* METAPHYSICAL INQUIRY 
 
 INTO THE METHOD OBJECTS AND RESULT OF 
 ANCIENT AND MODERN PHILOSOPHY 
 
 BY ISAAC PRESTON CORY ESQ. 
 
 , - 
 
 FELLOW OF CAIUS COLLEGE 
 CAMBRIDGE 
 
 LONDON: 
 WILLIAM PICKERING. 
 
 1833. 
 
The following Inquiry was originally published 
 in a more condensed form in 1831, as an Appen- 
 dix to a collection of Ancient Fragments. 
 
 Lambeth. ^ & * 3 February 5, 18,S:>. 
 
 ( . U imTINGHAM, LONDON. 
 
METAPHYSICAL INQUIRY. 
 
 1 HE revival of literature in modern times 
 was slowly followed by the introduction 
 of a better system of philosophy. In 
 some branches of literature we have not 
 surpassed the ancients, and in their phi- 
 losophy perhaps there are some points, 
 which, even at the present day, may not 
 be altogether unworthy of attention. 
 
 To Lord Bacon the philosophic world 
 justly looks up as the father and founder 
 of modern science. Yet we have, in many 
 respects, unconsciously departed from his 
 instructions, and have arrived at conclu- 
 sions directly the reverse of his. The 
 differences which occur are not such, as, 
 in the infancy of science, might have es- 
 B 
 
METHOD. 
 
 caped his notice : but they arise on points, 
 \\ ; ii< -ii >\'i(] been ably discussed before his 
 time, which he had himself examined 
 and scrutinized with the deepest atten- 
 tion, and which he at length admitted 
 from the philosophy of the ancients as 
 principles satisfactorily established. 
 
 In the following Inquiry into the Me- 
 thod, Objects, and Result, of the Ancient 
 and Modern systems of Philosophy, I have 
 no intention, nor would I presume to set 
 them in array against each other : but 
 have endeavoured patiently to examine 
 the foundations upon which they rest, 
 and to draw from the great storehouse 
 of antiquity some speculations, which 
 have been too generally slighted or over- 
 looked by the Metaphysician and Philo- 
 sopher, but which seem to be of such 
 practical utility, that they may tend to 
 the advancement of science, even amid 
 the brilliant discoveries of modern times. 
 
 If we were to ask, what was conceived 
 
ASCENDING SCALE. 
 
 to be the great engine of invention and 
 discovery among the ancients, it is highly 
 probable we should be answered that it 
 was Syllogism. And if we were to ask 
 the same question relative to modern sci- 
 ence, we should be unhesitatingly assured 
 that it was Induction : and, possibly, at 
 the same time we might be told, that the 
 method of the ancients was something 
 worse than useless. Yet, when we con- 
 sider, that human nature is the same, and 
 that such admirable productions have 
 been the result of human effort both in 
 ancient and modern times, we shall find 
 reason to suspect that the methods of dis- 
 covery, or the tools really used in all 
 ages, have been much alike, though their 
 names may have been misapplied, or 
 they may have had no distinct appella- 
 tions assigned them. 
 
 By the INDUCTIVE METHOD we are 
 supposed to go about to collect, by ex- 
 periment and observation, all the facts 
 
4 METHOD. 
 
 and circumstances within our reach, re- 
 lative to the subject in hand. We must 
 examine them in every light, compare 
 their similarities, and mark their differ- 
 ences ; we must reject the particulars 
 that are irrelative or negative ; and con- 
 clude upon the affirmatives that are left. 
 By these means, from the individuals we 
 rise to some general proposition, and we 
 rest assured of its truth as proved by In- 
 duction. 
 
 To take a common instance : a child 
 that has been burnt by a flame, is afraid 
 of the same result from the same cause ; 
 and such fear or expectation is said to 
 arise from experience : and in the ex- 
 pectation of the same result from similar 
 causes, he is said to reason by a species 
 of Induction, though not founded on an 
 enlarged experience. But by trying ex- 
 periments upon all objects which have 
 the appearance of flame, he learns to 
 distinguish such as are hurtful from 
 such as are otherwise, and excluding 
 
ASCENDING SCALE. 5 
 
 those that are harmless, he arrives at the 
 conclusion, that all such objects of a par- 
 ticular kind are hurtful. 
 
 Now, in this statement of the process, 
 it appears to me that two very different 
 instruments are used : the first of which 
 seems to be Analogy, avaXoy/a, a reason- 
 ing upwards from the known to the un- 
 known, the great instrument of Invention 
 and Generalization, which provides, as it 
 were, subjects for the exercise of Induc- 
 tion ; which Induction, cTraywy??, seems 
 to be rather the collection and examina- 
 tion of experiments, and the drawing a 
 conclusion from them ; and as this con- 
 clusion cannot be extended beyond what 
 is warranted by the experiments, the In- 
 duction is an Instrument of Proof and 
 Limitation. A person, that has been burnt 
 by a flame, feels certain that he will be 
 burnt again, if he try it ; he argues only 
 from same to same, and is said to be sure 
 of it by experience ; and it is upon this 
 constant expectation that all physical 
 
6 METHOD. 
 
 science is founded. By analogy he 
 argues that all flames will burn him, he 
 argues from like to like, he generalizes 
 and draws an inference ; and I conceive 
 it is by this analogical reasoning that all 
 science is advanced. The inference which 
 he thus draws a priori, is merely an hy- 
 pothesis, vTTodccncy a supposition, probable 
 indeed, but far from satisfactory. But 
 when he brings it to the test of induction, 
 and collects experiments, he either con- 
 futes or proves this hypothesis, or limits 
 it to something not quite so general. 
 
 This analogical reasoning, when it is ex- 
 tended only from individual to individual 
 of the same species, is commonly called 
 experience, and not analogy ; and from 
 the perfect uniformity of nature, perhaps 
 not improperly : thus, we say, we know 
 by experience that all stones gravitate to 
 the earth. But when we extend it from 
 species to species of the same genus, it 
 is analogy, properly so called. If from 
 the gravitation of all stones we reason to 
 
ASCENDING SCALE. 7 
 
 that of earths, we reason by analogy, 
 from like to like : we obtain a probable 
 inference, not satisfactory till experiment 
 be directed successively to individuals 
 of the different species of earths, and 
 thereby the inference converted into a 
 conclusion. Having thus included earths 
 as well as stones, we may proceed from 
 one species to another by the same pro- 
 cess of analogy and proof, till all bodies 
 upon the surface of the earth be included 
 under the general law of gravitation, 
 whence we may rise to more general 
 propositions. I am inclined to think 
 that such has been the common process 
 of discovery in all ages of the world. 
 
 When Sir Isaac Newton, from the fall 
 of an apple, was led to the consideration 
 of the moon's gravity, he is said to have 
 made the discovery by Induction ; which 
 is true as far as the proof of it went. But, 
 it is manifest, that, at first, he merely 
 formed a probable hypothesis by Analogy, 
 and then laboriously brought it to the 
 
METHOD. 
 
 test of observation ; and it is highly pro- 
 bable that the hypothesis he formed 
 was, that the moon gravitated to the 
 earth with a constant force, instead of a 
 force varying inversely as the square of 
 the distance ; which was the result of 
 another hypothesis, suggested by the el- 
 liptic orbits of the planets, and the force 
 necessary to confine the motion of a 
 projectile in such an orbit. 
 
 When Harvey observed the valves in 
 the veins, he is commonly said to have 
 made the discovery of the circulation of 
 the blood by reasoning fromjhwl causes, 
 or by asking of nature for what purpose 
 such valves could be intended : but, per- 
 haps he might have asked the question 
 for ever, unless the resemblance be- 
 tween the valve of a vein and that of a 
 pump had suggested a plausible hypo- 
 thesis, in which he was confirmed by re- 
 peated experiments and observations di- 
 rected to the point. 
 
 Analogy, so much slighted and over- 
 
ASCENDING SCALE. 9 
 
 looked, and to which such an inferior 
 part in the advancement of science has 
 been assigned, and that too with so much 
 suspicious caution, appears to me to be 
 the great instrument of generalization 
 and invention, by which hypotheses are 
 supplied, which are most commonly the 
 subjects that call for the exercise of In- 
 duction. By Induction, as usually un- 
 derstood, we make it a rule to exclude 
 all hypotheses : first of all, we collect the 
 experiments, and, having obtained these, 
 we are next to examine them and com- 
 pare them ; we then reject the irrelative 
 and negative, and conclude upon the 
 affirmatives that are left. By this means, 
 says Lord Bacon, we question nature, 
 and conclude upon her answers : yet I 
 would venture to suggest, that, ninety- 
 nine times out of a hundred, the Analogy 
 or comparison precedes the collection of 
 the experiments : some resemblance is 
 observed, some hypothesis is started, 
 which is the subject that is brought to 
 
10 METHOD. 
 
 the test of Induction. By this the hy- 
 pothesis is either proved, or confuted, or 
 more commonly limited to something less 
 general. 
 
 I would not be understood to assert 
 that the common inductive method is 
 barren ; for, no doubt, discoveries might 
 be so made ; but I really question whe- 
 ther a discovery was ever made according 
 to its rules, which the discoverer had not, 
 in his own mind, anticipated by Analogy 
 as an hypothesis long before he had 
 completed his investigation, and indeed 
 guided his investigation by it. But, 
 however that may be, it must be admitted, 
 that thousands and thousands of disco- 
 veries are made and inventions brought 
 into play, the result merely of analogy 
 and a few experiments, or very com- 
 monly of a single experimentum crucis. 
 By the common method proposed we 
 take too wide a range, we embrace the 
 whole subject at once, and require the 
 completion of its natural history ; but by 
 
ASCENDING SCALE. 11 
 
 the proper use of analogy as a guide, we 
 step cautiously but from one species to 
 the next. 
 
 Induction has two instruments of ope- 
 ration ; EXPERIMENT for all things within 
 our reach) and OBSERVATION for such as 
 are beyond us. And of these Observa- 
 tion is less efficient than Experiment; 
 for in all Experiments Observation is 
 involved : but in many investigations 
 Experiment is not attainable, and we are 
 reduced to Observation only, because we 
 cannot use Experiment. Now by Induc- 
 tion without Analogy we first ask innu- 
 merable irrelative and impertinent ques- 
 tions of nature, and then make use of 
 Observation upon the experiments in 
 hand ; but by Induction with Analogy 
 we try experiments or observe for a spe- 
 cific purpose, and obtain specific answers 
 to the point. 
 
 Having thus obtained a general law 
 or fact, or cause, for an entire genus, we 
 may proceed in the same manner from 
 
12 METHOD. 
 
 this genus to the next, till the whole 
 order be included under the same or 
 some more extensive generality : thus at 
 length we may arrive at certain most 
 general laws, or phenomena, or causes ; 
 beyond which it may not be within our 
 power to proceed. To arrive inductively 
 at a generality it is of course requisite to 
 have in hand a most extensive collection 
 of the facts or particulars, which must be 
 all included under it : and Aristotle, no 
 less specially than Bacon, insists upon 
 this preliminary. The only question is, 
 whether in reality we do not ascend to an 
 extensive generality by a series of parti- 
 cular conclusions, by successively re- 
 ducing each fact or individual under 
 some general law, conceived a priori by 
 Analogy from some single instance, in- 
 stead of deciding at once by a formal and 
 comprehensive survey of the whole. 
 
 The progress of science in the ascend- 
 ing scale consists in rising from Indivi- 
 duals to Generals and Universals. 
 
DESCENDING SCALE. 13 
 
 Having established these generals and 
 universals, from them we may extend 
 discovery in what may be termed the 
 DESCENDING SCALE : and here Syllogism, 
 in its common acceptation, has its use. 
 And, as an instrument of invention, Syllo- 
 gism may in this case supply corollaries ; 
 as in the former, Induction might yield 
 discoveries without the help of analogy. 
 Yet a very slight consideration will show, 
 that here also Analogy is the great engine 
 of invention, by which hypotheses or sup* 
 positions are supplied ; and that in the 
 descending scale Syllogistic Demonstra- 
 tion, as Induction in the ascending, is 
 the grand instrument for confuting, prov- 
 ing, or limiting those hypotheses. 
 
 But it is said, that, among the an- 
 cients, SYLLOGISM was the great engine 
 of discovery. If we examine this matter, 
 we are informed by Aristotle, that Syllo- 
 gism is a discourse or reasoning, in which, 
 certain things being admitted or supposed, 
 
14 METHOD 
 
 something different from these admitted 
 principles or propositions, necessarily fol- 
 lows, in consequence of their existence.* 
 He tells us, likewise, that Demonstration 
 is a species of Syllogism.f Now it is 
 really of no consequence whether a syllo- 
 gism is composed of two, three, four, or 
 any number of steps ; and, indeed, every 
 mathematical demonstration by synthe- 
 sis is no other than a chain of Syllogism. 
 If we inquire further of him, how the 
 first principles of all philosophy, and 
 every art and science are to be obtained, 
 from which such demonstrations may de- 
 pend ; he expressly informs us by Induc- 
 tion^ by collecting together all the in- 
 
 * SvXXoyioyiog c>6 iari \6yog ev J re$emn> -i- 
 vwr, trepov TL TWV /cciyueVwv, f ayciyKije crvpfiaivti 
 riji TCLVTCL elvcu. I. Pr. Anal. 1 Edit. Casaub. 
 1590. N.B. there is a great variation in the num- 
 bering of the chapters in the different editions of 
 Aristotle. 
 
 t I. Pr. Anal. 1. 
 
 t I. Pr. Anal. 3011. Pr. Anal. 1. 231. 
 Post. Anal. 1. 10. 14. 181. Top. 7 VIII. Top. 
 1 VIII. Phys. 4 IV. Meteor. 1. 
 
OF THE ANCIENTS. 15 
 
 dividuals, and drawing the conclusion 
 from them. His logical treatises, indeed, 
 being entirely directed against the so- 
 phists of that day, relate solely to syllo- 
 gistic demonstration. Of course, there- 
 fore, he does not investigate the method 
 of obtaining the universals themselves : 
 but he speaks repeatedly of it, that is, 
 of Induction, as the well known and fa- 
 miliar method of obtaining them, through 
 the senses, by experience.* He clearly 
 explains to us the progress of science, both 
 in the ascending and in the descending 
 scale.f We learn, says he, only by Induc- 
 tion or Demonstration ; by Demonstra- 
 tion from universals to particulars, i. e. 
 in the descending scale ; by Induction 
 from particulars to universals, or in the 
 ascending scale. Hence a person, who 
 is defective in any of his senses, can- 
 not use Induction, and therefore can- 
 
 * I. Pr. Anal. 301. Post Anal. 10. 15. 27 
 II. Post. Anal. 18. 
 
 f I. Top. 10 VIII. Top. 1. 
 
1C METHOD 
 
 not theorize to universals, or by abstrac- 
 tion obtain general propositions : hence, 
 also, his progress in the scale of demon- 
 stration must be equally defective with 
 his data.* 
 
 If we turn to Plato, he throws a new 
 light upon the method of investigation, 
 by requiring some previous hypothesis^ 
 or idea for examination ; and, in the be- 
 ginning of the Parmenides, lays down the 
 Eleatic or Dialectic method of examin- 
 ing it. The method is this Either, I., 
 The subject is, as it is supposed ; or II., 
 it is not. On the first supposition that it 
 is so, we must examine what happens 
 1st. To it with respect to itself: 2d. To 
 it with respect to all other things : 3rd. 
 To all other things with respect to it: 
 4th. To all other things with respect to 
 
 * I. Post. Anal. 15. See also the preceding 
 references. 
 
 f Aristotle uses the word thesis for hypothesis in 
 this sense. His dialectic also differs from that of 
 Plato 
 
OF THE ANCIENTS. 17 
 
 themselves. Four similar cases will result 
 when we examine what does not happen ; 
 and, according to the exposition of Pro- 
 clus, four more, when we examine what 
 does, and at the same time does not, hap- 
 pen. Upon the supposition, therefore, 
 that it is so, we must investigate its rela- 
 tions in all their bearings ; and we must 
 pursue the same method of investigation 
 upon the second supposition, that it is not 
 so. And if, in so doing, we were guided 
 according to certain categories, a more 
 thorough investigation could not possibly 
 be devised : and the method is equally 
 applicable to Experimental philosophy as 
 to Intellectual science.* 
 
 The ancients, then, professed, in the 
 ascending scale, to work by Hypothesis 
 and Induction ; and, in the descending 
 scale, by Syllogistic Demonstration or 
 Deduction from first principles or propo- 
 
 * For a method of starting ideas for examination, 
 see a curious description of Socrates, with his 
 hopeful pupil, in the Clouds of Aristophanes. 
 
 C 
 
18 METHOD. 
 
 sitions, inductively determined by expe- 
 rience upon the evidence of the senses. 
 If, then, as it is commonly asserted, the 
 Syllogistic method was held to be their 
 only method of discovery, though I am 
 not aware that such was indeed the case, 
 and the method was a process of reason- 
 ing from known to unknown, I conceive 
 that, in this respect, the terms must have 
 a more comprehensive signification than 
 is generally allowed.* I can find nothing, 
 however, to warrant the supposition, that 
 they accurately divided their method into 
 Analogy and Induction in the ascend- 
 ing scale, and into Analogy and Demon- 
 stration in the descending scale. They 
 seem to have imagined that by their me- 
 thod they went precisely to the point, 
 and no further, instead of often going 
 
 * Some papers, entitled Vindiciae Antiquse, in 
 the Classical Journal, throw some light upon these 
 subjects, though I cannot concur with the author 
 of them in his opinions of the perfection of ancient 
 science, much less in his abuse of modern philo- 
 sophers. 
 
LOGIC. 19 
 
 something beyond it by too extensive a 
 generalization, as we are led by analogy, 
 and then retreating to the point deter- 
 mined by the proof; which is a mistake 
 that has equally prevailed in modern 
 times. 
 
 LOGIC or FIRST PHILOSOPHY is the 
 science, to which these subjects belong. 
 
 In the CATEGORIES, which the ancients 
 used, they endeavoured to comprise the 
 relations of all things to themselves and 
 to one another. The categories of Aris- 
 totle are deficient. Those of Kant are 
 more comprehensive indeed, but are 
 much less applicable to ordinary phy- 
 sical investigations : they are likewise 
 imperfect, and in some respects redun- 
 dant, and even repetitions of one another. 
 Yet, if due attention were paid to the 
 subject, I believe the categories might 
 without much difficulty be supplied. 
 
 DEMONSTRATION is the concatenation, 
 the chain of reasoning by which a pro- 
 
20 METHOD. 
 
 position is connected with its principles 
 or data. And not only in the descend- 
 ing, but in the ascending scale, we are 
 frequently under the necessity of calling 
 in logical assistance for bringing our hy- 
 potheses to the proof. 
 
 MATHEMATICS are a branch of logic, 
 more particularly applicable to the phi- 
 losophy of matter, inasmuch as Number, 
 Quantity, and Measure, both in Time and 
 Space, are the peculiar subjects of that 
 science. And many physical hypotheses 
 are started, which cannot be examined 
 without a most accurate admeasurement 
 and an extensive knowledge of mathema- 
 tical science : and the proof or disproof 
 of them can thus only be exhibited. But 
 mathematics are not the only kind of 
 logic employed in philosophical, or even 
 in physical research : and I conceive 
 that Playfair's idea of the subject, in 
 supposing such to be the case, is but 
 partial, and wants something of the ge- 
 nerality of the ancients. The connect- 
 
DEMONSTRATION. MATHEMATICS. 2 ] 
 
 ing chain, for instance, among the pro- 
 positions of moral and metaphysical phe- 
 nomena, is a different species of this 
 same logic ; but, number, quantity, and 
 measure, having little to do with those 
 sciences, mathematics must, from their 
 very nature, be almost wholly inappli- 
 cable. An undue regard to mathematics 
 has often been productive of very serious 
 inconvenience, and of grievous mischief, 
 when brought to bear upon those sci- 
 ences : and, sometimes, even in physical 
 pursuits much misconception has resulted. 
 A mathematician can rise no higher than 
 his data ; and, eminently useful as his 
 science is, not only in the descending 
 scale, but in the examination of hypothe- 
 ses, it is not within its compass to prove 
 any simple physical proposition or first 
 principle. All the mathematical proofs 
 of the parallelogram of forces, for in- 
 stance, are vicious, and merely argu- 
 ments in a circle. Like all other sci- 
 ences, Mathematic must depend upon 
 
22 METHOD. 
 
 its own first principles : and its axioms 
 are only general propositions raised upon 
 individual, by induction. We know that 
 things equal to the same are equal to one 
 another. It is no innate scrap of know- 
 ledge ; nor need we have recourse, with 
 Plato, to a pre-existing state in which we 
 learnt it. We know it only inductively 
 from observation of the particulars, and 
 it is absurd to suppose, that, in the de- 
 monstration of any proposition, we admit 
 the particular by virtue of the axiom. 
 
 The origin of THE UNIVERSAL AND NE- 
 VER-FAILING EXPECTATION, that the same 
 or similar causes will always be attended 
 with the same or similar effects, an ex- 
 pectation upon which all physical sci- 
 ence is founded, has been a subject of 
 the ablest controversy. Hume denies it 
 to be the result either of Experience 
 or of Reason. ' It is not the result of 
 Experience,' says he, ' for Experience 
 is only of the past, and cannot pos- 
 
HUME'S PROBLEM. 23 
 
 sibly extend to the future. If it be the 
 result of Reasoning, produce the chain 
 of Reasoning, which connects the two 
 following propositions with one another ; 
 / have found that such an object has 
 always been attended with such an effect ; 
 (therefore) I foresee that other objects, 
 which are in appearance similar, will be 
 attended with similar effects. If there be 
 any chain of reasoning between them, it 
 is evidently not of the demonstrative 
 kind ; because the converse is equally 
 conceivable. It is therefore of the pro- 
 bable or moral kind. Now all probable 
 reasoning relates only to matter of 
 fact or real existences. And all argu- 
 ments concerning existence are founded 
 on the relation of Cause and Effect. Our 
 knowledge of that relation is derived en- 
 tirely from Experience. And all Experi- 
 mental conclusions proceed on the sup- 
 position, that the future will be conform- 
 able to the past. To endeavour therefore 
 the proof of this last supposition by pro- 
 
24 METHOD. 
 
 bable arguments, or arguments regarding 
 existence, must be evidently going in a 
 circle, and taking that for granted, which 
 is the very point in question.' 
 
 Such is the difficulty, respecting the 
 very foundations of our knowledge, which 
 is proposed by Hume. He attempts to 
 solve it by attributing the Expectation to 
 mere Custom or Habit, which he con- 
 ceives may be ultimately referred to 
 some instinct, or mechanical tendency. 
 Reid, as usual, has recourse to an innate 
 sense, instinct, or principle of our na- 
 ture : and Brown appears to acquiesce 
 in the same solution. 
 
 The principles of connexion among 
 our ideas, according to Hume, are Resem- 
 blance, Contiguity in time and place, and 
 Cause and Effect. They have been more 
 justly stated as Resemblance, Contiguity 
 in time and place, under which the re- 
 lation of Cause and Effect may be re- 
 duced, and Contrast. The ideas of men 
 flow in trains of thought, connected by 
 
HUME'S PROBLEM. 25 
 
 some one or other of these three primary 
 principles. Now, in the argument of 
 Hume, a fallacy seems to lurk under the 
 proposition, that c all probable or moral 
 reasoning relates only to matter of fact, 
 or real existence, and is therefore founded 
 upon experience.' The first time a tri- 
 angle, suppose an equilateral triangle, 
 was presented to us, we had no concep- 
 tion of its properties. By attentive con- 
 sideration we might demonstratively ac- 
 quire the knowledge, that the sum of 
 its angles is equal to two right angles. 
 Now if another triangle, nearly similar, 
 suppose an isosceles triangle, were pre- 
 sented to us ; if we took it into conside- 
 ration, I conceive, that, from our know- 
 ledge of the properties of the other, we 
 should a priori suppose or infer, as an 
 hypothesis, of this triangle also, that the 
 sum of its angles was equal to two right 
 angles : and such an inference would 
 have nothing whatever to do with Cause 
 and Effect, and the truth, from which it is 
 
20 METHOD. 
 
 inferred, was not obtained by Experience,* 
 but by Demonstration. In like manner, 
 if a Circle were first presented to us, and 
 then an Ellipse, we should, probably, be- 
 fore we paid much attention to the pe- 
 culiarities of the ellipse, infer that its 
 properties were the same with, or similar 
 to, the properties of the circle : or, if our 
 genius were of that turn, which is more 
 taken with Contrast than with Resem- 
 blance, we might infer the contrary : and 
 in either case an hypothesis would be 
 inferred, and probable reasoning intro- 
 duced. With respect to the triangle, 
 our inference or hypothesis would be 
 correct, and might be proved by demon- 
 stration. With respect to the ellipse, 
 
 * We might, perhaps, say, ' Knowing the pro- 
 perties of the equilateral triangle by experience, 
 we infer, &c.' But it is only the ambiguity 
 in the word experience, that requires to be ex- 
 posed. The truth was not obtained by Expe- 
 rience, neither is the inference drawn by Expe- 
 rience, in the sense in which Hume uses that 
 word. 
 
HUME'S PROBLEM. 27 
 
 our inference would be incorrect, and 
 might be refuted by demonstration. These 
 arguments a priori are analogical, and 
 only probable, and by them the hypo- 
 thesis is inferred directly, without need 
 of any other intermediate chain of rea- 
 soning. They have no reference to matters 
 of fact, or real existences ; nor are they 
 founded upon the relation of cause and 
 effect, nor do they depend upon expe- 
 rience. It is not true, then, that all pro- 
 bable or moral reasoning depends upon 
 experience. 
 
