more elements than one. There is concerned in it not one cause but a plurality of causes. A "factor" is specially a doer. It is that which works and does. It is a word appropriated to the conception of an immediate, an efficient cause. And of these causes there are more than one. Neither natural selection nor survival of the fittest is of itself a sufficient explanation. They must be supplemented. There are other factors which must be admitted and confessed.
This is the first and most notable feature of Mr. Spencer's articles. But there is another closely connected with it, and that is the emphatic testimony he bears to the fact that the existing popular conception is unconscious of any defect or failing in the all-sufficiency of the Darwinian hypothesis. He speaks of the process brought into clear view by Mr. Darwin, and of those with whom he is about to argue, as men "who conclude that taken alone it accounts for organic evolution."[1] In order to make his own coming contention clearer, he devises new forms of expression for definig acurately the hypothesis of Darwin. He calls it "the natural selection of favorable variations." Again and again he emphasizes the fact that these variations, according to the theory, were "spontaneous," and that their utility was only "fortunate," or, in other words, accidental. He speaks of them as "fortuitously arising";[2] and it is of this theory, so defined and rendered precise, that he admits that it is now commonly supposed to have been "the sole factor" in the origin of species.
It is surely worth considering for a moment the wonderful state of mind which this declaration discloses. When Mr. Herbert Spencer here speaks of the "popular" belief, he is not speaking of the mob. He is not referring to any mere superstition of the illiterate multitude. He is speaking of all ranks in the world of science. He is speaking of some overwhelming majority of those who are investigators of Nature in some one or other of her departments, and who are supposed generally to recognize as a cardinal principle in science, that the reign of law is universal there—that nothing is fortuitous—that nothing is the result of accident. Yet Mr. Herbert Spencer represents this great mass and variety of men as believing in the preservation of accidental variations as "the sole factor," and as the one adequate explanation in all the wonders of organic life.
Nor can there be any better proof of the strength of his impression upon this subject than to observe his own tone when he ventures to dissent. He speaks, if not literally with bated breath, yet at least with a deferential reverence for the popular
