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In conclusion, a few words must be said about the general agreement of the development theory with the facts of nature, and of the value of the theory as an aid to the comprehension of nature. Tried by a jury of experts, the biologists of Europe and America, the verdict of to-day is overwhelmingly strong for evolution.
Here and there an obstinate juror bas stood out; but the general voice of the scientific world is unmistakable. Oscar Schmidt says,
“Perhaps ninety-nine per cent of all living, or rather, of all working, zoologists, are convinced by inductive methods of the truth of the doctrine of descent.” 1
Opinions are and may long remain divided as to the share which natural selection has borne in the production of new species; but there is a general agreement as to the certainty that all living organisms, animal and vegetable, have been derived from some few original, simple forms, possibly from one. This agreement is most creditable to the fair-mindedness of the elder generation of naturalists, so many of whom (beginning with Lyell) have laid aside the views of a lifetime to adopt the theory. This result may in no small degree be attributable to the fact that there is no other theory but that of evolution which brings forward any evidence to show that it naturally accounts for the origin of the species of animals and plants. All the objections raised against the development theory have been negative, and not positive. The so-called specialcreation theory is not, and never was, an answer to the fundamental question, “How are species formed ?”
i Quoted in Haeckel's Freedom of Science and Teaching,
Let one attempt to imagine the creation of any new species of animal or plant, not in a remote geological age or a distant country, but in the nearest garden, field, or wood, and he can hardly fail to realize how unmeaningly the words ** special creation ” are employed. In fact, the whole special-creation idea is itself a fossil, the reminder of a time when no one knew that the earth had any past life-history.
It is impossible, on any save some evolutionary theory, — unless, indeed, one go back and adopt the Oriental belief in a supreme evil spirit governing the world, -to account for the essential selfishness of the world of living beings. Says Mr. Romanes,
“ Amid all the millions of mechanisms and instincts in the animal kingdom, there is no one instance of a mechanism or instinct occurring in one species for the exclusive benefit of another species, although there are a few cases in which a mechanism or instinct that is of benefit to its possessor has come also to be utilized by other species. Now, on the beneficent design theory, it is impossible to explain why, when all the mechanisms in the same species are invariably correlated for the benefit of the species, there should never be any such correlation between mechanisms in different species, or why the same remark should apply to instincts; for how magnificent a display of divine beneficence would organic nature have afforded if all, or even some, species had been so inter-related as to minister to each other's necessities! Organic species might, then, have been likened to a countless multitude of voices, all singing in one harmonious psalm of praise. But as it is we see no vestige of such co-ordination: every species is for itself, and for itself alone — an outcome of the always and everywhere fiercely raging struggle for
Of the light thrown by the development theory on some heretofore obscure facts of the organic world, leading biologists must be the most competent judges. Out of the volumes of evidence to show how points long unintelligible have been cleared up by the theory, I can only quote here and there a line. The whole subject of embryology was utterly mysterious before the evolution idea was brought forward to give reasons for some of the curious facts which have been outlined in a previous chapter. Pro
Scientific Evidences of Organic Evolution, pp. 74, 75.
fessor Allen Thomson was led to say in his address as president of the British Association in 1877,
“I consider it impossible, therefore, for any one to be a faithful student of embryology, in the present state of science, without at the same time becoming an evolutionist.”
Professor Huxley's opinion in regard to the bearings of the facts of paleontology on evolution has already been quoted. Professor H. A. Nicholson, a very high authority, and a very cautious reasoner, says,
· Upon the whole, it must be unhesitatingly replied, that the evidence of paleontology is in favor of the view that the succession of life-forms on the globe has been to a large extent regulated by some orderly and constantly acting law of modification and evolution. Upon no other theory can we comprehend how the fauna of any given formation is more closely related to that of the formation next below in the series and to that of the formation next above than to that of any other series of deposits. On no other view can we explain the appearance of “intermediate' or “transitional’ forms of life filling in the gaps between groups now widely distinct.” 1
To the evidence of zoology and botany there is no need of here adding any thing further
1 Ancient Life-History of the Earth, pp. 372, 373.
than has already been cited in earlier chapters. Such works as Darwin's “ Animals and Plants under Domestication” and Wallace's new book,
Darwinism,” are crammed from cover to cover with the amplest testimony. In short, as Romanes has well put it, we do not need any more testimony: nothing but a demonstration, such as is possible in the mathematical, but impossible in the natural-history, sciences, could make the fact of organic evolution more certain than it now is. But objectors have said, the picture of a world in which the very existence of each individual depends on its power to crowd other individuals out of existence is not a pleasant one. What of that? Science is concerned only to learn and to state the facts of the universe, not to sugar-coat them into palatableness. And the man, be he scientist or not, who chooses to disbelieve a theory because it does not fall into line with his personal preferences, is even less logical than the Hindoo, who bought and destroyed the microscope that had shown him the impossibility of so much as taking a drink of water without violating his religion by destroying animal life.
The value of the development theory to the biological sciences is twofold: it has rendered unnecessary the childish supposition that each