 Again, if a cause should be presented 
 to our notice as about to operate, with 
 which, hitherto, we had been utterlyunac- 
 quainted ; it is universally admitted, that 
 we should not have the slightest concep- 
 tion of what would be its effect. And, if 
 all the possible effects were set before us, 
 we should be equally at a loss to guess 
 which of them would result. But if the 
 same cause were a second time presented 
 to our notice as about to operate ; and if, 
 
28 METHOD. 
 
 having observed its result in the former 
 instance, we were again to consider what 
 its effect would probably be, this second 
 time ; we should lie under the same com- 
 plete ignorance as before, with one ex- 
 ception, that is to say, the effect which 
 was its former result : and with this ex- 
 ception, we could have as little hope of 
 guessing* as we had at first. The only 
 well founded expectation, then, that could 
 possibly arise, that is, the only plausible 
 
 f The doctrine of Chances applied to Moral, 
 and Metaphysical, and even to Physical reasoning, 
 has been driven to such a length by some of the 
 ablest Mathematicians, and so thoroughly abused, 
 that I am afraid it needs some apology for intro- 
 ducing it ; especially as it commonly involves within 
 itself a glaring fallacy, and is, as Euler observes of 
 the Sufficient Reason of Leibnitz, only a very in- 
 genious method of setting up our ignorance as an 
 instrument to ascertain, and a standard to judge of 
 truth. In the above argument, however, I hope I 
 have drawn the true conclusion ; yet upon the doc- 
 trine of Chances only, I scarcely see any sufficient 
 reason why the chance is not infinite to one against 
 the same result following the same cause twice 
 alike. 
 
HUME'S PROBLEM. 29 
 
 hypothesis we could frame, would be 
 6 that the same cause would be attended 
 with the same effect.' So far it would 
 only be an hypothesis for examination : 
 every successive trial would confirm us 
 in our belief ; and when upon an induc- 
 tion coextensive with our knowledge, we 
 met with no single exception, we should 
 justly learn to regard it as a general law ; 
 liable nevertheless to be limited by any 
 future exception, which might thereafter 
 be produced. I see no necessity to pro- 
 duce a chain of reasoning to account for 
 the primary supposition, or for any sup- 
 position whatsoever. As, in demonstra- 
 tion, we intuitively perceive the relation 
 of equality, so, in probable reasoning, we 
 intuitively perceive the relation of resem- 
 blance. And if, in establishing the first 
 principles of demonstrative reasoning, 
 we infer that the properties of things 
 equal, are equal or the very same ; so 
 in probable reasoning we infer that the 
 properties of things similar are similar. 
 
30 METHOD. 
 
 And, in both cases, these inferences are 
 established or refuted by Induction. The 
 first step in each proceeding is an hy- 
 pothesis, inferred by analogy from a pre- 
 ceding truth or fact. In the first set of 
 examples, I have taken, it is confirmed 
 by Demonstration, from principles ad- 
 mitted or gathered inductively by in- 
 tuitive Observation : and in the second, it 
 is gradually strengthened by Experience. 
 What is 'common in the foundations of 
 the two different cases, is not the relation 
 of Cause and Effect, which is confined 
 solely to the last, but it is Resemblance. 
 The general law, whose foundations are 
 disputed by Hume, seems to be estab- 
 lished precisely in the same manner as is 
 every piece of knowledge we acquire. 
 
 The error of Hume, then, appears to 
 me to spring from a contracted view of 
 the subject ; in supposing that all pro- 
 bable or moral reasoning is founded upon 
 one single relation, that is to say, upon 
 Cause and Effect, which, so far from being 
 
HUME'S PROBLEM. ANALOGY. 31 
 
 of a general nature, is itself, in this res- 
 pect, comprehended as a species of Con- 
 tiguity : whereas he should have ex- 
 tended his view, so as to have embraced 
 all the three primary principles which, as 
 it were, connect and regulate our trains of 
 thought : upon the relations of every one 
 of which, I conceive, that, probable rea- 
 sonings and analogical* arguments are 
 continually based. 
 
 ANALOGY can hardly be called Re- 
 semblance or any species of Resem- 
 blance as it is ranked by Brown ; but it 
 is a kind of argument, a probable argu- 
 ment founded chiefly upon that relation. 
 And it is also manifest, that the very 
 
 * As the word Analogy is not necessarily, though 
 it is commonly and even anciently, connected with 
 Resemblance alone, I see no reason why a probable 
 argument, founded upon either of the other rela- 
 tions of Contiguity and Contrast, should not be 
 termed Analogical, especially as all the three prin- 
 ciples are probably reducible to one and the same, 
 viz. that of Contiguity. 
 
32 METHOD. 
 
 common restriction of the word 
 thesis, to imaginary causes only, is incor- 
 rect, and springs from the same error 
 which would confine probable or moral 
 reasoning to the relations of Causation. 
 
 The great ABUSE OF ANALOGY is rest- 
 ing in its hypotheses, without bring- 
 ing them to the test, building systems 
 upon such hypotheses, and bending the 
 facts to their support. Of this, the Ti- 
 maeus of Plato exhibits a curious ex- 
 ample. He professes in that discourse 
 to philosophize by Xoyot a^ortc, which 
 may be translated analogical reasonings, 
 alone : and this dialogue, no less than 
 many of the physical treatises of Aris- 
 totle, is a proof how little the ancients 
 were in the habit of attending to the ex- 
 cellent rules of investigation, which they 
 had themselves laid down. 
 
 An ascertained fact, or law, or cause, 
 is like a centre or a stem, from which 
 many hypotheses branch forth on all 
 
ANALOGY. 33 
 
 sides, varying according to the different 
 resemblances, which the different objects 
 or genera bear to one another. One 
 only of these hypotheses can be the 
 truth : but each of them, if assumed, be- 
 comes another centre or stem, from which 
 as many more hypotheses proceed : and 
 such is the case ad infinitum. The 
 chances of error, therefore, increase in a 
 very high geometrical proportion, whose 
 ratio of course must be indefinitely va- 
 riable, so as to include all the possibi- 
 lities. A single hypothetical step into 
 the regions of discovery we may, pro- 
 bably, make aright, but it is not to be 
 depended upon, till it is proved : and the 
 chances are very much against it. Ne- 
 vertheless, we may, possibly, even make 
 a second step into these unknown regions 
 without proving the first : but the chances 
 against it are prodigiously multiplied. 
 And any attempt at a second step, before 
 the first is proved, is a false method of 
 proceeding. It is like false heraldry, 
 D 
 
34 METHOD. 
 
 laying colour upon colour. The colour 
 can only be blazoned on a metal, nor 
 ought an hypothesis to be laid but upon 
 the sterling basis of a truth. When we 
 make a step into these regions of ima- 
 gination, a new field is opened to us, 
 presenting us with explanations of phe- 
 nomena and objects of attention, which 
 we had never before conceived, each in- 
 viting us to make another step ; and so 
 delighted are we with the wide and fair 
 prospects before us, that we are apt to 
 forget that we are but in the fields of 
 imagination, and that it signifies but 
 little, which hypothesis we had assumed, 
 which path we followed, as all of them 
 open to us prospects as delightful, as 
 they are visionary. It is a fault and an 
 abuse, almost equally to be imputed to 
 modern as to ancient philosophers. 
 
 Another abuse of Analogy is arguing 
 from individuals to genera, or from ge- 
 >?//.? to genus, when these genera are too 
 remote ; which is skipping to generalities 
 
ANALOGY THEORY. 35 
 
 instead of cautiously proceeding from 
 species to species : .not that it is of very 
 material consequence, save only, that, the 
 difficulty of the proof being increased, 
 an hypothesis, so obtained, is apt to be 
 received upon insufficient grounds. 
 
 But the most dangerous abuse of all 
 is arguing from Matter to Mind, of 
 which, as well as of the kind of simila- 
 rity that exists between them, I shall have 
 occasion presently to speak more at 
 large. 
 
 I would observe, also, the great laxity 
 in the significations of the word THEORY. 
 It is sometimes used for a general law or 
 principle obtained by Induction, and as 
 something almost synonymous with hy- 
 pothesis : in this view it might be looked 
 upon as a proved hypothesis. In its 
 other and more general signification it 
 implies the whole system or chain of 
 reasoning from general laws and prin- 
 ciples, and sometimes the result of such 
 
36 METHOD. 
 
 a chain. Its real signification seems to 
 be the Survey itself.* In the descend- 
 ing scale the result of the survey is 
 termed a Theorem, Sewp^ta : and in the 
 ascending scale the general law obtained, 
 the result of the survey, might perhaps 
 likewise be termed a Theorem : whilst 
 the Theory, 3fwp/a, the Survey itself, may 
 be taken for the whole system or chain, 
 which, as it proceeds, every now and 
 then, as it were, deposits these theorems. 
 An HYPOTHETICAL SYSTEM differs 
 from a Theory, as does an hypothesis 
 from a general law or fact ; and is de- 
 pendant upon Hypotheses instead of 
 Facts ; and its productions are of the 
 same description. But it must be re- 
 marked, that the productions of such 
 systems, that is to say, Hypotheses de- 
 (/itcedi are, of all other hypotheses, the 
 most susceptible of error; inasmuch as 
 they embody all the hypothetical un- 
 
 * See an excellent paper upon the subject in 
 Blackwood's Magazine, August, 1830. 
 
THEORY AND PRACTICE. 37 
 
 certainty of the data in one single con- 
 clusion, independently of the chances of 
 error in their deduction. 
 
 The more extensively a legitimate 
 Theory is unfolded, the greater is its 
 approximation to the truth. The more 
 extensively an Hypothetic System is de- 
 duced, the greater are its deviations. 
 And one of the easiest and most forcible 
 methods of proving the accuracy of a 
 system, is, unflinchingly to drive it 
 home. 
 
 From one or more general laws or 
 data we deduce certain results or theo- 
 rems, such as the different expressions 
 for the range, velocity, &c. of a shot, in 
 the theory of Projectiles ; and each of 
 these expressions would be practically, 
 as well as theoretically true, but for the 
 innumerable other circumstances to be 
 taken into consideration. It is therefore 
 only an approximation to practical truth. 
 From a certain other set of general laws 
 we deduce a theory of Resistances; and, 
 
38 METHOD. 
 
 
 
 by a combination of these two Theories, 
 we approximate still nearer to practical 
 truth in all the theorems which they 
 contain. And by adding theory to the- 
 ory, relative to the powder, form, texture, 
 elasticity, &c. of the shot, climate, and a 
 variety of other circumstances, we might 
 still nearer approximate. And all these 
 Theories taken together might be termed 
 the Theory of Gunnery ; and by uniting 
 these approximations with practical ex- 
 perience, a sufficient degree of certainty 
 is attained. 
 
 But it is utterly impossible, upon the 
 surface of this earth, by Theory, to arrive 
 at practical results, even in the most 
 simple and advanced of all practical 
 sciences, Mechanics ; particularly, as it 
 sometimes happens, when the results of 
 each Theory, instead of being Theorems, 
 are themselves merely approximations. 
 Of this the ancients were perfectly 
 aware ; for, both in ascending and des- 
 cending, they excluded the individuals, 
 
THEORY AND PRACTICE. 39 
 
 as objects of sense and not of science. 
 And all men of experience seem to be 
 equally aware of it. For, however accu- 
 rately contrived, and well considered, 
 any proposed combination may have 
 been, they never expect it to be carried 
 into execution off hand. Every new step 
 must be actually tried, before the engi- 
 neer can be confident of success. Some- 
 thing or other, either in the theory it- 
 self, in the materials employed, in the 
 workmen, in the weather, and a variety 
 of other circumstances, is sure to arise 
 at almost every turn, which has been 
 overlooked, or unprovided for. And 
 such unexpected obstacles very often 
 prove insuperable ; and would do so 
 more frequently, but for the talent and 
 patient perseverance, which is enabled 
 by new applications, experiments, and 
 inventions, successively to overcome such 
 repeated disappointments. 1 have my- 
 self so frequently witnessed this, in at- 
 tempts to reduce to practice some of the 
 
40 METHOD. 
 
 most admirable combinations for the ad- 
 vancement of the arts, that in every ge- 
 neral estimate I should be inclined to 
 allow no inconsiderable sum at each new 
 introduction for unforeseen contingen- 
 cies, and to calculate upon the failure 
 and readjustment of at least one half the 
 combination before it can be reduced to 
 practice. 
 
 Much less, then, is it possible to re- 
 duce Theory to practice in Politics, or 
 any other moral or intellectual science ; 
 where not only so few general laws, uni- 
 versals, or data, are ascertained, but the 
 springs of action are so manifold and 
 various, independently of the free-will 
 and perversity of the individuals, that 
 human intellect can scarcely hope to 
 form even a likely approximation to the 
 details. The speculative philosopher, 
 as is justly observed by Stewart, pos- 
 sesses a fund of knowledge, invaluable 
 in all untried cases, which will guide 
 him a certain way in approximation to 
 
PREJUDICES. 41 
 
 the truth. But if he attempt to reduce 
 such theoretical principles immediately 
 to practice, of course he fails in every 
 instance, and produces nothing but con- 
 fusion and mischief; of which the state 
 of this kingdom, at this moment, is a 
 most lamentable proof: and the pro- 
 bable result of persevering in such a 
 course cannot be contemplated without 
 the utmost alarm, the more anxiously, as 
 many of the systems, still acted upon, 
 are built upon false principles, and are 
 merely hypothetic systems. 
 
 It is common in all philosophical trea- 
 tises, to say something upon a general 
 abandonment of PREJUDICES ; and to 
 assert that we should begin our re- 
 searches, unswayed by any of the Idols, 
 which have unquestionably retarded the 
 advancement of science But what are 
 Prejudices? Prejudices are presumed 
 to be deeply rooted opinions, taken up 
 on trust without sufficient proof. In- 
 
42 METHOD. 
 
 numerable are the opinions, which we 
 must necessarily and for ever hold with- 
 out any proof at all, and upon very slight 
 analogies. And what are Inferences 
 drawn a priori by Analogy but unproved 
 opinions? And if such Inferences or 
 Hypotheses are, as I have endeavoured 
 to point out, the first steps to knowledge, 
 it appears to me to be a false conclusion, 
 that because they have been abused, they 
 ought therefore without examination, to 
 be abandoned. Prejudices differ from 
 such inferences and opinions, only in de- 
 gree, the degree of strength.* If, then, 
 slight opinions and inferences, founded 
 but on a single analogy, are to be exa- 
 mined, and not abandoned, it appears to 
 follow a fortiori that such deep-rooted 
 
 * Prejudices are often confounded with the evil 
 passions by which they are accompanied and fos- 
 tered. In such instances it is the passion that 
 should be eradicated ; and the mere opinion, if it 
 has no other support than the passion, will quickly 
 vanish. 
 
PREJUDICES. 43 
 
 opinions, as prejudices are commonly 
 represented to be, so far from being 
 flippantly laid aside, are worthy of an 
 investigation, still more attentive and 
 minute. 
 
 Prejudices, which have obtained a 
 general ascendancy, must either have 
 been originally founded upon some strong 
 analogical reasonings ; or have been the 
 conception of some master-spirit of a by- 
 gone age, so brilliant, as, at the time, to 
 have commanded universal assent; or> 
 having been struck out in the ordinary 
 course of analogical inquiry, they must 
 have been corrected by succeeding hands, 
 till they obtained a place among the 
 standard opinions of the world. Very 
 often, from the increase of knowledge, 
 we find upon examination that these pre- 
 judices are mistakes : but the very mis- 
 takes of a man of genius are valuable, 
 and deserve all due consideration. But 
 for the paradoxical errors of Hume, we 
 should possibly not even yet have thought 
 
44 METHOD. 
 
 of investigating the phenomena of causa- 
 tion. The attempts of Reid to refute 
 these paradoxes, or rather to evade their 
 conclusions, conferred a lasting benefit 
 on science, not so much by the success 
 of his attempt, as by his erroneous mul- 
 tiplication of the senses, faculties, and 
 powers, of the human mind. And, how- 
 ever mistaken in his views upon the 
 subject, they have been the occasion of 
 far more accurate investigations and 
 analyses. 
 
 The attempt to make the mind a mere 
 tabula rasa, must surely be as injudicious 
 as it is impracticable. If it were in our 
 power to shake off our opinions, and we 
 attempted to supply their places by our 
 own individual research, it would take 
 us almost the labour of a life to master 
 the far from contemptible acquirements 
 of a naked Indian. If we had recourse 
 to men or books, with the first informa- 
 tion we received, we should receive ano- 
 ther set of opinions, if not for belief, 
 

 PREJUDICES. 45 
 
 at least for examination : and we might 
 busy ourselves in examining the mere 
 opinions of some single philosopher, in- 
 stead of the standard opinions of the 
 world ; having abandoned, in the mean 
 time, all practical principles of conduct. 
 Three times at least in four, a philoso- 
 pher is wrong in any novel speculation, 
 even where he flatters himself he is 
 proceeding upon the strictest induction : 
 and his suggestions only become practi- 
 cable and useful, by being corrected or 
 continued by the repeated improvements 
 of his successors : after which, if they be 
 of such a nature as to be incapable of 
 proof, they are received among the pro- 
 fessed opinions and prejudices of the 
 world, to be examined thereafter, by any 
 succeeding philosopher, and sifted to his 
 heart's content, to be improved, estab- 
 lished, or overthrown, as the case may 
 happen, but not to be wilfully aban- 
 doned. " Instead of casting away all 
 our old prejudices," says one of the ablest, 
 
46 METHOD. 
 
 and the most prophetic of politicians, that 
 ever instructed mankind, " we cherish 
 them to a very considerable degree ; and, 
 to take more shame to ourselves, we che- 
 rish them because they are prejudices ; 
 and the longer they have lasted, and the 
 more generally they have prevailed, the 
 more we cherish them. We are afraid 
 to put men to live and trade, each on 
 his own private stock of reason ; because 
 we suspect, that this stock in each man 
 is small, and that the individuals would 
 do better to avail themselves of the ge- 
 neral bank and capital of nations and of 
 ages."* Though the foregoing extract 
 may be a little in the extreme, yet every 
 practical politician must be sensible how 
 much more productive of human happi- 
 ness is a steady adherence to ancient 
 prejudice than a general adoption of 
 new-fangled theories. The first are prac- 
 ticable, if they are false ; they produce 
 
 * Burke's Reflections, p. 129. 
 
PREJUDICES. 47 
 
 no irremediable mischiefs ; and when 
 their falsehood is detected, they are gra- 
 dually mended and superseded ; but the 
 latter are very generally impracticable, 
 if they are true. And the statesman, 
 that should attempt to reduce to prac- 
 tice, the novel speculations of a single 
 brain or school, would prove himself a 
 man, but very partially acquainted with 
 the springs of human action, and of such 
 contracted views, as we have not been 
 in the habit of expecting from the states- 
 men of this enlightened age. 
 
 Men, who pride themselves upon a 
 superiority to all prejudices, are gene- 
 rally found shallow in their acquire- 
 ments, sceptical to demonstrated truth, 
 and in a remarkable degree credulous, 
 and apt to take upon trust some favourite 
 novelty or other, that intrinsically is 
 scarcely worth a moment's consideration. 
 Nevertheless all have their use : and the 
 flippant sophist often renders service to 
 science, by drawing the attention of men, 
 
48 METHOD. 
 
 more able than himself, to the examina- 
 tion of established prejudices, and the 
 result most commonly is, as Burke 
 justly observes, that they are reestablished 
 upon a firmer basis, their ancient founda- 
 tions, which had been concealed, are 
 openly tried, and their soundness pub- 
 licly declared. When, however, the re- 
 verse is the result, a service even more 
 valuable is rendered to truth by their ex- 
 posure. But, unfortunately, it too fre- 
 quently happens, that the whole is for a 
 time discarded, its truths rejected with 
 its errors, till future examination par- 
 tially recalls the opinion, and reestab- 
 lishes its truths alone. In the philoso- 
 phical world of the present day it is a 
 strong and deep-rooted prejudice, that all 
 prejudices ought to be abandoned. But 
 if this prejudice were itself abandoned 
 with examination, we might rush into 
 the opposite extreme, and incalculable 
 might be the mischiefs that would result. 
 As a nearer approximation to the truth, 
 
PREJUDICES. 49 
 
 than was the system, which was in use 
 before the time of Bacon, this prejudice 
 has rendered essential service to science, 
 and to mankind. But from the time 
 of Burke to the present its errors have 
 been more acted upon than its truths ; 
 and it has become mischievous. With 
 respect to prejudices, then, it appears that 
 they are not to be abandoned without 
 examination ; but rather to be retained 
 till they are overthrown ; that they are 
 to be subjected to the strictest scrutiny 
 and investigation, and that c&teris paribus 
 the leaning should be decidedly in their 
 favour and support. 
 
 Lord Bacon has made the general 
 abandonment of prejudices the active 
 principle of curiosity in his method of 
 investigation, and the exclusion of hypo- 
 theses the clog and safeguard. It might 
 be recommended to consideration, whe- 
 ther a process, directly the reverse of 
 this, could not be acted upon, not only 
 E 
 
50 METHOD. 
 
 more naturally, but with greater facility 
 and greater safety ; whether the ardour 
 of inventive genius, instead of being at 
 once damped by the rejection of its spe- 
 culations without examination as wild 
 hypotheses, should not be encouraged to 
 pour forth the brilliancy of its concep- 
 tions ;* and whether a sterner and a safer 
 check might not be placed upon its 
 flights, by Prejudice, rigidly insisting 
 upon proof of every novelty proposed. 
 The former method is evidently a strain 
 
 * It was amusing, upon a late occasion, to hear 
 the reverse of this proposition driven home by a de- 
 monstration," that Genius was rather detrimental 
 than otherwise/' Some men are more apt to dis- 
 cover, invent, and generalize, their minds being- of 
 that kind, which is more taken with Resemblance ; 
 and such men are geniuses of the highest order. 
 Others, being more observant of Differences than 
 Resemblances, are better able to examine any sub- 
 ject or hypothesis proposed. Both are equally 
 wanted for the prosecution of science ; but the 
 present system almost amounts to an exclusion of 
 the former. See, in many of the dialogues of 
 Plato, his curious speculations upon The Same and 
 The Different, The Similar and The Dissimilar. 
 
PREJUDICES. 51 
 
 and a task upon the mind, both with 
 respect to the check and the incitement ; 
 but the latter falls in with the natural 
 inclinations of all men. 
 
 Thus far I have spoken of the Method 
 of proceeding. It is a method univer- 
 sally applicable to every inquiry ; inas- 
 much as it is perfectly independent of 
 every science, and is merely an exposi- 
 tion of the Laws, or manner, in which 
 the mind pursues the objects of its in- 
 quiry. And I have used the terms Laws, 
 Facts, Universals, and the rest, in their 
 common acceptation. But these terms 
 are so confounded with each other, and 
 with Causes and Effects, Power, Agent, 
 and the like, that we scarcely know what 
 we are in search of; and some of the 
 most able views of Bacon's Novum Or- 
 ganum have become as much lost to the 
 world, as have some of the very finest 
 speculations of the ancients. In examin- 
 ing the proper Objects or Aim of science, 
 
52 OBJECT OF PHILOSOPHY. 
 
 I would endeavour to point out, as they 
 arise, the distinctions, which, for the 
 sake of perspicuity, so necessary to the 
 cultivation of science, ought ever to be 
 maintained among them. 
 
 Our knowledge, both of the mental 
 and of the material worlds, relates to the 
 Substances which compose those worlds, 
 either in respect of their Qualities as they 
 coexist , or of their successive Changes. 
 
 The Qualities of matter coexist in 
 Space ; and all its Changes are but the 
 successive motions which occur in Time. 
 But the coexisting and complex pheno- 
 mena of mind, and the successive changes, 
 of which it is the subject, notwithstand- 
 ing these strong analogies are wholly 
 independent of Space, and Motion, and 
 probably of Time* 
 
 * That they are wholly independent of Span- 
 and Motion, few but the Materialists dispute : that 
 they are independent of Time is not so universal lv 
 allowed. Such an opinion, however, is most ably 
 maintained. 
 
NATURAL HISTORY. 53 
 
 Now if we could become acquainted 
 with every Object as it exists in Space ; 
 and if we could intimately perceive its 
 conformation, and the circumstances on 
 which its qualities depend ; and if we 
 arranged them all into classes, according 
 to the Resemblances, which they exhibit, 
 and then described them, giving names 
 both to the individuals and to the classes, 
 we should have completed one great 
 branch of Natural History. And this 
 single branch is not unfrequently re- 
 garded as the whole of that science. 
 But there is another great branch, equally 
 the object of classification and descrip- 
 tion, that is, the Changes which occur in 
 Time. And the forces, actions, passions, 
 and accidents of bodies, the phenomena 
 of Attraction, Galvanism, &c., so far as 
 they are the subject of classification and 
 description only, are no less to be ranked 
 as the objects of Natural History, than 
 are the Qualities and the Individuals 
 themselves. 
 
54 OBJECT OF PHILOSOPHY. 
 
 Natural History then is the classifica- 
 tion and description of the substances, 
 of their coexisting qualities, and of their 
 successive changes. 
 
 Struck with the resemblances to each 
 other, which the Individuals exhibit, we 
 have arranged them naturally into Species. 
 By a comparison of the species Genera 
 are formed : and again Orders, Classes, 
 and Kingdoms in the ascending scale. Or 
 if we pursue the classification in the des- 
 cending scale, an order becomes divided 
 into genera, by observing the Resent- 
 blances, which prevail among the various 
 groups, and the specific Differences by 
 which they are distinguished. Thus, 
 Trees may be divided into Oaks, Elms, 
 Ash, &c. resembling each other in their 
 general features, but distinguished by cer- 
 tain differences. Oaks, again, are divided 
 into the different species of Oak, till at last 
 we arrive at the individuals themselves. 
 In the same manner we group the pheno- 
 mena of change or action, as Attractions 
 
 
NATURAL HISTORY. 55 
 
 into Electric, Magnetic, Elective, &c. 
 of Gravitation, of Cohesion, &c. 
 
 Each class is distinguishable by its 
 definition consisting of the genus and of 
 the specific difference. As science ad- 
 vances new and unlocked for resem- 
 blances and differences are observed: 
 and the great instrument of Classifica- 
 tion is RESEMBLANCE. 
 
