is ac- 
 counted for by the supposition that S. man walked 
 along the sand some time previous. The statements 
 of a historical writer are accounted for by the in- 
 ference that the events which he describes actually 
 occurred. Any particular phenomenon or complex 
 series of phenomena being given, we account for its 
 existence and character by inferring hypothetically 
 some antecedent cause sufficient to account for it. 
 In many cases we may never be able to verify the 
 inference by direct knowledge ; but it matters not, 
 the inference must be made, nevertheless, to satisfy 
 that insatiable craving after a knowledge of the 
 causes of things which is our birth-right as rational 
 beings. In many other cases the hypothetical 
 inference may be verified, as in the discovery of the 
 planet Neptune, and in the discovery of certain 
 new metals which had been inferred to account for 
 peculiar phenomena in the spectroscope. In cases 
 where the hypothetical inference cannot be verified 
 by direct observation, various degrees of probability, 
 or even a practical certainty, may be obtained 
 by considering the degree of completeness with 
 which the particular inference accounts for the 
 phenomena, and the absence of a foundation for 
 any other inference. 
 
 § 230. The Particidar Inference founded upon 
 siihjective association is very familiar. Two or more 
 
 CHAP. V. 
 SECT. XII. 
 
 Particular 
 Inference. 
 
344 
 
 THE ELEMENTS OF THE 
 
 CHAP. V. 
 SECT. XII. 
 
 Inductive 
 Inference. 
 
 objects of knowledge Laving occurred together a few 
 or several times, there is formed an expectation that 
 where one of them appears the others maybe looked 
 for. The occurrence of these objects together leads 
 the mind to suppose that there is some objective 
 connection between them, and this supposition forms 
 the ground of the inference. When this supposition 
 is converted into actual knowledge, and the con- 
 nection between the two associated phenomena is 
 ascertained, the inference is no longer problematical 
 but acquires the character of a certainty. The Par- 
 ticular Inference founded upon a comparison of simple 
 Intuitions is also characterised by certainty from 
 the very first. When we infer that the lines A and 
 B, being each equal to C, are equal to one another, 
 there is no other inference which we could possibly 
 draw. 
 
 § 231. The Inductive Inference J founded upon uni- 
 formity of experience, never amounts to more than a 
 high degree of probability. But it is not therefore 
 to be despised, because in many cases nothing but a 
 certain degree of probability is attainable. And in 
 the practical concerns of life probability is our usual 
 guide. 
 
 The Inductive Inference, founded upon a Icnoivledge 
 of the essential relations of the things concerned, 
 partakes of the same amount of certainty as the 
 knowledge on which it is founded. Illustrations of 
 this are seen in the axioms of mathematics and of 
 natural forces, and in the inductive generalisations 
 regarding natural orders and species. 
 
PSYCHOLOGY OF COGNITIOK 
 
 345 
 
 The Deductive Inference is based upon some general 
 principle, and rests for its conformity to truth upon 
 the assumed trutli of tlie principle from wliicli it 
 starts. The general propositions in which the dif- 
 ferent species of induction terminate are the 
 starting-point from which deduction proceeds in 
 reverse order. 
 
 § 232. With reference to the form in which 
 inferences should be expressed, it appears to be a 
 matter of very little consequence. All knowledge 
 may be resolved into the knowledge of objects and 
 their relations, and all inferences are concerned 
 about the existence and relations of objects, or the 
 occurrence of events, not directly known, and about 
 the relations of known objects. Every inference 
 referring to an object or a relation not directly 
 known must be founded upon some relation which 
 is known either by intuition or some preceding in- 
 ference. And, in the arrangement of the different 
 elements of the reasoning process, the grand re- 
 quisite is that the mind should be able to pass 
 readily, and without hesitation, from the ground to 
 the inference. To secure this requisite is sometimes 
 very difficult in consequence of the obscurity or com- 
 plexity of the subject with which we may be dealing. 
 And we need not expect to get much assistance 
 from the formulae of the logician. Difficulties in 
 thinking are not to be overcome by any formal rules 
 which may be laid down, but by careful and per- 
 severing attention to the subject, and sometimes 
 by a natural genius with which some people are 
 
 2 A 
 
 CHAP. V. 
 SECT. XII. 
 
 Deductive 
 inference. 
 
 Conclu- 
 sion. 
 
346 
 
 ELJSMEJSfTS OF PSYCHOLOGY OF COGNITIOm 
 
 CHAP. V. 
 SECT. XII. 
 
 peculiarly endowed. Consistency and truth are tbe 
 two things which we should strive after in our 
 thoughts. The former has reference to the mutual 
 relations of the different elements of our knowledge 
 or belief; the latter to the conformity of our 
 thoughts with the essential order of things. For 
 the satisfaction of that rational nature, the pheno- 
 mena of which we have been studying, there is 
 demanded not merely an elaborate and consistent 
 system of doctrine which may after all be a mere 
 airy castle, but also and especially a certain con- 
 fidence that what we think is a counterpart and 
 expression of that which is- 
 
YOOABULAEY 
 
 OF 
 
 PHILOSOPHICAL TEEMS. 
 
 As this Manual of Psychology may be used by some who are 
 not accustomed to reading philosophical works, the Author has 
 deemed it advisable to append a vocabulary of terms which are 
 not likely to be familiar to such readers, hoping thereby to make 
 the work more iiseful. The terms explained are mostly found 
 in the present work and widely employed in books upon this and 
 kindred subjects. 
 
 Abstract. — To withdraw the attention from certain qualities 
 or elements of any object of knowledge with a view of fastening 
 it upon other elements or qualities. For example, when we 
 attend to the colour of an object we abstract the mind from its 
 form and weight. 
 
 Abstracted. — The quality or element to which the attention 
 is thus turned is usually said to be abstracted from the others, 
 although, properly speaking, it is the mind which is abstracted 
 from them. 
 
 Abstraction. — The quality or element of the objects of our 
 knowledge singled out from the others for special attention is 
 often called an abstraction. Various qualities or elements of 
 knowledge may be singled out from a number of objects, and 
 these qualities, which are the same or similar, joined together in 
 a mental image which is called an abstraction. 
 
 Accident. — in forming classes of objects there are found 
 some qualities which are present in some of the objects but 
 absent in others ; these are called accidents. 
 
 2 A 2 
 
348 VOCAJBULABY OF PHILOSOPHICAL TERMS. 
 
 Accidental. — A quality or element of objects or of classes 
 which is thus sometimes present and sometimes absent is said to 
 be accidental, to distinguish it from those elements which, being 
 universally present, are called essential. 
 
 Affinity. — A term expressive of a variety of relations be- 
 tween objects of our knowledge. Objects which are related to 
 one another, as a cause and effect, parts and a whole, sign and 
 thing signified, and so on, have a natural connection with one 
 another, so that when one is thought of the others naturally come 
 before the mind. Such objects are said to have mutual affinity. 
 
 Analogous. — When two things are similar in some of their 
 qualities or effects, although entirely different in others, they are 
 said to be analogous. The fin of a fish, for example, is analogous 
 to the wing of a bird, or the leg of a horse. 
 
 Analogy. — A resemblance between two or more objects in 
 some particular qualities or actions is called an analogy. 
 
 Analyse. — when we separate any object of knowledge into 
 the simple elements of which it is made up we analyse it. 
 
 Analysis. — The act or process of separating objects of know- 
 ledge into their constituent elements. A careful analysis of any 
 complex product is a most important condition of obtaining a 
 thorough understanding of it. 
 
 Antecedent. — When one object of knowledge comes into 
 the mind before another it is called the antecedent. 
 
 Appetite. — The desire which we have to satisfy those wants 
 which originate in some condition of our physical organism, such 
 as hunger or thirst, is called an appetite. 
 
 A posteriori. — When the progress of knowledge or reason- 
 ing is from effects or consequents to causes, or conditions, or 
 antecedents, we are said to proceed d posteriori. 
 
 A priori. — Knowledge or thought is d priori when we pro- 
 ceed from causes or conditions to effects or consequents. 
 
 Assertion. — When the mind affirms that any object of 
 knowledge exists, or that any relation, simple or complex, exists 
 between two or more objects, an assertion is made. Assertion 
 expressed in words is predication. 
 
