With this analysis of his observation and his thought we are ready to take up the supreme interest of Darwin’s life, the dramatic study of the conception, elaboration, promulgation, and triumph of his evolutionary theory.
CHAPTER III
DARWIN: THE DISCOVERER
I
The word ‘evolution’ is so popularly accepted and so generally employed in connection with Darwin’s theories that it will never be displaced; but it is not wholly satisfactory, because it always suggests progress from a lower to a higher and hence involves a difficult and invidious definition of terms. Some such phrase as ‘descent with modification’ would probably be more exact. But whatever the term used, to associate it as a scientific theory or discovery exclusively with Darwin or any other one man would be absurd. The natural hypothesis of earlier thinkers was that divine creative power, in whatever shape, had established the different forms of life on the earth pretty much as they exist to-day. But those who looked more deeply, were inclined to surmise, in view of the close and evident bonds of kinship between all living things, that variety had developed from comparative unity and that the vital impulse, having first appeared in elementary forms, became gradually elaborated into more and more complicated organisms. The vast pains that Darwin took to substantiate this view, together with his particular explanation of how the process came about, have forever bound up the idea of evolution with his name, but he did not originate it nor did he claim to have done so.
The various hints and manifestations of earlier evolutionary theory are admirably elucidated in Professor Osborn’s ‘From the Greeks to Darwin.’ The vast curiosity and reflection of Aristotle anticipated here, as everywhere, and some of his sentences have a striking evolutionary bearing: ‘Variety in animal life may be produced by variety of locality.’[389] ‘Locality will differentiate habits also; for instance, rugged highlands will not produce the same results as the soft lowlands.’[390] And Empedocles suggests Darwin’s views even more directly. Under the régime of Biblical and Christian tradition evolutionary thought naturally made little progress. But with the greater freedom of the eighteenth century, notions of modification by descent again appeared. In England Darwin’s grandfather, Erasmus, the botanical poet, speculated curiously on the subject, and there were various other intimations, notably in Chambers’s ‘Vestiges of Creation,’ while Darwin himself felt that he was much influenced by the geological theories of Lyell. In Germany Goethe became profoundly interested in the metamorphoses of life. Especially in France Buffon and St.-Hilaire led up to the ‘Philosophie Zoologique’ of Lamarck, which propounded the theory of modification in a very definite form, and suggested the mode in which the modification was accomplished. Lamarck’s idea was that plants and animals, by an inborn, vital impulse, adapted themselves to their environment, and that these adaptations were transmitted by inheritance. Thus wading birds acquired webbed feet and the neck of the giraffe was elongated in its effort to obtain its food from the branches of the trees. The great stumbling-block of this theory has always been the difficulty of proving that acquired adaptations are inherited.[A]
FOOTNOTES:
[A] Investigators have of course worked constantly and persistently upon this point and I find Professor William McDougall quoted in a Boston Herald editorial of August 16, 1926, as saying: ‘Species may change and undergo evolution through the efforts of the individual parents to adapt themselves to conditions.’
What is of interest to us, however, is Darwin’s attitude toward his more immediate predecessors, Buffon, Lamarck, Chambers, etc. This attitude has been a matter of much comment by Samuel Butler and others and it is not perfectly easy to understand. That Darwin in his earlier thinking as well as in his later was influenced by previous investigators is evident enough, for instance in touches like that in the ‘Voyage of the Beagle’: ‘Nature by making habit omnipotent, and its effects hereditary, has fitted the Fuegian to the climate and productions of his miserable country.’[391] Also, his frequent comments show that he knew what had been written before him and had profited by it, and in the later editions of the ‘Origin’ he took some pains to acknowledge the obligation. Yet his tone in his letters is by no means respectful and of Lamarck especially, who had done the most, it is difficult for him to speak without a sneer. Thus, in 1844 he writes: ‘Heaven forefend me from Lamarck nonsense of a “tendency to progression,” “adaptations from the slow willing of animals,” etc.! But the conclusions I am led to are not widely different from his; though the means of change are wholly so.’[392] Again, a little later: ‘With respect to books on this subject, I do not know any systematical ones, except Lamarck’s which is veritable rubbish.’[393] And later still, in 1859, he writes to Lyell: ‘You often allude to Lamarck’s work; I do not know what you think about it, but it appeared to me extremely poor; I got not a fact or idea from it.’[394]
Various explanations of Darwin’s treatment of Lamarck have been offered. One at least, that of a disposition to run down a predecessor from jealousy, we may exclude as absolutely as is possible with poor human nature. Everything we know of Darwin in other connections justifies us in doing this. Professor Osborn, after referring to ‘the disdainful allusions to him [Lamarck] by Charles Darwin (the only writer of whom Darwin ever spoke in this tone)’[395] observes that ‘it is very evident from all Darwin’s criticisms of Lamarck, that he had never studied him carefully in the original.’[396] But against this view we have to set Darwin’s own comment (italics mine): ‘What I consider, after two deliberate readings, as a wretched book, and one from which (I well remember my surprise) I gained nothing.’[397] It is true that Darwin, as in the quotation above as to ‘adaptations from the slow willing of animals,’ apparently misinterpreted Lamarck’s view of the self-adaptation of the individual to its environment into the absurd assumption that animals and even plants deliberately willed their own evolutionary progress; but on the other hand Darwin all his life and especially in his later period wavered toward Lamarck’s adaptation theories. It has been suggested that in Darwin’s university years French thought and French scientists were distinctly in disfavor and that Darwin imbibed an enduring dislike of them.[398] Darwin himself hints that he may have been influenced by a prejudice in favor of his grandfather as Lamarck’s predecessor. But it seems more probable that he disliked Lamarck because he regarded him as a theorist and speculator who did not found his argument on a sufficiently broad basis of fact, whereas Darwin toiled for years at observation and experiment before he gave his theory to the world at all. This explanation is indicated in Darwin’s remark to Lyell: ‘As for Lamarck, as you have such a man as Grove with you, you are triumphant; not that I can alter my opinion that to me it was an absolutely useless book. Perhaps this was owing to my always searching books for facts.’[399] In any case one cannot help wishing that Darwin had spoken of a man so prominent and so highly esteemed as Lamarck a little differently.