 But does Philosophical Inquiry ex- 
 tend only to this knowledge of Natural 
 History? And if we ask why such a 
 phenomenon occurs ; will our curiosity 
 be satisfied with this classification and 
 description only ? Often, very generally 
 indeed, we are directly answered in the 
 affirmative ; and are told by modern phi- 
 losophers that such inquiries into the 
 causes of things are either beside the ob- 
 jects of true Philosophy, or are beyond 
 our limited faculties to determine ; and 
 that we must content ourselves with 
 the laws only, or with the resolution 
 
56 OBJECT OF PHILOSOPHY. 
 
 of all particular phenomena into those 
 of a more general nature. " If it be 
 asked," says Dr. Reid, " why such a 
 body gravitates towards the earth ? all 
 the answer that can be given, is, Be- 
 cause all bodies gravitate towards the 
 earth. This is resolving a particular 
 phenomenon into a general one. If it 
 should be again asked, why do all bo- 
 dies gravitate towards the earth ? we 
 can give no other solution of this phe- 
 nomenon, but that all bodies whatsoever 
 gravitate towards each other. This is 
 resolving a general phenomenon into a 
 more general one. If it should be asked, 
 why all bodies gravitate to one another ? 
 we cannot tell : and if we could tell, it 
 would only be by resolving this universal 
 gravitation of bodies into some other 
 phenomenon still more general, and of 
 which the gravitation of all bodies is a 
 particular instance. The most general 
 phenomena we can reach, are w r hat we 
 call the laws of nature. So that the 
 
CAUSATION. 57 
 
 laws of nature are nothing else but the 
 most general facts relating to the opera- 
 tions of nature, which include a great 
 many particular facts under them."* 
 
 On this very common system of phi- 
 losophizing, a person, making the Inquiry 
 proposed, receives no other than this 
 most unsatisfactory reply ' That the 
 body gravitates, because it (in common 
 with every other body) gravitates' It 
 may be true that we are ignorant of 
 any reason ; nevertheless the question 
 is not to be evaded. The inquiry is 
 directed to the Cause ; and the answer of 
 Dr. Reid is a reply from Natural History 
 to a question upon Causation. And it 
 is one of the most common errors of the 
 philosophy of the present day to con- 
 found the second great branch of natural 
 history with causation. Causation, how- 
 ever, is a distinct, and strict object of 
 philosophical inquiry: and, so far from 
 being dismissed as beyond us, it is of 
 
 * Inq. p. 278. 
 
58 OBJECT OF PHILOSOPHY. 
 
 more importance both in a scientific and 
 in a practical point of view, than is natural 
 history itself. Both involve considera- 
 tions of individuals and phenomena in 
 space and time. Natural history is the 
 classification and description of the in- 
 dividuals, phenomena, or facts them- 
 selves : Causation is the investigation of 
 the Causes which produce these pheno- 
 mena, of the manner in which they are 
 produced, and the purposes for which 
 they are produced. The two sciences 
 go hand in hand. By the extension of 
 Natural History, the knowledge of Cau- 
 sation is advanced : nor is Natural His- 
 tory less indebted to Causation, which 
 is continually bringing to light new pro- 
 perties, and phenomena, and unlooked 
 for circumstances, which point out un- 
 heeded similarities and differences, 
 among objects and events ; and thus cor- 
 rects and extends the classifications 
 which had hitherto prevailed. 
 
 It is most true, that the subject of 
 
CAUSATION. 59 
 
 Causation is involved in great obscurity. 
 But I conceive, that this arises chiefly 
 from a confusion of words : and, that by 
 the introduction and improper use of 
 certain terms, and too great a reliance 
 upon certain favourite but unproved hy- 
 potheses, we have in some measure lost 
 sight of the proper objects of Philo- 
 sophy. 
 
 By the word Cause the ancients ap- 
 pear to have understood that without 
 the co-operation of which no sensible 
 phenomenon could be produced :* and 
 they divided Causes into the Material, 
 the Formal, the Efficient, and the Final. 
 And this division was excellent, and in 
 perfect keeping with a system, which held 
 
 * See the 67th epistle of Seneca, wherein he ex- 
 plains the common and Platonic division of causes ; 
 and unjustly arraigns both, because he conceives that 
 Space, Time, and Motion, ought to be included. 
 Motion, however, was always especially included 
 in the efficient cause, and Space and Time are but 
 the measures of that motion. The objections of 
 Reid to this division are equally inconclusive. 
 
60 OBJECT OF PHILOSOPHY. 
 
 a Soul of the world as a prime mover of 
 Efficient causes, to which every action in 
 the universe was remotely to be re- 
 ferred in a connected chain.* Aristotle 
 is almost inclined, yet hesitates, to claim 
 this division as his own discovery : but 
 it is evidently of a much more ancient 
 standing. He gathers it however by an 
 extensive Induction, and by the resolution 
 of the assumed or proposed causes of all 
 preceding philosophers into those which 
 he enumerates. And Lord Bacon, though 
 he*denies to the ancients the knowledge 
 of Induction, must have been satisfied 
 with the Induction of Aristotle in this res- 
 pect, or from his own researches and exa- 
 mination have arrived at the same con- 
 clusion, before he admitted this division 
 of Causes, with such unqualified appro- 
 bation as he does. There is nevertheless 
 a slight variance between the two, in 
 words, rather than in substance, owing 
 to Bacon's deviation, from the ancient 
 * See Arist. VII. Phys. 1 VIII. Phys. 5. 
 
CAUSATION. 61 
 
 language, which is however immaterial 
 to our present investigation. 
 
 Among the successors of Lord Bacon, 
 this division of Causes appears to have 
 been but little attended to or understood, 
 and has been generally supposed to be 
 superseded : and, since the time of 
 Hume, by the word Cause they seem at 
 times to understand some Tye or Bond 
 of Connexion between one event and its 
 preceding : and in this view it is asserted, 
 that no causes of things have ever been 
 discovered ; and that philosophy lies not 
 in the discovery of causes, but only in 
 the discovery of the facts and general 
 laws of nature. The same assertion is 
 likewise made, because no one can pre- 
 tend to have discovered the first of secon- 
 dary causes. Sometimes the Cause is 
 looked upon as implying nothing more 
 than an antecedent phenomenon : and 
 these phenomena, under the names of 
 Cause and Effect, are supposed to be 
 continued in an endless chain of succes- 
 
62 OBJECT OF PHILOSOPHY. 
 
 sive conjunctions. Brown is of this 
 opinion, and he gives the following as a 
 summary of his doctrine of Causation. 
 " To express shortly what appears to me 
 to be the only intelligible meaning of the 
 three most important words in Physics : 
 Immediate invariable antecedence is 
 Power. 
 
 The immediate invariable antecedent, in 
 any sequence, is Cause. 
 The immediate invariable consequent^ 
 in any sequence, is the correlative ef- 
 fect"* And again. " The form of 
 bodies is the relation of their elements 
 to each other in space. The power of 
 bodies is their relation to each other in 
 time; and both Form and Power, if 
 considered separately from the number 
 of elementary corpuscles and the changes 
 that arise successively, are equally ab- 
 stractions of the mind and nothing 
 more." 
 
 Before we examine any instances of 
 * 7 Br. 38. 
 
CAUSATION. 63 
 
 the phenomena, let us dismiss the Final 
 Cause, that is, the ultimate object and 
 end of every action, without further con- 
 sideration, as less properly a cause than 
 a motive, and equally admitted in all 
 systems, in which nothing is referred to 
 chance, and as unconnected with the 
 Physical subject we have now in hand. 
 To take, then, an example : when we 
 hear a clock strike, if we attend to the 
 chains of successive causes to go no 
 farther back they may be traced in the 
 stroke of the hammer, which causes the 
 vibration of the bell, which causes the 
 undulatory movement among the par- 
 ticles of the air, which causes some kind 
 of motion on the organs of hearing and 
 on the brain ; a certain sensation follows, 
 and the soul perceives that the clock has 
 struck. Now, for the production of this 
 ultimate effect, we may observe not only 
 one, but three distinct chains of what 
 the ancients would call Causes. 1st. 
 The chain of the material substances, 
 
64 OBJECT OF PHILOSOPHY. 
 
 whose matter is in contact with one ano- 
 ther, and without which matter the phe- 
 nomenon could not have been produced, 
 viz. the matter of the hammer, of the bell, 
 of the air, of the auditorial nerve, of the 
 sensorium, and these are the coexisting 
 Material causes. Again, each of these 
 portions of matter is endued with certain 
 qualities, without which also the eifect 
 could not have been produced : and these 
 depend upon what the ancients would 
 call the form ; and they consist of the 
 form, texture, elasticity, vibratory and 
 other qualities of the bell, of the air, 
 nerve, &c. These are the Formal causes. 
 To these must be superadded the parti- 
 cular accidents by which they are af- 
 fected, viz. the fall of the hammer, the 
 vibration of the bell, and the others, by 
 which motion is successively communi- 
 cated : and of this chain of causes eacli 
 accident, action, or phenomenon, is no- 
 thing else than motion, modified by the 
 body through which it passes, and may 
 
CAUSATION. 65 
 
 be regarded as a proximate Efficient 
 cause* 
 
 Let us take another example of a 
 statical instead of a dynamical nature 
 If we squeeze a piece of wood in a vice, 
 and have so far squeezed it as to be able 
 to produce no further compression, but 
 nevertheless continue to apply the same 
 force, so that the whole remains in equi- 
 librio, we may here again trace the ma- 
 terial and formal causes, in the hand, 
 the lever, the screw, and the limb of 
 
 * It might be objected, that the common example 
 of the ancient causes, viz. of a founder casting a 
 statue, does not quadrate with what I have ad- 
 vanced : for in the example, the Efficient cause a 
 quo is the Founder, the Material ex quo is the 
 brass, the Formal in quo is the shape. A more 
 attentive consideration, however, will show that it 
 is only a particular case of the more general that I 
 have taken, as is explained at large by Aristotle 
 (II. Phys. 3.). The Platonists added to the above 
 the Ideal or Exemplary cause, ad quod, according 
 to which it is fashioned, which commonly related 
 rather to the metaphysical, than to the physical 
 forms. 
 
66 OBJECT OF PHILOSOPHY. 
 
 the vice ; its fulcrum and other parts 
 concurring. And the chain of action, 
 accident, or force, is a continued strain, 
 endeavour, or tendency, propagated from 
 the hand through the parts of the vice, 
 communicating the pressure to the wood : 
 and it may be traced still further if 
 requisite. 
 
 Here then we must mark a distinc- 
 tion among Forces or Powers. Where 
 Motion is actually produced, the force 
 by which it is produced, proximately, 
 is nothing more than the Momentum or 
 Quantity of Motion communicated from 
 one body to another in a connected suc- 
 cession, as in the example of the Bell. 
 Such force is called Dynamical. Sta- 
 tical force is of the same nature, though 
 no motion is produced, the force being 
 counteracted in its effect, as in the ex- 
 ample of the Vice. It produces, how- 
 ever, a continual Stress or Endeavour 
 and is the cause of a continued series 
 of such Stresses, Endeavours, and Ten- 
 
 
CAUSATION 7 . 67 
 
 dencies among bodies in contact : and it 
 is only requisite that some impediment 
 be removed that motion may take effect. 
 In the phenomena, then, above referred 
 to, and indeed in every other with which 
 we are thoroughly acquainted, we may 
 trace the Material, Formal, and Efficient 
 or Physical causes of the ancients, a 
 Chain of Being coexisting in Space, and 
 a Chain of Action, Accident, or Force, 
 successive in Time : all which are neces- 
 sary for the production of the Effect. 
 And we may perceive that the ancient 
 and modern doctrines upon the subject 
 of Causation, so far as both of them 
 maintain the connected chain, are not 
 inconsistent with one another : but we 
 must carefully distinguish a circum- 
 stance, which is in general wholly over- 
 looked, that is to say, whether the Cause 
 be defined as the Action itself, or the 
 Instrument affected with the action 
 the Vibration of the bell, or the Bell in 
 the act of vibrating ; the Strain propa- 
 
68 OBJECT OF PHILOSOPHY. 
 
 gated through the lever, or the Lever 
 itself in the act of straining upon the 
 screw. 
 
 I am sorry to differ, upon the subject 
 of causation, with a writer so justly 
 celebrated as Brown. But there seems 
 to be a remarkable vagueness and obscu- 
 rity* in many of his definitions and 
 explanations relative to the words Power, 
 
 * I have given above what appears to me to be 
 Brown's system, as he intended to be understood : 
 but according to different passages, which might be 
 culled, Cause is sometimes a substance, an event, 
 a relation, an invariable antecedent, whilst he 
 likewise uses the word Power, as an object or sub- 
 stance in the concrete, as antecedence in the ab- 
 stract, as a relation, as an event, as the priority 
 of two events. Reid had objected to Hume, that, 
 upon his doctrine of Causation, Day would be the 
 cause of Night, and Night of Day. Brown very 
 needlessly endeavours to assist Hume out of this 
 consequence, while he passes it over as an objection 
 to his own doctrine, to which it appears to me to 
 he much more formidable ; as is likewise the whole 
 class of phenomena, in which the same combined 
 set of causes produce alternating effects, such as 
 Vibrations, &c. for they come directly under his 
 definition. 
 
CAUSATION 1 . 69 
 
 Cause, and Effect. Strange results might 
 be deduced from his doctrines, were 
 we to drive them home, with reference 
 not only to the coexistence of one body 
 with another, but to the continued suc- 
 cessive existence of the same body with 
 itself. And again, Time and Space may 
 be abstractions of the mind : and I am 
 inclined to think that such is the case ; 
 so is Form in the abstract: but the 
 Dynamical and Statical forces, mentioned 
 in the two examples above, are very 
 different from mere antecedence, or any 
 abstraction of the mind : and they are 
 Powers in the concrete and in reality, as 
 well as causes. But, by the doctrine of 
 Brown, who follows Hume in this 
 respect, we are either led to exclude all 
 Power, as a reality, from the universe, 
 or to confound it with cause in general. 
 
 Again, if we wish to know the cause 
 of roughness, either as a Quality or as a 
 Sensation, where are we to look? Like 
 all continued stresses it is a coexisting 
 
70 OBJECT OF PHILOSOPHY. 
 
 cause in time, though it may be preceding 
 in order. It is a formal cause, and all 
 formal causes are excluded from this sys- 
 tem of mere antecedence in time. In 
 truth the definitions are too limited ; and 
 we have no right to restrict the meaning 
 of a common word to any philosophical 
 hypothesis which we may entertain : but 
 we must accommodate our definitions to 
 the common usage of mankind, unless 
 we can refute the notions, upon which 
 that usage proceeds. 
 
 Thus far we have examined in its out- 
 line only the subject of causation. But, 
 in the examples we have produced, there 
 is another subject of examination, in 
 that Bond of connexion, which has been 
 so great a stumbling-block among the 
 moderns. When we come more narrowly 
 to inspect this triplicated chain of Causes, 
 between many of the links there is a 
 joint, if I may so call it : for instance, 
 the aggregate motion of the hammer is, 
 in the bell, converted into atomic mo- 
 

 CAUSATION. 71 
 
 tion. Now this cannot be performed 
 simultaneously, though the manner or 
 law, according to which it is performed, 
 escapes the observation of our senses. 
 If ever the Bell itself was regarded 
 by Philosophers, as it is among the vul- 
 gar, as the proximate cause of sound ; 
 and the intermediate air was unnoticed 
 and unknown, as necessary for the pro- 
 duction of that effect ; the hammer, the 
 bell, and the ear, alone, would have 
 been considered as the coexisting links 
 in the chain of Causation : whilst the 
 air and its vibrations might have been 
 classed among those obscure pheno- 
 mena, which were evidently necessary 
 for the completion of the chain ; but 
 which the researches of science had not 
 then enabled them to ascertain. In most 
 instances these phenomena, which inter- 
 vene as joints between the links of the 
 chain, may be resolved into the same 
 triplicated chain of causes, as the ad- 
 vancement of science every day demon- 
 
/2 OBJECT OF PHILOSOPHY. 
 
 strates ; and nothing mysterious inter- 
 venes. The Latens Processus, or the 
 latent process, which Bacon is so anxious 
 to have investigated, refers to such a 
 chain of intervening actions : and it is 
 often noticed by the ancients, particularly 
 by Plato in the Parmenides and Phaedo ; 
 and was one of the leading doctrines of 
 Leucippus, Democritus, and all the Ato- 
 mists. The Latens Schematismus of 
 Bacon, the latent form or structure, upon 
 which the properties of bodies are sup- 
 posed to depend, refers merely to their 
 qualities, whether formal or derived from 
 Force and Motion : though, perhaps, 
 more accurately, the former should be 
 referred to the Latens Schematismus ; 
 and the latter to the Latens Processus. 
 And as the grosser bodies are said to be 
 incapable of contact, a Latens Materia, 
 a Latens Schematismus, and a Latens 
 Processus, at every joint in the chain, 
 become objects of inquiry. The inquiry 
 into the efficient cause, the matter, the 
 
CAUSATION. 73 
 
 latent process, and the latent structure, 
 constitutes Physics, according to the no- 
 tions of Bacon ; which differs but little 
 from the ancient doctrine. 
 
 But there is a still more curious sub- 
 ject yet remaining, a kind of Latens Pro- 
 cessus, the examination of which will 
 throw light upon a controversy, which 
 has been as keenly agitated, as any, that 
 has ever attracted the attention of Phi- 
 losophers. At some of these joints in 
 the chains a most remarkable phenomenon 
 presents itself, the introduction of an 
 extraordinary external force. If we strike 
 a flint and a steel together, a spark is the 
 result. This spark falls upon a charge 
 of powder. An explosion ensues, in 
 which thousands of such sparks are ge- 
 nerated in a moment; and the motion 
 which had preceded that event, and was 
 conveyed by the spark itself, (if indeed 
 it is at all to be taken into consideration,) 
 after undergoing some modification of a 
 latens processus, is multiplied, in an in- 
 
74 OBJECT OF PHILOSOPHY. 
 
 stant, to perhaps a millionfold. Whence 
 does all this motion come, what is its 
 antecedent, and from and through what 
 is it derived ? If we attempt to reduce 
 it under any of our three laws of motion, 
 each of them is inadequate, and all are 
 equally overthrown. If we suppose that 
 all this motion is generated among the 
 particles of gunpowder by a Latens Pro- 
 cessus, or in other words that the mo- 
 tion, the high prerogative of Mind, is 
 generated or merely increased and multi- 
 plied by the matter itself, such an hypo- 
 thesis is not worth the consideration of 
 a moment. If we say that the fire forms, 
 or compounds, or merely lets loose an 
 elastic fluid ignotum per ignotius we 
 only remove the difficulty a step further : 
 what is the force which makes this fluid 
 elastic ? Elasticity itself and all similar 
 powers are involved in the same consi- 
 deration. If we should assert, with Brown 
 and many modern philosophers, that the 
 spark is the antecedent ; and that the Deity 
 
 
CAUSATION. 75 
 
 has ordained the explosion as the con- 
 sequent, independently of all other secon- 
 dary causes, we fall into the hypothesis 
 of Malebranch, and hold that the spark 
 is but the occasional cause, while the 
 explosion is the immediate production of 
 the Deity himself, the only efficient cause ; 
 or we must take refuge in the extrava- 
 gant hypothesis of the preestablished 
 harmony of Leibnitz : which hypotheses 
 every succeeding philosopher has been 
 at no small trouble to expose. We 
 may set down the spark and the explo- 
 sion as immediate invariable antecedent 
 and consequent, as phenomena like day 
 and night immediately successive and 
 proximately connected in time, for future 
 consideration, if we please : but, if, in so 
 doing, we assign the one as the efficient 
 cause of the other, we assign a cause 
 wholly inadequate to the effect. We do 
 well to confess our ignorance : but if 
 we imagine that inquiry stops with this 
 confession, and sit down, as Lord Bacon 
 
76 OBJECT OF PHILOSOPHY. 
 
 calls it, with the received and inveterate 
 opinion, that the inquisition of man is 
 not competent to find out such matters, 
 we make the most unphilosophical as- 
 sumption of all, and forge a chain, which 
 may for ages bind us in our ignorance. 
 
 The phenomenon itself is one of those 
 unaccountable, yet not uncommon cases, 
 which have led to the distinction between 
 Physical and Efficient causes the spark 
 being the Physical cause, and this un- 
 known intervening something, which 
 forms, as it were, the Bond of Connexion, 
 the Efficient. There is manifestly an 
 extraordinary extrinsic power introduced 
 between the apparent antecedent and its 
 consequent, which affords at least some 
 ground for the distinction between Phy- 
 sical and Efficient causes, unless the 
 Physical be confounded with the Ma- 
 terial. Even the present state of Science 
 gives room to entertain the hope, that all 
 the proximate Efficient causes will sooner 
 or later be resolved into Physical, and 
 
CAUSATION. 77 
 
 that the chain may be completed : yet in 
 the mean time those words are usefully 
 employed to distinguish things so mani- 
 festly distinct. 
 
 It is this notion of an Efficient inter- 
 vening cause, extended by analogy to 
 other cases, in which some ordinary La- 
 tens Processus intervenes, though no in- 
 crease of Power is to be observed, ex- 
 tended again, to every case whatsoever, 
 that I imagine has had no small influence 
 in giving rise to the fiction of an inter- 
 vening Bond of Connexion. It has been 
 attended, also, with a much more mis- 
 chievous effect; and, inasmuch as no 
 Efficient cause has hitherto been disco- 
 covered, and such discovery is deemed 
 impossible, it has led to the assertion, 
 that no Cause whatever has been disco- 
 vered, that the discovery of Causes is 
 impossible, and that Causation is not the 
 proper object of Philosophy. 
 
 In Physics, when we look for Causes, 
 we seek nothing more than the chain of 
 
OBJECT OF PHILOSOPHY, 
 
 motion, or stress, or force, in Time, and 
 the proximate continuity* of being with 
 its qualities in Space : which are no other 
 than the Material, Formal, and Efficient 
 Causes of the ancients. If it should be 
 asked why it is thus to be presumed a 
 priori, that this chain of causes is con- 
 tinued throughout nature, the only answer 
 to it is this, that, in every branch of 
 science, which has been investigated, and 
 is thoroughly understood, such is the 
 case ; it has been ascertained by Induc- 
 tion : and as we can reason only from 
 what we know, we reason by analogy 
 from this known to the unknown, and 
 draw a strong presumption in its favour. 
 It might, perhaps, be at once objected, 
 not only that such poT/ers as Gravity, 
 Repulsions, &c. are at variance, but that 
 
 * The celebrated Law of Continuity, insisted 
 upon by Leibnitz, applies rather to the efficient 
 cause than to the material, i. e. to the continuity of 
 motion rather than of being : the two should be di: 
 tinguished. 
 
 
CAUSATION. 79 
 
 the grosser bodies themselves never come 
 into contact. With respect to this ob- 
 jection I would observe, that all the 
 experiments and observations from which 
 it is deduced, that the grosser bodies 
 never come into contact, particularly the 
 optical experiments, might equally, and, 
 in some instances, almost conclusively, 
 be adduced to prove, that there is some 
 substance intervening. That there is a 
 Latens phenomenon between almost every 
 link in the chain of causation is unques- 
 tionable. But in collisions, and in most 
 of the other phenomena, upon which 
 Boscovich founds his system, there is 
 evidently no introduction of extrinsic 
 force ; because the momenta both before 
 and after the collisions, &c. are equal or 
 the same. There is, therefore, only an 
 ordinary Latens phenomenon to be ex- 
 plained. Before philosophical research 
 had extended itself, the links only in the 
 chain of causation were observed : and 
 from them, when observation was ex- 
 
80 OBJECT OF PHILOSOPHY. 
 
 tended to the joints of the chain, we were 
 directed by analogy to seek the same 
 continuity of being and action, as was 
 observable from link to link. Many 
 cases of these ordinary latent phenomena 
 at the joints have been investigated, and 
 in all of them, which have been explained, 
 that continuity of being and action has 
 been found universally to obtain. Our 
 proper course then is clearly to pursue 
 the investigation upon that analogy. It 
 is no wild or far-fetched hypothesis, but 
 the very first that rises in the ordinary 
 course of investigation : and, as far as we 
 have proceeded, it rests upon an induction 
 coextensive with our knowledge. Whilst 
 conjecture runs furthest afield, truth is 
 often overlooked, because it is seated 
 almost within the homestall. It is, how- 
 ever, readily granted, that this idea of a 
 connected and continuous chain of causa- 
 tion, though it is established by induction 
 as far as our knowledge actually extends, 
 may, nevertheless, as to its universality, 
 
CAUSATION. 81 
 
 be false ; and it cannot be proved other- 
 wise till all science is perfected ; but the 
 burden of finding and demonstrating an 
 exception lies with its opponents, who 
 might thus confute or limit it. Such 
 
 flH^ 
 
 systems, however, as that ^Boscovich, 
 start with hypotheses, far-fetched, and 
 opposed to all the preconceived opinions 
 and prejudices of mankind ; and, but for 
 the prevalence of the idea that prejudices 
 ought to be abandoned, instead of being 
 carefully examined, could never have 
 worked themselves into notice, without 
 the preliminary overthrow and new es- 
 tablishment of almost all the fundamental 
 principles of science. With respect to 
 Gravity, Repulsions, and the like, as I 
 shall speak of them more fully presently, I 
 shall here merely point out that it should 
 be particularly noted, that they are phe- 
 nomena with which we are not thoroughly 
 acquainted ; and with whose causes we 
 are not acquainted at all. We cannot, 
 therefore, legitimately build an hypo- 
 
82 OBJECT OF PHILOSOPHY. 
 
 thesis upon them ; and if we reason from 
 them, we reason from the unknown against 
 the known, a method of proceeding grossly 
 absurd and altogether inadmissible. 
 
 Not only are the causes, which produce 
 any effect, the objects of philosophical 
 research ; but the manner, in which 
 those causes act, is an object of such 
 importance, as almost to have super- 
 seded the inquiry into Causation itself. 
 In modern experimental Philosophy it is 
 often laid down as a maxim, that the 
 laws of nature are the only proper objects 
 of human inquiry : and all investigation 
 of causes is stifled by the dogma, which 
 maintains, that the human faculties 
 are incapable of investigating their na- 
 ture. 
 
 There is scarcely a term in science, so 
 obscure, and so much abused, as this 
 word Law. It is said to be a La\ 
 That the three angles of a triangle ar 
 equal to two right angles That certaii 
 
CAUSATION. LAWS. 83 
 
 substances crystallize in certain forms 
 That all stones gravitate to the earth 
 That gravity varies inversely as the 
 square of the distance. It is a law of 
 the understanding, that we are convinced 
 by demonstration ; and of the affections, 
 that we love our friends. These different 
 applications of the word agree in this, 
 that they are all general propositions; 
 and most of them are general facts. The 
 word law sometimes relates to the Classi- 
 fication of objects in Space, or of events 
 in Time, to the phenomena of Causation, 
 Material, Formal, and Efficient, indis- 
 criminately, and frequently to the Man- 
 ner in which these causes act : the latter 
 of which is, perhaps, its most appro- 
 priate meaning. But the word Law 
 has even a more extended signification, 
 and is not unfrequently substituted for 
 the Cause itself: and among the gene- 
 rality of men, who have thought some- 
 what, but not deeply, upon such matters, 
 this usage of the term, with respect to 
 
84 OBJECT OF PHILOSOPHY. 
 
 the phenomena of gravity, is even the 
 most prevalent of all : and, though never 
 entertained for a moment by those who 
 have paid due attention to the subject, 
 it has become a form of speech, so com- 
 mon, that the most eminent philosophers* 
 occasionally fall into it. 
 