 Association. — The mental union which binds together two 
 or more objects of knowledge, so that when the one appears 
 before the mind the others follow, is called association. 
 
 Assumption. — At the beginning of any course of thought 
 or discussion certain things must be taken for granted as 
 known ; these constitute the basis of argument or assumption, 
 and, if put into the form of a syllogism, will be found in the 
 premises. 
 
VOCABULARY OF PHILOSOPHIGAL TEEMS. 349 
 
 Audible. — That whicli is capable of affecting the organ of 
 hearing so as to produce a sound is said to be audible. 
 
 Being. — The most abstract of all mental products. When 
 the mind withdraws its attention from all the qualities by which 
 objects are known and thinks only of the fact that things are or 
 exist, it reaches, as nearly as possible, to the conception of a 
 Being. To think of Being, but without any particular qualities 
 or things to he, is the highest attainment of metaphysical skill. 
 
 Belief. — Things which we receive and admit as true although 
 not directly known to us are said to be believed, and the act of 
 the mind in assenting to this truth is belief. 
 
 Category. — The classes of things to one or other of which 
 all known objects must belong Avere called, by Aristotle, 
 categories ; into some one or more of these classes everything 
 knowable could be placed. They were ten in number : sub- 
 stance, quantity, quality, relation, action, passion, time, place, 
 situation, and habit. Hence category comes to be nearly 
 synonymous with class or list. And, as the categories indicate 
 the assertions or predications which may be made regarding any 
 object, a proposition affirming any of these assertions is called 
 categorical. Hence, generally, categorical means direct or abso- 
 lute as distinguished from indirect, conditional, or hypothetical. 
 
 Causal. — Pertaining to a cause. 
 
 Causation. — The act of causing or producing anything which 
 begins to be. 
 
 Cause. — The agent or power by the operation of which any 
 change is produced or any action or condition effected. By 
 some writers cause is held to mean the invariable antecedent of 
 some event without which the event could not be. 
 
 Class. — A group of individual objects of knowledge collected 
 together in consequence of their resemblance in certain elements 
 is called a class. 
 
 Classification. — The act of arranging individuals into classes, 
 or lower into higher classes. 
 
 Cognise. — A term frequently used in psychology, meaning 
 to know. 
 
 Cognition. — The act of Icnoiuing, in the proper sense of the 
 term, is called cognition. This term is used especially in contra- 
 distinction to feeling and volition, two other and distinct classes 
 of mental phenomena. The powers of the mind engaged in the 
 different processes of cognition are called cognitive. 
 
 Colour. — The name of that quality which is known through 
 the sense of sight. There is an ambiguity in the application of 
 the term colour; sometimes it is applied to the sensation in the 
 
350 VOCABULARY OF PEILOSOPEICAL TERMS. 
 
 mind which results froili our looking at objects through the eyes ; 
 sometimes to the appearance of colour located upon the object ; 
 sometimes to the unperceived cause or condition which gives 
 rise to the sensation. The second of these applications appears 
 the most natural and correct. 
 
 Compare. — To observe the resemblance, difference, or other 
 relation between two objects of knowledge. The act or process 
 of comparison is an important means of acquiring knowledge. 
 
 Conceive. — To bring before the mind the idea or image of 
 some quality or object which has been previously directly known. 
 Thus it is nearly synonymous with imagine. 
 
 Concept. — Literally that which has been conceived or 
 imagined. But the word is generally used in a restricted sense 
 to indicate the conceived qualities of a class of objects by which 
 all the members of the class are characterised and distinguished 
 from other classes. 
 
 Conceptualism. — The name of a doctrine according to which 
 the concept of a class of objects is regarded as being general 
 instead of the nameoi the class or the class itself. 
 
 Concomitant. — When several objects of knowledge or 
 thought appear before the mind at the same time they are said 
 to be concomitant. 
 
 Conscience. — The ability which we have to discern between 
 the rightness and wrongness of actions. 
 
 Consciousness. — The immediate knowledge which the mind 
 has of its own acts or operations is called consciousness. 
 
 Conscious-subject. — That which is conscious of the opera- 
 tions and objects of the mind in immediate knowledge is called 
 the conscious. subject, self or ego. 
 
 Consequence. — The act or condition of following from some- 
 thing that has gone before. Used chiefly in logic. 
 
 ConseCLUent. — When two objects of knowledge appear in 
 sequence, the one following the other, that which follows is the 
 consequent. 
 
 Contiguity. — A principle of association uniting two or more 
 objects that have appeared before the mind, the bond of union 
 being that they have been known near to one another either in 
 time or place. 
 
 Correlation. — When two objects or series of objects are 
 mutually related to one another they are said to be in corre- 
 lation, and they are called correlatives. 
 
 Cosmology. — That branch of universal philosophy which 
 treats of the formation and laws of the cosmos or universe. 
 
 Critical. — The name of a method of studying the phenomena 
 
( 
 
 VOGABULABY OF PHILOSOPSIGAL TEBMS. 35 1 
 
 <oi the mind which discriminates between some of these phe- 
 nomena as being accidental and others which are characterised 
 by necessity and universality. The process of thus discrimin- 
 ating is called criticism. The school of philosophy, founded by 
 Kant, which makes prominent use of this method, is called the 
 critical school. 
 
 Data. — Things that are given or assumed at the commence- 
 ment of any course of study or argument. 
 
 Define. — To state the essential qualities of a class of objects, 
 or the meaning of a concept. 
 
 Definition. — The result of the above process. It is to be 
 distinguished from a general description, which deals with any 
 qualities by which objects or classes are known. 
 
 Desire. — A feeling of want in the mind, leading us to seek 
 after objects fitted to satisfy the want. The desires are distin- 
 guished from the appetites in being of a higher character, and 
 not originating in a condition of the organism. 
 
 Development.— The process of unfolding what is contained 
 in the germ of any organism. The seed of a tree or the young 
 of an animal developes into maturity. The application of this 
 process to the explanation of the production of all things in the 
 universe is usually called the development hypothesis. 
 
 Difference. — One of the original relations perceived between 
 objects, in virtue of which we a&rm that they are, in some 
 respects, unlike one another. 
 
 Differentia. — In classification, the qualities which distin- 
 guish one species from others belonging to the same genus are 
 <jalled the diffei-entice. 
 
 Divide. — To separate a class of objects into subordinate 
 classes. The process of division is the counterpart of dejhiition, 
 the former being occupied with the members of a class, the latter 
 with its constituent qualities. 
 
 Dualism. — The doctrine that there are two different series 
 of things, the one mental and the other material, is called 
 dualism. This is either a psychological or an ontological doc- 
 trine. In the former case it refers to the dualism of phenomena, 
 or objects of knowledge; in the latter case to the dualism of 
 existence considered as apart from knowledge. 
 
 Ego. — The I or conscious-subject of knowledge. 
 
 Elaboration. — The process of comparing, combining, classi- 
 fying, and drawing inferences from the primitive objects of 
 knowledge. The power or ability to do these things is some- 
 limes called the eldborative faculty. 
 
352 VOCABULARY OF PHILOSOPHICAL TERMS. 
 
 Element. — Any of the simple qualities, parts, or charac- 
 teristics of complex objects are called its elements. 
 
 Ether. — A hypothetical fluid, incapable of being perceived, 
 invented to explain the phenomena of light and colour. 
 
 Ethics. — That department of philosophy which deals with 
 conscience, and the laws of human conduct in relation to its 
 Tightness and wrongness. 
 
 Evolution. — Another term for development. 
 
 Expectation. — A form of imagination in which the object 
 or event before the mind is expected to bo realised or occur at 
 some future time. 
 
 Experience. — The process of acquiring knowledge by direct, 
 personal observation or study of the things to be known. It is 
 a question amongst psychologists whether all our knowledge is 
 derived from experience, or whether some elements of know- 
 ledge are the conditions of experience. 
 
 Experiment. — That process of pursuing knowledge which 
 makes use of an artificial arrangement or combination of elements 
 is called experiment, and the method is called experimental. 
 
 Extended. — An object is said to be extended when it occu- 
 pies a certain portion of space. 
 
 Extension. — That quality of objects in virtue of which one 
 part of them is recognised as being luithout the other. Extension 
 i& a limited portion of space. 
 
 External. — The condition of heing ivithout. The parts of an 
 extended object are external to one another. All material objects 
 are external in reference to the mind. 
 
