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DISCUSSION 
DARWIN AND WHEWELL 

PAUL R. THAGARD 

IN a recent article, Michael Ruse describes some important respects in which 
Charles Darwin’s work was influenced by William Whewell.’ However, the 
influence of Whewell on Darwin was even greater than Ruse suggests. I shall 
show this by presenting new evidence that Darwin had read Whewell’s 
Philosophy of the Inductive Sciences and then arguing that Darwin was strongly 
influenced by Whewell’s views on consilience of inductions and true causes. 

No direct evidence has been found that Darwin owned or read Whewell’s 
Philosophy of the Inductive Sciences. This is surprising, since Darwin admired 
Whewell’s History of the Inductive Sciences, and after reading J. F. W. 
Herschel’s review of the History and Philosophy he wrote in a notebook: ‘I must 
study Whewell on Philosophy of Science.” But indirect evidence that Darwin 
read Whewell’s Philosophy is to be found in Darwin’s The Variation of 
Animals and Plants Under Domestication, published in 1868. Late in the book, 
Darwin introduces his controversial theory of pangenesis. He puts it forward as 
a provisional hypothesis, one that brings together a multitude of facts and may 
thus be serviceable until a better hypothesis is advanced. Darwin defends this 
procedure by quoting Whewell: ‘As Whewell, the historian of the inductive 
sciences remarks: - “Hypotheses may often be of service to science, when they 
involve a certain portion of incompleteness, and even of error.“‘3 Except for the 
spelling of ‘errour’, the capitalization of ‘hypotheses’, and the absence of 
italics, this is the exact wording of the maxim as stated by Whewell in the second 
volume of The Philosophy of the Inductive Sciences.4 

Of course, Darwin may have quoted the maxim from some source other than 
Whewell’s Philosophy. One possible source is Whewell’s own History, but 
although that work contains the ideas expressed in the maxim,5 I have not 
‘Michael Ruse, ‘Darwin’s Debt to Philosophy: An Examination of the Influence of the 

Philosophical Ideas of John F. W. Herschel and William Whewell on the Development of Charles 
Darwin’s Theory of Evolution’ Studies in the History andPhilosophy ofScience, 6 (1975), 159-181. 

*Quoted by Ruse in ibid., 166. 
3Charles Darwin. The Variation of Animals and Plants Under Domestication (London: John 

Murray, 1868). Vol. 2, p. 357. 
4 William Whewell, The Philosophy of the Inductive Sciences, facsimile of the 2nd edn, London, 

1847, (New York: Johnson Reprint Corporation, 1%7), Vol. 2, p. 60. 
SWhewell, The History of the Inductive Sciences facsimile of the 3rd edn, London, 1857, 

(London: Frank Cass, 1967), p. 140). 
Stud. Hist. Phil. Sci. 8, (1977). No. 4. Printed in Great Britain. 

353 



354 Studies in History and Philosophy of Science 

found in it a statement of the maxim as such. Whewell’s characterization of the 

division between the History and the Philosophy implies that the statement of 
such maxims be reserved for the latter work.6 Another likely source for Darwin 

of Whewell’s maxim is Herschel’s review of Whewell’s books. Herschel 

commends Whewell for emphasizing the value of imcomplete hypotheses, but 

he does not actually quote the maxim .’ Hence the most probable source of 

Darwin’s quotation from Whewell is the original one: Whewell’s Philosophy. 
That Darwin quoted Whewell in 1868 would be of interest even if it did not 

show that he had read Whewell’s Philosophy. Darwin’s references to 
methodologists were infrequent, and it is significant that he would refer to 

Whewell long after he knew him personally and read his History. 
The conclusion that Darwin read Whewell’s Philosophy is reinforced by 

noticing Darwin’s use of Whewell’s important notion of the consilience of 

inductions. Whewell says that ‘the evidence in favour of our induction is of a 

much higher and more forcible character when it enables us to explain and 

determine cases of a kind different from those which were contemplated in the 

formation of our hypothesis.‘8 According to Whewell, ‘the cases in which 

inductions from classes of facts altogether different have thus jumped together 
belong to the best established theories which the history of science contains.‘g A 

theory achieves a consilience of inductions by explaining a number of different 

classes of facts, some of which were not contemplated in the formation of the 

hypothesis. I shall now present two striking passages where Darwin, without 

using the term ‘consilience of inductions’, recommends consilience as the 

criterion for judging his theory of evolution. 

