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.
It now appears that there is not one natural selection, and one survival of the fittest only, but two natural selections, and two survivals of the fittest, the one of which may be objected to as an expression more fit for religious and general literature than for science, but may still be admitted as sound in intention, while the other, inasmuch as it supposes accident to be the main purveyor of variations, has no correspondence with the actual course of things; for if the variations are matters of chance or hazard unconnected with any principle of constant application, they will not occur steadily enough, throughout a sufficient number of successive generations, nor to a sufficient number of individuals for many generations together at the same time and place, to admit of the fixing and permanency of modification at all. The one theory of natural selection, therefore, may, and indeed will, explain the facts that surround us, whereas the other will not. Mr. Charles Darwin’s contribution to the theory of evolution was not, as is commonly supposed, “natural selection,” but the hypothesis that natural selection from variations that are in the main fortuitous could accumulate and result in specific and generic differences.