 Faculty. — The power possessed by the mind of performing 
 certain kinds of actions. The power of knowing is called the 
 cognitive faculty; the power of determining to do anything, the 
 faculty of volition, and so on. 
 
 Feelings. — The name applied to the second great class of 
 mental phenomena, intermediate between the cognitions and 
 voluntary efforts. The feelings are not elements of knowledge ; 
 they are incentives to action. 
 
 Force. — That which causes motion or change. It is known 
 immediately as exerted by ourselves, and thence inferred as the 
 cause of motion or change without us. 
 
 Form. — The conditions, or setting, or relations in which the 
 objects of conscious knowledge are placed. All things that are 
 known must be either simultaneous or successive. The former 
 relation is the basis of the form of extension or space ; the latter 
 of that of time. 
 
 Formal. — In psychology, the elements of space, time, and 
 
VOGABULABY OF PHILOSOPHICAL TEBM8. 353 
 
 other relations of objects are called /or hi aZ. Formal logic studies 
 the forms of thought. 
 
 Function. — The peculiar kind of action performed by any 
 particular organ or faculty is called its function. It is the 
 function of the leg to walk and of the eye to see. 
 
 General. — Any quality which is found in a large number of 
 objects is called general. So is a name which is applied to a 
 whole class. Anything found in, applied to, or belonging to all 
 the members of a class is commonly called general. 
 
 Generalise. — To argue from a limited number of cases to 
 a general law is to generalise ; as, e.g., when we conclude that 
 because some bodies gravitate, therefore all bodies do so. 
 
 Generalisation. — The process of extending to all the mem- 
 bers of a class what is found true of some. 
 
 Hypothesis. — An explanation of an event or condition of 
 things whose cause is unknown is called an hypothesis. A hypo- 
 thetical explanation is frequently made use of for the purpose 
 of finding the true explanation. If the hypothesis is found to be 
 correct it is then called a theory. 
 
 Idea. — A term used in psychology with a variety of mean- 
 ings. It often means the revival of a sensation, or the repre- 
 sentation of some mental object formerly presented. By the 
 older psychologists external qualities of objects were supposed 
 to be known by means of their ideas conveyed to the mind 
 through the senses. This doctrine is no longer held, and ideas 
 are generally used in the former sense. 
 
 Ideal. — Distinguished from the actual by being better and 
 more perfect. Plato held that in the divine mind there were 
 ideals of all earthly objects after which they have been created. 
 The ideal is that perfect condition of excellence in art or life 
 which we should attempt to realise. 
 
 Idealism. — The name of a system of philosophy which holds 
 that we cannot know anything except ideas. If it is held that 
 nothing exists except ideas and minds by which these ideas are 
 perceived, it might be called absolute idealism. When the ideas 
 known are held to be the representatives of unknown material 
 objects or qualities we have cosmothetic idealism. 
 
 Identical. — When an object now known is found to be 
 exactly the same as one previously known it is called identical. 
 
 Identity. — Sameness. Applied to the conscious-subject, 
 which continues the same through every variety of mental 
 phenomena, it is known as personal identity. 
 
 Imagination. — The power or act of recalling and holding 
 before consciousness the mental objects already known. It is a 
 
354 VOCABULARY OF PHILOSOPHICAL TERMS. 
 
 power of very extensive operatioB, being exercised in perception, 
 memory, expectation, science, art, ethics, and religion, and being 
 frequently combined with other mental powers. 
 
 Immediate. — A term applied to direct knowledge, or the 
 knowledge of objects by consciousness. That which is known in 
 consciousness is immediately known. Sometimes, however, it is 
 used in a logical sense to distinguish directly-acquired know- 
 ledge from that which is the result of a course of reasoning. 
 
 Impression. — An effect supposed to be produced upon the 
 senses or the mind by the qualities of objects. This word was 
 much used by the older English psychologists, but is now almost 
 or entirely obsolete in its psychological use. 
 
 Individual. — An organised body which cannot be divided or 
 broken up without destroying it is called an individual. 
 
 Induction. — The process of reasoning from a number of 
 particular cases to a general truth or principle. A system of 
 philosophy which largely or exclusively adopts this method is 
 called inductive. 
 
 Infer. — To draw a conclusion from something which we now 
 know to the'existence of some object or relation not already known. 
 
 Innate. — Some condition in the constitution of the mind not 
 acquired by experience but inherited. Used chiefly by the older 
 psychologists, and applied incorrectly to ideas. 
 
 Integration. — The act of constructing in the mind a unity 
 of objects. It is the highest law of association. 
 
 Intellectual. — A name applied to the mental powers engaged 
 in cognition. 
 
 Interference. — A doctrine of some older psychologists who 
 held that matter and mind are two distinct and separate forms 
 of existence without a natural means of communication, and that 
 knowledge is brought about by divine interference. 
 
 Intuition. — The knowledge which we have in consciousness 
 of the primary relations of objects. Applied by some writers to 
 the self-evident and necessary axioms or laws of thought. 
 
 Judge. — To assert the existence of any relation between 
 objects of knowledge. Synonymous with to 'predicate. 
 
 Know. — A term used in two senses, a narrower and a wider. 
 In the narrower sense it is applied to conscious knowledge ; in 
 the wider sense it comprehends the results of the elaboration 
 of knowledge as well, and thus may be applied to any of the 
 contents of science. 
 
 Knowable. — Things which may be known directly or by the 
 employment of recognised scientific methods, or by legitimate 
 inference from what is known, are Icnovoahle, 
 
VOCABULARY OF PHILOSOPHICAL TEEMS. 355 
 
 Latent. — A term applied in psychology to alleged mental 
 activities going on beneath the sphere of consciousness. Sub- 
 conscious mental activity. 
 
 Light. — (1) The sensible phenomenon which we see by means 
 of the eyes. (2) That which, coming into contact with the 
 retina of the eye, gives rise to light or colour as seen. 
 
 Localise. — In psychology, when we learn what group of 
 sensations or possible sensations are invariably connected with 
 some particular one, we are said to localise it. 
 
 Logic. — That department of philosophy in which we study 
 the laws and forms of thought. 
 
 Matter. — A term applied first to the sensible objects of the 
 world, and secorJtlj, to the inferred substratum or sv.hstance 
 underlying the sOTsible qualities. 
 
 Mediate. — Knowledge which is not acquired by direct ob- 
 servation in cQj)»sciousness but through the medium of some 
 process of reasoning is mediate. 
 
 Memory. — A form of representative knowledge in which 
 we recognise the object remembered as having been previously 
 known. 
 
 Metaphysics. — That department of philosophy which is 
 concerned with the ultimate or necessary principles of in- 
 telligence, and with real as distinguished from phenomenal 
 existence. 
 
 Method. — The order of procedure in seeking for a solution 
 of the problems of philosophy. For example, the inductive, or 
 the analytic method. 
 
 Mind. — That part of our complex nature which perceives, 
 thinks, feels, wills, and performs other such operations is the 
 mind. 
 
 Moral. — Pertaining to right conduct. 
 
 Name. — 'A word which is applied to an object or class for 
 the purpose of distinguishing it from others is its name. 
 
 Necessary. — A quality attaching to certain kinds of truth. 
 There are some things which not only are so and so, but raust be 
 so and so. Material objects must be extended. Every change 
 must have a cause. Truths such as these are characterised by 
 necessity. 
 
 Nominalism. — A doctrine connected with classification, ac- 
 cording to which the name of a class is general instead of the 
 class itself. See Conceptualism. 
 
 Non-ego. — A name applied generally to all objects wLich 
 come into the relation of knowledge with the ego. The nou-ego 
 may be mental as well as material. 
 
35^ VOCABULABY OF PHILOSOPmCAL TERMS. 
 
 Noumenon. — That which cannot be known directly in con- 
 sciousness, but is conceived or inferred by the mind to account 
 for the existence and character of phenomena. 
 
 Object. —Anything that is known by the conscious-subject is 
 called an object. The object may be a mental condition, a sen- 
 sation, a condition of the organism, or a group of sensible 
 qualities — anything, in short, which can be set over against the 
 subject in the relation of knowledge. 
 
 Objective. — Pertaining to an object ; the correlative of 
 suhjective. 
 
