'Lamarck was an ardent advocate of uniformity, as against the Cataclysmal School. The main principles are laid down in his Hydrogéologie, that all the revolutions of the earth are extremely slow. "For Nature," he says, "time is nothing. It is never a difficulty, she always has it at her disposal; and it is for her the means by which she has accomplished the greatest as well as the least results[86]."'
On the subject of subaerial denudation (the action of rain and rivers in wearing down the earth's surface), Lamarck's views were as clear and definite as those of Hutton himself; though it is almost certain that he could never have seen, or even heard of, the writings of the great Scottish philosopher. On some other questions of geological dynamics, however, it must be confessed that Lamarck's views and speculations were rather crude and unsatisfactory.
In his Philosophie Zoologique, published in the same year that Charles Darwin was born (1809), Lamarck brought forward a great body of evidence in favour of evolution, derived from his extensive knowledge of botany, zoology and geology. He showed how complete was the gradation between many forms ranked as species, and how difficult it was to say what forms should be classed as 'varieties' and what as 'species.'
But when he came to indicate a possible method by which one species might be derived from another, he was less happy in his suggestions. He recognised the value of the evidence derived from the study of the races which have arisen among domestic animals, and from the crossing of different forms. But his main argument was derived from the acknowledged fact that use or disuse may cause the development or the partial atrophy of organs—the case of the 'blacksmith's arm.' Unfortunately some of the suggestions made by Lamarck, in this connexion—like that of the elongation of the giraffe's neck to enable it to browse on high trees—were of a kind that made them very susceptible to ridicule. His theory was of course dependent on the admission that acquired characters were transmitted from parents to children, and in the absence of any suggestion of 'selection,' it did not appeal strongly to thinkers on this question.
Lyell first became acquainted with the writings of Lamarck in 1827. As he was returning from the Oxford circuit for the last time—having now resolved to give up law and devote himself to geological work exclusively—he wrote to his friend Mantell as follows:—
'I devoured Lamarck en voyage.... His theories delighted me more than any novel I ever read, and much in the same way, for they address themselves to the imagination, at least of geologists who know the mighty inferences which would be deducible were they established by observations. But though I admire even his flights, and feel none of the odium theologicum which some modern writers in this country have visited him with, I confess I read him rather as I hear an advocate on the wrong side, to know what can be made of the case in good hands. I am glad he has been courageous enough and logical enough to admit that his argument, if pushed as far as it must go, if worth anything, would prove that men may have come from the Ourang-Outang. But after all, what changes species may really undergo! How impossible will it be to distinguish and lay down a line, beyond which some of the so-called extinct species have never passed into recent ones. That the earth is quite as old as he supposes, has long been my creed, and I will try before six months are over to convert the readers of the Quarterly to that heterodox opinion[87].'
Lyell was at that time at work on his review for the Quarterly of Scrope's Central France, and was also completing the 'first sketch' of the Principles. But it is evident that as the result of continued study of Lamarck's book, Lyell found it, in spite of its fascination, to embody a theory which he could not but regard as unsound and not calculated to prove a solution of the great mystery of evolution. Accordingly when the second volume of the Principles was issued in 1832, it was found to contain in its opening chapters a very trenchant criticism of Lamarck's theory.
It is only fair to remember, however, that in 1863, after Lyell had accepted the theory of Natural Selection he wrote to Darwin:
'When I came to the conclusion that after all Lamarck was going to be shown to be right, and that we must "go the whole orang" I re-read his book, and remembering when it was written, I felt I had done him injustice[88].'
It is interesting also to notice that Darwin, like Lyell, gradually came to entertain a higher opinion of the merit of Lamarck's works, than he did on his first perusal of them. In 1844, Darwin wrote to Hooker, 'Heaven forfend me from Lamarck nonsense!' and in the same year he speaks of Lamarck's book as 'veritable rubbish,' an 'absurd though clever work[89].' When, after the publication of the Origin of Species, Lyell referred to the conclusions arrived at in that work as similar to those of Lamarck, Darwin expressed something like indignation, and he wrote to their 'mutual friend' Hooker, 'I have grumbled a bit in my answer to him' (Lyell) 'at his always classing my book as a modification of Lamarck's, which it is no more than any author who did not believe in the immutability of species[90].' In this case, as is so frequently seen in the writings of Darwin, it is evident that he attaches infinitely less importance to the establishment of the fact of the evolution of species, than to the demonstration of a possible mode of origin of that evolution. But that later in life Darwin came to take a more indulgent view of the result of Lamarck's labours is shown by a passage in his 'Historical Sketch' prefixed to the Origin, in 1866. Lamarck, he says, 'first did the eminent service of arousing attention to the probability of all change in the organic world, as well as in the inorganic world, being the result of law and not of miraculous interposition[91].'