Life and Habit

by Samuel Butler

Mr. Darwin himself has admitted that in the earlier editions of his “Origin of Species” he “underrated, as it now seems probable, the frequency and importance of modifications due to spontaneous variability.” And this involves the having over-rated the action of “natural selection” as an agent in the evolution of species. But one gathers that he still believes the accumulation of small and fortuitous variations through the agency of “natural selection” to be the main cause of the present divergencies of structure and instinct. I do not, however, think that Mr. Darwin is clear about his own meaning. I think the prominence given to “natural selection” in connection with the “origin of species” has led him, in spite of himself, and in spite of his being on his guard (as is clearly shown by the paragraph on page 63 “Natural Selection,” above referred to), to regard “natural selection” as in some way accounting for variation, just as the use of the dangerous word “spontaneous,”—though he is so often on his guard against it, and so frequently prefaces it with the words “so-called,”—would seem to have led him into very serious confusion of thought in the passage quoted at the beginning of this paragraph.

For after saying that he had underrated “the frequency and importance of modifications due to spontaneous variability,” he continues, “but it is impossible to attribute to this cause the innumerable structures which are so well adapted to the habits of life of each species.” That is to say, it is impossible to attribute these innumerable structures to spontaneous variability.

What is spontaneous variability?

Clearly, from his preceding paragraph, Mr. Darwin means only “so-called spontaneous variations,” such as “the appearance of a moss-rose on a common rose, or of a nectarine on a peach-tree,” which he gives as good examples of so-called spontaneous variation.

And these variations are, after all, due to causes, but to unknown causes; spontaneous variation being, in fact, but another name for variation due to causes which we know nothing about, but in no possible sense a cause of variation. So that when we come to put clearly before our minds exactly what the sentence we are considering amounts to, it comes to this: that it is impossible to attribute the innumerable structures which are so well adapted to the habits of life of each species to unknown causes.

“I can no more believe in this,” continues Mr. Darwin, “than that the well-adapted form of a race-horse or greyhound, which, before the principle of selection by man was well understood, excited so much surprise in the minds of the older naturalists, can thus be explained” (“Natural Selection,” p. 171, ed. 1876).

Or, in other words, “I can no more believe that the well-adapted structures of species are due to unknown causes, than I can believe that the well-adapted form of a race-horse can be explained by being attributed to unknown causes.”

I have puzzled over this paragraph for several hours with the sincerest desire to get at the precise idea which underlies it, but the more I have studied it the more convinced I am that it does not contain, or at any rate convey, any clear or definite idea at all. If I thought it was a mere slip, I should not call attention to it; this book will probably have slips enough of its own without introducing those of a great man unnecessarily; but I submit that it is necessary to call attention to it here, inasmuch as it is impossible to believe that after years of reflection upon his subject, Mr. Darwin should have written as above, especially in such a place, if his mind was really clear about his own position. Immediately after the admission of a certain amount of miscalculation, there comes a more or less exculpatory sentence which sounds so right that ninety-nine people out of a hundred would walk through it, unless led by some exigency of their own position to examine it closely but which yet upon examination proves to be as nearly meaningless as a sentence can be.

The weak point in Mr. Darwin’s theory would seem to be a deficiency, so to speak, of motive power to originate and direct the variations which time is to accumulate. It deals admirably with the accumulation of variations in creatures already varying, but it does not provide a sufficient number of sufficiently important variations to be accumulated. Given the motive power which Lamarck suggested, and Mr. Darwin’s mechanism would appear (with the help of memory, as bearing upon reproduction, of continued personality, and hence of inherited habit, and of the vanishing tendency of consciousness) to work with perfect ease. Mr. Darwin has made us all feel that in some way or other variations are accumulated, and that evolution is the true solution of the present widely different structures around us, whereas, before he wrote, hardly any one believed this. However we may differ from him in detail, the present general acceptance of evolution must remain as his work, and a more valuable work can hardly be imagined. Nevertheless, I cannot think that “natural selection,” working upon small, fortuitous, indefinite, unintelligent variations, would produce the results we see around us. One wants something that will give a more definite aim to variations, and hence, at times, cause bolder leaps in advance. One cannot but doubt whether so many plants and animals would be being so continually saved “by the skin of their teeth,” as must be so saved if the variations from which genera ultimately arise are as small in their commencement and at each successive stage as Mr. Darwin seems to believe. God—to use the language of the Bible—is not extreme to mark what is done amiss, whether with plant or beast or man; on the other hand, when towers of Siloam fall, they fall on the just as well as the unjust.

One feels, on considering Mr. Darwin’s position, that if it be admitted that there is in the lowest creature a power to vary, no matter how small, one has got in this power as near the “origin of species” as one can ever hope to get. For no one professes to account for the origin of life; but if a creature with a power to vary reproduces itself at all, it must reproduce another creature which shall also have the power to vary; so that, given time and space enough, there is no knowing where such a creature could or would stop.