 Objectification. — The act of converting a mental state into 
 an object of consciousness by turning attention to it. 
 
 Odour. — That which affects the sense of smell. 
 
 Ontology. — The department of philosophy which is con- 
 cerned with real as distinguished from phenomenal existence. 
 
 Opposition. — A doctrine of logic concerning the relations of 
 propositions having the same terms, but differing in quantity, 
 quality, or both. 
 
 Organism. — A name applied to the body considered as com- 
 posed of a variety of organs all together forming a living system. 
 
 Particular. — A word used to designate one or a few mem- 
 bers of a class, as distinguished from general and universal. 
 
 Passion. — A very powerful appetite, desire, or emotion. 
 
 Perceive. — To know objects beyond the sphere of simple 
 consciousness. That which is perceived may be called a percept. 
 
 Perception. — The complex and acquired process by which 
 we know extra-mental and distant objects. 
 
 Person. — Applied in philosophy to an individual man con- 
 sidered as being one and the same during succeeding periods of 
 time. 
 
 Personality. — The condition of being a person. That which 
 constitutes an individual one and the same notwithstanding 
 many successive changes. 
 
 Personify. — To attribute personal characteristics to inani- 
 mate things. 
 
 Phantasm. — An image or representation appearing in corr- 
 sciousness. The power of producing phantasms in the mind is 
 called phantasy. 
 
 Phenomenon. — An appearance. Anything which appears 
 in consciousness, and thus is an object of knowledge, is a phe- 
 nomenon. The correlative of noumenon. 
 
 Philosophy. — Literally, the pursuit of wisdom. A term 
 applied very widely to a variety of subjects of study, but pro- 
 perly applicable to the study of the mind. 
 
VOCABULARY OF PHILOSOPniGAL TEEMS. 357 
 
 Power. — Synonymous with force as applied to physical 
 power, but often applied to mental abilities also. 
 
 Predicate. — To affirm some relation to exist between two or 
 more objects of knowledge. The act of doing so as well as the 
 verbal expression of the act is a 'predication. 
 
 Prescind. — To separate some quality of an object for the 
 purpose of studying it. 
 
 Presentation. — A name applied to objects or qualities 
 brought directly before consciousness. This direct knowledge 
 is called presentative. 
 
 Projection. — The process of transferring sensations to a 
 distance outside of the organism, the ability to do which is 
 acquired during the unconscious period of infancy. A very 
 important element of perception. 
 
 Psychology. — That department of philosophy which studies 
 mental phenomena. 
 
 Psychological. — Pertaining to psychology. It is, however, 
 used by some writers to designate a particular method of study- 
 ing psychological problems. 
 
 Psychogenetical. — That method of studying psycholog.cal 
 problems which accounts for certain mental conditions now 
 existing by postulating a long process of mental development 
 during past generations. 
 
 Quality. — A sensation projected beyond the organism and 
 united with a group of other projected sensations is known as a 
 quality. Colour, hardness, softness, odour, &c., are qualities. 
 Anything pertaining to quality is qualitative. 
 
 Quantity. — A term applied to the relations or form of 
 qualities, as their extension, figure, motion, continuance, and so 
 on. Anything pertaining to quantity is quantitative. 
 
 Keal. — A term applied first to anything which has an 
 objective as distinguished from a mental or ideal existence ; 
 and secondly, to noumenal as distinguished from phenomenal 
 existence. , 
 
 Realise. — To convert an object thought of or imagined that 
 is an ideal object into an actual object. 
 
 Bealism. — A philosophical doctrine opposed generally to 
 idealism. It affirms that there exists a real, material world 
 known either directly or mediately. In the former case it has 
 been called natural^ in the latter hypothetical realism. 
 
 Recognise. — To perceive the sa/)neness of an object now 
 known to one known previously. Recognitioji is the most im- 
 portant element of memory. 
 
 Redintegration. — A law of association according to which 
 
35S VOGABULABY OF PHILOSOPEIOAL TERMS. 
 
 the mind seeks to complete the sphere of a past and partially 
 forgotten knowledge. 
 
 Reflect. — To turn the attention of the mind backwards upon 
 its own operations. Reflection is almost synonymous with con- 
 sciousness. 
 
 Relation. — "Any sort of connection which is perceived or 
 imagined between two or more things, or any comparison which 
 is made by the mind, is a relation." 
 
 Relative. — Two or more things thus existing in any kind of 
 mutual connection are relative to one another, and may be called 
 relatives or correlatives. 
 
 Relativity. — The condition of being relative. 
 
 Relativity of Knowledge.— The doctrine that in know- 
 ledge the conscious-subject must be brought into relation with 
 the object known, and vice verso,. This is an absolutely essential 
 condition of true knowledge. 
 
 Represent. — To bring again before consciousness something 
 f ormex'ly 'presented. 
 
 Representation. — That which is thus represented is called 
 a representation, idea, or image. 
 
 Representationism. — A doctrine of perception according 
 to which external objects are known by means of intermediate 
 and representative ideas or images. 
 
 Resemblance. — One of the primary relations existing be- 
 tween objects by virtue of perceiving which we are able to afl&rm 
 that they are more or less nearly like one another. 
 
 Revival. — When a past mental act or object, once forgotten, 
 is again brought into consciousness it is called a revival or 
 rejpresentation. 
 
 Sapidity. — The quality of objects perceived by taste. 
 
 Sceptical. — A name of a philosophical system which either 
 proceeds by the method of doxibt as in Descartes, or terminates 
 in dovbht as in Hume. Scepticism as a method is legitimate ; 
 as an end it is disastrous and suicidal. 
 
 Science. — The demonstrated and systematically arranged 
 knowledge of phenomiena is properly called science. Sometimes 
 the term is applied, beyond its legitimate sphere, to the doc- 
 trines of metaphysics or theology dealing with non-phenomenal 
 objects. 
 
 Self. — A term synonymous with ego or conscious-subject. 
 
 Sensation.— One of the original elements of knowledge, 
 being a feeling in consciousness arising from some affection of 
 the organism. 
 
 Sensationalism. — The philosophical doctrine which derives 
 
VOCABULARY OF PSILOSOPEICAL TEEMS. 359 
 
 all the elements of our matured knowledge from simple 
 sensations. 
 
 Senses. — The organic means of communication between the 
 mind and the external world. 
 
 Sensorium. — The organism considered as being the sphere 
 of the operation of the senses is called the sensorium. 
 
 Seciuence. — The relation existing between objects which 
 follow one another. 
 
 Sight. — The power of perceiving light or colour. 
 
 Simultaiieity. — One of the primary relations of mental 
 objects consisting in their being before consciousness at the 
 same time. 
 
 Sound. — That quality which is heard by the ears. 
 
 Space. — The form in which all material objects are perceived 
 by the mind. The lohole of extension is space. 
 
 Speculative. — A term sometimes, but incorrectly, applied 
 to philosophy to distinguish it from scientific. Asa matter of 
 fact, science, in the hands of its leading exponents, is quite as 
 speculative as philosophy. 
 
 Subject. — That which knows and is conscious. Synonymous 
 with self or ego. 
 
 Subjective. — Pertaining to the subject of the mental phe- 
 nomena. Correlative of objective. 
 
 Substance. — That which was inferred by the older philo- 
 sophers to underlie the qualities of material objects ; otherwise 
 called the substratum. 
 
 Succession. — One of the primary relations of objects of 
 knowledge in virtue of which we affirm that they come after one 
 another in time. 
 
 Synthesis. — The process of constructing the objects of know- 
 ledge from their simple elements. The correlative of analysis. 
 The synthetic method adopts synthesis principally in building up 
 a philosophy. 
 
 System. — The orderly arrangement of elements, whether 
 subjective or objective, for a certain end is called a system. 
 
 Tactile. — The quality of hodiea felt in touch. 
 
 Term. — Literally a boundary. Objects brought together in 
 a relation are called its terms; so also are words joined together 
 in a predication or 'proposition. 
 
 Temporal. — Pertaining to time. 
 
 Theology. — The doctrine concerning God and His relations 
 to the universe, spiritual and physical. 
 
 Theory. — An established explanation of any phenomena. 
 Distinguished from hypothesis, which is an explanation proposed 
 
3<5o VOCABULARY OF PEILOSOPHIGAL TEEMS. 
 
 for examination and trial as a means of reaching the true 
 theory. 
 
