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.
In the foregoing paragraph I have given the point of difference between Mr. Charles Darwin and his predecessors. Why, I wonder, have neither he nor any of his exponents put this difference before us in such plain words that we should readily apprehend it? Erasmus Darwin and Lamarck were understood by all who wished to understand them; why is it that the misunderstanding of Mr. Darwin’s “distinctive feature” should have been so long and obstinate? Why is it that, no matter how much writers like Mr. Grant Allen and Professor Ray Lankester may say about “Mr. Darwin’s master-key,” nor how many more like hyperboles they brandish, they never put a succinct résumé of Mr. Darwin’s theory side by side with a similar résumé of his grandfather’s and Lamarck’s? Neither Mr. Darwin himself, not any of those to whose advocacy his reputation is mainly due, have done this. Professor Huxley is the man of all others who foisted Mr. Darwin most upon us, but in his famous lecture on the coming of age of the “Origin of Species” he did not explain to his hearers wherein the Neo-Darwinian theory of evolution differed from the old; and why not? Surely, because no sooner is this made clear than we perceive that the idea underlying the old evolutionists is more in accord with instinctive feelings that we have cherished too long to be able now to disregard them than the central idea which underlies the “Origin of Species.”
What should we think of one who maintained that the steam-engine and telescope were not developed mainly through design and effort (letting the indisputably existing element of luck go without saying), but to the fact that if any telescope or steam-engine “happened to be made ever such a little more conveniently for man’s purposes than another,” &c., &c.?
Let us suppose a notorious burglar found in possession of a jemmy; it is admitted on all hands that he will use it as soon as he gets a chance; there is no doubt about this; how perverted should we not consider the ingenuity of one who tried to persuade us we were wrong in thinking that the burglar compassed the possession of the jemmy by means involving ideas, however vague in the first instance, of applying it to its subsequent function.
If any one could be found so blind to obvious inferences as to accept natural selection, “or the preservation of favoured machines,” as the main means of mechanical modification, we might suppose him to argue much as follows:—“I can quite understand,” he would exclaim, “how any one who reflects upon the originally simple form of the earliest jemmies, and observes the developments they have since attained in the hands of our most accomplished housebreakers, might at first be tempted to believe that the present form of the instrument has been arrived at by long-continued improvement in the hands of an almost infinite succession of thieves; but may not this inference be somewhat too hastily drawn? Have we any right to assume that burglars work by means analogous to those employed by other people? If any thief happened to pick up any crowbar which happened to be ever such a little better suited to his purpose than the one he had been in the habit of using hitherto, he would at once seize and carefully preserve it. If it got worn out or broken he would begin searching for a crowbar as like as possible to the one that he had lost; and when, with advancing skill, and in default of being able to find the exact thing he wanted, he took at length to making a jemmy for himself, he would imitate the latest and most perfect adaptation, which would thus be most likely to be preserved in the struggle of competitive forms. Let this process go on for countless generations, among countless burglars of all nations, and may we not suppose that a jemmy would be in time arrived at, as superior to any that could have been designed as the effect of the Niagara Falls is superior to the puny efforts of the landscape gardener?”
For the moment I will pass over the obvious retort that there is no sufficient parallelism between bodily organs and mechanical inventions to make a denial of design in the one involve in equity a denial of it in the other also, and that therefore the preceding paragraph has no force. A man is not bound to deny design in machines wherein it can be clearly seen because he denies it in living organs where at best it is a matter of inference. This retort is plausible, but in the course of the two next following chapters but one it will be shown to be without force; for the moment, however, beyond thus calling attention to it, I must pass it by.
I do not mean to say that Mr. Darwin ever wrote anything which made the utility of his contention as apparent as it is made by what I have above put into the mouth of his supposed follower. Mr. Darwin was the Gladstone of biology, and so old a scientific hand was not going to make things unnecessarily clear unless it suited his convenience. Then, indeed, he was like the man in “The Hunting of the Snark,” who said, “I told you once, I told you twice, what I tell you three times is true.” That what I have supposed said, however, above about the jemmy is no exaggeration of Mr. Darwin’s attitude as regards design in organism will appear from the passage about the eye already referred to, which it may perhaps be as well to quote in full. Mr. Darwin says:—
“It is scarcely possible to avoid comparing the eye to a telescope. We know that this instrument has been perfected by the long-continued efforts of the highest human intellects, and we naturally infer that the eye has been formed by a somewhat analogous process. But may not this inference be presumptuous? Have we any right to assume that the Creator works by intellectual powers like those of men? If we must compare the eye to an optical instrument, we ought in imagination to take a thick layer of transparent tissue, with a nerve sensitive to light beneath, and then suppose every part of this layer to be continually changing slowly in density, so as to separate into layers of different densities and thicknesses, placed at different distances from each other, and with the surfaces of each layer slowly changing in form. Further, we must suppose that there is a power always intently watching each slight accidental alteration in the transparent layers, and carefully selecting each alteration which, under varied circumstances, may in any way, or in any degree, tend to produce a distincter image. We must suppose each new state of the instrument to be multiplied by the million, and each to be preserved till a better be produced, and then the old ones to be destroyed. In living bodies variation will cause the slight alterations, generation will multiply them almost infinitely, and natural selection will pick out with unerring skill each improvement. Let this process go on for millions on millions of years, and during each year on millions of individuals of many kinds; and may we not believe that a living optical instrument might thus be formed as superior to one of glass as the works of the Creator are to those of man?” [92a]
Mr. Darwin does not in this passage deny design, or cunning, point blank; he was not given to denying things point blank, nor is it immediately apparent that he is denying design at all, for he does not emphasize and call attention to the fact that the variations on whose accumulation he relies for his ultimate specific difference are accidental, and, to use his own words, in the passage last quoted, caused by variation. He does, indeed, in his earlier editions, call the variations “accidental,” and accidental they remained for ten years, but in 1869 the word “accidental” was taken out. Mr. Darwin probably felt that the variations had been accidental as long as was desirable; and though they would, of course, in reality remain as accidental as ever, still, there could be no use in crying “accidental variations” further. If the reader wants to know whether they were accidental or no, he had better find out for himself. Mr. Darwin was a master of what may be called scientific chiaroscuro, and owes his reputation in no small measure to the judgment with which he kept his meaning dark when a less practised hand would have thrown light upon it. There can, however, be no question that Mr. Darwin, though not denying purposiveness point blank, was trying to refer the development of the eye to the accumulation of small accidental improvements, which were not as a rule due to effort and design in any way analogous to those attendant on the development of the telescope.