 If it be not advisable, altogether to 
 discard a term, so generally abused, it 
 might advantageously be confined to the 
 manner or rule according to which a 
 Cause acts, or an Object is constructed, 
 whether by immediate or secondary 
 
 * Dr. Young* sometimes uses it in this significa- 
 tion, and Sir J. Herschel has inadvertently fallen 
 into the same manner of speaking; " In the theory 
 of gravitation," says he, in his celehrated Dis- 
 course, " the Law is all in all, applying itself at 
 once to the materials, and directly producing the 
 result." What produces the result ? The Law ? 
 4 The laws of nature/ says Dr. Reid, in his ma- 
 turest work, ' are the rules, according- to which 
 effects are produced : but there must be a cause, 
 which operates according to these rules. The 
 rules of navigation never steered a ship' nor the 
 law of gravity a planet. 
 
CAUSATION. LAWS. 85 
 
 means. Human agents act in a manner 
 capricious and uncertain: but the inva- 
 riable constancy, observable in all the 
 works of the Creator, enables us to look 
 forward with certainty to the result : and 
 th$ manner according to which it is per- 
 formed is so determinately appointed, 
 and as it were preordained, that we may 
 not improperly denominate it a LAW. 
 
 Natural Philosophy, then, relates to 
 the Material Substances which compose 
 the universe : which Substances are 
 known to us only by their Qualities as 
 they coexist in Space, or their Forces, 
 actions, motions, or accidents, as they 
 operate in Time. Of these two great 
 branches, Natural History is the mere 
 classification, into genera and species, and 
 description. Causation equally relates to 
 both, and is the investigation of the 
 nature and continuity of the Material, 
 Formal, and Efficient Causes, the Chain 
 of Being existing in Space, and the Chain 
 
86 OBJECT OF PHILOSOPHY. 
 
 of Action successive in Time, together 
 with the manner or Laws, according to 
 which the Individuals are constructed, 
 or Forces propagated ; and this not only 
 in the Links, but in the Joints. If the 
 investigation were completed through 
 the connected links only, we should, in a 
 manner, have perfected the grand out- 
 line of science ; though the more deli- 
 cate parts, the latent substances, and 
 forms or qualities, and the latent pro- 
 cesses at the joints should for ever be 
 concealed. But, above all things, our 
 attention is to be directed to that mighty 
 introduction of Efficient Power, which 
 forms the Bond of Connexion between 
 so many of the phenomena commonly 
 occurring in the universe. " As to the 
 possibility," says Lord Bacon, upon this 
 very subject, " they are ill discoverers, 
 who think there is no land, where they 
 can see nothing but sea." Let the 
 opinion but once be afloat, that such 
 things are not beyond us, and every 
 
CAUSATION. LAWS. 87 
 
 hypothesis, that is started, examined, 
 and rejected, will give us a further in- 
 sight into the subject, or, at least, con- 
 tract the circle of conjecture : and we 
 might stand a chance of being delivered 
 from that stagnation in this branch of 
 science, which has involved the philo- 
 sophical world almost ever since the 
 time of Newton. For notwithstanding 
 the vast strides, that Speculative Science 
 has made in astronomy, deduced to a 
 degree of accuracy and approximation to 
 the truth, heretofore inconceivable, which 
 however, in its sublimest theorems, are but 
 deductions and links in the descending 
 chain and calculations of effects ; not- 
 withstanding the mighty applications of 
 science in the Operative division of philo- 
 sophy ; and notwithstanding the great 
 disconnected discoveries, and the mass 
 of facts, which, from time to time, expe- 
 rimentalists have brought to light, rather 
 as it were by chance, than by any well 
 chosen system of investigation ; it is not 
 
88 OBJECT OF PHILOSOPHY. 
 
 to be concealed, that in the ascending 
 scale of Causation, we have scarcely ad- 
 vanced one single step for upwards of a 
 century ; though every ascent therein 
 must necessarily open to the world pros- 
 pects, more wide and brilliant than even 
 the discoveries of Newton. And it is 
 here that we must look for the next great 
 step in the advancement of science. 
 
 From what has been said, it is evident 
 of what vast importance are Natural his- 
 tory and Classification to philosophical 
 pursuits. And of all the numerous 
 systems of Classification, which the innu- 
 merable Resemblances of objects present, 
 it is equally evident, that that system 
 must be the most advantageous, which 
 is rendered subservient to the investiga- 
 tion of Causes. How admirably, for 
 instance, are the classification and no- 
 menclature of Chemistry, describing the 
 component parts, &c. adapted to such a 
 purpose ! and how lamentably deficient 
 
OBJECT OF PHILOSOPHY. 89 
 
 is the Linnaean system of Botany ! If 
 we proposed to ascertain the causes of 
 the properties of a plant, what possible 
 assistance could be derived from the in- 
 formation that its Class and Order are the 
 Hexandria Monogynia?* And perhaps 
 we may regard it rather as a fortunate cir- 
 cumstance, than otherwise, that none of 
 the systems of Mineralogy have hitherto 
 obtained a universal ascendency. In 
 Natural History the great instrument of 
 Classification is Resemblance : but it is 
 not always that we are able at once to 
 determine upon which, of the vast variety 
 of similarities presented to us, an appro- 
 priate Classification may be formed. 
 And, as many of the most important 
 resemblances are intimately connected 
 
 * It is true that great service is rendered by any 
 classification if generally adopted. If Hippocrates 
 or Pliny had described their plants, medicines, &c. 
 in the Linnsean system of Botany, it would have 
 been of essential service. But in all systems of 
 Natural history this ought to be but a very secon- 
 dary consideration. 
 
90 OBJECT OF PHILOSOPHY. 
 
 with causation, a considerable advance 
 must be made in that science, before we 
 can ascertain whether our classifications 
 are either useful or correct. We may 
 class the Elements into Earth, Air, Fire, 
 and Water. Such a classification will 
 afford certain analogies or hypotheses, 
 and assist us, to a certain extent, in our 
 researches into causation. As soon, 
 however, as we shall have pushed that 
 science a little farther, we find it neces- 
 sary to correct the classification which 
 we had adopted : for we are as apt to err 
 in our classifications, as we are in our 
 analogical reasoning upon causation. 
 The two sciences are intimately con- 
 nected, and have a mutual tendency to 
 correct each other's errors. 
 
 The preceding observations will throw 
 some further light upon the Method of 
 proceeding. If we would literally pur- 
 sue Bacon's method, hunt for facts, clas- 
 sify them in tables according to his direc- 
 tions, and dismiss all prejudice and hypo- 
 
OBJECT OF PHILOSOPHY. 91 
 
 theses, such a method is not in our 
 power. Not only will hypotheses sug- 
 gest themselves, which we cannot get 
 rid of if we would ; for we feel an irre- 
 sistible desire at every step to bring 
 them to the test ; but our discoveries in 
 Causation will be continually disturbing 
 our arrangements in Natural history. 
 If however the tables were already con- 
 structed and perfect, if we had Natural 
 History at our command, we could no 
 more proceed in the investigation of 
 Causes without Analogy and Hypo- 
 thesis, than we could arrange and clas- 
 sify without Resemblance. 
 
 Having thus endeavoured to inves- 
 tigate the Method and Objects of Philo- 
 sophy, to compare the ancient with the 
 modern systems, and to glean from the 
 former what appears to be of indispen- 
 sable service to the prosecution of the 
 pursuit, let us now turn to the Result. 
 
 That Matter or Substance, by which 
 
92 RESULT. 
 
 Qualities are supported, exists, is an 
 article of belief the earliest acquired, and 
 the most universal among mankind : 
 though its existence can only be inferred 
 from the qualities which it upholds. 
 And it is by the chemical resolution of 
 compound substances into more simple 
 substances, and by the establishment of 
 the Atomic Theory that this branch of 
 science has of late years made its greatest 
 advancement. 
 
 Three out of the four elements of the 
 ancients have been resolved into more 
 simple substances ; and, as might natu- 
 rally be expected at first, the progress of 
 science has multiplied, instead of dimi- 
 nishing, the acknowledged number of 
 undecompounded substances. Its further 
 progress, and the more severe analyses, 
 that are applied, sometimes increase, but 
 have a natural tendency to diminish that 
 number. And it is the business of Phi- 
 losophy, as far as it regards Matter, to 
 ascertain how many, and what these 
 
MATTER. 93 
 
 simple substances may be, of which it is 
 composed ; and whether it consists of 
 ultimate atoms, indivisible impenetrable 
 particles ; or whether it is infinitely di- 
 visible. It is often supposed that among 
 the ancients, the Epicurean school alone 
 maintained the existence of atoms : but 
 the Pythagoreans and Plato maintained 
 it likewise, though not such a wilful de- 
 mocracy of Atoms as that of Epicurus : 
 nor am I aware that any of the ancients, 
 previously to Aristotle, held the infinite 
 divisibility of matter. Neither of these 
 opinions, perhaps, can be brought to the 
 test of experiment ; we can rest only in 
 analogy ; but I think the accuracy of the 
 results and calculations upon the Atomic 
 theory, plainly induces us to prefer the 
 atomic opinion, upon the same grounds 
 that our faith in the law of gravitation 
 is strengthened, by the accuracy with 
 which the planetary movements coincide 
 with their calculated courses, that is, it 
 rests upon analogy confirmed by obser- 
 
94 MATTER. 
 
 vation. The inference also, in favour of 
 atoms, drawn by analogy from a sub- 
 stance, always dividing and compounding 
 at the same angle, is far superior to an 
 argument resting upon the infinite divi- 
 sibility of a mathematical line : inas- 
 much as it is suggested by a fair analogy 
 from one physical phenomenon to ano- 
 ther : whereas the latter is only a mathe- 
 matical illustration of a physical possi- 
 bility : they are not at all of the same 
 kind ; the subject under consideration is 
 purely material, the illustration purely 
 ideal. The same may be said of Euler's 
 ingenious argument, " All matter is en- 
 dued with extension. It therefore pos- 
 sesses all the qualities of extension ; one 
 of which is infinite divisibility." For it 
 does not follow, because all matter is en- 
 dued with extension in the concrete, that 
 it has all the properties of extension 
 in the abstract ; only that it might have 
 had, if it had pleased God to make it so. 
 We can never expect to ascertain what 
 
QUALITIES OF MATTER. 95 
 
 matter itself is, or in what manner it 
 subsists. If we should ever succeed 
 in determining the number of the simple 
 substances ; and, if they are composed 
 of atoms, the forms with which those 
 atoms are invested, we shall then have 
 completed all that is within our reach. 
 And if all the qualities of bodies, inde- 
 pendent of force and motion, shall be 
 resolved into the mere form and hard- 
 ness of these component atoms, what the 
 substances themselves may be, it would 
 be absurd to inquire : but we might fear- 
 lessly conclude that the same substance 
 ran throughout the whole. 
 
 Almost all the Qualities of Matter 
 were resolved by the ancients into its 
 Form : and by the union of Form with 
 Matter the Sensible world was supposed 
 to be produced. As I would bring for- 
 ward those parts only of the ancient phi- 
 losophy, which may be turned to account, 
 I omit mention of their ingenious meta- 
 
96 QUALITIES O! MATTKK. 
 
 physical speculations upon the nature of 
 Form and Matter, Bound and the Bound- 
 less ; and shall merely observe that the 
 system would naturally tend to resolve all 
 the qualities of Matter into the primary 
 ones of its extension or Form, and the 
 absolute hardness or Impenetrability of 
 its component parts. 
 
 Besides the obvious formal qualities 
 of matter, there are certain other secon- 
 dary qualities, which may be termed 
 supposititious, conventional, or occult,* 
 inasmuch as the words Elasticity Co- 
 lour, Inertia, Gravity, and many others, 
 
 * I use the word supposititious, which implies 
 spurious, as well as hypothetical, in preference to 
 occult, not only to avoid oftence, but in better keep- 
 ing- with what I have written upon theory and hy- 
 pothesis. The word secondary, has been used : 
 but it neither expresses the meaning intended to IK* 
 conveyed, nor includes under it all the qualities 
 which it ought. The word occult, as well known, 
 would perhaps be better, but it has been sadly 
 abused. The occult qualities, however, of Aris- 
 totle are not the nonsense usually fathered upon 
 him. He uses the words (iravity, tor instance 
 
 
QUALITIES OF MATTER. 97 
 
 are words conventionally assumed to 
 express certain phenomena themselves, 
 or the unknown causes of such phe- 
 nomena, which have been traced no 
 higher, but which still remain deside- 
 rata, to which the attention of science 
 should be directed. They may perhaps 
 be resolved into some immediate formal 
 cause, or into several intermediate links 
 in the chain of efficient causes, or latent 
 processes. JBut it should never be for- 
 gotten, for a moment, that these words, 
 expressive of what are called the qua- 
 
 and Levity, precisely as we do ourselves in re- 
 ference to heavy and what we call imponderable 
 bodies, expressly however denying them to be 
 occult qualities or virtues ; and endeavours to seek 
 the causes not only of these, but of the properties 
 of the Loadstone, and of the Inertia of Projectiles : 
 and, however nugatory his attempt, it is evident 
 from the attempt itself, that he never dreamt of 
 advocating such doctrines as have been imputed to 
 him. Again, with respect to the abhorrence of a 
 Vacuum, I verily believe there is not one . syllable 
 upon the subject throughout his works. See VIII. 
 Phys. 4. 10^-111. De Crelo 2 IV. Met. 14. 
 
 H 
 
98 QUALITIES OF MATTER. 
 
 lities and properties of matter, in them- 
 selves, convey no explanations, but are 
 merely assumed, conventionally, from 
 the necessity, which our ignorance im- 
 poses upon us, to use some stated general 
 terms as names for the unknown causes 
 of certain classes of phenomena, the indi- 
 vidual phenomena of which classes, how- 
 ever they may differ among themselves 
 in some respects, have nevertheless cer- 
 tain similarities, which obviously point 
 them out as the effects of one and the 
 same kind of cause. If we mean any 
 thing further by the words, we wilfully 
 deceive ourselves. If we really imagine 
 that bodies are attracted by Attraction, we 
 should be equally justified in accounting 
 for their lightness by Levity, for their 
 cohering by Cohesion or Suction, for 
 their parting from one another by Par- 
 tition, or by any barbarous term it might 
 be our good pleasure to coin : for nothing 
 is easier than to convert the verb, ex- 
 pressive of the effect, into a corresponding 
 
QUALITIES OF MATTER. 99 
 
 substantive. The words are nevertheless 
 extremely convenient, and are not lightly 
 to be rejected, but must be gradually laid 
 aside as the real causes are ascertained : 
 thus we have laid aside the term Levity 
 as a supposititious Cause, having at 
 length revolved the phenomena of light- 
 ness into those of Gravity, confirming 
 the hypothesis of Timaeus. In like 
 manner, the word Suction has almost 
 been forgotten, by the resolution of the 
 phenomena of the pump into the weight 
 of the incumbent air. Sir Isaac New- 
 ton attempted to resolve the Elasticity of 
 light, as far as it concerned reflection, 
 into a latent process, the attractions of a 
 fluid upon the surfaces of bodies : and 
 if he had succeeded, the word Elasticity 
 would, long ere this, have been lost to 
 us as a supposititious cause. 
 
 With respect to the Qualities of mat- 
 ter, we are led, by all the Analogies of 
 nature, to suppose that they may be re- 
 solved either into formal causes, or into 
 
100 QUALITIES OF MATTER. 
 
 phenomena depending upon motion : 
 and it must be our grand object to as- 
 certain the real causes corresponding to 
 the words we use to express them ; and 
 gradually to expel those phrases, with 
 which philosophy is overrun. I must, 
 however, defer the further examination of 
 them till I speak of the Efficient causes, 
 to which they more properly belong. 
 
 In the phenomenon of COLOUR, which 
 comes more properly under this division, 
 the Metaphysical distinction drawn be- 
 tween the Sensation and Perception by 
 the Mind and the Quality of the body, 
 which was the cause of that perception, 
 between the redness, with which the 
 senses are affected, and the supposititious 
 quality of the body, which so operates 
 upon light as to produce that sensation and 
 perception, cleared away several strange 
 incumbrances. But the grand discovery 
 that redness or any other colour may be 
 communicated to bodies by the mere 
 
COLOUR. 101 
 
 alteration of their superficial textn-'k, h&s" 
 gone far to resolve the colouring qua- 
 lity into the texture or form of the super- 
 ficies, and to merge the supposititious or 
 conventional quality into a formal cause, 
 one of the primary qualities of matter. 
 From the perception of colours we may 
 trace the chain of antecedent causes of 
 Matter and Form through the optic nerve, 
 through the eye, to the light, to the co- 
 loured body, and again to the light. And 
 we may trace also the descending chain 
 of action or motion from the general un- 
 modified motions of the light, as first 
 admitted into a chamber, before it strikes 
 upon the body, its alteration at the body, 
 every point of which becomes a centre 
 from which a sphere of motion is propa- 
 gated, of such a nature, as, when passed 
 through the eye and optic nerve, to pro- 
 duce that sensation, which is followed 
 by the perception of colour. 
 
 In England, till within the last few 
 
102 LIGHT. 
 
 s; the Newtonian hypothesis of LIGHT 
 has had a very general ascendency ; but 
 at present that of Huygens bids fair en- 
 tirely to supplant it. From the similarity 
 which obtains in nature between one 
 fluid and another, I would venture to 
 suggest, that these two hypotheses may 
 not be altogether and fundamentally op- 
 posed, but are capable of being recon- 
 ciled, at least in part ; and that light has 
 not only a progressive, but a vibratory 
 motion also ; that to its progressive mo- 
 tion are to be attributed the phenomena 
 of brightness, illumination, shadow, and 
 some instances of inflection, reflection, 
 and polarity; and that upon its vibra- 
 tions depend the phenomena of colour, 
 sight, and all the rest; and that the 
 vibratory motion, requisite for the pro- 
 duction of Vision, is caused by the pro- 
 gressive, reflected, and impeded motion 
 of the sunbeams, by a change from the 
 aggregate progressive motion of the rays 
 into the atomic vibrations of the fluid. 
 
LIGHT. 103 
 
 Such an hypothesis is suggested by the 
 analogies of air and water, in their pro- 
 gressive motions of wind and streams, 
 and in their vibratory motions of sound 
 and waves. It is a fair hypothesis, which, 
 if it be confuted when brought to the 
 test of experiment by Induction, may 
 afford some results, upon which something 
 more plausible may be offered. 
 
 If we cast a stone into a pool of water, 
 waves proceed from the point of the sub- 
 mersion of the stone on every side, form- 
 ing a number of concentric and expanding 
 circles. As these circular undulations 
 reach the sides of the pool, or if they 
 meet with any stakes set up in the pool, 
 they are rebounded : and the front of 
 each stake or object becomes the centre 
 of another set of concentric waves, which 
 cross and pass over one another in every 
 direction, with little or no interruption. 
 And if the agitation of the pool be great, 
 so as to be well rebutted from its sides, 
 concentric circles will be completely 
 
104 LIGHT. 
 
 formed round every stake. If a stream 
 of water be projected through or into the 
 pool, and interrupted in any manner, so 
 as to cause a vibration of the water, the 
 same result may be observed. But it 
 must likewise be remarked that in the 
 production of such effects, the primary 
 momentum, causing the agitation of the 
 pool, either by the stone, or by the in- 
 jected stream, must necessarily be greater 
 or at least equal to the sum of the mo- 
 menta of all the separate concentric 
 waves. 
 
 If a bell be struck by a hammer, or, 
 in any manner, be put into agitation suf- 
 ficient to cause similar undulations in 
 the air, similar concentric waves are 
 formed, which, when received upon the 
 ear, affect us with the sensation of sound. 
 If a blast of wind rush violently through 
 any place, in which different bodies are 
 contained, it causes an agitation of the 
 air ; and certain objects, peculiarly sus- 
 ceptible, are affected and emit sounds, 
 
LIGHT. 105 
 
 becoming centres of vibration ; but all 
 the rest are silent. And their silence is 
 a matter of course, because the most 
 violent hurricane, that blows, travels at 
 little more than one-tenth of the velocity 
 of sound : and nothing, that can be op- 
 posed to it, is capable of converting its 
 aggregate into atomic motion. If this 
 could be done, and a shock could be 
 communicated to the air, so intense as to 
 be capable of affecting the particles of 
 the bell, in the same degree as it is 
 affected by a stroke from the hammer, 
 there can be little question, that not only 
 the bell, but even the dullest rocks, under 
 similar circumstances, would ring, and 
 become centres of sonorous undulations, 
 as is partially to be observed under a 
 discharge of artillery, and in an .echo. 
 It is even possible that, like some musical 
 pillars, they do so, as it is ; for notes so 
 base and deep, as they would necessarily 
 produce, probably could not be appre- 
 hended by our faculty of hearing. 
 
106 LIGHT. 
 
 Having marked the vibratory and pro- 
 gressive properties in water, a gross and 
 inelastic fluid, and again in greater per- 
 fection in the air, we might with much 
 reason argue, that in such an elastic and 
 subtile fluid as light, both the vibratory 
 and progressive motions might a fortiori 
 be expected. 
 
 Ten years ago I commenced a series 
 of experiments in examination of this 
 hypothesis, which were interrupted by 
 occupations of a very different nature. 
 Since that time a complete revolution 
 has taken place in this branch of science. 
 But in the splendid discoveries, which 
 indefatigable research has brought to 
 light, I have seen no reason to think it 
 open to refutation. And in the substi- 
 tution of an entire Hypothesis of Huy- 
 gens for that of Newton, I think we are 
 pursuing the course, so common, and in- 
 deed so natural in the overthrow of every 
 prejudice, of running into the opposite 
 extreme, and rejecting the truths of the 
 
LIGHT. 107 
 
 Newtonian hypothesis with its errors, 
 and pushing the rival system further than 
 is warranted by the facts. I put it forth, 
 however, now, merely as an hypothesis 
 for examination, and shall forbear, in a 
 treatise like the present upon the mere 
 theory and not upon the detail of science, 
 to enter into any experimental inquiries, 
 further than is necessary to obviate a 
 few of the following objections, which, 
 by the partizans of either of the rival 
 systems, have been deemed insuperable 
 to the other. And I abstain the more 
 readily, because, when an hypothesis is 
 proposed on such a subject as this, in 
 which there is such an ample collection 
 of facts, a hostile hand is more capable 
 of detecting its defects. 
 
 Upon the hypothesis that light is a 
 projectile only, it is maintained, that it 
 ought always to have momentum : but, 
 in the phenomena of colour, this is not 
 found to be the case. Upon the hypo- 
 thesis that light is but a vibratory mo- 
 
108 LIGHT. 
 
 tion, it ought to have no perceptible mo- 
 mentum in any case whatever : but when 
 a sunbeam impinges upon any object, 
 it has momentum, and causes an atomic 
 motion in the form of heat, sensible to 
 the hand, and intolerable to the eye : 
 and if the aggregate motion of the sun- 
 beam is not the antecedent in the chain 
 of action, being converted into this atomic 
 motion, whence does this atomic motion 
 come? The perceptible momentum of 
 light in a sunbeam is a serious objection 
 to the hypothesis of Huygens ; the want 
 of it in the phenomena of colour, is an 
 objection to that of Newton. In the 
 hypothesis, which I have advanced, both 
 these objections vanish : since, in ana- 
 logy to the air, it has momentum, when 
 projected like the wind : and in its vi- 
 bratory movements, analogous to the 
 sonorous undulations, none can be per- 
 ceived. 
 
 Again the very common objection, 
 that, upon any vibratory hypothesis, our 
 
LIGHT. 109 
 
 vision ought to extend round corners, has 
 no force in it whatever, if properly consi- 
 dered. 
 
 All that we see of any object is its colour 
 and not its form. 
 
 It is quite an acquired perception, and 
 merely a matter of experience, that we 
 are able to refer either colour or form to 
 the object we perceive. 
 The visible appearance of every object is 
 so different from its tangible form, that it 
 is likewise by experience alone, that we 
 are capable of judging of the form of 
 any object whatsoever. 
 Bearing in mind these three prelimi- 
 nary observations, which are well estab- 
 lished facts,* let us examine the proposed 
 objection. 
 
 If a single sound be propagated from 
 any sonorous object, we are sensible of 
 it, though we should hear it behind a 
 corner. In like manner, if any single 
 
 * See Berkeley, Reid, and, in short, every meta- 
 physical treatise upon the senses. 
 
110 LIGHT. 
 
 colour, such as the glare of a red brick 
 wall, of snow, or the greenness of a forest 
 were presented alone behind a corner, we 
 ought according to the analogy to per- 
 ceive the tint, which ought to be con- 
 veyed into the room, provided the fluid 
 light were in a state of very intense agi- 
 tation, as is the air when a bell is struck. 
 Again, as the ear receives successive 
 sounds, and thus we are enabled to com- 
 prehend the syllables which compose a 
 sentence ; so the analogy requires, that, 
 if objects, glaringly coloured, were suc- 
 cessively presented behind a corner, we 
 ought to be able to enumerate the suc- 
 cessive colours, as the red, the white, 
 the green.* And this, from many ob- 
 servations, I have great reason to believe 
 is actually the case, though I should be 
 
 * N.B. We must not confound such coloured 
 objects with luminous bodies emitting coloured ray 
 such as blue or red flames, from which the light 
 may be propagated progressively, as well as in vi- 
 bration. 
 
LIGHT. 1 1 1 
 
 cautious in positively asserting it, without 
 many more experiments than I have yet 
 been able to direct to that subject : for 
 the total exclusion of reflected rays is so 
 difficult, and the overwhelming influence 
 of any coloured object upon the field of 
 vision is so intense, as to render these 
 experiments extremely inconclusive, from 
 the great delicacy they require. 
 