 Think. — To study objects and their relations, with a view of 
 reaching a knowledge of causes and principles, and forming a 
 system of truth. Thought is the product of thinTcing. 
 
 Time. — The form in which all objects, mental and material, 
 are known. An abstract derived from the study of phenomena 
 as succeeding one another. 
 
 Ultimate. — That which is reached as the last result of a 
 process of investigation. 
 
 Unity. — The condition of oneness or completeness. The grand 
 aim of the mind in the pursuit of knowledge is unity. 
 
 Universal. — That which is found in, or true of, all the mem- 
 bers of a class is universal. What is true of all objects of actual 
 or possible knowledge is universal by pre-eminence. 
 
 Unknowable. — That which cannot be brought within the 
 relation of knowledge to the mind. Some would put into the 
 sphere of the unlinoivahle everything which cannot be directly 
 known by some human mind, as in consciousness or perception. 
 Others consider to be hyiowable anything which may be legiti- 
 mately inferred from things directly known. 
 
 Volition. — The act of the will in determining to do anything. 
 The doing of the action thus willed may, be called a voluntary 
 activity. 
 
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PHYSICAL SCIENCE. 
 
 15 
 
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PHYSICAL SCIENCE. 17 
 
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PHYSICAL SCIENCE. 19 
 
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 Taylor. — sound and music : A Treatise on the Physical 
 
 - Constitution of Musical Sounds and Harmony, including the Chief 
 
 Acoustical Discoveries of Professor Helmholtz. By Sedley 
 
 Taylor, M.A., late Fellow of Trinity College, Cambridge. With 
 
 Illustrations. New Edition. Extra crown 8va %s. 6d. 
 
 " In no previous scientific treatise do zue remember so exhaustive and 
 
 so richly illustrated a description of forms of vibration and of 
 
 wave-motion in fluidsP— Musical Standard. 
 
 Thompson (Silvanus P.). — ELECTRICITY AND MAG- 
 
 . NETISM, ELEMENTARY LESSONS IN. By Silvanus 
 
 P. Thompson, B.A., D.Sc, F.R.A. S., Professor of Experimental 
 
 Physics in University College, Bristol. With Illustrations. New 
 
 Edition. Fcap. 8vo. 4^. 6r/. 
 
24 SCIENTIFIC CATALOGUE. 
 
 Thomson.— Works by Sir Wyville Thomson, K.C.B., F.R.S. 
 THE DEPTHS OF THE SEA : An Account of the General 
 Results of the Dredging Cruises of H.M.SS. "Porcupine" and 
 "Lightning" during the Summers of 1868-69 and 70, under the 
 scientific direction of Dr. Carpenter, F.R.S., J. Gwyn Jeffreys, 
 F.R.S., and Sir Wyville Thomson, F.R.S. With nearly 100 
 Illustrations and 8 coloured Maps and Plans. Second Edition. 
 Royal 8 vo. cloth, gilt. 'i^is. 6d. 
 
 The Athenaeum says : ** The book is full of interesting matter^ and 
 is written by a master of the art oj popular exposition. It is 
 excellently illustrated, both coloured maps and woodcuts possessing 
 high merit." 
 
 THE VOYAGE OF THE "CHALLENGER."— THE ATLAN- 
 TIC. A Preliminary account of the Exploring Voyages of H.M.S. 
 "Challenger," during the year 1873 and the early part of 1876. 
 With numerous Illustrations, Coloured Maps & Charts, & Portrait 
 of the Author, engraved !byC. H. J EEN.S. 2 Vols. Medium 8vo. 45^-. 
 
 The Times says : *^ The paper, printings and especially the numerous 
 illustrations, are of the highest quality. . . . We have rarely, if 
 ever, seen more beautiful specimens of wood engraving than abound 
 in this work. . . . Sir Wyville Thomson^ s style is particularly 
 attractive ; he is easy and gracejul, but vigorous and exceedingly 
 happy in the choice of language, and throughout the work there 
 are touches which show that science has not banished sentiment 
 f-om his bosom.'* 
 
 Thudichum and Dupre. — a TREATISE ON THE 
 
 ORIGIN, NATURE, AND VARIETIES OF WINE. 
 
 Being a Complete Manual of Viticulture and CEnology. By J. L. 
 
 W. Thudichum, M.D,, and August Dupre, Ph.D., Lecturer on 
 
 Chemistry at Westminster Hospital. Medium 8vo. cloth gilt. 25J. 
 
 ** A treatise almost unique for its usefulness either to the wine-grower, 
 the vendor, or the consumer oftuine. The analyses of wine are the 
 most complete we have yet seen, exhibiting at a glance the constituent 
 principles of nearly all the wines known in this country.*' — Wine 
 Trade Review. 
 
 Ty lor.— ANTHROPOLOGY : an Introduction to the Study of 
 Man and Civilization. By E. B. Tylor, D.C.L., F.R.S. With 
 numerous Illustrations. Crown 8vo. 'js. 6d. 
 *Wf all manuals were like this, a generation over educated for its 
 
 intellect would have no reason to complain. . . . A most attractive 
 
 and entertaining introduction to the science of ant hropolog}'. , , . 
 
 His writing is clear and luminous, and his arrangements masterly. 
 
 . . . Mr. Tylor writes with as much caution as learning** — 
 
 Saturday Review 
 
SCIENCE PRIMERS. 25 
 
 V/^allace (A. R.). — Works by Alfred Russel Wallace. 
 THE GEOGRAPHICAL DISTRIBUTION OF ANIMALS, 
 with a study of the Relations of Living and Extinct Faunas as 
 Elucidating the Past Changes of the Earth's Surface. With Maps, 
 and numerous Illustrations by Zwecker, 2 vols. 8vo. Ais. 
 ISLAND LIFE; OR, THE PHENOMENA AND CAUSES 
 OF INSULAR FAUNAS AND FLORAS, including a re- 
 vision and attempted solution of the problem of geological 
 climates. With Maps. 8vo. i8j. 
 TROPICAL NATURE: with other Essays. 8vo. \2s. 
 
 ** Nowhere amid the many descriptions of the tropics that have been 
 given is to be found a sujumary of the past history and actual 
 phenomena of the tropics which gives that which is distinctive of 
 the phases of nature in them more clearly^ shortly^ and impres- 
 sively." — Saturday Review. 
 
 Warington.— THE WEEK OF CREATION; OR, THE 
 COSMOGONY OF GENESIS CONSIDERED IN ITS 
 RELATION TO MODERN SCIENCE. By George War- 
 INGTON, Author of " The Historic Character of the Pentateuch 
 Vindicated." Crown 8vo. \s. 6d. 
 
 Wilson. — RELIGIO CHEMICI. By the late George Wilson, 
 M.D., F.R.S.E., Regius Professor of Technology in the University 
 of Edinburgh. With a Vignette beautifully engraved after a 
 design by Sir Noel Paton. Crown 8vo. 8j-. 6d. 
 
 Wilson (Daniel). — CALIBAN: a Critique on Shakespeare's 
 "Tempest" and ** Midsummer Night's Dream." By Daniel 
 Wilson, LL.D., Professor of History and English Literature in 
 University College, Toronto. 8vo. ioj-. 6d. 
 
 ** The whole volume is most rich in the eloquence of thought and 
 imaginatio7i as well as of words. It is a choice contHbution ^ at 
 once to science, theology, religion, and literature.''^ — British 
 Quarterly Review. 
 
 Wright.— METALS AND THEIR CHIEF INDUSTRIAL 
 APPLICATIONS. By C. Alder Wright, D.Sc, &c., Lec- 
 turer on Chemistry in St. Mary's Hospital School. Extra fcap. 
 8vo. 3^-. dd. 
 
 Wright (Lewis). — LIGHT. A Course ot Experimental 
 Optics, chiefly with the Lantern. By Lewis Wright. With 
 nearly 200 Illustrations and Coloured Plates. Crown 8vo. 
 7J. dd. 
 
 WurtZ.— A HISTORY OF CHEMICAL THEORY, from the 
 
 Age of Lavoisier down to the present time. By Ad. Wurtz. 
 