The first is from the same source as Darwin’s quotation from Whewell - 

The Variation of Animals and Plants Under Domestication. Darwin states: 

In scientific investigation it is permitted to invent any hypothesis, and if it explains 
various large and independent classes of facts it rises to the rank of a well-grounded 
theory. The undulations of the ether and even its existence are hypothetical, yet 
every one now admits the undulatory theory of light. The principle of natural 
selection may be looked at as a mere hypothesis, but rendered in some degree 
probable by what we positively know of the variability of organic beings in a state 
of nature, - by what we positively know of the struggle for existence, and the 
consequent almost inevitable preservation of favourable variation, - and from the 
analogical formation of domestic races. Now this hypothesis may be tested, - and 
this seems to me to be the only fair and legitimate manner of considering the whole 
question, - by trying whether it explains several large and independent classes of 
facts; such as the geological succession of organic beings, their distribution in past 
and present times, and their mutual affinities and homologies. If the principle of 
natural selection does explain these and other large bodies of facts, it ought to be 

Glbid., Vol. 1, pp. 4-5. 
75. F. W. Herschel, Review of William Whewell, Hisrory of the Inductive Sciences and 

Philosophy of the Inductive Sciences, Qmrterly Review, 68 (1841), 194. 
8Whewel1, Philosophy, Vol. 2, 65. 
91bid., Vol. 2, 65. 



Discussion 355 

received. On the ordinary view of each species having been independently created, 
we gain no scientific explanation of any of these facts.‘O 

This passage concisely summarizes Darwin’s long argument in The Origin of 
Species. Darwin believes that his theory deserves to be accepted because it 
explains several large and independent classes of facts. In short, it achieves a 

consilence of inductions. 

To the second edition of the Origin Darwin added the sentence: ‘I cannot 
believe that a false theory would explain, as it seems to me that the theory of 

evolution does explain, the several large classes of facts above specified.“’ In 

the sixth edition of 1878, Darwin replaced this with the following passage which 

shows definite awareness that he was using an established pattern of argument: 

It can hardly be supposed that a false theory would explain, in so satisfactory a 
manner as does the theory of natural selection, the several large classes of facts 

above specified. It has recently been objected that this is an unsafe method of 
arguing; but it is a method used in judging of the common events of life, and has often 
been used by the greatest natural philosophers. The undulatory theory of light has 
thus been arrived at; and the belief in the revolution of the earth on its own axis was 
until lately supported by hardly any direct evidence.12. 

Again, Darwin emphasizes the explanation of different classes of facts, the 

achievement of a consilience of inductions. It is also noteworthy that the 

undulatory theory of light, mentioned in both of the long passages quoted 

above, was one of Whewell’s favourite examples of the consilience of 

inductions. 

Another methodological issue on which Darwin followed Whewell was the 

controversial issue of true causes, verae causae. I believe that Ruse is mistaken 
in attributing to Darwin a position on true causes akin to that of J. F. W. 

Herschel.13 Ruse claims that Darwin’s major motive for stressing the analogy 

between artificial and natural selection was that the analogy enabled him to 

show, by Herschel’s standards, that natural selection is a true cause. As Ruse 

points out, Herschel maintained that hypotheses must employ only true causes, 

but allowed that a cause could be judged to be true if it were analogous to causes 
directly perceived.14 

However, Whewell rejected Herschel’s emphasis on analogy, arguing that 

analogy cannot serve as a guide to true causes, since the restriction of causes to 

those of such kinds as we know to exist is no restriction at a11.15 It admits for 

‘ODarwin, Vuriation, Vol. 1, 8f. 
“See The Origin of Species by Charles Darwin, A Variorum Text, Morse Peckham (ed.) 