 From the case of sounds and colours, 
 propagated singly or in succession only, 
 let us proceed to that, in which many 
 are propagated at the same time. When 
 several sounds are propagated at once, 
 if we should endeavour to attend to them 
 all together, we quickly find it to be im- 
 possible : and it is only by directing at- 
 tention to each successively, that we are 
 able to comprehend them. Where two 
 or more sounds are in unison, and even 
 when they are only in concord, we receive 
 them together but as one single complex 
 harmonious tone : if they are not in con- 
 cord, we receive them alternately as the 
 
112 LIGHT. 
 
 successive gratings and jarring of a dis- 
 cord. The analogy then requires us to 
 receive the colours, propagated from 
 several objects, (where those objects are 
 not in the direct line of the eye, but their 
 colours are propagated round a corner 
 indiscriminately,) either as a single com- 
 plex colour, or in succession only. 
 
 Again, not only can we comprehend 
 the successive sounds which compose a 
 sentence uttered behind a corner; but 
 by experience we can form an estimate 
 of their distance from the ear, if we are 
 acquainted with the voice. In like man- 
 ner we might expect, by experience and 
 attention, not only to be able to enume- 
 rate the separate colours, if successively 
 presented, but, given their brilliancy, w r e 
 might form some estimate of their dis- 
 tance. 
 
 These are all the points of similarity, 
 that the analogy between sounds and 
 colours presents, relative to the subject 
 in hand. In all analogical cases, how- 
 
LIGHT. 113 
 
 ever, we must not only look to the re- 
 semblances, but to the differences, which 
 appear between the phenomena, that are 
 compared. Now there is one great dif- 
 ference between sounds and colours, in 
 that, the former are, for the most part, of 
 short duration and adapted more parti- 
 cularly to succession : whereas the latter 
 are generally permanent, every point of 
 every object shedding without intermis- 
 sion its own peculiar sphere of colour. 
 There is likewise a great difference be- 
 tween the articulation of a sentence, and 
 the perception of the distinct parts of 
 any object of vision ; which two are often 
 supposed to bear some kind of resem- 
 blance to one another. The ear could 
 never comprehend a sentence, whose 
 every syllable was pronounced at once ; 
 and the eye is enabled to perform an office 
 analogous to such comprehension, that 
 is to say, of presenting us simultaneously 
 with the different points of the object, 
 only by its telescopic construction in the 
 I 
 
114 LIGHT. 
 
 peculiar formation of its retina and lenses. 
 The great difference, then, is, that by the 
 ear we comprehend sounds only in suc- 
 cession, by the eye we simultaneously 
 perceive the different coexisting points 
 upon the field of vision. 
 
 To enable us to see an object, it is 
 requisite that, an image of that object 
 should be formed upon the retina. The 
 principal circumstances, upon which the 
 formation of such an image depends, are 
 the distance of the object from the retina, 
 the preservation of the proper divergency 
 of the coloured rays emanating from the 
 different points of the object, and the 
 perception of the real situation of the 
 object itself, and of the relative situation, 
 which every point bears to every other 
 point of the same object. 
 
 With respect to the distance, if one 
 single colour alone were transmitted 
 round the corner, or a mere succession of 
 colours, then, as I observed before, the 
 analogy of sounds gives us reason to ex- 
 
LIGHT. 115 
 
 pect, that if we were acquainted with 
 their brilliancy, we might form some 
 vague estimate of their distance, and 
 nothing more. But any thing so vague 
 as this is evidently not sufficient for the 
 formation of an image. 
 
 Again, with respect to the preserva- 
 tion of the divergency of the rays, which 
 is the grand requisite for the formation 
 of an image upon the retina, it is mani- 
 fest, that when each propagated sphere 
 of coloured rays is modified by passing 
 round a corner, the proper divergency 
 must be entirely lost : or if any thing by 
 way of an image could be formed by 
 rays propagated in such a manner, it is 
 clear, from the mathematical principles 
 of optics, that every point of that image 
 must be referred to the corner itself, and 
 not to any object that is behind it. And 
 this must necessarily be the case, unless 
 the divergency of the rays from every 
 point of the object be preserved, by being 
 reflected or refracted by a mirror or some 
 
116 LIGHT. 
 
 similar contrivance, which may present 
 to us a virtual image in the direct line 
 or axis of vision. 
 
 Supposing, however, for a moment, 
 that the divergency were preserved in 
 the vibration so as to form an image of 
 a point upon the retina, still no image of 
 an object could be formed, unless the 
 relative situation of all the points of the 
 object to one another, and the real situ- 
 ation of the object itself could be pre- 
 served and ascertained. Now the analogy 
 of sound gives us no reason to expect 
 any thing of the kind, but directly the 
 reverse. For though we may form some 
 vague estimate of the distance of a sono- 
 rous body, which is out of sight ; we 
 are utterly unable, by merely attending 
 to its sound, to determine whereabouts 
 it is : and if we attempt to guess at 
 the precise point, having no previous 
 knowledge of the circumstances in which 
 it is situated, we are invariably deceived. 
 
LIGHT. 117 
 
 The analogy, therefore, does not teach 
 us to expect to determine the situation 
 of any single point : much less, then, 
 can we expect to ascertain the places, 
 either real or relative of all the innume- 
 rable points which compose the object. 
 If we heard two bells tinkling behind a 
 corner, we should be as likely to judge 
 them close to one another as to be two or 
 three yards asunder : and what reason 
 we can have to suppose, that the relative 
 situation of the different points of vision 
 could be more accurately conveyed, I 
 cannot conceive ; certainly no analogical 
 reason. 
 
 In addition to all this, we must recol- 
 lect, that the image upon the retina is no 
 real picture of the object, but only, as it 
 were, a transcript of its visible form, and 
 that the perception of the object itself is 
 only a judgment of what is its tangible 
 or real form and situation, and an infe- 
 rence of experience only, from our sensa- 
 
118 LIGHT. 
 
 tion of the image upon the retina ; which 
 image is only, as it were, the sign by 
 which we judge. 
 
 But let us suppose that an image could 
 really be formed upon the retina by rays 
 vibrating round a corner, and that thereby 
 we actually perceived the object. Where 
 would the object appear to be situated ? 
 Evidently it must appear in the axis of 
 vision, that is, in the straight line drawn 
 from the eye to the corner and produced : 
 and in the very same axis every object 
 behind the corner, and in the same plane, 
 must also appear : so that we should 
 have every object whatsoever behind the 
 corner apparent, as it were, upon the 
 same meridian, together with all the ob- 
 jects which might happen really and 
 actually to be situated upon it : but for 
 all this the analogy of sound does not 
 afford the slightest pretext. 
 
 It is perfectly clear, then, that the 
 expectation of seeing objects round 
 corners, upon any vibratory hypothesis 
 
LIGHT. 119 
 
 whatever, arises from inattention to the 
 subject. Upon the hypothesis of Huy- 
 gens, it is not to be expected that an 
 image should be formed, or an object 
 seen, in such circumstances ; but only 
 that rays of light as well as colours 
 should expand themselves in every way. 
 Upon the hypothesis, which I have pro- 
 posed, colours alone, and not the rays of 
 light, should be expanded ; and this only 
 when they are presented in succession 
 and never several at a time ; and not 
 even could this take place unless the 
 agitation of the fluid were intense. 
 
 As an objection, therefore, it is com- 
 pletely a mistake of the question. I have 
 been more particular and I am afraid te- 
 diously minute upon this point, because 
 the objection has been considered so ex- 
 tremely formidable, and I do not recol- 
 lect ever to have met with a proper refu- 
 tation of it. 
 
 But, however futile such an objection 
 may be, when directed against the phe- 
 
120 LIGHT. 
 
 nomena of colours, and objects of vi- 
 sion ; it assumes a very different aspect, 
 when directed against the supposition, 
 that a sunbeam is propagated by vibra- 
 tion only : for the propagation of light or 
 brightness itself round corners, is a very 
 different thing from the transmission of 
 images or forms. If a sunbeam passes 
 into a chamber, through an aperture ; 
 with certain allowances to be made, 
 easily accounted for, on the principles 
 of refraction, inflection,* &c. it never 
 deviates from its course, it never expands 
 itself in a glare of brightness or of co- 
 lour, as if it were a mere vibration, it 
 forms no concentric spheres or circles 
 round the aperture, but passes in a 
 straight line, direct, as far as it is per- 
 mitted, like a current of wind or water. 
 And it is apprehended, that, could the 
 
 * Under which allowances may perhaps be 
 classed the phenomena, which appear, when the 
 apertures are very small. See Dr. Young's ob- 
 servations upon that subject. 
 
LIGHT, 121 
 
 experiment be accurately tried by the 
 exclusion of the motes, which float in it* 
 and break and reflect the ray, and of the 
 cross beams from the aperture, it would 
 pass through an opening on the oppo- 
 site side of the room, and leave the room 
 itself in darkness as complete, as are the 
 parts behind a planet, over whose edges 
 the light is poured in a continued stream. 
 It is an experiment, that in the heavens 
 is tried on the largest scale : and a sha- 
 dow is extended from one planet to ano- 
 ther, without the appearance of any 
 vibration of the sort. It is likewise 
 apprehended that no objects, which are 
 not in themselves luminous, ever become 
 visible, unless the rays of light intro- 
 duced be broken and dispersed through- 
 out the chamber, so that their aggregate 
 motion is converted into atomic, and 
 
 * Nam jubar soils in cubiculo tenebroso non cer- 
 nitur, nisi quatenus lux reflectitur e pulverum et 
 fumorum particulis per aerem semper volitantibus. 
 Newt. Princ. 509. Edit. 1726. 
 
 ! 
 
122 LIGHT. 
 
 causes a general and intense vibration of 
 the fluid. 
 
 The objection that if a sunbeam or a 
 ray of light is a vibration, there could 
 be neither shadow nor darkness, I think, 
 remains in full force against the vibratory 
 system of Huygens. Upon the hypothe- 
 sis I have proposed, both of projection 
 and vibration, it is evidently harmless : 
 for, if applied to air, it would insist, that, 
 because sound is propagated by the 
 vibration of the air, a person could not 
 stand out of the wind by placing him- 
 self under the lea of some sheltering 
 object. 
 
 A ray of light appears to me to follow 
 the laws of other fluids. It acts and is 
 acted upon by mechanical causes in the 
 same manner as a stream of wind or 
 water ; and is subject also to similar me 
 chanical operations in a vibratory capa- 
 city. In some instances, as in the phe 
 nomena of prismatic colours, it seems 
 combine the two notions at once, analc 
 
LIGHT. 123 
 
 gously to the vibratory blast which 
 issues through a trumpet. And in- 
 deed it is highly probable, that, on its 
 progressive motion a vibration is uni- 
 versally attendant. And upon this 
 hypothesis perhaps some of the curious 
 phenomena of polarity would meet with 
 an easy solution. 
 
 We see object's for the most part by 
 means of colour, and therefore, as I 
 think, by means of the vibratory motion 
 of the fluid. But it by no means fol- 
 lows that we should not also distin- 
 guish them by means of the projected 
 rays. Our perception of the form and 
 superficies of an object, as I observed 
 before, is a mere matter of experience, 
 and a judgment from the visible form 
 impressed upon the retina. When we 
 perceive an object by its colour, we draw 
 our judgment of its tangible form, not 
 always from the colours only, but from 
 the variety of lights and shades apparent 
 upon its surface : and we may form a 
 
124 LIGHT. 
 
 similar judgment when the lights and 
 shades are exhibited in splendor instead 
 of colour, though we cannot perhaps so 
 well examine its minutiae. Thus, in 
 any luminous body, or in a body from 
 which Splendor is reflected, by its bril- 
 liancy in one part, its deficiency in ano- 
 ther, and its total absence from a third, 
 or around its external edge we may form 
 a judgment of the inequalities of its sur- 
 face and of its figure, as in the case of 
 the sun and moon. The phenomena of 
 Splendor and of Lights and Shades have 
 not been properly attended to : and a 
 thorough examination of the subject is a 
 desideratum in philosophy. If we would 
 paint the lights upon the prominent parts 
 of the human face, or upon any metallic 
 utensil, or other object whatsoever, we 
 should paint them, not with a thicker 
 coat of colouring laid upon the part, 
 but with a different and a whiter tint. 
 Is this to be esteemed a more intense 
 vibration, or is it splendor ? Inasmuch 
 
LIGHT. 125 
 
 
 
 as the position of the illuminated spot 
 varies with every variation of the posi- 
 tion of our eye, and inasmuch as it makes 
 the angles of incidence and reflection 
 with the luminous point and our eye 
 equal to one another, the ray, by which 
 we perceive it, follows the laws of a pro- 
 jectile only. Inasmuch as its brightness 
 may be increased so as to become painful 
 to the eye (and the mildest of these phe- 
 nomena differ from the most intense 
 only in degree and not in kind,) it follows 
 that they have all momentum. And I 
 think that from hence we might infer 
 that the phenomena of Splendor might 
 with propriety be referred to the cases of 
 projected light. 
 
 The ancients reckoned Splendor as a 
 distinct colour. This however it is not : 
 for when it is attended with great heat, 
 it exhibits the appearance of the red ; in 
 its intensest glow, of the white ; in a less 
 vivid form as upon ordinary occasions, 
 and in reflected light, it commonly ap- 
 
126 LIGHT. 
 
 pears as the yellow : and in such cases, 
 if the reflected ray be a fluid in progres- 
 sive motion, it is possible that that pro- 
 gressive motion may partake at the same 
 time of the vibration which is peculiar 
 to the yellow tint. In other cases, the 
 reflected ray partakes of the colour of 
 the surface from which it is reflected, 
 and possibly its vibratory motion receives 
 a modification by being reflected at the 
 surface. 
 
 Transparency also among the ancients 
 was deemed a distinct colour. In every 
 great continuity of a transparent medium 
 a resemblance is in this respect remark- 
 able. A distant mountain, seen through 
 a considerable space of air, is blue ; so 
 is the sky itself, so is a glacier, when we 
 look down into it, and so likewise is the 
 sea off soundings. And this blueness 
 may be the result of a continued but 
 more gentle motion of this universal 
 fluid. 
 
 Another observation I would make, 
 
LIGHT. 127 
 
 which I deem of much importance to the 
 solution of some of the most intricate 
 optical phenomena, viz. That we have 
 every reason to suppose that the momen- 
 tum, with which a sunbeam is projected 
 into a room, is far greater than, or at 
 least equal to, the sum of the momenta 
 of all the vibrations that it causes, such 
 momenta being imperceptible ; though 
 its actual velocity may probably be less 
 than that of any separate vibration ; as 
 the velocity of the hammer, which 
 strikes upon a bell, is incomparably less 
 than the velocity of the faintest sound 
 which it excites. 
 
 Upon the different hypotheses of 
 Light, that have been proposed, much 
 confusion has arisen from three distinct 
 significations, in which that single word 
 is used. The fluid, conceived to be in 
 progress, as a sunbeam, by the New- 
 tonians, is termed Light or a ray of 
 Light. The fluid in a state of vibration, 
 according to the hypothesis of Huygens, 
 
128 LIGHT. 
 
 causing sight, analogous to the aerial 
 undulations, causing sound, is likewise 
 termed Light, or when partially examined 
 a ray of Light. Whilst our nomenclature 
 affords us no other term for the undis- 
 turbed fluid in a room, analogous to the 
 undisturbed air or water in the pool. 
 Hence difficulties frequently occur, which 
 arise only from a misapprehension of the 
 terms. 
 
 If we turn our attention to the Chain 
 of Action, we shall find that it consists 
 of Motion or Stress, both of which imply 
 Force, communicated through different 
 portions of the material world. 
 
 All motion and tendencies may per- 
 haps be ultimately traced to the forces of 
 Animals, Gravity, Inertia, Elasticity, and 
 the Etherial powers of nature. 
 
 The natural or common motions and 
 pressure of Water are resolvable into the 
 forces of Air, Gravity, and the like. 
 The natural or common motions and 
 
CHAIN OF ACTION. 129 
 
 powers of the Air may be again resolved 
 into those of Gravity, Elasticity, and 
 Heat. Galvanism, Electricity, and cer- 
 tain Chemical phenomena, might per- 
 haps, if science were properly directed 
 to the investigation, with little difficulty 
 be resolved into a chain of the varied 
 action of one and the same etherial fluid, 
 of which Fire is but another form : inas- 
 much as chief part of the results appear 
 to be but the conversion of aggregate 
 into some species of atomic motion, and 
 the reconversion of this atomic motion 
 into aggregate. The phenomena of Mag- 
 netism might perhaps be similarly re- 
 solved. 
 
 Now in these phenomena the great 
 dispute among philosophers does not so 
 much concern the chain of action and 
 motion, which is, however, far from as- 
 certained, as the chain of being through 
 which such action is propagated ; whether 
 the motion be communicated through 
 the grosser particles of matter, or through 
 K 
 
130 CHAIN OF ACTION. 
 
 some subtile fluid which pervades all 
 nature, or through several different fluids 
 endowed with different properties, such 
 as the Galvanic, Electric, Magnetic, and 
 other fluids. From the sameness of 
 many of their effects, and from the con- 
 sideration that they all appear equally 
 extended throughout the universe, if we 
 should presume that they were but one 
 and the same fluid, we should start an 
 hypothesis indeed, but an hypothesis 
 particularly worthy of attention, for un- 
 less such be the case we shall have in 
 nature several fluids coextended through 
 the universe, all of which, as it has been 
 ably shown, continually perform each 
 other's offices, that is to say, several dif- 
 ferent causes more than are necessary for 
 the solution of the phenomena. 
 
 The investigations of Lord Bacon U 
 him to conclude that HEAT was motior 
 Many recent philosophers of the greate 
 eminence incline to the opinion, that 
 
HEAT. 131 
 
 is a fluid substance, of great subtilty, 
 which they denominate Latent Heat, 
 Caloric, or the like. Between these 
 opinions there is not necessarily any real 
 opposition, and if both of them were as- 
 certained to be true, but little more than 
 one half the problem would be solved. 
 If Heat be Motion, there must be some- 
 thing moved ; there must be a chain of 
 being through which such motion is pro- 
 pagated ; whether it be a subtile fluid, 
 or only the grosser particles of bodies 
 subjected to the heat. But if Heat be 
 admitted to be an Etherial fluid, surely 
 none of the supporters of that opinion 
 will undertake to deny, that this fluid is 
 in motion, wherever it appears under the 
 form of Heat. When it is at rest we 
 may term it Latent heat, or Caloric, or 
 Ether, if we think proper ; but, unless 
 we recollect that such terms are merely 
 conventionally assumed to express a sup- 
 posititious material cause, the use of 
 them is liable to degenerate into an abuse 
 I 
 
132 
 
 of a very serious nature : inasmuch as 
 under each of them lurks an hypothesis, 
 which is but flimsily concealed.* 
 
 With respect to Heat itself the truth 
 appears to me to be that Lord Bacon, 
 Sir Isaac Newton, Dr. Young, and Sir 
 Humphrey Davy more particularly di- 
 rected their attention to the chain of its 
 action only ; whilst other philosophers 
 have gone very far to ascertain, that the 
 chain of being , through which this action 
 is propagated, is not the solid particles 
 of bodies, but a substance distinct from 
 
 * Ether more than half assumes that all the 
 etherial fluids are reducible to one and the same. 
 Latent Heat and Sensible Heat likewise assume 
 that the fluid is connected with the phenomena 
 of heat alone, to the exclusion of the rest, and arc 
 neither more nor less than a revival of the an- 
 cient distinctions of Aristotle, of Heat in Capa- 
 city, and Heat in Energy. Caloric leans rather too 
 much to Bacon's hypothesis. It is also used some- 
 times to express a kind of indefinite superfluity of 
 temperature. Caloric, if restricted, seems best 
 adapted to present purposes ; though probably Ether 
 will ultimately prevail. 
 
HEAT. 133 
 
 them, a subtile fluid. Yet, if, in all 
 these phenomena, relating to the etherial 
 powers of the Universe, we should make 
 no further question, but were fully satis- 
 fied upon this part of the subject, the 
 problem is still unsolved even as to its 
 Natural History, without going into its 
 Causation. 
 
 The next step in the investigation is 
 to ascertain what species or kind of mo- 
 tion it may be. Is it vibratory ? Is it 
 progressive ? Is it direct, or reverbe- 
 rating, or radiating, or circulating, or 
 what? The difference of the species of 
 motion appears to constitute chief part 
 of the difference between Heat, Light, 
 the Electric, Nervous, Magnetic, and 
 other similar phenomena. When we have 
 ascertained what species of motion it is, 
 the further questions remain. Whence 
 is it derived? What are the causes, 
 which produce this motion, and this 
 species of motion rather than any other ? 
 and in what manner do they act ? 
 
134 HEAT. 
 
 We look with contempt upon the not 
 very happy division of Aristotle ; of the 
 different species of motion : and, with 
 much complacency, we reduce them all 
 to one and the same kind, that is to say, 
 a Change of Place : and then we charge 
 him with a misconception of the subject, 
 for thus unnecessarily introducing the 
 same idea, under a different form, as a 
 new idea, a misconception, as usual, 
 to be found only in our own misappre- 
 hension of his doctrine : for upon that 
 subject he maintains * precisely the same 
 tenets that we do ourselves. Motion, as 
 a Change of Place or Position,t is in 
 
 * VIII. Phys. 7. See also Plato De Leg. 10. 
 
 t We are accustomed to hear that motion is a 
 simple idea, and therefore cannot be defined. Yet 
 Aristotle, Dr. Young, and many of the most eminent 
 philosophers have given definitions of motion. It 
 is evident that no objection to its definition can be 
 maintained on account of its being a simple idea ; 
 for, as it is a generic term comprehending under 
 it species and particulars, it can unquestionably 
 be defined as the genus, comprising the particulars, 
 which we may enumerate, such as Progression, 
 
HEAT. 135 
 
 fact the primary, which is accessory to 
 all other motions, and indeed the genus 
 under which they must be classed : and 
 so far from rejecting all the subdivisions 
 or species of motion, I suspect we shall 
 find it necessary to enlarge, instead of 
 contracting the vocabulary. 
 
 The most remarkable of the supposi- 
 titious qualities of matter, depending 
 
 Increase, Diminution, Vibration, Circulation, Walk- 
 ing, Swimming, Running, &c. Aristotle has given 
 its Definition as a Change of Place or Position, 
 that is, by a genus and a specific difference. To 
 this it is objected, that we cannot define the word 
 Change without the use of the word Motion in 
 some form or other. Now this is the real difficulty, 
 which lies, not in motion being a simple idea, and 
 therefore indefinable, but, in the definition of the 
 word change, as its genus. It is, however, a 
 matter of curiosity, rather than of difficulty. The 
 Species comprehended under the word Change 
 are, physically, only two, viz. Changes in the ma- 
 terial world, which are motions ; and Changes in 
 the mental, as in the train of thought, and the like. 
 From the structure of language, it happens, that 
 we have no means of describing any phenomena 
 
136 GRAVITY. 
 
 upon action, are Inertia, Gravity, and 
 Attraction. 
 
 GRAVITY, in the present state of sci- 
 ence, is an anomaly in nature, to which 
 no parallel exists : for we are acquainted 
 only with its laws, without a trace of 
 the antecedent proximate links in the 
 chains of Being, and Motion or Force. 
 
 The conceptions of Sir Isaac Newton, 
 upon the subject of Gravity and Attrac- 
 tion, are perfectly clear and defined : 
 
 whatever in the mental world, except in words 
 and images drawn from the material. Hence we 
 find it impossible to describe change in the mental 
 world, except in words and images taken some way 
 or other from changes in the material, that is, ex- 
 cept in words expressive of motion. Hence it 
 happens, accidentally, as it were, that the generic 
 term cannot be described, except in terms, involving" 
 the specific difference of one of its species : and 
 thus the definition, apparently, but not absolutely, 
 becomes imperfect. The same may be said of 
 some other definitions, which have been rejected 
 upon similar grounds. Motion, so far from being 
 a simple idea, is in fact an idea so general, that the 
 real question is, whether or no we can find a generic 
 term, under which to comprehend it. 
 
 
GKAVITY. 137 
 
 though there is an ambiguity in the 
 words, as they are used both for the 
 cause, and for the effect, that has led to 
 some misunderstanding. In the Prin- 
 cipia, and in general, he uses the words, 
 not for the effect itself, as Dr. Clarke, in 
 his controversy with Leibnitz, affirms, 
 not for any inherent quality, with which 
 matter may be endued, nor for any 
 sti*ess or motion with which it may be 
 affected : but he uses them merely con- 
 ventionally, for the antecedent cause of 
 the effect of gravitation ; whether the 
 cause be a formal cause, or whether it 
 be motion or force communicated through 
 an antecedent chain of being, or what- 
 ever it may be hereafter ascertained. 
 By the universal effect of gravitation or 
 the tendency itself, proved by Induction 
 from Experiment and Observation upon 
 bodies within our reach, and extended 
 by Analogy, confirmed by Observation, 
 to the celestial bodies and those which 
 are beyond us, it is evident that such a 
 
138 GRAVITY". 
 
 cause exists, be it material or be it spi- 
 ritual : and the knowledge of its exis- 
 tence, and of the law according to which 
 it acts, are sufficient for all the purposes 
 to which, in mathematical deductions, i 
 can be applied. 
 
 Sir Isaac Newton laid down as the 
 first rule of philosophizing, ' that no other 
 causes ought to be introduced than such 
 as are true, and sufficient to account for 
 the phenomena/ And he followed his 
 predecessors in maintaining the Inertia 
 of Matter as exerted in the first law of 
 motion, as an inherent, though it may be 
 supposititious quality. But, to account 
 for the undiminished motions of the 
 planets, he was compelled to assert a 
 Vacuum, or at least a quasi vacuum. 
 Yet he hesitated to maintain Gravity as 
 an innate quality of matter, as it would 
 have involved him in an inconsistency in 
 his idea of causation, as expressed in his 
 own rule. He therefore left directions 
 to succeeding philosophers to seek its 
 
 i 
 
GRAVITY. 139 
 
 cause ; and pointed out, as a fit subject 
 for speculation, an hypothetical subtile 
 ether, with which the supposed vacuum 
 might be filled, as capable of supplying 
 the deficient links in the chain of causa- 
 tion. And he left such directions ex- 
 pressly to clear himself from the impu- 
 tation of holding gravity among the essen- 
 tial properties of bodies.* The notion, 
 however, of attraction or gravity, as an 
 occult quality actually inherent in matter, 
 is extremely ancient : and, as it has ever 
 been a received opinion among very emi- 
 nent men, the philosophical world would 
 
 * " Et nequis gravitatem inter essentiales cor- 
 porum proprietates me habere existimet, quaes- 
 tionem unam de ejus causa investiganda subjeci. 
 Qucestionem, inquam : quippe qui experimentis 
 rem istam nondum habeam exploratam." Mo- 
 nitio altera ad lectorem ; prefixed to the Optics. 
 Again, in the second letter to Dr. Bentley, he says; 
 " You sometimes speak of Gravity as essential, and 
 inherent to matter. Pray do not ascribe that no- 
 tion to me : for the cause of Gravity is what I do 
 not pretend to know, and therefore would take 
 more time to consider." p. 20. 
 
