The distinction between Darwinism and Neo-Darwinism is generally believed to lie in the adoption of a theory of natural selection by the younger Darwin and its non-adoption by the elder.  This is true in so far as that the elder Darwin does not use the words “natural selection,” while the younger does, but it is not true otherwise.  Both writers agree that offspring tends to inherit modifications that have been effected, from whatever cause, in parents; both hold that the best adapted to their surroundings live longest and leave most offspring; both, therefore, hold that favourable modifications will tend to be preserved and intensified in the course of many generations, and that this leads to divergence of type; but these opinions involve a theory of natural selection or quasi-selection, whether the words “natural selection” are used or not; indeed it is impossible to include wild species in any theory of descent with modification without implying a quasi-selective power on the part of nature; but even with Mr. Charles Darwin the power is only quasi-selective; there is no conscious choice, and hence there is nothing that can in strictness be called selection.

It is indeed true that the younger Darwin gave the words “natural selection” the importance which of late years they have assumed; he probably adopted them unconsciously from the passage of Mr. Matthew’s quoted above, but he ultimately said, {87a} “In the literal sense of the word (sic) no doubt natural selection is a false term,” as personifying a fact, making it exercise the conscious choice without which there can be no selection, and generally crediting it with the discharge of functions which can only be ascribed legitimately to living and reasoning beings.  Granted, however, that while Mr. Charles Darwin adopted the expression natural selection and admitted it to be a bad one, his grandfather did not use it at all; still Mr. Darwin did not mean the natural selection which Mr. Matthew and those whose opinions he was epitomising meant.  Mr. Darwin meant the selection to be made from variations into which purpose enters to only a small extent comparatively.  The difference, therefore, between the older evolutionists and their successor does not lie in the acceptance by the more recent writer of a quasi-selective power in nature which his predecessors denied, but in the background—­hidden behind the words natural selection, which have served to cloak it—­in the views which the old and the new writers severally took of the variations from among which they are alike agreed that a selection or quasi-selection is made.