Mr. Darwin frequently complains that our actual knowledge is incomplete. But instead of discovering in our lack of precise and extensive information a motive for caution, he appears to derive from it only greater daring. Doctrines based on the instability of species have often been combated by geologists and palæontologists. In reply to their objections Darwin devotes a whole chapter to shewing the imperfection of the geological record. "For my part," he concludes, "I look at the geological record as a history of the world imperfectly kept and written in a changing dialect; of this history we possess the last volume alone, relating only to two or three countries. Of this volume, only here and there a short chapter has been preserved; and of each page, only here and there a few lines. Each word of the slowly-changing language, more or less different in the successive chapters, may represent the forms of life, which are entombed in our consecutive formations, and which falsely appear to have been abruptly introduced. On this view, the difficulties above discussed are greatly diminished, or even disappear."
On my part [continues M. de Quatrefages] I will ask whether such a conclusion is the correct one. No doubt, Darwin is right in refusing to certain naturalists the[{183}] right to dogmatize on the strength of uncompleted studies, or scanty and isolated observations. Is he therefore entitled to allege as proofs on his own behalf the very gaps of science, appealing to the lost volumes and leaves of Nature's chronicle? Clearly not. But the slightest reflection suffices to recognize that this appeal to the unknown, so frankly evidenced in the above passage, lies at the root of all argumentation analogous to that which I have tried to describe—that of Maillet, Lamarck, and Geoffroy,[216] as well as Darwin. Only the unknown, in sooth, can open the boundless region of speculation, where the possible replaces the actual, and where, despite the widest knowledge and the soundest intelligence, one comes as by a fatality to find a conclusive proof on one's own side, precisely in that of which we profess to know nothing.
So again, speaking of a certain conclusion of Professor Haeckel's concerning the embryology of lemurs, which MM. Grandidier and Alphonse Edwards afterwards proved experimentally to be altogether erroneous, de Quatrefages writes:[217]
Haeckel will perhaps answer that the publication of his book preceded the observation of the French savants. But such a plea itself discloses a method of procedure which is common to the majority of evolutionists, and of which, it must be added, Darwin set the example. When confronted by a question about which nobody knows anything, they appeal precisely to this want of[{184}] knowledge, and draw arguments from their very ignorance.
In like manner speaks the Reviewer already cited more than once. Thus:[218]
The peculiarities of geographical distribution seem very difficult of explanation on any theory. Darwin calls in alternately winds, tides, birds, beasts, all animated nature, as the diffusers of species, and then a good many of the same agencies as impenetrable barriers.... With these facilities of hypothesis there seems to be no particular reason why many theories should not be true. However an animal may have been produced, it must have been produced somewhere, and it must either have spread very widely or not have spread, and Darwin can give good reasons for both results.
And again:[219]
We are asked to believe all these maybes happening on an enormous scale, in order that we may believe the final Darwinian "maybe" as to the origin of species. The general form of his argument is as follows:—"All these things may have been, therefore my theory is possible, and since my theory is a possible one, all those hypotheses which it requires are rendered probable." There is little direct evidence that any of these maybes actually have been.
In no respect, moreover, have Darwin's followers more closely imitated their master than in the construction[{185}] of such hypotheses, which would appear to constitute in the eyes of many the most important work of Science. Attention has very largely been diverted from Nature as actually existing, which seems to be studied more for the light it can be supposed to throw upon evolutionary history, than simply for itself, and it seems to be thought that to imagine the mode of an evolutionary process is equivalent to establishing the facts which that process supposes. By this method lengthy and learned papers are written concerning the transformation of one species into another, which in reality do no more than describe in minute detail all the changes which must have taken place, if the said transformation really occurred. That Science is thus benefited, is not the opinion of some at least who are well entitled to speak on her behalf, for as the President of the Linnean Society recently observed,[220] as one grows older, it becomes more and more apparent that facts alone are of any serious interest, and that speculations however ingenious and attractive are best left to the constructive and destructive energies of the young. So too, a few years ago, the President of the Microscopical Society complained that interest in living creatures is largely supplanted by dead ones.[221]
We read much [he said] of the animal's organs: we see plates showing that its bristles have been counted,[{186}] and its muscular fibres traced to the last thread; we have the structure of its tissues analyzed to their very elements; we have long discussions on its title to rank with this group or that; and sometimes even disquisitions on the probable form and habits of some extremely remote, but quite hypothetical, ancestor, who is made to degrade in this way, or to advance in that, or who is credited with one organ or deprived of another, just as the ever-varying necessities of a desperate hypothesis require....