140 GRAVITY. 
 
 not be exactly justified in rejecting it at 
 once with the contemptuous expressions,* 
 in which it has pleased Sir Isaac Newton 
 to reprobate it. 
 
 Many of the professed followers of Sir 
 Isaac Newton, little appreciating the 
 depth of his views, but sufficiently alive 
 to the physical inconsistency of rnain- 
 
 * " It is inconceivable that inanimate brute 
 matter should, without the mediation of something 1 
 else, which is not material, operate upon, and 
 affect other matter without mutual contact, as it 
 must be, if Gravitation in the sense of Epicurus, be 
 essential and inherent in it. And this is one reason 
 why I desired you would not ascribe innate Gravity 
 to me. That Gravity should be innate, inherent, 
 and essential to Matter, so that one body may act 
 upon another at a distance through a vacuum with- 
 out the mediation of any thing else, by and through 
 which their action and force may be conveyed from 
 one to another, is to me so great an absurdity, that 
 I believe no man who has in philosophical matters 
 a competent faculty of thinking, can ever fall into 
 it. Gravity must be caused by an agent acting 
 constantly according to certain laws ; but whether 
 that agent be material or immaterial I have left to 
 the consideration of my readers/' Newton s III. 
 Letter to Dr. Bentley, p. 26. 
 
GRAVITY. 141 
 
 taining the Vacuum and rejecting Gra- 
 vity as a quality, hesitated not to assert 
 the absolute vacuum, and gravitation as 
 an inherent quality of matter; not ad- 
 verting to the insuperable metaphysical 
 difficulty thus introduced, that they even- 
 tually maintained two distinct and inde- 
 pendent chains of causation, continually 
 crossing each other and assuming each 
 other's offices : by one of which motion 
 was communicated, through matter in 
 contact, by impulse and vibration, in 
 continued succession ; and by the other 
 through vacuum by means of occult 
 qualities commonly so called : by either 
 of which the same effects might be pro- 
 duced. Euler and other foreign philo- 
 sophers, more sensible of the real diffi- 
 culty of the case, rejected without a 
 scruple such a 'version of Sir Isaac New- 
 ton's opinions, upon the express grounds, 
 that two secondary causes of motion, one 
 from Inertia, the other from Attraction, 
 were utterly incongruous and inadmis- 
 
142 GRAVITY. 
 
 sible : and such has been no less gene- 
 rally the opinion of all metaphysicians 
 than of Sir Isaac himself. Stewart, 
 equally sensible of the same insuperable 
 difficulty, strangely proposes to resolve 
 all such phenomena into attractions and 
 repulsions, upon the principles of Bos- 
 covich. This, as I observed before, is 
 the strangest method of philosophizing, 
 that human ingenuity ever devised : for, 
 instead of arguing from the known to 
 the unknown, we are desired to reverse 
 the process, build an hypothesis upon 
 the unknown, upon phenomena, respect- 
 ing which hardly any two individuals 
 agree, and argue from it against the 
 known, against phenomena and causes, 
 which even the most speculative and 
 hypothetical have scarcely even ventured 
 to call in question. 
 
 With respect to the Causes of Gra- 
 vitation, if we had reasoned justly, and 
 from what we knew, to what was un- 
 known, we should never have been in- 
 
GRAVITY. 143 
 
 volved in the difficulties, with which 
 this subject is perplexed. Let us but 
 follow out the analogies of nature, and 
 much of the obscurity will vanish. In 
 all the phenomena, which we really un- 
 derstand^ motion does not ensue, but by 
 the communication of motion, from some 
 proximate body ; or by the exertion of a 
 force, propagated through some proxi- 
 mate body, whose action is counteracted 
 by some impediment. If we examine 
 the bodies subject to the force of gravity, 
 we find them, either in motion, or, in all, 
 that are not actually in motion, we find 
 a continued tendency to move towards 
 the centre of the earth, and we find that 
 this tendency in them is converted into 
 motion on the removal of some impeding 
 obstacle. Now if we argued, by Ana- 
 logy, from similar phenomena with which 
 we are acquainted, we should without 
 hesitation be led to infer, that the motion 
 is communicated to the gravitating body 
 through some proximate substance, arid 
 
144 GRAVITY. 
 
 that the tendency is derived from a stress 
 impressed upon it, likewise through the 
 instrumentality of some proximate sub- 
 stance. And this is in the true spirit of 
 Newton's second rule of philosophizing ; 
 ' That the same causes are to be as- 
 signed to natural effects of the same kind, 
 as nearly as may be.' 
 
 In the legitimate use of analogy we 
 are entitled to start such an hypothesis : 
 and it is the business of Philosophy to 
 bring it to the test of Experiment or Ob- 
 servation by Induction; by which it may 
 be confuted, proved, or limited to some- 
 thing less general. Now, by Newton's 
 first rule of philosophizing, no other 
 causes ought to be admitted, than such 
 as are true and sufficient to account for 
 the phenomena. The inquiry therefore 
 instantly resolves itself into the two fol- 
 lowing. First, with respect to the cau> 
 assigned ; Is there such a chain of beinu , 
 or nny such substance, as is supposed, in 
 contact with the gravitating body ? And 
 
GRAVITY. 145 
 
 if there be, Is there a stress propagated 
 through that substance to it, causing that 
 tendency, which, by experiment, we find 
 it has ? And secondly, If such causes be 
 realities, are they sufficient to account for 
 the phenomena ? 
 
 The present state of science enables 
 us to resolve the first of these three re- 
 sulting questions at once into the In- 
 quiry, whether there is a PLENUM or a 
 VACUUM in the heavens ? A priori, 
 from analogy, we should infer a plenum, 
 from the very phenomenon itself. Yet 
 the notion of a vacuum has obtained 
 such a general ascendency, and is so 
 commonly supposed to be founded upon 
 demonstration, that upon such analogy, 
 in this case, it would be unphilosophical 
 to lay even the ordinary stress. The be- 
 lief in a vacuum has become an estab- 
 lished prejudice. I conceive, therefore, 
 that it is entitled to the privileges of 
 prejudice : and though it is to be sub- 
 jected to examination, it would be highly 
 I 
 
146 VACUUM. 
 
 improper to lay it aside, till it be over- 
 thrown, or rendered improbable, if refu- 
 tation be impossible from the nature of 
 the case. 
 
 It is true that the Vacuum has an ap- 
 pearance of demonstration. But if such 
 demonstration depend upon hypothetical 
 data, the vacuum, so proved, is but an 
 hypothesis : and, what is worse, it is but 
 an hypothesis deduced; and is therefore 
 liable, not only to all the individual defects 
 of its data, and to erroneous deduction, 
 but also to that complication of error, 
 which may arise from the combination 
 of two or more hypothetical data.* 
 
 The data, upon which all the demon- 
 strations of a vacuum rest, are these I. 
 The uudiminished motions of the planets. 
 This may be granted as a fact. But 
 even this, late observations upon the 
 periodic times of the comets have ren- 
 dered extremely questionable. Never-- 
 theless let it be granted. II. The bicr- 
 * See p. 36. 
 
VACUUM. 147 
 
 tia of Matter. That bodies in motion 
 will continue to move uniformly for- 
 ward in a right line, or to maintain 
 a rotatory motion communicated to 
 them, is also granted as &fact: and it is 
 likewise granted that the more extraneous 
 obstacles we remove, such as the air, fric- 
 tion, &c. the longer such motion will 
 continue. But it must be observed, that 
 all such extraneous obstacles are conse- 
 quents in the chain of being ; and, as con- 
 sequents, they receive motion from, and 
 therefore of course abstract from the mo- 
 tion of the projectile, which, with regard 
 to them, is itself the antecedent. But 
 whether the propensity to proceed uni- 
 formly in a right line is an inherent and 
 independent property of matter, or whe- 
 ther it is maintained by any stress oj* 
 action propagated through any etherial 
 medium or antecedent chain of being, is 
 a question, which the experiments, that 
 establish the mere fact, have not the 
 slightest tendency to determine. And 
 
148 VACUUM. 
 
 the assumption of the Inertia of matter, 
 as an inherent property, independent of 
 such external action, (the only supposi- 
 tion that can avail for the demonstration 
 of a vacuum,) is an assumption of the 
 very point in question, a petitio principii. 
 This, then, as one of the data for the 
 demonstration of a vacuum, is only an 
 hypothesis. III. Another of the data 
 is the assumption, That perpetual motion 
 can only be maintained in a vacuum. 
 This again is an hypothesis. And it is 
 an hypothesis deduced : and the proof 
 of it is, That if a body be put in motion 
 in a plenum, it communicates part of its 
 motion to the surrounding particles ; and 
 what it communicates, it loses ; and 
 hence a perpetual motion cannot be 
 maintained in a plenum. This is ex- 
 actly the same petitio principii as the 
 last, though in another form, involving 
 the same confusion between the conse- 
 quents and antecedents, and assuming, 
 that such motion is not maintained by 
 
VACUUM, 149 
 
 any external force, but that the body, as 
 it were, runs away with the motion pri- 
 marily communicated : And the whole 
 of this deduction is in the teeth of thou- 
 sands of the most familiar experiments, 
 which daily prove, that a perpetual 
 motion* might be preserved by Fire, 
 Steam, Air, Electricity and other powers 
 of nature, but for the wear and tear of 
 the machinery, the lack of fuel, and 
 other extrinsic circumstances : and this, 
 in many instances, in spite of friction ; 
 but in all, an absolute plenum of one or 
 
 * When I say perpetual motion, of course, I do 
 not allude to the frivolous attempts often made 
 to produce it by mechanical combinations acted 
 upon by gravity. As a general refutation of such 
 schemes, it may be considered, that if there were 
 no friction of the machine or air, Gravity and In- 
 ertia would always exactly produce a perpetual mo- 
 tion in pendulums, or combinations of machinery 
 whose centre of Gravity is at rest ; but it could pro- 
 duce nothing more, no constantly accelerated mo- 
 tion. If, therefore, friction is to be taken into ac- 
 count, it must produce something less : or a regular 
 diminution of motion must be the result. 
 
150 VACUUM. 
 
 more fluids is necessary for the production 
 of the effect : while it is far from evident, 
 that a man could move any one of his 
 limbs if it were placed in perfect vacuo. 
 
 A vacuum never has been demon- 
 strated : and if we can find no better 
 data, from which it may be deduced, 
 than these, it never will : for all such 
 demonstrations are, at best, but argu- 
 ments in a circle. And if we apply New- 
 ton's first rule to the vacuum, it is not 
 shewn to be a true cause ; and though, 
 upon the assumption of the planets being 
 projectiles, and upon the further assump- 
 tion of an innate gravitating property of 
 matter, it is sufficient to account for the 
 astronomical phenomena; it is utterly 
 insufficient to account for, but is directly 
 at variance with almost all the rest. 
 
 It is scarcely worth while to notice a 
 small vacuum, upon which, sometimes an 
 argument is built in favour of the possibi- 
 lity of a larger, viz. that, which must con- 
 tinually occur, as an interstice between 
 the finest atoms in nature, when they are 
 
PLENUM. 151 
 
 in motion. Of course such a vacuum is 
 granted, but it has no bearing upon the 
 question. A posse ad esse gives no 
 conclusion : and this gives not even a 
 probability. Still less conclusive are 
 several other metaphysical and mathe- 
 matical curiosities of a similar descrip- 
 tion, which have been sometimes urged 
 as arguments on both sides. 
 
 From the strong analogies of nature 
 we should a priori infer a PLENUM, as 
 an hypothesis : nor does it signify, or 
 make the slightest difference to the pro- 
 positions of astronomy, whether a Va- 
 cuum with Inertia as an independent 
 quality, or whether a Plenum, capable of 
 maintaining motion according to the same 
 laws is supposed. Having obtained such 
 an hypothesis, the next step in philo- 
 sophical investigation is to bring it to the 
 test. 
 
 First then with respect to the possi- 
 bility of perpetual motion being main- 
 tainable in a plenum. Among the innu- 
 
152 PLENUM. 
 
 merable and every -day experiments which 
 might be advanced, it may be brought 
 to the test at once, by the following 
 decisive experimentum crucis, which I 
 shall merely abridge, and attach to it 
 some of the reflections of its author.* 
 ' At the extremities of a rod of about two 
 feet in length let two lights be suspended. 
 Over these lights let there be two vanes 
 fixed to the rod with contrary aspects, 
 and inclined at half a right angle. The 
 rod thus furnished is to be poised upon 
 a point, supported by a foot and pillar. 
 As soon as the lamps are lighted the ma- 
 chine will begin to turn upon its centre, 
 making several revolutions in a minute, 
 and will continue thus to move so long 
 as the lights continue burning : and sup- 
 posing the lights to have a perpetual 
 supply, the consequence would be a per- 
 petual motion in the machine. t 
 
 * Rev. W. Jones's Essay on the First Principles 
 of Natural Philosophy 1762. 
 
 f I have often seen the above experiment tried 
 
PLENUM. 153 
 
 1 Let us suppose' continues the in- 
 genious author, ' Let us suppose a phi- 
 losopher to be contemplating this sight 
 at a distance. If his eye is in the plane 
 of the motion, the lights will appear 
 [like two stars in a binary combination] 
 to move backward and forward in a 
 straight line : but as their velocity will 
 be apparently unequal in different parts 
 of the line, he will conclude they move 
 in a curve : and, by considering atten- 
 tively in what proportion the apparent 
 motion is accelerated and retarded, he 
 will discover that curve to be a perfect 
 circle. Thus far he argues as an astro- 
 nomer and a geometrician : therefore his 
 conclusion will be undeniable : and I 
 mention this to shew the distinction be- 
 
 with an apparatus of no greater expense than two 
 pieces of tin, two bits of candle, and the rod of a 
 staircase carpet. Might not this machine be intro- 
 duced with advantage as a regulating fly wheel, or 
 even as a source of motion, in some of the delicate 
 branches of the arts ? 
 
154 PLENUM. 
 
 tween astronomy and physics. But in 
 the next place he proceeds to investigate 
 the causes of this motion : and, having 
 found, as he imagines, that all matter 
 must resist motion in proportion to its 
 quantity; if the lights circulate in a re- 
 sisting medium, their velocity, he con- 
 cludes, must be diminished, and by de- 
 grees utterly lost. But having observed 
 for several days, and he might do it for 
 as many hundred years, that they con- 
 tinue to move with the same velocity, 
 and complete their periods in exactly 
 the same time, as when he first began to 
 make his observations, he concludes that 
 they must move in an unresisting space : 
 and, having dispatched all material im- 
 pulses out of the way, he assigns a pro- 
 jectile force as the cause of their pro- 
 gressive motion, and an attractive force, 
 exactly counterbalanced to it, as the cause 
 of their circular motion, affirming at the 
 same time that these two forces are suffi- 
 cient to account for all the phenomena, 
 
PLENUM. 155 
 
 and will do it better than any material 
 medium whatsoever; and that in the 
 whole course of this reasoning he has 
 not made one supposition : Hypotheses 
 non jingo? 
 
 If we examine by the help of this 
 experiment the foundations upon which, 
 the assumption, that perpetual motion 
 can only be sustained in a Vacuum, is 
 hazarded * In the first place the lamps 
 do not communicate their motion to the 
 surrounding fluid, because they were 
 left at rest y and had none to communicate. 
 They are no projectiles, and had no 
 original motion independently of the air. 
 2dly, Instead of losing motion, they are 
 continually receiving a fresh and equable 
 supply : [or rather they receive the supply 
 from the air as the antecedent in the chain 
 of causation, and communicate it to the 
 machine as the consequent^. For which 
 reason, 3dly, they are not retarded, but 
 are possessed of a motion, which in 
 Theory is absolutely a perpetual one. 
 
156 PLEXL'M. 
 
 And 4thly the well known inference from 
 a continuance of motion is worst of all : 
 for if the machine were placed in a /v/- 
 cuum, that is, in a space void of air, the 
 lights would expire, and motion be at an 
 end. If a projectile force were then 
 given to the machine, without its lights, 
 it is true that it would continue to move 
 round in the exhausted receiver, and for 
 a much longer time than if the receiver 
 under such circumstances were filled 
 with air : for the air without the lights 
 would be but a resisting medium instead 
 of an impelling one, a consequent in the 
 chain of being, instead of an antecedent, 
 and to preserve such a motion, commu- 
 nicated by a projectile force, the sooner 
 it were removed the better. Cotes, and 
 several philosophers of eminence, have 
 been so assured of the truths of these sup- 
 positions, that they have actually given 
 us some ingenious mathematical demon- 
 strations, that a plain every-day matter 
 of fact is an impossibility in nature.' 
 
PLENUM. 157 
 
 The truth indeed is, that, from a few 
 particulars relative to projectiles, we 
 have skipped to a generality. This ge- 
 nerality, thus lawfully obtained, ought 
 to have been regarded only as an hypo- 
 thesis, and like every other hypothesis 
 ought to have been subjected to the test 
 of Induction : but instead of so testing it, 
 not only with regard to projectiles, but 
 as it relates to other phenomena of bodies 
 in motion, we have received it as a fact, 
 applicable to every case, and founded 
 upon it a mighty system as baseless as a 
 dream. We have assumed a vacuum as 
 a demonstrated and indisputable truth, 
 and we have banished with the plenum 
 all the mighty powers of nature, with 
 which we are surrounded : and all the 
 discoveries of these powers, which we 
 have made, have been owing rather to 
 accident than to any really scientific pro- 
 cess of investigation. 
 
 Having thus refuted the alleged im- 
 possibility of perpetual motion existing 
 
158 PLENUM. 
 
 in a plenum ; the ground upon which 
 the hypothesis of a plenum already 
 stands, is preferable to that upon which 
 the vacuum is maintained : inasmuch as 
 it is an hypothesis, inferred directly by 
 analogy from the known to the unknown 
 in the proper course of philosophical 
 proceeding : whereas the hypothesis of a 
 vacuum is but an hypothesis deduced, 
 its data being hypothetical, and one of 
 them absolutely false. And with respect 
 to all astronomical phenomena and laws, 
 each hypothesis may be equally appli- 
 cable. 
 
 In attempting, then, to establish the 
 plenum as a truth, I observe If Light 
 be a material substance, it is manifest, 
 that there is at least a partial plenum, 
 both in the heavens and in an exhausted 
 receiver. But a partial plenum, whose 
 only effect could be to counteract motion, 
 is not suggested by the analogies, but a 
 plenum through which a force could be 
 propagated which might act as a con- 
 
PLENUM. 159 
 
 tinued stress or as a continued preserva- 
 tive of motion. Such a partial plenum, 
 then, however it must embarrass the hy- 
 pothesis of a projectile force and a va- 
 cuum, is but a very small step towards 
 the establishment of the plenum re- 
 quired. 
 
 ' In the year 1719, a meteor very far 
 exceeding the moon in lustre, and nearly 
 as large in appearance, was seen overall 
 the parts of Great Britain, Ireland, and 
 Holland, the near parts of Germany, 
 France, and Spain, at one and the same 
 instant of time. Its apparent altitudes 
 were accidentally observed by skilful 
 persons at London, Oxford, and Worces- 
 ter ; and near enough to the truth by the 
 assistance of the stars. From these ob- 
 servations its absolute height was deter- 
 mined to have been above 70 statute miles 
 high. Over Devonshire, Cornwall, and 
 the neighbouring counties, an explosion 
 was heard equal to a report from a broad- 
 side of the heaviest cannon at some dis- 
 
160 PLENUM. 
 
 tance, which was soon followed by a 
 rattling noise, as if many small arms had 
 been promiscuously discharged. This 
 sound was attended with an uncommon 
 tremor of the air, and every where in 
 those counties shook the glass windows 
 and doors of the houses, and, according 
 to some accounts, even the houses them- 
 selves, beyond the usual effects of can- 
 non, when fired near at hand. It was 
 also heard in the neighbourhood of Lon- 
 don and beyond Lewes in Sussex. The 
 meteor continued its course at the same 
 height till it at length expired with a 
 more violent explosion over the coast of 
 Brittany. The account of this meteor 
 was drawn up at length by Dr. Halley 
 from the intelligence received upon the 
 occasion by the Royal Society :* and he 
 adds to the account the following reflec- 
 
 * Phil. Trans. No. 360, p. 978. The above 
 description is from Jones's Essay, before referred 
 to, slightly corrected from Motte's Continuation of 
 Lowthorp's Abridgment, vol. ii. p. 138. 
 
PLENUM. 
 
 161 
 
 tion " What may be said to the propa- 
 gation of sound through a medium, ac- 
 cording to the received theory of the air, 
 about 300,000 times rarer than what we 
 breathe, and next to a vacuum, I must 
 confess I know not." A similar observa- 
 tion might have been made with respect 
 to the appearance of a meteor at all at 
 such a height beyond the limits of the 
 atmosphere. 
 
 This meteor, then, to which might be 
 added several of a similar nature,* ap- 
 pears fully to establish the fact, that 
 there is an absolute plenum at 70 miles 
 at least above the surface of the earth. 
 Thus far then we have established a par- 
 tial plenum throughout the whole heavens, 
 and an absolute plenum to about twice 
 the height which the received hypothesis 
 allows. Further than this from the very 
 nature of the case, we can only reason 
 upon analogy and observation. In the 
 
 * See references in page 160. 
 M 
 
162 PLENUM. 
 
 heavens experiment is not within our 
 reach. 
 
 It might be urged that the vacuum of 
 an exhausted receiver, affords the foun- 
 dation for an analogical argument in fa- 
 vour of the vacuum in the heavens. It 
 i 
 
 must be admitted that it does. And if 
 the vacuum of the receiver prove to be 
 plenum, it must be admitted likewise, 
 and a fortiori, that such a plenum of the 
 receiver affords an analogical argument 
 in favour of the plenum of the heavens. 
 Let us then examine the case of an ex- 
 hausted receiver. 
 
 The notion of a vacuum has so com- 
 pletely taken possession of the scientific 
 world, that experiments upon this sub- 
 ject are extremely scarce, attention never 
 having been properly directed to the 
 point. Of late years, however, we have 
 been introduced to a more familiar ac- 
 quaintance with a fluid, or perhaps se- 
 veral fluids, more rare than air. To the 
 Magnetic we have learned to attribute 
 
PLENUM. 163 
 
 the Magnetic properties. Place a com- 
 pass in any part of an exhausted receiver. 
 Its natural action and the operations upon 
 it by a magnet are in no wise inter- 
 rupted by such a vacuum ; whence it is 
 clear, that, at least, the magnetic fluid, 
 whatever that may be, pervades every 
 part of this receiver; and not only the 
 chain of being, but the chain of ac- 
 tion is propagated through it. Divert 
 the northerly position of the needle with 
 a magnet, and let it return. Whence 
 does it receive its motion ? By several 
 experiments with the thermometer and 
 other instruments, we find such an ex- 
 hausted receiver is replete with Heat* as 
 well as with Light, and with the Electric 
 and Galvanic fluids, and this not in a 
 diffuse and scattered manner, but in every 
 part and point subjected to human ob- 
 servation. And it is of little consequence 
 which hypothesis we adopt as to these 
 
 * See Newton Opt. 18th Query. 
 
164 PLENUM. 
 
 phenomena of Heat, Magnetism, and the 
 rest,for if thehypotheses be rejected,which 
 maintain them to be one, or to be distinct 
 fluids and substances, the hypothesis, 
 which would resolve them into motion 
 only, answers the purpose of proving 
 that the receiver is not a vacuum just as 
 well, for these electric or any other mo- 
 tions, as we well know, cannot be pro- 
 pagated but through some substance 
 moved, be it subtile medium or the 
 grosser particles of bodies. 
 
 Again, if an elastic fluid, such as air, 
 be projected into a vacuum, or into such 
 a space as is only partially occupied, or 
 occupied only by a rarer fluid, (under 
 one or other of which denominations we 
 must place an exhausted receiver, if it 
 be not a plenum,) we find by experiment 
 that it will not pass through such a space 
 in a defined column ; but, by its elastic 
 force, immediately expands itself to every 
 part of the receiver : nor will it pass to 
 any distance, unless it is confined in the 
 
PLEN 7 UM. 165 
 
 column by a surrounding medium of 
 about its own specific density. Light 
 and Electricity are even more elastic than 
 air. But when they are projected into 
 an exhausted receiver, we find that, in- 
 stead of expanding by their elasticity, 
 they pass directly through it, in a con- 
 densed column. From this experiment 
 we can draw but two conclusions. We 
 must either conclude, that the space 
 through which these columns pass, is not 
 a vacuum, nor any part thereof, but that 
 the whole is occupied by a fluid, at least 
 about as dense as the projected column ;* 
 or we must conclude, that such fluids as 
 Light and Electricity are not elastic. U"pon 
 the former of these conclusions the ex- 
 hausted receiver is a plenum : and the 
 latter makes a more fatal inroad among 
 the qualities, and as applied to any of 
 the hypotheses of light in the former 
 experiments, involves within itself the 
 
 * For this experiment see Jones's Essay before 
 referred to. 
 
166 PLENUM. 
 
 most complete refutation of the heavenly 
 vacuum, that can be desired. 
 
 Carrying with us this analogy into 
 the heavens ; if they are but a vacuum, 
 how comes it that the solar light glances 
 along the edges of a planet, leaving be- 
 hind the planet such a defined and ex- 
 tended shadow as is apparent in eclipses? 
 It is not conceivable that such an elastic 
 fluid as light would pass by such an 
 empty space, without filling it by its im- 
 mediate expansion. Whether we assume 
 the hypothesis of Newton, or that of 
 Huygens, with respect to the nature of 
 light, or combine them both, the conse- 
 quences involved are as absolutely con- 
 clusive of the plenum as any analogical 
 argument is capable of being. 
 
 Sir Isaac Newton directs our attention 
 to the following analogy upon the ascent of 
 a comet's tail to the higher regions of the 
 heavens.* c Smoke ascends in a chimney 
 
 * See Jones's Essay, p. 121. 
 