(Philadelphia: University of Pennsylvania Press, 1959), p. 748. 
‘ZIbid., p. 784. 
‘3 Ruse, op. cit. note 1, pp. 175-6. 
14Herschel, Preliminary Dbcourse on the Study of Natural Philosophy (London: Longman, 

1830), pp. 149, 197, Cf. Condillac, Oeuvres Philosophiques (Paris, Presses Universitaires de 
France, 1947), 1, p. 204; and Dugald Stewart, Collected Works, Sir William Hamilton (ed.), 
(Edinburgh: Thomas Constable, 1854), 3, 305. 

‘5 Whewell, Philosophy, Vol. 2, p. 283. 



356 Studies in History and Philosophy of Science 

example the Cartesian hypothesis of vortices, since we are familiar with whirling 

fluids carrying bodies around in orbit. Whewell concluded that a cause is true if 

it leads to a consilience of inductions: 
We may, provisorily, assume such hypothetical causes as will account for any given 
class of natural phenomena; but that when two different classes of facts lead us to 
the same hypothesis, we may hold it to be a true cause.16 

Darwin shared this anti-Newton, anti-Herschel position on true causes. In 1860, 

he wrote to J. D. Hooker, following a lecture given by T. H. Huxley to the 

Royal Institution: ‘I must confess that as an exposition of the doctrine the 

lecture seems to me an entire failure.“’ Darwin’s main complaint against 

Huxley is: 

He gave no just idea of Natural Selection. I have always looked at the doctrine of 
Natural Selection as an Hypothesis, which, if it explained several large classes of 
facts, would deserve to be ranked as a theory deserving acceptance.18 

Darwin remarks that the difference between him and Huxley is ‘that he rates 

higher than I do the necessity of Natural Selection being shown to be a vera 
causa always in action.“g In accord with the doctrine of Whewell, Darwin had 
no special concern about whether his hypothesis involved a true cause; all that 

mattered is that it explained several classes of facts and thus achieved a 

consilience of inductions. Hence Darwin did not need the analogy between 

natural and artificial selection to show that natural selection is a true cause. The 

analogy was important to him for other reasons, such as its heuristic value and 

its contribution, independent of the issue of true causes, to the acceptability of 

the theory of evolution by means of natural selection.20 

A strong case thus exists to support my contention that Darwin read 

Whewell’s Philosophy of the Inductive Sciences. Certainly, Darwin’s 
methodology was similar to Whewell’s on two very important matters, 

consilience of inductions and true causes. Darwin’s debt to Whewell was 

therefore considerable.2’ 

University of Michigan, Dearborn 

‘Glbid., Vol. 2, p. 286. See also Robert E. Butts, ‘Whewell On Newton’s Rules of Philosophizing’, 
in R. E. Butts and J. W. Davis (eds.), The Methodological Heritage of Newton, (Toronto: 
University of Toronto Press, 1970), 132-149. 

“Charles Darwin, More Letters of Charles Darwin, Frances Darwin and A. C. Seward (eds.), 
(London: John Murray, 1903). 1, p. 139. 

‘albid., 1, 139f. 
191bid., 1, 140. 
20On the heuristic value of the analogy, see for example Darwin, On the Origin of Species, 

facsimile of 1st edn, (Cambridge, Mass.: Harvard University Press, 1964). p. 4. On the contribution 
of the analogy to the acceptability of the theory, see for example ibid., p. 17, and Darwin, The Life 
and Letters, reprint of 1888 edition, (New York: Johnson Reprint Corp., 1969) 3, p. 25. Ruse 
mentions this contribution in ‘Charles Darwin’s Theory of Evolution: An Analysis’, Journal of the 
History of Biology, 8 (1975). pp. 219-241. 

21 See also W. Faye Cannon, ‘The Whewell-Darwin Controversy’, Journal of the Geological 
Society of London, 132 (1976), 377-384.