Darwin's Precursors and Influences

4. Natural selection

by John Wilkins

Copyright © 1996-2003

[Last Update: 21 February 2003]

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Theories not unlike natural selection have been around for a while. Here, courtesy of Cosma Shalizi, is Aristotle's version, based on Empedocles' older view:

A difficulty presents itself: why should not nature work, not for the sake of something, nor because it is better so, but just as the sky rains, not in order to make the corn grow, but of necessity? What is drawn up must cool, and what has been cooled must become water and descend, the result of this being that the corn grows. Similarly if a man's crop is spoiled on the threshing-floor, the rain did not fall for the sake of this--in order that the crop might be spoiled--but that result just followed. Why then should it not be the same with the parts in nature, e.g. that our teeth should come up of necessity -- the front teeth sharp, fitted for tearing, the molars broad and useful for grinding down the food -- since they did not arise for this end, but it was merely a coincident result; and so with all other parts in which we suppose that there is purpose? Wherever then all the parts came about just what they would have been if they had come be for an end, such things survived, being organized spontaneously in a fitting way; whereas those which grew otherwise perished and continue to perish, as Empedocles says his 'man-faced ox-progeny' did.¹

Empedocles' previous view was that random parts of animals would associate in the beginning and those assemblages that were successful would live on, while the others would perish and not reproduce. Once so generated, though, Empedocles did not expect further evolution. Dennett observes that Hume had a similar flirtation with something similar to natural selection. However, none of these throwaway comments were developed, and in Aristotle's case they were eventually ignored in favour of his more general views on final causation.

In the "Historical Sketch" Darwin admitted that he, and Richard Owen who claimed priority after the Origin was published (as was his wont²), had been pre-empted by two writers, Patrick Matthew in 1831, and William Charles Wells in 1813, published in 1818³. Darwin had read neither, as Wells' views were solely applied to human races, and Matthew's were presented in an appendix to a work on naval timber. Neither author developed their views further, and Darwin clearly deserves credit for the global applicability of selection as a mechanism of evolution. Darwin developed his mechanism from an analogy with the processes of selection by breeders for traits they considered desirable, and tied it in which the process he read in Malthus so that "it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones would be destroyed. The result of this would be the formation of new species. Here, then, I had at last got a theory by which to work ..."⁴. While Matthew was an evolutionist of the social radical variety, he did not present selection as a mechanism of evolution.

Edward Blyth had also published a natural selection theory in 1837, but he argued against transmutation of species because if it occurred it would destroy species' integrity: "we should seek in vain for those constant and invariable distinctions which are found to obtain"⁵. As de Beer says, it is unlikely that Darwin was indebted to him if his views were so opposed to Darwin's⁶. Darwin had read Blyth, but not until after his own formulation, and Blyth later became a valued and constant correspondent of Darwin's. If he felt that Darwin had, as Eiseley claimed, plagiarised natural selection from him, he would not have become such a strong friend and supporter of Darwinian evolution. Interestingly, Blyth was one of the authors who Darwin mentioned to Wallace when responding to his 1855 paper.

Other candidates include Prichard, Lawrence and Naudin, but their statements are vague and undeveloped⁷.

Richard Owen (right) as an old man

Some historians believe that Owen tried to claim priority for natural selection, but it was clear that he was never entirely happy with evolution. However, had he not been as difficult a man as he was (although of many virtues, and having suffered from the revisionism of the Darwinian tradition), he may have become a supporter of Darwin, for the foundations of his views were not so very different from Darwin's⁸. Nevertheless, there is no real evidence that he in any way gave the idea to Darwin. Richards (1992) thinks that Owen had been slapped down in his youthful transmutationist views by the geologist Sedgwick and orthodox religious leaders in 1837, and that he ran up his orthodox colours then. In a review of his own response to the Origin, an anonymous reviewer noted that "so far as we can gather from his communication, he denies the Darwinian doctrine, admits the accuracy of its basis, and claims to be the first to point out the truth of the principle on which it is founded"⁹. Owen may have some justice on his side, but the evidence is ambiguous, and there is no sign of his direct influence on Darwin concerning natural selection, then or later.

A more serious claim to have influenced Darwin can be made for the Scottish economist Adam Smith, in his work The Wealth of Nations of 1776. There is a clear analogy between the survival of the corporation through successful trading and the survival of a hereditary lineage through advantageous traits. It is known that Darwin read Smith and those political and social commentators that followed him, and it would be surprising if these ideas did not lodge in his thoughts. However, the biological and social and moral worlds were thought at that time to be completely divorced. Remember, this was a time when even the existence of an involuntary reflex was considered unthinkable: biology simply could not overcome conscious will (for example Marshall Hall in 1832 was unable to publish his reflex studies in the Royal Society's proceedings¹⁰). Malthus' views, e.g., were based on the assumption that the poor were simply lacking in the moral fibre and strength of will. The extension of this pattern of explanation to the biological world was a major leap of imagination.

Smith thought that there was an `Invisible Hand' effect that a free market created, ensuring that efficient trading bodies and manufacturers flourished purely as a result of the pursuit of self-interest. He characterised the market in terms of a division of labour, and the resulting equilibrium was not due to any planning or intention on the part of individual corporations or agents to maximise the common good; that was an undesigned outcome. Smith's views, via Malthus, were applied by David Ricardo to the British Corn Laws from 1815, and they were also influential on John Stuart Mill. The idea of a mechanism that determined the mean effect of the activities of populations and their survival and spread may have influenced Darwin's desire to come up with a mechanism not based upon design to explain organic change, and may have suggested a way to do it¹¹. However, Ricardo's and Malthus' views tended to make a virtue of these necessities, which Darwin's mechanism of natural selection did not, despite the interpretation of the misnamed "social Darwinists" later that century.

Darwin's terminology for natural selection was based on an analogy with the breeding practices of animal husbandry, artificial selection. Wallace, whose view did not derive from a similar analogy, was uncomfortable with the voluntarist implications of the term and proposed instead Spencer's phrase "survival of the fittest" which Spencer had developed in a purely philosophical manner. Darwin later bemoaned this choice, but he adopted it in later editions of the Origin. However, he wrote that it was a metaphorical use similar to those expressions astronomers use describing God keeping things in their orbit and of no direct importance, but wished instead he had used the term "natural preservation" to avoid confusion¹².

In sum, while there were precursors, it can be fairly concluded that Darwin was not either plagiarising or directly influenced by anyone who had proposed natural selection as an explanation of adaptation in living organisms. And Wallace's discovery was truly independent, though based on many of the same influences, and he deserves the title co-discoverer, although for the rest of his life he cheerfully gave priority and credit to Darwin, even after the latter's death.

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