PLENUM. 167 
 
 by the impulse of the air, in which it 
 floats. The air, rarefied by heat, ascends 
 on account of the diminution of its spe- 
 cific gravity : and it carries off the smoke 
 entangled with it. Why may not the 
 tail of a comet ascend from the sun after 
 the same manner ?'* It is a fair and ob- 
 vious analogy ; and if it accounts for the 
 ascent of the comet's tail, it leads us di- 
 rectly to inference of a plenum, instead 
 of the inferences which Kepler or Sir 
 Isaac would deduce. The smoke and va- 
 pour from the fire do not ascend because 
 they are carried up by the light, but be- 
 cause they are more rarefied than the air 
 descending to the earth and fire. If, then, 
 we strictly follow out the analogy, we 
 must infer, not that the tail of the comet 
 is carried up through vacuum by the 
 
 * Ascendit fumus in camino impulsu aeris cui 
 innatat. Aer ille per calorem rarefactus ascendit, 
 ob diminutam suam gravitatem specificam, et fu- 
 mum implicatum rapit secum. Quidni cauda co- 
 me tse ad eundem modum ascenderit a sole. 
 Pr.514. 
 
168 PLENUM. 
 
 light, but that the tail and light ascend 
 together by the descent of some denser 
 fluid towards the solar fire. And this is 
 the more particularly decisive, when we 
 consider, that the sun itself is the great 
 centre of gravitation ; and that the only 
 philosophical account, that can be given 
 of the ascent of any such body, is, that 
 it is the well known consequence of the 
 descent of some denser fluid or substance 
 towards the centre of gravitation. 
 
 Lord Bacon, cautious as he was with 
 respect to every hypothesis, decidedly 
 and unhesitatingly maintained the ple- 
 num. Every analogy in nature leads to 
 the same inference : and the few expe- 
 riments and observations, that have hi- 
 therto been directed to the point, go far 
 to convert that inference into a conclu- 
 sion. If it be thus suggested as an hy- 
 pothesis, it is the duty of philosophy to 
 test it. And if it shall be hereafter ad- 
 mitted as a reality, the great chain of 
 being is supplied, which is requisite to 
 
PLENUM. 169 
 
 unite the different, and often apparently 
 conflicting phenomena of Physics with 
 each other in one connected system. 
 
 The same analogies, which suggest a 
 plenum as the connecting chain of being, 
 suggest likewise a continued stress im- 
 pressed upon the plenum, and everlast- 
 ingly maintained by its Creator, as the 
 chain of action, to which the motions and 
 powers of nature must be referred. 
 
 Having started such an hypothesis, if 
 we pleased, we might amuse ourselves, 
 with respect to Gravity, by calculating, 
 upon our present theories of pressure, 
 what would be the effect, upon two inde- 
 pendent solid bodies, placed in a plenum, 
 affected on all sides with a continued 
 strain. We might perhaps arrive at the 
 conclusion, that, each intercepting the 
 strain from the other, a mutual gra- 
 vitation would ensue. We might also 
 attempt to calculate the laws of such a 
 gravitation ; and, if our theories of pres- 
 sure had been well established by Indue- 
 
170 PLENUM. 
 
 tion, such a calculation would at once 
 bring the hypothesis to the test, and de- 
 termine whether it were sufficient or no 
 to account for the phenomena. But, 
 unfortunately, those, which we call our 
 theories, are one of the most deficient 
 branches of philosophy, raised upon very 
 partial inductions, and are only hypothe- 
 tical systems. As we have not the data, 
 upon which these calculations can be 
 made, such a proceeding would be no 
 better than ingenious trifling. Our only 
 resource, then, is to bring it to the test of 
 Experiment; and, what would be the 
 effect, it is not in our power a priori to 
 decide. Experiments for such a purpose 
 may easily be devised. But in this trea- 
 tise it is not my intention to follow up, 
 by such experiments, the suggestions 
 which the present state of science enables 
 us to propose. Nor should I have said 
 so much upon the vacuum, but that the 
 prejudices of the philosophical world lie 
 so strongly in the opposite direction, that 
 
v 
 
 PLENUM. 171 
 
 the doctrine of a plenum has never yet 
 had an impartial examination : yet I 
 humbly conceive, that this notion of a 
 vacuum is the main obstacle to the in- 
 troduction of a new era in science, and 
 even to its completion in the ascending 
 scale. 
 
 Here it might be required Upon 
 the hypothesis of a plenum how are the 
 celestial motions to be accounted for? 
 If, by such a question, a complete ex- 
 planation of the causes, which maintain 
 those motions, be demanded ; it is a de- 
 mand for an hypothetic system, and mere 
 trifling. Galileo, Kepler, and Sir Isaac 
 Newton, have ascertained the laws of the 
 system of the universe. These laws are 
 admitted by all : and thus far there is 
 neither question nor dispute. The next 
 object is to ascertain the causes. And 
 of these, almost all men, whether they 
 believe in the hypothesis of a plenum or 
 of a vacuum, profess themselves in equal 
 ignorance. Such, as presume in the 
 
172 PLENUM. 
 
 present state of science to any real know- 
 ledge of the causes, only display that 
 ignorance the more, by proving that they 
 do not even comprehend what is the 
 subject under consideration. 
 
 To the causes, then, we must induc- 
 tively ascend step by step. The first 
 and fundamental question in this new 
 inquiry is, whether there is a plenum or a 
 vacuum. Two opposite hypotheses are 
 started. And, until one of them is ac- 
 tually proved, all further proceedings 
 must necessarily be purely hypothe- 
 tical. To explain the phenomena upon 
 the hypothesis of a vacuum we must 
 graft upon it two more hypotheses, viz. 
 the Inertia of Matter as an inherent 
 quality, and Gravity likewise as an in- 
 herent quality. To explain the phe- 
 nomena upon the hypothesis of a ple- 
 num, we might in like manner graft 
 upon that assumption two more hypo- 
 theses ; one to account for the continu- 
 ance of the motion in a right Hue, such 
 
PLENUM. 173 
 
 as the hypothesis of Aristotle, that a 
 stream of air follows* a projectile, or a 
 stream of ether, or of electricity, or the 
 like, maintained by a continued external 
 stress upon the fluid ; the other to ac- 
 count for the gravitation of one body to 
 another, such as intercepted pressure, or 
 intercepted stellar rays, or some such 
 hypothesis as has been founded upon 
 the circumstance that the circle of illu- 
 mination on a body enlightened by the 
 sun varies inversely as the square of the 
 distance, or that the action of the electric 
 fluid varies according to the same laws, 
 or any other of the numerous hypotheses, 
 that have been suggested. But in both 
 
 * If the arm be bared and whisked swiftly 
 through the air, the action of the air behind it, 
 and apparently impelling- it, is far more sensibly 
 felt, than the resistance in front of it. It might 
 be a question, by how much the resistance exceeds 
 the impulse ? and whether such impulse be in fact 
 aerial or etherial ? It is evident, however, that the 
 supposition of a vacuum behind a projectile is only 
 an hypothesis deduced. 
 
174 PLENUM. 
 
 cases it is only laying one hypothesis 
 upon another, a method of proceeding 
 not to be admitted. The first hypothesis 
 must be converted into a conclusion, be- 
 fore we can legitimately proceed. If, 
 however, we use the terms Inertia, Gra- 
 vity, and the like, only conventionally, 
 to express the unknown causes of the 
 phenomena, all is right. And every dis- 
 pute, that can arise, will be a disputation 
 upon words, and not upon things : and 
 it may be immediately settled, by a de- 
 mand for the definition of the terms em- 
 ployed. 
 
 I might adduce some curious obser- 
 vations, I have met with, to show that the 
 Attraction of Cohesion, as well as all the 
 phenomena of Repulsion, might also be 
 resolved into this continued strain, im- 
 pressed upon the etherial plenum. But 
 such a course would be also deviating 
 into the regions of hypothesis and placing 
 one hypothesis upon another. It may, 
 therefore, be sufficient, here, to obviate 
 
COHESION. 175 
 
 an objection, upon which some stress 
 has been unnecessarily laid. If we ex- 
 amine any solid body, we find it is con- 
 structed of independent particles, but 
 loosely as it were, and permeated by 
 pores, through which such a fluid, or it 
 may be motion, as the electric, flies al- 
 most uninterruptedly : and, if these pores 
 be pervaded by the supposed etherial 
 fluid, a strain, operating upon that fluid, 
 would not act upon the surface of the 
 body, as Sir Isaac Newton suggests, but 
 on its internal structure, and upon every 
 particle which composes it. But whe- 
 ther it would operate to its dissolution, 
 or to its cohesion, and gravitation to any 
 other body directly as its mass or as its 
 surface, is not matter for our mere conjec- 
 ture, but is a subject for experimental 
 examination. 
 
 Upon the other Powers of Nature I 
 shall say but little at present. It is well 
 known to Mechanicians, that man cannot 
 
176 MECHANICAL POWERS. 
 
 increase his power, by any combination 
 of Machinery, save only as by such 
 means he can bring his force to bear 
 more regularly and uninterruptedly. 
 What he gains in power, he loses in 
 time. And if by the aid of simple ma- 
 chinery he can raise an undivided ton in 
 5 minutes to the height of 20 feet, he 
 could raise a quarter of hundred weight 
 to the same height by his unassisted 
 power in 1-SOth part of the same time. 
 How comes it, then, that he is enabled 
 to construct machinery, by which he can 
 produce effects far beyond all human 
 power ? It is thus. By various contri- 
 vances and combinations he is enabled 
 to press into his service powers, that are 
 not his powers forces with which he is 
 surrounded, and which are at his bid- 
 ding in every place and time. The 
 powers supplied him are not created nor 
 increased by his machinery, but are sup- 
 plied indefinitely to the exertions of his 
 skill. Knowledge is indeed power, in- 
 
NATURAL POWERS. 177 
 
 asmuch as it enables its possessor to bend 
 to his will powers superior to his own. 
 And the extension of knowledge has 
 given to this kingdom in particular a 
 supply of force unequalled by any na- 
 tion upon earth. 
 
 Again, If we examine some of the 
 common operations of nature, over which 
 man has little or no control, we find new 
 forces and movements introduced, unac- 
 countable upon any of the received sys- 
 tems of philosophy. Wherever a fire is 
 lighted, a wonderful kind of motion com- 
 mences among the elements, very diffe- 
 rent from what can be supposed to have 
 been communicated by the agent that 
 produced the spark, or could have resided 
 within the spark itself. Light issues on 
 all sides from the fire, and an incessant 
 draft of air sets into it ; and there ensues 
 a motion continually accumulating and 
 increasing, and communicated to the 
 objects around it ; and instead of losing 
 motion by such communication, the 
 
 N 
 
178 NATURAL POWERS. 
 
 longer it continues the more violent, in- 
 tense, and extended it becomes, producing 
 such a variety of movements by the de- 
 scent of walls and timbers, by the over- 
 throw of houses, trees, and all obstacles 
 within its reach, as to bid defiance to all 
 ordinary rules of action and re-action, 
 cause and effect : ' and no man knoweth 
 whence it cometh, or whither it goeth.' 
 To the explanation of such phenomena 
 as these, our laws of motion are utterly 
 inadequate : and in every attempt we 
 feel ourselves beyond our depth. Not 
 that these laws of motion are overthrown 
 so far as they relate to projectiles and 
 the like ; for, with respect to them, they 
 are founded upon Induction. And when 
 we shall have advanced into these higher 
 regions of philosophy, I question not, but 
 that their empire will be extended, so as 
 to embrace these phenomena themselves. 
 Or perhaps some more general laws of 
 motion will be discovered, which will 
 
ORIGIN OF POWER. 179 
 
 comprehend the present under them, in 
 like manner as the law of gravity, con- 
 stant upon the surface of the earth, was 
 nevertheless, by the extension of science, 
 comprehended under the more general 
 law of its inverse variation. 
 
 That, in a great multitude of instances, 
 new efficient forces are introduced is very 
 evident. We may satisfy our immediate 
 purposes of use and language by calling 
 them the Powers of Elasticity, Expan- 
 sion, Inertia, and the like : but the ques- 
 tion still returns Whence are these forces 
 proximately derived ? Stewart* has enu- 
 merated the following hypotheses, which 
 have been started for the solution of this 
 question. 
 
 That the phenomena of nature are the 
 result of certain active powers essentially 
 inherent in matter. This doctrine is 
 commonly called Materialism. 
 
 * See his Outlines, p. 184, and also his Appen- 
 dix to the first volume of his Essay on the Active 
 Powers. 
 
180 ORIGIN OF POWER. 
 
 That they result from certain active 
 powers communicated to matter at its 
 first formation. 
 
 That they take place in consequence 
 of general laws established by the Deity. 
 That they are produced by a vital and 
 spiritual, but unintelligent and neces- 
 sary agent, created by the Deity for 
 the execution of his purposes the hypo- 
 thesis of Cudworth, which he attributes 
 to Plato and Aristotle. 
 That they are produced by mind, con- 
 nected with the particles of matter. 
 That the universe is a machine founded 
 and put in motion by the Deity ; 
 and that the multiplicity of effects 
 which take place may perhaps have 
 all proceeded from one single act of his 
 power. 
 
 To which he adds the following, which 
 he maintains, That the order of the uni- 
 verse is not only at first established, but, 
 every moment, maintained by the inces- 
 sant agency of one supreme mind : which 
 
ORIGIN OF POWER. 181 
 
 doctrine, says he, does not exclude the 
 possibility of the Deity's acting occasion- 
 ally by subordinate agents or instru- 
 ments.* 
 
 That the powers of nature are powers 
 independently inherent in matter, none 
 but the materialist maintains : and we 
 must admit them either immediately or 
 ultimately to be the result of some 
 spiritual agency. To pass over such of 
 the hypotheses as no one now maintains, 
 the inquiry resolves itself into the follow- 
 ing Whether, in the present constitu- 
 tion of the world, the spiritual agent acts 
 directly by his immediate power, or by 
 secondary causes. 
 
 That subordinate material instruments 
 are occasionally employed is manifest to 
 every observer every moment of his life. 
 Upon the notion of a vacuum and the 
 impressed or inherent qualities, it is 
 equally manifest that secondary causes 
 cannot be universally instrumental to the 
 * Pao-e 185. 
 
182 ORIGIN OF POWER. 
 
 phenomena. Upon this system, then, 
 as proposed by Stewart, we either miss 
 the real question entirely, or we are 
 driven to conclude, that the operations 
 are conducted, partly by secondary 
 causes, though chiefly by immediate 
 influence. Thus, for instance, when the 
 twig of a tree is bent by the wind, and 
 recovers its former position by its elas- 
 ticity ; the first operation is performed 
 by means of secondary causes, the other 
 by the immediate interference of the 
 Deity : and if a perpetual vibration of 
 the twig is kept up, it is kept up alter- 
 nately by the one and by the other. 
 Again, in the working of a steam engine, 
 the pressure and operations of the water, 
 the air, and the different combinations of 
 the wheels and machinery attached, are 
 secondary causes, acted upon, and acting 
 upon each other, according to mechanical 
 laws and principles : while the gravity 
 of the piston, the elasticity of the steam, 
 and the inertia of the fly-wheel, are the 
 
ORIGIN OF POWER. 183 
 
 result of the immediate interference of 
 the Deity, likewise acting according to 
 mechanical laws. And upon this suppo- 
 sition of immediate interference and con- 
 trol, we are urged to conceive, that we 
 ascribe unto the Lord a mightier display 
 of majesty and power, which cannot fail 
 to impress a more devout dependence 
 upon him, as our Ruler and Creator. 
 We ascribe unto him however a broken, 
 confused, and disjointed production ; and 
 such an hypothesis, as I before observed, 
 has been almost universally rejected by 
 the ablest metaphysicians upon the a pri- 
 ori argument of Causation. Alphonso, 
 King of Spain, would probably have 
 received it with the same sarcasm as he 
 used toward the Ptolemaic hypothesis of 
 the universe. The implied censure of 
 Newton rests upon it. But it has been 
 more sternly reprobated by that great 
 philosopher, whom we justly venerate as 
 the father of modern science, whose en- 
 larged views and chastened wisdom, in 
 
184 ORIGIN OF POWER. 
 
 every thing which concerns this branch 
 of philosophy, have been most lamentably 
 overlooked. " Certain it is/' says Lord 
 Bacon,* " that God worketh nothing in 
 nature but by second causes ; and if 
 they would have it otherwise believed, 
 it is mere imposture, as it were in favour 
 towards God ; and nothing else but to 
 ofler to the Author of truth the unclean 
 sacrifice of a lie." 
 
 Of the Force of Animals, it may well 
 be questioned whence it is derived, whe- 
 ther it be originally communicated by 
 the Soul of the animal itself to the mate- 
 rial world through its connexion with the 
 body, or whether the soul has power only 
 to influence and divert the motion and 
 force, with which that body may be sur- 
 rounded. No part of physical science 
 is involved in such obscurity. " I will 
 to raise a weight," says Dr. Reid,| u and 
 
 * Advancement of Learning. |>auv \'2. 
 t Active Powers, 109. 
 
ORIGIN OF POWER. 185 
 
 no sooner is this volition exerted than 
 the machinery behind the curtain falls to 
 work, and raises the weight." This is 
 well nigh the sum and substance of all 
 we know about the matter. The Gal- 
 vanic powers and structure of the brain, 
 alluded to by Dr. Arnott and Sir J. Her- 
 schel,* have a tendency to show that the 
 mere animal motions are conducted upon 
 the same principles as is the other me- 
 chanism of nature, whatever may be the 
 influence, through which the soul operates 
 to govern and promote its action. 
 
 To the ancients, who held the World 
 to be their God, Matter its body, and the 
 Etherial powers of the heavens its soul, 
 little difficulty could occur in resolving 
 the motions and forces of the elements 
 and gravity, as well as all individual 
 animal force into the powers of this pre- 
 sent universal Deity. By such a solu- 
 
 * See also Aristotle, VIII. Phys. 2. 6. and his 
 treatise De Motu Animalium, and III. De Crelo 2. 
 
186 ORIGIN OF POWER. 
 
 tion, it is true, they completed and per- 
 fected their bastard system of Physics; 
 and reduced all causes to one simple 
 triplicated chain : and the Efficient, the 
 Formal, and the Material, might be suc- 
 cessively traced from the highest intel- 
 lectual operation to the lowest sensible 
 phenomenon. 
 
 To us, however, who hold the Spiritual 
 world perfectly distinct from the Mate- 
 rial, it must be the grand object of phi- 
 losophy to trace the chain of causes from 
 matter to matter, to the first of secondary 
 causes. At these secondary causes, pre- 
 viously to the great reformation of their 
 religious systems, introduced shortly be- 
 fore the time of Pythagoras, the earlier 
 nations of the world unfortunately stop- 
 ped, nor raised their minds above the 
 material system of the universe. They 
 appear originally to have been acquainted 
 with revealed truth, and by the refine- 
 ments of philosophy to have fallen into 
 materialism, and naturally and gradually 
 
ORIGIN OF POWER. 187 
 
 to have descended to the grossest depth 
 of atheism and idolatry. 
 
 It is well observed by Lord Bacon 
 That it is " an assured truth and a conclu- 
 sion of experience, that a little or super- 
 ficial knowledge of philosophy may in- 
 cline the mind of man to atheism : but a 
 further proceeding therein doth bring the 
 mind back again to religion : for, in the 
 entrance of philosophy, when the second 
 causes, which are next unto the senses, 
 do offer themselves to the mind of 
 man, if it dwell and stay there, it may 
 induce some oblivion of the highest 
 cause : but when a man passeth on fur- 
 ther, and seeth the dependance of causes 
 and the works of providence ; then, ac- 
 cording to the allegory of the poets, he 
 will easily believe that the highest link 
 of nature's chain must needs be tied to 
 the foot of Jupiter's chair." Natural 
 history leads us to the contemplation of 
 the wisdom and goodness of the Al- 
 mighty : and Causation directs us to a 
 
188 ORIGIN OF POWER. 
 
 perception of his power ; to regard this 
 universal frame, with all its myriads of 
 worlds, as one connected whole, and as 
 it were his footstool, bearing upon it the 
 continued impress of his might. 
 
 Such is the hypothesis upon the con- 
 struction and the powers of the universe, 
 which I would venture to suggest, or, 
 with greater propriety I would say, to 
 revive. That all physical force is prox- 
 imately dependant upon the powers of 
 the heavens, and that they consist of a 
 plenum, is no new hypothesis, but as old 
 as Heathenism itself : and the hypothesis 
 properly modified, I believe, is even of 
 still higher antiquity. Yet it is advanced, 
 not as a system to be believed, but as an 
 hypothesis to be tested by Induction. In 
 England, every such hypothesis, of late, 
 has generally been passed by unnoticed, 
 and unworthy even of examination, upon 
 the idle unfounded supposition, that the 
 Vacuum has been demonstrated in the 
 Principia of Newton, and that the Pie- 
 
ORIGIN OF POM'ER. 189 
 
 num runs counter to the mathematical 
 principles of the Newtonian philosophy. 
 It is a fallacy, however, by which, 
 few of the most celebrated philosophers 
 have ever been misled : and unhesita- 
 tingly they have received the laws of gra- 
 vitation, announced by Newton, without 
 in any manner abandoning their specu- 
 lations upon Causation. 
 
 We profess to follow Bacon, we ad- 
 mit his principles and experimental me- 
 thod to be correct, and we desert him in 
 the very next step, upon Causation, that 
 is to say, upon the objects, to which our 
 attention should be directed. He argues 
 justly, from what he knew to what was 
 unknown, and arrives at the same result 
 as did the ancients, that the Heavens are 
 a plenum, and that all the operations in 
 the world are conducted by the Almighty 
 through the instrumentality of second 
 causes. Modern philosophers generally 
 maintain a position directly the reverse. 
 
190 ORIGIN OF POWER. 
 
 It is not for any one at present to venture 
 a decision on the question : and herein I 
 have but endeavoured to bring the sub- 
 ject more fairly before the world. And 
 Time will shew, whether this, which is 
 held to be the weak part of Bacon's phi- 
 losophy, is weaker than the rest. 
 
 The origin of motion and force is one 
 of the grandest physical problems that 
 ever engaged the attention of philoso- 
 phers. Perpetual motions acting in any 
 system must influence all things within 
 their reach : and from them secondary 
 motions must in a great measure, or at 
 least in some measure be derived. All 
 motions imply force : and such force 
 must be derived ultimately or imme- 
 diately from a spiritual agent. It was a 
 favourite problem among the ancients to 
 distinguish the primary from the deriva- 
 tive motions, and to ascertain at what 
 parts of the system the spiritual forces 
 were applied. 
 
ORIGIN OF POWER. 191 
 
 The hypothesis and opinions of cele- 
 brated men upon such a question, how- 
 ever wild and vague, are not unworthy 
 of consideration. Many, like Descartes, 
 have conceived that a certain quantity of 
 motion was originally communicated to 
 the world ; that no part of it was ever 
 lost ; but that it was bandied from one 
 portion of matter to another in an eternal 
 succession. 
 
 I omit further mention of the specula- 
 tions of Cud worth, Berkeley, and of some 
 eminent philosophers, ancient as well as 
 modern, who have taken singular views 
 upon the subject, as their speculations 
 have been frequently and fully examined, 
 and have been the subject of much con- 
 troversy among metaphysicians, and their 
 attendant difficulties ably pointed out. 
 
 Lord Bacon, as a strenuous advocate 
 for the plenum, has forcibly directed our 
 attention to several curious phenomena, 
 connected with the preservation and 
 origin of motion, which unfortunately 
 
192 SYSTEM OF THE ANCIENTS. 
 
 have never received that consideration 
 from the philosophical world, which the 
 suggestions of Lord Bacon of right de- 
 mand, and usually obtain. 
 
 If we pass on into antiquity, in the 
 writings of Aristotle we find a clearer 
 and a steadier light. He connects the 
 problem at once with Causation : and 
 from a very extensive induction and 
 examination of the opinions of preceding- 
 philosophers, he presents us with the 
 two chains of Being and Motion* as 
 the proper objects of physical investiga- 
 tion. He derives the chain of motion 
 proximately from the Heavens, which, in 
 common with almost all the heathens, he 
 regarded as a vast, incorruptible, and 
 ever circulating God : but through the 
 intervention of this deity, he derives it 
 ultimately from the immoveable first 
 
 * He does not, that I am aware of, make any 
 distinction between the Dynamical and Statical 
 forces, both which 1 have comprehended under 
 the term action as a generic word. 
 
SYSTEM OF THE ANCIENTS. 193 
 
 principle of all things. And he con- 
 ceived that it was applied at the circum- 
 ference to revolve the sphere : while 
 many others, as he informs us, imagined 
 that it was applied at the centre. Plato 
 has handed down to us much the same 
 conceptions : but he has not entered so 
 fully into the discussion of the chain of 
 action. Both Plato and Aristotle, how- 
 ever, appear to have derived their notions 
 chiefly from the Pythagoreans,* who im- 
 ported them from abroad. It is true that 
 Aristotle is inclined to claim for himself 
 the discovery of the causes upon the in- 
 duction, which he has given. Yet his 
 arguments, as well as those of Plato, on 
 these and very many other subjects are 
 so inconclusive, with so many omissions 
 of the intermediate steps, in the natural 
 progress to such generalities, which ap- 
 pear to have been, to them, unnoticed 
 
 * The Pythagoreans, however, conceived it was 
 applied at the centre. 
 
 O 
 
194 SYSTEM OF THE ANCIENTS. 
 
 and unknown, and which have only been 
 supplied by the science of modern times, 
 that the conclusions seem rather to be the 
 broken fragments of some earlier con- 
 nected system than any inventions of 
 their own. And if we had not been 
 acquainted with the fact, that they had 
 largely borrowed elsewhere, we could 
 hardly have given them credit as the ori- 
 ginal inventors of such speculations as 
 are to be met with in their writings. 
 