 Translated by Henry Watts, F.R.S. Crown 8vo. ds, 
 
 *• The discourse, as a resume of chemical theory and research, unites 
 
 singular luminousness and grasp. A few judicious notes are added 
 
26 SCIENTIFIC CA TALOGUE, 
 
 Wurtz — continued. 
 
 by the translator."— Tall Mall Gazette. " T/ze treatment of the 
 subject is admirable, and the translator has evidently done his duty 
 most efficiently.'''' — Westminster Review. 
 
 Ziegler— Macalister — text-book OF PATHOLOGICAL 
 
 ANATOMY AND PATHOGENESIS. By Professor Ernst 
 Ziegler, of Tubingen. Translated and Edited for English 
 Students by Donald Macalister, M.A., M.B., B.Sc, Fellow 
 of St. John's College, Cambridge. With numerous Illustrations. 
 Medium 8vo. Part I.— GENERAL PATHOLOGICAL ANA- 
 TOMY. \2s. 6d. [Part II. in the press. 
 
 SCIENCE PRIMERS FOR ELEMENTARY 
 SCHOOLS. 
 
 Under the joint Editorship of Professors Huxley, Roscoe, and 
 Balfour Stewart. 
 
 Introductory. By Professor Huxley, P. R.S. i8mo. is. 
 
 Chemistry By H. E. Roscoe, F.R.S., Professor of Chemistry 
 
 in the Victoria University, the Owens College, Manchester. With 
 numerous Illustrations. i8mo. i^*. New Edition. With 
 Questions. 
 
 Physics.— By Balfour Stewart, F.R.S., Professor of 
 Natural Philosophy in the Victoria University, the Owens College, 
 Manchester. With numerous Illustrations. i8mo. is. New 
 Edition. With Questions. 
 
 Physical Geography. —By Archibald Geikie, F.R.S., 
 Director Genex-al of the Geological Sm-veys of the United Kingdom, 
 With numerous Illustrations. New Edition With Questions. 
 i8mo. is. 
 
 Geology. — By Archibald Geikie, F.R.S. With numerous Illus- 
 trations. New Edition. iSmo. cloth, is. 
 
 Physiology — By Michael Foster, M.D., F.R.S. With 
 numerous Illustrations. New Edition. i8mo. is. 
 
 Astronomy. — By J. Norman Lockyer, F.R.S. With numerous 
 Illustrations. New Edition. i8mo. is. 
 
 Botany By SinJ. D. Hooker, K.C.S.L, C.B., F.R.S. With 
 
 numerous Illustrations. New Edition. i8mo. is. 
 
 Logic — By Stanley Jevons, LL.D., M. A., F.R.S. New Edition. 
 
 i8mo. is. 
 Political Economy By Stanley Jevons, LL.D., M.A., 
 
 F.R.S. i8mo. is. 
 
 Others in preparation. 
 
SCIENCE CLASS-BOOKS. 27 
 
 ELEMENTARY SCIENCE CLASS-BOOKS. 
 
 Agriculture.— ELEMENTARY LESSONS IN AGRICUL- 
 TURAL SCIENCE. By Professor H. Tanner, F.C.S., 
 Examiner in the Principles of Agriculture under the Government 
 Department of Science. Fcap. 8vo. 3^. 6d. 
 
 Astronomy POPULAR ASTRONOMY. With Illustrations. 
 
 By Sir G. B. Airy, K.C.B., late Astronomer Royal. New- 
 Edition. i8mo. \s. 6d. 
 
 Astronomy — elementary lessons in astronomy. 
 
 With Coloured Diagram of the Spectra of the Sun, Stars, and 
 Nebuloe, and numerous Illustrations. By J. Norman Lockyer, 
 F.R.S. New Edition. Fcap. 8vo. ^s. 6d. 
 QUESTIONS ON LOCKYER'S ELEMENTARY LESSONS 
 IN ASTRONOMY. For the Use of Schools. By John 
 Forbes Robertson. iSmo, cloth limp. is. 6d. 
 
 Botany — LESSONS IN elementary botany. By D. 
 Oliver, F.R.S., F.L.S., Professor of Botany in Univei'sity 
 College. London. With nearly Two Hundred Illustrations. New 
 Edition. Fcap. 8vo. ^s. 6d. 
 
 Chemistry LESSONS IN elementary chemistry, 
 
 INORGANIC AND ORGANIC. By Henry E. Roscoe, 
 F.R.S., Professor of Chemistry in the Victoria University, the 
 Owens College, Manchester. With numerous Illustrations and 
 Chromo-Litho of the Solar Spectrum, and of the Alkalies and 
 Alkaline Earths. New Edition. Fcap. 8vo. /\s. 6d. 
 A SERIES OF CHEMICAL PROBLEMS, prepared with 
 Special Reference to the above, by T. E. Thorpe, Ph.D., 
 Professor of Chemistry in the Yorkshire College of Science, Leeds. 
 Adapted for the preparation of Students for the Government, 
 Science, and Society of Arts Examinations. With a Preface by 
 Professor Roscoe. New Edition, with Key. iSmo. 2s. 
 
 Practical Chemistry — the owens COLLEGE JUNIOR 
 COURSE OF PRACTICAL CHEMISTRY. By Francis 
 Jones, F.R.S. E,, F.C.S., Chemical Master in the Grammar School, 
 Manchester. With Preface by Professor Roscoe, and Illustrations. 
 New Edition. i8mo. 2s. 6d. 
 
 Chemistry.— QUESTIONS ON. A Series of Problems and 
 Exercises in Inorganic and Organic Chemistry. By F. Jones, 
 F.R.S. E., F.C.S. i8mo. 3^. 
 
 Electricity and Magnetism. — By Silv anus P. Thompson, 
 B.A., D.Sc, F.R.A.S., Professor of Experimental Physics in 
 University College, Bristol. With Illustrations. Third Edition. 
 Fcap. 8vo. 4i". (>d. 
 
28 SCIENTIFIC CATALOGUE. 
 
 Elementary Science Class-books— ^(7«//««^^. 
 
 Physiology.—LESSONS IN elementary PHYSIOLOGY, 
 With numerous Illustrations. By T. H. Huxley, F.R.S., Pro- 
 fessor of Natural History in the Royal School of Mines. New 
 Edition. Fcap. 8vo. 4^. dd. 
 QUESTIONS ON HUXLEY'S PHYSIOLOGY FOR 
 SCHOOLS. By T. Alcock, M.D. i8mo. \s,bd. 
 
 Political Economy — political economy for be- 
 ginners. By MiLLiCENT G. Fawcett. New Edition. 
 i8mo. 2s. 6d. 
 
 Logic— ELEMENTARY LESSONS IN LOGIC ; Deductive and 
 Inductive, with copious Questions and Examples, and a Vocabulary 
 of Logical Terms. By W. Stanley Jevons, LLD., M.A., 
 F.R.S. New Edition. Fcap. 8vo. 3J. 6d. 
 
 Physics — LESSONS IN ELEMENTARY PHYSICS. By 
 Balfour Stewart, F.R.S., Professor of Natural Philosophy in 
 the Victoria University, the Owens College, Manchester. With 
 numerous Illustrations and Chromo-Litho of the Spectra of the 
 Sun, Stars, and Nebulae. New Edition. Fcap. 8vo. 4J. 6d. 
 QUESTIONS ON STEWART'S LESSONS IN ELEMENTARY 
 PHYSICS. By Professor T. H. Core. i2mo. 2s. 
 
 Anatomy.—LESSONS IN ELEMENTARY ANATOMY. By 
 St. George Mivart, F.R.S., Lecturer in Comparative Anatomy 
 at St. Mary's Hospital. With upwards of 400 Illustrations. Fcap. 
 8vo. 6s. 6d. 
 
 Mechanics — an ELEMENTARY TREATISE. By A. By 
 W. Kennedy, C.E., Professor of Applied Mechanics in University 
 College, London. With Illustrations. [7« preparation. 
 
 Steam — an elementary treatise. By John Perry, 
 B.E., Whitworth Scholar; Fellow of the Chemical Society, Lec- 
 turer in Physics at Clifton College. With numerous Woodcuts and 
 Numerical Examples and Exercises. New Edition. i8mo. 4^. 6d. 
 
 Physical Geography. _ elementary LESSONS IN 
 
 PHYSICAL GEOGRAPHY, By A. Geikie, F.R.S., Director 
 General of the Geological Surveys of the United Kingdom. With 
 numerous Illustrations. Fcap. 8vo. 4J. 6d. 
 