 With their philosophical speculations, 
 the Heathens invariably blended their 
 theology. I have elsewhere collected 
 the fragments, and endeavoured to trace 
 the changes and modifications, which 
 took place in the philosophical and theo- 
 logical speculations of the higher an- 
 cients. Nothing perhaps is more uni- 
 formly insisted upon among them than 
 the plenum, and divinity of the hea- 
 vens, and that the first great moving 
 principle of the universe sprung forth 
 from them. In the beginning were the 
 
SYSTEM OF THE ANCIENTS. 1 95 
 
 Ether, and Chaos, or, in the language of 
 the philosophers, Mind and Matter, which 
 were regarded as two primeval, eternal, 
 and independent principles, the first of 
 a vivifying and intellectual nature, the 
 other, a watery chaos, boundless and 
 without form ; both which continued for 
 a time without motion, and in darkness. 
 By a mystic union of the two was formed 
 the great Pantheistic deity, the One, the 
 Universe itself; of which the Chaotic 
 matter presently became the body, and 
 the Etherial Intellectual principle the 
 soul. At the commencement of this 
 union, from the Ether sprung forth the 
 Triad, Phanes or Eros, a triple divinity, 
 the most prominent character of which 
 was Light. He organized and completed 
 the fabrication of the system, and, at the 
 conclusion of his work, he became the 
 sun, thenceforth the Soul and Ruler of 
 the world. The primeval Ether and a 
 triad of three distinct and coequal powers 
 or persons, concentred in the sun, cor- 
 
196 SYSTEM OF THE ANCIENTS. 
 
 responding in their human character to 
 the great Patriarch of mankind and his 
 three sons, appear not only from the frag- 
 ments, which have reached us through 
 the medium of the Greek language, but 
 from the Hindu, Peruvian, and many 
 other independent mythological sources, 
 to have been the original Monad and 
 Triad of the Gentile world. An exami- 
 nation and comparison of the different 
 systems show, that the persons of this 
 solar triad, viewed under a physical as- 
 pect, were regarded as the Fire, the 
 Light, and the Ether, three conditions of 
 one and the same etherial fluid substance 
 of the heavens : while in a metaphysical 
 aspect they were commonly conceived 
 as certain attributes of the Supreme rnind, 
 and were variously combined as the Prin- 
 ciple of action, Power, or Will, the In- 
 tellect or Reason, and the Spirit of the 
 world ; accordingly as the prior Monad 
 was contemplated, physically in its Ethe- 
 rial, or metaphysically in its Intellectual 
 subsistence. 
 
SYSTEM OF THE ANCIENTS. 197 
 
 The constitution of this triad of the 
 Sim, as the secondary origin of motion 
 to the system, scarcely enters into the 
 subject of the present inquiry. But as 
 we have arrived, by a very different path, 
 to nearly the same hypothesis, which, in 
 his excentric speculations, was maintained 
 by Hutchinson, as the physical system 
 of the Scriptures, it may not be amiss to 
 say some few words upon it, as a subject 
 of curiosity, which, in the earliest ages, 
 appears to have been maintained as a 
 fundamental tenet of a mighty system of 
 speculation ; traces of which are to be 
 found in the antiquities of every nation 
 upon earth. 
 
 Neither Hutchinson nor any of his fol- 
 lowers seem to have been aware, what 
 strong confirmation of their hypothesis, in 
 this particular, is to be found among the 
 relics of the earlier Gentile world. And 
 he appears to have fallen into the very 
 same mistake, which originally tended 
 to mislead, and plunge the nations into 
 
198 SYSTEM OF THE ANCIENTS. 
 
 materialism, and the worship of the hea- 
 vens, in that he resolved the strain upon 
 the heavens, and all the derived force in 
 the universe, into the expansion caused 
 by the motions of the solar triad. And 
 he regarded the world as a machine, 
 originally constructed and set in motion 
 by its Creator, and thereafter left as a 
 self-acting and independent combination, 
 whose powers were concentred in the 
 sun ; instead of reversing the hypothesis, 
 and resolving the motions of the solar 
 triad, and of all the mundane operations, 
 into the force upon the plenum, originally 
 impressed, and still maintained by, and 
 dependent upon, its Creator. The system 
 of Hutchinson has long since passed into 
 oblivion ; or is remembered only as an 
 ingenious speculation. The discovery 
 of the bases and component gases of the 
 air overthrew its fundamental tenet, that 
 the Fire, Light, and Air, were only dif- 
 ferent appearances of the same etherial 
 substance. Yet, from the resemblance 
 
SYSTEM OF THE ANCIENTS. 199 
 
 of the Sun to common fire, and the dis- 
 covery of the chemical union of the bases 
 of the air with those of the consumed 
 fuel, in the process of combustion, evol- 
 ving water, and carbonic acid gas, ac- 
 counting accurately for all the mate- 
 rials, except the ether of the gases lost 
 or destroyed, and the light generated or 
 thrown off, leaving these as residual 
 phenomena, perhaps convertible into one 
 another, I conceive that the substitution 
 of the word Caloric or Latent Heat or 
 Ether, for Air in that hypothesis, or it 
 may be only the converging force con- 
 verted at the centre into that diverging 
 motion which may be light, would sug- 
 gest a modification right well worthy of 
 attention. Many, however, are the steps, 
 which must be proved, before this part 
 of the subject can even be legitimately 
 approached. By all such speculations 
 we are only tacking one supposition to 
 another, and weaving but an hypothetic 
 system ; using analogy not in its legiti- 
 
200 METAPHYSICAL INQUIRY. 
 
 mate province, but, as Lord Bacon calls 
 it, for the purpose of anticipating nature ; 
 and running into the common error of 
 the ancients, of proceeding from one step 
 to another without stopping to prove our 
 progress. 
 
 Upon the Metaphysical triad of the 
 ancients, most probably derived, at least 
 in part, by analogical reasoning from the 
 contemplation of the human mind ; and 
 upon the divisions of the mental powers 
 which have obtained among philosophers, 
 I would make some few observations. 
 
 Metaphysicians have at length ap- 
 proximated to a truth, which, in the 
 Metaphysics of Christianity, is laid down 
 with as much perspicuity and decision, 
 as is the Immortality of the Soul, or any 
 other of those points which have been so 
 continually agitated among philosophers, 
 modern as well as ancient. The dis- 
 tinction between the Intellect, and the 
 Emotions or Affections, to which, simple 
 
METAPHYSICAL INQUIRY. 201 
 
 as it may appear, such laborious ap- 
 proaches have been made through the 
 mazy paths of Metaphysics, is clearly 
 drawn in the Scriptures ; and the res- 
 pective seats of them are assigned, it 
 may be figuratively, but most naturally, 
 to the Head and Heart :* and to the 
 heart the Scriptures most constantly ap- 
 peal, as Religion is rather directed to the 
 Feelings than to the Understanding. 
 
 The old division of the Mental Powers 
 into those of the Will and the Under- 
 standing, has long been superseded by 
 the division of the school of Reid, into 
 the Intellectual and Active Powers. But, 
 under the name of the Active Powers, 
 are comprehended the Will and some 
 
 * The Faith mentioned by St. James is evidently 
 the mere opinion or belief, which arises upon the 
 conviction of the Intellect alone. Nor does it be- 
 come the justifying faith, insisted upon by St. 
 Paul, till this belief is enlivened by the Affections 
 of the heart. When the Head and Heart concur, 
 the Works of the whole man must of course tend 
 to one and the same object. 
 
202 METAPHYSICAL IN'QUIRT. 
 
 part of the Emotions : while the more 
 refined Emotions, and the complex In- 
 tellectual and Emotional Feelings have 
 been confounded with the Intellect ; an 
 error, which likewise runs through the 
 writings of Kant, Plato, and many of 
 the ancients. Metaphysical science is 
 greatly indebted to Brown, for having 
 so forcibly directed attention to the dis- 
 tinction between the Intellect and the 
 Emotions; but, in common with later 
 writers, he appears generally to regard 
 the Will as a subordinate appendage to 
 the Emotions, connected perhaps w 7 ith the 
 material structure of the animal. 
 
 There is an ambiguity in the words 
 Will and Volition. The Will may be di- 
 vided into the general capability of Wish- 
 ing , and into the general Power of acting ; 
 the Volition into the particular Wix/i, 
 and into the particular exertion of the 
 Power* The Soul thinks, ivishes, acts ; 
 
 * Dr. Clarke draws a distinction somewhat si- 
 milar. " But it plainly appears to me, that there 
 
METAPHYSICAL IN 7 QUIRY. 203 
 
 and the Power to act appears to me to 
 be a mental Power, as distinct from the 
 Wish or any of the Emotions, as it is in- 
 dependent of any material structure or 
 combination. We may conceive a dis- 
 embodied spirit with the Intellectual 
 Powers, the Train of Thought, only, 
 without the Emotions; and again such 
 a spirit, with the Intellect and Emotions, 
 without the Power of action : and such 
 
 is an error which lies under the word Volition. 
 Under that term you include both the final percep- 
 tion of the Understanding, which is passive, and 
 also the first operation or exertion of the Active 
 faculty or Self-motive Power. These two you 
 think to be necessarily connected. I think there 
 is no connexion at all between them : and that in 
 their not being connected lies the difference between 
 Action and Passion ; which difference is the essence 
 of Liberty." //. Letter to a Gentleman, p. 410. 
 Here the Active faculty or Self-motive Power is 
 distinguished from the Intellect: but no notice is 
 taken of the Emotions : yet it is most questionable, 
 whether the Self-motive Power is ever exercised 
 without the intervention of some Desire or Emo- 
 tion. 
 
204 METAPHYSICAL INQUIRY. 
 
 a being might be susceptible of every 
 sentiment terminating in contemplation, 
 such as all intellectual Tastes, Memory, 
 Regret, and a variety of others. Stewart, 
 in his speculations upon persons dream- 
 ing, supposes the Intellectual Powers 
 with the Train of Thought in exercise, 
 while the Active powers are suspended. 
 But, of the Faculties which are con- 
 founded under the name of Active 
 Powers, it is manifest that the Emotions 
 are not suspended : and. though the vo- 
 luntary Power over the material frame 
 is very generally unexerted during sleep, 
 it is a very singular phenomenon, that 
 when the Wish or desire itself to do any 
 particular action arises, the Soul pre- 
 sently takes it for granted that the deed 
 required is actually done ; and the train 
 of thought is influenced and diverted 
 though the power is not exercised ; and, 
 though the wish is not really gratified. 
 And there is nothing more common in 
 nature than to have the wish without 
 
METAPHYSICAL INQUIRY. 205 
 
 the power to act, or the power without 
 the wish. 
 
 That animal motions are in a great 
 measure carried on by the mechanical 
 powers of nature, supplied externally to 
 the occasion, is highly and extremely 
 probable : yet at the same time it is evi- 
 dent that the soul must exercise some 
 Power of action distinct from the desire, 
 however hidden and mysterious it may 
 be : and that Power of action, whatever 
 it is, I conceive should be ranked as a 
 distinct division of the Faculties. 
 
 It is ably shown by Brown, that to 
 the Power of action in the human frame, 
 we are indebted, as to another sense, for 
 our ideas of Causation, which is, as it 
 were, the object of that mental faculty ; 
 as Science is the proper object of the 
 Intellect and Head ; and Religion and 
 Ethics of the Feelings and the Heart ; 
 while what we distinguish, as Sensation, 
 is but the internal feeling of the mind, 
 when excited by some external cause. 
 
206 METAPHYSICAL INQUIRY. 
 
 If we look more closely into the con- 
 struction of animal bodies, we may ob- 
 serve in their involuntary motions, and 
 a variety of other phenomena, something 
 of a material or corporeal spirit or frame 
 of life, acting independently, though 
 occasionally influenced by the immortal 
 soul. It is common also to vegetable 
 beings : and its operations appear to 
 be carried on solely by the powers of 
 nature through the instrumentality of 
 the Sympathetic nerve. Many philoso- 
 phers have attempted to account for it by 
 a secondary soul, as did Plato ; others 
 by a plastic nature, or by the immediate 
 interference of the Creator. But analogy 
 seems to direct us to seek it among se- 
 condary causes only ; and would lead us 
 to the inference, that Nature, with all 
 its powers, is no other than this Machine 
 of the universe, for which it is but a 
 name, a machine wonderfully and fear- 
 fully contrived, whose action, motions, 
 and forces are preserved by the continued 
 
METAPHYSICAL INQUIRY. 207 
 
 impress of Almighty Power. To this 
 beautiful and wonderful combination of 
 the material frame, not only of the uni- 
 verse, but of all the organic bodies it 
 contains, carried on apparently with so 
 little of external aid, is to be attributed 
 much of that materialism, which is to be 
 met with among men, of some philoso- 
 phical pretensions indeed, but whose 
 views are so warped by the pursuit of 
 one particular branch of science, as to 
 rest solely in the secondary causes first 
 presented to the senses, without lifting 
 up their eyes to comprehend the higher 
 and more intellectual bearings of phi- 
 losophy. 
 
 Upon the metaphysical speculations, 
 drawn from the material world, and upon 
 the proper use and abuse of Analogy in 
 that respect, I would make some further 
 observations. 
 
 Of all arguments whatever, the most 
 dangerous are those, which are deduced 
 
208 METAPHYSICAL INQUIRY. 
 
 by analogies drawn from the material to 
 the mental world ; between which there 
 is no natural similarity. Mind and 
 Matter, in their substances are equally 
 to us unknown ; and in their qualities or 
 properties, if we may justly apply such 
 terms to mental phenomena at all, they 
 are the very reverse of one another. 
 What similarity can possibly be traced 
 between the solid, extended, tangible, 
 visible, divisible, inert, and moveable 
 masses of matter ; and the invisible, un- 
 extended, impartible, ever-active, and 
 probably immoveable essence, which we 
 conceive under the name of mind ? When, 
 therefore, we reason analogically from 
 one to the other, so far from arguing 
 from like to like, from species to species, 
 WB argue not even from genus to genus 
 in the most remote degree, but from one 
 thing to its contrary. Is it then at once 
 to be acknowledged, that no analogy 
 whatever can be sustained between them ? 
 The experience of every moment tells us 
 
METAPHYSICAL INQUIRY. 209 
 
 that this is not the case : for, though it is 
 most true, that they exhibit no similarity 
 of substance, form, or quality, yet, strange 
 as it may appear, there are nevertheless 
 the strongest analogies upheld between 
 them. And it is upon these analogies, 
 that some of the most important in- 
 terests and speculations of the human 
 race depend. " The analogy of the ma- 
 terial world," says Sir James Mackin- 
 tosh, " is indeed faint, arid often delu- 
 sive, yet we dare not utterly reject that, 
 upon which the whole technical language 
 of mental and moral science is neces- 
 sarily framed."* All our ideas of sen- 
 sation are necessarily derived from the 
 Sensible world : and in the language 
 of its images are all our mental specu- 
 lations clothed. We might indeed have 
 gathered up metaphysical notions from 
 mental contemplation and analysis ; but 
 unless we expressed them in the lan- 
 guage of physical ideas, and of the ma- 
 
 * Dissertation, 406. 
 P 
 
210 METAPHYSICAL INQUIRY. 
 
 terial world, we should have been alto- 
 gether unable to converse upon such 
 subjects. Had there, then, been no 
 kind of similarities between them, the 
 most important subjects could never 
 have been disseminated amongst us : 
 and, unless a different constitution had 
 been provided us, we must for ever have 
 remained in the deepest ignorance of the 
 great ends and objects of our existence. 
 It has not unfrequently been a puz- 
 zling question to philosophers to account 
 for this strange paradox, of such striking 
 analogies as are presented between these 
 two great classes of subjects, the most 
 unlike in nature, and the very opposite 
 of one another. I would venture to 
 suggest that this apparent anomaly takes 
 its rise from inattention to the subject 
 of Causation, and its two distinct chains 
 of Being and Action.. Between the 
 mental and material Beings, it is true, 
 that no similarity exists ; but between 
 the chains of mental and material Ac- 
 
METAPHYSICAL INQUIRY. 211 
 
 tion, between their Adjuncts, Relations, 
 and Circumstances, the most striking re- 
 semblances must be acknowledged. Nor 
 do these Resemblances appear to be ac- 
 cidental ; but rather to be thus adjusted 
 and contrived by the Creator, for the 
 purposes to which they have been so 
 universally applied. Force, Motion, 
 Place, and Time, have precisely the 
 same relation to Matter, as Power, 
 Change, Coexistence, and Succession, 
 have to Mind, and, as it were, typify 
 each other to our comprehension ; whilst 
 all the relations of Number are equally 
 applicable to both. 
 
 We talk justly of analyzing and com- 
 bining ideas; for, as we must express 
 ourselves in some material images, the 
 language of Chemistry is perhaps the 
 most adapted to explain our sentiments. 
 Moral qualities are said to excite our mo- 
 ral feelings of disgust or approbation, 
 pain or pleasure, as the same feelings 
 are actually excited by the physical qua- 
 
212 METAPHYSICAL INQUIRY. 
 
 lities of the bodies with which we are 
 conversant. But it is in the unceasing 
 agency, exerted by external causes, in 
 the continued action by the powers of 
 nature upon our bodies, maintaining their 
 life, and functions, and involuntary mo- 
 tions and in the unceasing, ever-flowing 
 train of thought and feelings in our souls, 
 maintained in like manner, indepen- 
 dently of our will, we know not how, 
 but it must be by some spiritual and not 
 mechanical agency, that the closest simi- 
 larities are to be observed. Nor are such 
 similarities to be traced only in the indi- 
 viduals ; but perhaps more decidedly in 
 the great continued chain of external ac- 
 tion, by which each individual is con- 
 nected with each of its own world. 
 
 The independent chains of mental and 
 material successions of action appear, as 
 it were, continually to come into contact, 
 yet never cross. When a clock has 
 struck, a material movement is conveyed 
 along the auditorial apparatus to the 
 
METAPHYSICAL INQUIRY. 213 
 
 sensorium ; and according to other sys- 
 tems besides those of the materialists, 
 motion is communicated to the soul it- 
 self. Yet analogy, I may say experience 
 upon all natural bodies, would lead us 
 immediately to presume that the mo- 
 tion, after a momentary concentration 
 in the sensorium, is again communicated 
 through the brain and skull to the sur- 
 rounding air, and that no part of it 
 can be lost to the material world by 
 being communicated to the immaterial. 
 Through our sensations the internal 
 train of thought is continually varied by 
 the external chain of action : and through 
 our mental power the external chain of 
 action is influenced and diverted in com- 
 pliance with our inward thoughts and 
 designs. And by means of this subser- 
 vient chain of material action our com- 
 munication with each other is upheld. 
 
 Yet by such analogies, how often are 
 we led astray ! We talk of being acted 
 upon by motives, as by weights in a 
 
214 METAPHYSICAL INQUIRY. 
 
 balance. We ponder, we weigh argu- 
 ments, we balance objections, and we 
 decide. In these instances we do not 
 speak improperly ; yet, if, by such lan- 
 guage, we are led to fancy, that the 
 mind, which weighs, is to be compared 
 with the balance itself, instead of with 
 the person, who holds the balance and 
 judges of the operation of the weights ; 
 if we are led to imagine that the same 
 irresistible influence is exerted upon our 
 minds, as is exerted upon the scales ; we 
 use analogy, not in its proper sphere, as 
 the mere suggestion of a probability, but 
 as a proof: and we wander still further 
 from the path, and conceive a similarity, 
 where none exists, comparing the weight 
 itself a material being, an antecedent 
 cause, with the Motive, no being at all, 
 no antecedent cause, but a mere object, a 
 jinal cause, which some spiritual agent or 
 antecedent cause proposes to compass or 
 avoid. Yet it is to this favourite and 
 fallacious argument, that the assertors 
 
METAPHYSICAL INQUIRY. 215 
 
 of the philosophical scheme of Fatalism 
 and Necessity have most commonly re- 
 course : and chiefly upon such grounds 
 as these are our Free will and Responsi- 
 bility denied. 
 
 Analogy, as an instrument of proof \ is 
 feeble, and never to be relied on : as an 
 instrument of invention, founded upon 
 similarities, suggesting probabilities and 
 hypotheses, it is the very right arm of 
 science : and as a weapon of defensive 
 argument against the sceptic, it is one of 
 the most powerful that was ever wielded. 
 In its first capacity, unfortunately, it has 
 been but too generally used ; in its se- 
 cond, almost wholly overlooked ; but in 
 its third, its powers and temper have been 
 most ably proved in one of the first meta- 
 physical works in the English language, 
 Butler's Analogy. 
 
 The analogical arguments of Butler 
 are unanswerable. If such and such 
 particular circumstances occur, or are 
 
216 METAPHYSICAL INQUIRY. 
 
 permitted here in the material world, 
 God's book of nature, why should we 
 object to similar apparent anomalies in 
 the moral : or why should we think cer- 
 tain truths in God's book of Revelation 
 too hard for us, when we behold them, 
 typified before our eyes ? 
 
 If plagues and earthquakes break not heaven's 
 
 design, 
 Why then a Borgia or a Cataline ? 
 
 If the Chrysalis, having put off the 
 earthy existence of the worm, is raised 
 to an aerial and more glorious life : why 
 should not this corruptible put on incor- 
 ruption, this mortal, immortality ? Where 
 is the stumbling block to the resurrection 
 of the body ? 
 
 If the slightest incident o*ccurs not in 
 the material world by chance ; but the 
 causes of its occurrence may be traced 
 in the great chain of universal guidance ; 
 if every flower of the field is reared by 
 second causes, nor broken but by direc- 
 tion Is it to be supposed that war, and 
 
METAPHYSICAL INQUIRY. 217 
 
 pestilence, and suffering, are loosed upon 
 mankind by accident ; or that any human 
 being is subjected to injury or sorrow by 
 mere chance, or at the caprice of such a 
 creature as himself? Are we not a 
 fortiori instructed by the analogy, unhe- 
 sitatingly to receive the truths of revela- 
 tion, that there is a moral and a final 
 cause for moral suffering ? Are we not 
 directed to look beyond the chilling 
 figment of the Optimist and Heathen, 
 which would limit the power of omnipo- 
 tence to general workings only, and to 
 rely upon an overruling providence 
 having an especial regard to the welfare 
 of every individual creature ? to rest 
 in faith, that no Spirit can inflict an 
 injury upon another, unless by its own 
 assistance or default; that the crimes 
 of the oppressor are only injuries to 
 himself; and, if humbly received and 
 appreciated, are converted immediately 
 or ultimately into blessings to the op- 
 pressed ? 
 
218 METAPHYSICAL INQUIRY. 
 
 When we see that every particle of 
 the material world is connected in its 
 bearings with every other portion of the 
 same, not on this earth alone, but 
 throughout the system of which it is 
 a part when we observe likewise that 
 the conduct of each individual upon the 
 surface of that earth extends its moral 
 influence to his neighbours, expanding 
 in a wider and a wider circle, concurring 
 with the rest, till it influences the destiny 
 of the whole May we not conceive the 
 possibility of a moral connexion beyond 
 its sphere ? And when we comprehend 
 the glorious discoveries of Herschel, and 
 find the earth c and all that it inherit* 
 shrinking to a less conspicuous station 
 in the whole, than we may now conceive 
 is occupied by the humblest individual 
 upon her surface Are we not almost 
 tempted to regard, not only the material 
 globe but the moral system, to which it is 
 subservient, as a small and individual pnrt 
 of a comprehensive and connected whole ; 
 
METAPHYSICAL INQUIRY. 219 
 
 and a priori to suppose that a primeval 
 taint upon its purity, like the crime of 
 any human being, would remain with it 
 in its consequences, rankling to the last 
 hour of its existence, unless redeemed 
 and rectified, according to its wants, by 
 superhuman aid ? 
 
 And if future discovery should ever 
 present to us the great ruler of our 
 material system here below, under the 
 trinitarian aspect of Fire at its orb, of 
 Light proceeding from it, and of Spirit 
 returning to it, three conditions of one 
 and the same etherial substance if such 
 an hypothesis is merely conceivable, 
 though unproved if such a mystery 
 can take place in matter why should 
 the minute philosopher shrink from the 
 revelation, that has condescended to 
 instruct him in the great mystery of the 
 Christian faith, of Three Persons in one 
 God, each uncreate, almighty and in- 
 comprehensible, in glory equal, in ma- 
 jesty co-eternal ? 
 
220 METAPHYSICAL INQUIRY. 
 
 The passages in the Scriptures in 
 which the persons of the Christian Tri- 
 nity are shadowed forth, physically, by 
 the same natural powers which are sup- 
 posed to constitute the original triad of 
 the Gentiles, and spiritually, not as 
 the mere attributes or faculties of a 
 supreme mind, as represented in the 
 heathen triads, but as distinct persons, 
 claiming such peculiar attributes or 
 respectively condescending, in the co- 
 venant of grace, to address themselves 
 to such faculties of man, are too nu- 
 merous to require to be specifically 
 referred to. The Father is continually 
 typified as a Fire accepting the sacrifices, 
 consuming and punishing the guilty, as 
 the Lord of all power and might, the 
 dispenser of blessings, to whom all 
 prayers are commonly addressed, the 
 fountain of divinity, approached and 
 known to us only through the mediation 
 of the Son the Son as Light, as a 
 Mediator and a Teacher, enlightening- 
 
METAPHYSICAL INQUIRY. 221 
 
 the understanding, addressing himself 
 more particularly to the Intellect, point- 
 ing out the distinctions between good 
 and evil ; the Spirit, as Spirit or Air, a 
 mighty rushing wind, operating upon 
 the Affections, Feelings, or Emotions. 
 We are commanded by the Christian 
 faith to look to the Son for knowledge, 
 to obey his instructions, and to accept 
 the conditions of Salvation he has offered 
 to the Spirit, for grace to influence us 
 in all our feelings, wishes and intentions 
 and to the Father, our prayers are to 
 be directed for pardon for blessings and 
 for the power to act. 
 
 I w r ould not presume to lay stress upon 
 any of the hypotheses I may have ad- 
 vanced or adduced in this inquiry. Man 
 is apt to indulge his fancy in building 
 systems, which he conceives may set 
 forth the wisdom and goodness or mag- 
 nify the power of his Creator ; but when 
 he brings them to the test, and finds the 
 
222 METAPHYSICAL INQUIRY. 
 
 truth itself, he finds it infinitely more 
 sublime than the happiest flight of his 
 imagination. Yet as we must neces- 
 sarily take all our ideas, as well as our 
 language, from the sensible world as 
 we are taught that it is a glass, in which 
 things spiritual are purposely, but darkly, 
 shadowed forth and as Physical sci- 
 ence is naturally subservient to Mental, 
 and both are but the handmaids of Reli- 
 gion ; I deem that we outstep not the 
 bounds of true philosophy, when, in the 
 glorious works of the Almighty, we 
 humbly trace a confirmation of his word. 
 
 FINIS. 
 
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