 QUESTIONS ON THE SAME. i^. 6d 
 
 FIELD GEOLOGY, OUTLINES OF. By the same Author. 
 With numerous Illustrations. Third Edition. Fcap. 8vo. 3J. 6d. 
 
 GEOLOGY, ELEMENTARY LESSONS IN. By the same 
 Author. \In preparation. 
 
MANUALS FOR STUDENTS. 29 
 
 Elementary Science Class-books— ^^«/^Vn/^^. 
 
 Psychology. — elementary lessons in psycho- 
 logy. By G. Groom Rorertson, Professor of Mental 
 Philosophy, &c., University College, London. [In preparation. 
 
 Geography.— CLASS-BOOK OF GEOGRAPHY. By C. B. 
 Clarke, M.A., F.G.S., F.R.S. New Edition, with eighteen 
 coloured Maps. Fcap. 8vo. 3^. 
 
 Moral Philosophy. — AN ELEMENTARY TREATISE. 
 
 By Professor E. Caird, of Glasgow University. [In preparation. 
 
 Natural Philosophy.— natural philosophy FOR 
 
 BEGINNERS. By I. Todhunter, M.A., F.R.S. Part L 
 The Properties of Solid and Fluid Bodies. i8mo. 3^. 6d. Part 
 II. Sound, Light, and Heat. i8mo. 3^. 6d. 
 
 The Economics of Industry.— By A. Marshall, M.A., 
 late Principal of University College, Bristol, and Mary P. 
 Marshall, late Lecturer at Newnham Hall, Cambridge. Extra 
 fcap. 8vo. 2 J. 6d. 
 
 Sound — AN ELEMENTARY TREATISE. By Dr. W. H. 
 Stone. With Illustrations. i8mo. 3^-. 6d. 
 
 Electricity and Magnetism. — ABSOLUTE MEASURE- 
 MENTS IN. By Andrew Gray, M.A., F.R.S.E., chief 
 Assistant to the Professor of Natural Philosophy in the University 
 of Glasgow. Pott 8vo. 3^. 6d. 
 
 Easy Lessons in Science. — Edited by Professor W. F. 
 Barrett. 
 I. HEAT. By C. A. Martineau. Illustrated. Extra fcap. 
 8vo. 2J. 6d. 
 II. LIGHT. By Mrs. W. Awdry. Illustrated. Extra fcap. 
 ^yo. 2s. 6d. 
 
 Others in Preparation. 
 
 MANUALS FOR STUDENTS. 
 
 Crown 8vo. 
 
 Cossa. — GUIDE TO THE STUDY OF POLITICAL 
 ECONOMY. By Dr. Luigi Cossa, Professor of Political 
 Economy in the University of Pavia. Translated from the Second 
 Italian Edition. With a Preface by W. Stanley Jevons, F.R.S. 
 Crown 8vo. 4f. dd. 
 
 Dyer and Vines the structure of plants. By 
 
 Professor Thiselton Dyer, F.R.S., assisted by Sydney 
 Vines, B.Sc, Fellow and Lecturer of Christ's College, Cambridge. 
 With numerous Illustrations. \In preparation. 
 
30 SCIENTIFIC CATALOGUE. 
 
 Manuals for Students — contimud. 
 
 Fawcett a manual of political economy. By 
 
 Right Hon. Henry Fawcett, M.P., F.R.S, New Edition, 
 revised and enlarged. Crown 8vo. \2s. 
 
 Fleischer — a system OF volumetric analysis. 
 
 Translated, with Notes and Additions, from the second German 
 Edition, by M. M. Pattison Muir, F.R.S. E. With Illustra- 
 tions. Crown 8vo. 'js. 6d. 
 
 Flower (W. H.) — an introduction to the oste- 
 ology OF THE MAMMALIA. Being the Substance of the 
 Course of Lectures delivered at the Royal College of Surgeons of 
 England in 1870. By Professor W, H. Flower, F.R.S., 
 F.R.C.S. With numei-ou3 Illustrations. New Edition, enlarged. 
 Crown 8vo. los. 6d. 
 
 Foster and Balfour. — the ELEMENTS OF EMBRY- 
 OLOGY. By Michael Foster, M.A., M.D., LL.D., F.R.S., 
 Professor of Physiology in the University of Cambridge, Fellow 
 of Trinity College, Cambridge, and the late Francis M. Balfour, 
 M.A., LL.D., F.R.S., Fellow of Trinity College, Cambridge, 
 and Professor of Animal Morphology in the University. Second 
 Edition, revised. Edited by Adam Sedgwick, M.A., Fellow 
 and Assistant Lectui-er of Trinity College, Cambridge, and Walter 
 Heape, Demonstrator in the Morphological Laboratory of the 
 University of Cambridge. With Illustrations. Crown 8vo. 
 los. 6d. 
 
 Foster and Langley — a course of elementary 
 
 PRACTICAL PHYSIOLOGY. Bv Professor Michael Foster, 
 M.D., F.R.S., and J. N. Langley^ M.A., F.R.S. New Edition. 
 Crown 8vo. ^s. 6d. 
 
 Frankland— AGRICULTURAL chemical analysis, 
 
 a Handbook of. By Percy Faraday Frankland, Ph.D., 
 B.Sc., F.C.S., Associate of the Royal School of Mines, and 
 Agricultural Demonstrator of Practical Chemistry in the Normal 
 School of Science and Royal School of Mines, South Kensington 
 Museum. Founded upon "Leitfadea fur die Agricultur-Che- 
 mische Analyse," von Dr. F. Krocker. Crown 8vo. 7^. Sd. 
 Hooker (Dr.)— THE STUDENT'S FLORA OF THE BRITISH 
 ISLANDS. By 'Sir J. D. FIooker, K.C.S.L, C.B., F.R.S., 
 M.D., D.C.L. New Edition, revised. Globe Svo. 10s. 6d. 
 
 Huxley — PHYSIOGRAPHY. An Introduction to the Study of 
 Nature. By Professor Huxley, F.R.S. With numerous 
 Illustrations, and Coloured Plates. New and cheaper Edition. 
 Crown Svo. 6s. 
 
SCIENTIFIC TEXT-BOOKS. 31 
 
 Manuals for Students — continued. 
 
 Huxley and Martin.— a COURSE OF practical in- 
 struction IN ELEMENTARY BIOLOGY. By Professor 
 Huxley, F.R.S., assisted by H. N. Martin, M.B., D.Sc. New 
 Edition, revised. Crown 8vo. ds. 
 
 Huxley and Parker.— elementary BIOLOGY, part 
 
 II. By Professor HuXLEY, F.R.S., assisted by T. J. Parker. 
 With Illustrations. \In preparation. . 
 
 Jevons — By W. Stanley Jevons, LL.D., M.A., F.R.S. :— 
 THE PRINCIPLES OF SCIENCE. A Treatise on Logic and 
 
 Scientific Method. New and Revised Edition. Crown 8vo. \2s. 6d. 
 STUDIES IN DEDUCTIVE LOGIC. A Manual for Students. 
 
 Crown 8vo. 6s. 
 
 Kennedy.— MECPIANICS OF MACHINERY. By A. B. W. 
 Kennedy, M. Inst. C.E., Professor of Engineering and 
 Mechanical Technology in University College, London. With 
 Illustrations. Crown 8vo. {In ike Press. 
 
 Kiepert. — a manual of ancient geography. From 
 the German of Dr. H. Kiepert. Crown 8vo. 5^. 
 
 Lang. — experimental physics. By P. R. Scott Lang, 
 M.A., Professor of Mathematics in the University of St. Andrews. 
 Crown 8vo. [hi preparation. 
 
 Lankester.— A TEXT-BOOK of ZOOLOGY. By Professor 
 E. Ray Lankester, F.R.S. Crown 8vo. \In preparation. 
 
 Martin and Moale.— on the dissection of verte- 
 brate ANIMALS. By Professor H. N. Martin and W. A. 
 Moale. Crown 8vo. {In preparation. 
 
 Oliver (Professor) — first BOOK OF INDIAN botany. 
 
 By Professor Daniel Oliver, F.R.S., F.L.S., Keeper of the 
 Herbarium and Library of the Royal Gardens, Kew. With 
 numerous Illustrations. Extra fcap. 8vo. 6s. 6d. 
 
 Parker.— A COURSE OF INSTRUCTION IN ZOOTOMY 
 (VERTEBRATA). By T. Jeffrey Parker, B.Sc. Lond., 
 Professor of Biology in the University of Otago. With Illus- 
 trations. Crown 8vo. [/« the Press. 
 
 Parker and Bettany.— the MORPHOLOGY OF THE 
 
 SKULL. By Professor Parker and G. T. Bettany. Illus- 
 trated. Crown Svo. los. 6d. 
 
32 SCIENTIFIC CATALOGUE. 
 
 Manuals for Students— r^«^/«z/^^. 
 
 Robinson — marine surveying, an elementary 
 
 TREATISE ON. Prepared for the use of younger Naval 
 Officers. With Questions for Examinations and Exercises princi- 
 pally from the papers of the Royal Naval College. With Results. 
 By Rev. John L. Robinson, Chaplain and Instructor to the 
 Royal Naval College, Greenwich. With Illustrations. Crown 
 8vo. 7^. dd. 
 
 Contents.— Symbols used in Charts and Surveying — The Con- 
 struction and Use of Scales — Laying off Angles — Fixing 
 Positions by Angles— Charts and G hart- Dr awing— Instrw7ie7its 
 and Observing— Base Lines — Triangulation — Levelling — Tides 
 and Tidal Observations — Soundings — Chronoitieters — Meridian 
 Distances— Method of Plotting a Survey — Miscellaneous Exer- 
 cises — Index. 
 
 Tait — HEAT. P. G. Tait, M.A., Sec. R.S.E. Formerly Fellow 
 of St. Peter's College, Cambridge; Professor of Natural Philosophy 
 in the University of Edinburgh. Illustrated. Crown 8vo. "js. 6d. 
 
 Tyler.— ANTHROPOLOGY : An Introduction to the Study of Man 
 and Civilization. By E. B. Tylor, M.A., F.R.S. Illustrated. 
 Crown 8vo. 'js. 6d. 
 
 Other volumes of these Manuals will follow. 
 
 SCIENTIFIC TEXT-BOOKS. 
 Balfour.— A treatise on comparative embry. 
 
 OLOGY. With Illustrations. By F. M, Balfour, M.A., 
 F.R.S., Fellow and Lecturer of Trinity College, Cambridge. In 
 2 vols. 8vo. Vol. I. i2>s. Vol. II. 21S. 
 
 Ball (R.S.,A.M.). —experimental mechanics, a 
 
 Course of Lectures delivered at the Royal College of Science for 
 Ireland. By R. S. Ball, A.M., Professor of Applied Mathema- 
 tics and Mechanics in the Royal College of Science for Ireland. 
 Royal Svo. los. 6d. 
 
 Brunton. — TABLES OF MATERIA MEDIC A. A Companion 
 to the Medica Museum. By T. Lauder Brunton, M.D., 
 ¥.R.S.,'E6.i{ox oi The Practitioji^, kc. New Ed. Svo. los. 6d. 
 
 Brunton. —A TREATISE ON MATERIA MEDICA. By T. 
 Lauder Bruntpn, M.D., F.R.S. Svo. [In f reparation. 
 
 Chalmers. — graphical determination of forces 
 
 IN engineering structures. By James B. Chal- 
 mers, C.E. With Illustrations. Svo. 24J. 
 Clausius.— MECHANICAL THEORY OF HEAT. By R. 
 Clausius. Translated by Walter R. Browne, M.A., late 
 Fellow of Trinity College, Cambridge. Crown Svo. los. 6d. 
 
SCIENTIFIC TEXT-BOOKS. 33 
 
 Scientific T^^it-^OOk^— continued. 
 
 Cotterill.—A TREATISE ON APPLIED MECHANICS. 
 By James CoxrERiLL, M.A., F.R.S., Professor of Applied 
 Mechanics at the Royal Naval College, Greenwich. With Illus- 
 trations. 8vo. iln preparation. 
 
 Daniell.— A TEXT-BOOK OF THE PRINCIPLES OF 
 PHYSICS. By Alfred Daniell, M.A. Lecturer on Physics 
 in the School of Medicine, Edinburgh. With Illustrations. 8vo. 
 2\s. 
 
 Fawcett— A manual of political economy. By 
 Right Hon. Henry Fawcett, M.P., F.R.S. New Edition, 
 revised. With a Chapter "On the Nationalisation of the Land," 
 and an Index. Crown 8vo. I2x. 
 
 Foster.— A TEXT-BOOK OF PHYSIOLOGY. By Professor 
 Michael Foster, M.D , F.R.S. With Illustrations. Fourth 
 Edition, revised. 8vo. 21s. 
 
 Gamgee.— A textbook of the physiological 
 
 CHEMISTRY OF THE ANIMAL BODY. Including an 
 account of the chemical changes occurring in Disease. By A. 
 Gamgee, M.D., F.R.S., Professor of Physiology in the Victoria 
 University, the Owens College, Manchester. 2 vols. 8vo. With 
 Illustrations. Vol.1. i8j. [Vol. II. in the Press. 
 
 Gegenbaur.— ELEMENTS OF comparative ana- 
 
 TOMY. By Professor Carl Gegenbaur. A Translation by 
 F. Jeffrey Bell, B A. Revised with Preface by Professor E. 
 Ray Lankester, F.R.S. With numerous Illustrations. 8vo. 
 21s. 
 
 Geikie.— A text-book of geology. By Archibald 
 Geikie, LL.D,, F.R.S., Direcioi'-General of the Geological 
 Surveys of the United Kingdom. With numerous Illastrations. 
 Medium 8vo. 28^. 
 
 ** // is a manual worthy to take rank beside Sach's * Botany ' or 
 Hei-mann's ^ Phyiiology,' as a complete elucidatioti of all the most 
 fundamental ideas in the department of knowledge ztnth which it 
 deals. . . It will be clear to our readas from this brief analysis 
 that Dr. Geikiis text-book must remain for some ti?ne to come the 
 great digest of general geological authority and reasoning for the 
 entire English-speaking woj'ld.'" — St. James's Gazette. 
 
 Gray.— STRUCTURAL BOTANY, OR, ORGANOGRAPHY 
 
 on THE BASIS OF MORPHOLOGY. To which are added 
 
 the principles of Taxonomy and i'hytpgraphy, and a Glossary of 
 
 Botanical Terms. By Professor Asa Gray, LL.D. Svo. los. 6d, 
 
 C 
 
34 SCIENTIFIC CATALOGUE, 
 
 Scientific Text-Books — continued. 
 
 Miiller.— THE fertilisation of flowers. By Pro- 
 fessor Hermann MiJLLER. Translated and Edited by D'Arcy 
 W. Thompson, B.A., Scholar of Trinity College, Cambridge. 
 With a Preface by Charles Darwin, F.R.S. With numerous 
 Illustrations. Medium 8vo. 2IJ. 
 
 Newcomb.— POPULAR astronomy. By S. Newcomb, 
 LL.D., Professor U.S. Naval Observatory. With II2 Illustra- 
 tions and 5 Maps of the Stars. Second Edition, revised, 8vo. i8j. 
 ^^ It is unlike anything else of its kind, and will be of more use in 
 circulating a knowledge of astronomy than nine-tenths of the books 
 which have appeared on the subject of late years" — Saturday 
 Review. 
 
 Reuleaux.— THE kinematics of machinery. Out- 
 lines of a Theory of Machines. By Professor F. Reuleaux. 
 Translated and Edited by Professor A. B. W. Kennedy, C. E. 
 . With 450 Illustrations. Medium Svo. 2.\s. 
 
 Roscoe and Schorlemmer. — inorganic CHEMIS- 
 TRY. A Complete Treatise on Inorganic Chemistry. By Pro- 
 fessor H. E. Roscoe, F.R.S., and Professor C. Schorlemmer, 
 F.R.S. With numerous Illustrations. Medium Svo. Vol. I. — 
 The Non-Metallic Elements. 21J. Vol. II.— Metals.— Part I. 
 \%s. Vol. I L— Metals. Part IL iSj. 
 organic CHEMISTRY. A complete Treatise on Organic 
 Chemistry. By Professors RoscoE and Schorlemmer. With 
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