DARWINISM AND OTHER ESSAYS. I. DARWINISM VERIFIED. IT is not often that the propounder of a new and startling scientific theory has lived to see his daring innovations accepted by the scientific world in general. Harvey's great discovery of the circulation of the blood was scoffed at for nearly a whole generation; and Newton's law of gravitation, though proved by the strictest mathematical proof, received from many eminent men but a slow and grudging acquiescence. Even Leibnitz, who as a mathematician hardly inferior to Newton himself might have been expected to be convinced on simple inspection of the theory, was prevented from accepting it by the theological objection that it appeared to substitute the action of a physical force for the direct action of the Deity. In France, where ideas not of French origin are very apt to be but slowly apprehended, the opposition to the Newtonian theory was not silenced till 1759, when Clairaut and Lalande, by calculating the retardation of Halley's comet, furnished such crucial proof as could not possibly be overcome. At this time Newton had been thirty-two years in his grave; seventy-two years had elapsed since the publication of the Principia, and ninety-four since the hypothesis was first definitely conceived. In the present age, when the number of scientific inquirers has greatly increased and the interchange of thoughts has become rapid and constant, it takes much less time for a new generalisation to make its way into people's minds. It is now barely eighteen years since Mr. Darwin's views on the origin of species were announced in a book which purported to be only the rough preliminary sketch of a greater work in course of preparation. But, though greeted at the beginning with ridicule and opprobrium, the theory of natural selection has already won a complete and overwhelming victory. One could count on one's fingers the number of eminent naturalists who still decline to adopt it, and the hesitancy of these appears to be determined in the main by theological or metaphysical, and therefore not strictly relevant, objections. But it is not simply that the great body of naturalists have accepted the Darwinian theory: it has become part and parcel of their daily thoughts, an element in every investigation which cannot be got rid of. With a tacit consent that is almost unanimous, the classificatory relations among plants and animals have come to be recognised as representing degrees of genetic kinship. One needs but to read constantly such scientific journals as Nature, or to peer into the proceedings of scientific societies, to see how thoroughly all contemporary inquiry is permeated by the conception of natural selection. The record of research, whether in embryology, in palæontology, or in the study of the classification and distribution of organised beings, has come to be the registration of testimony in support of Mr. Darwin's hypothesis. So deeply, indeed, has this mighty thinker impressed his thoughts on the mind of the age that in order fully to unfold the connotations of the word "Darwinism" one could hardly stop short of making an index to the entire recent literature of the organic sciences. The sway of natural selection in biology is hardly less complete than that of gravitation in astronomy; and thus it is probably true that no other scientific discoverer has within his own lifetime obtained so magnificent a triumph as Mr. Darwin. The comparison of the doctrine of natural selection with the Newtonian theory is made advisedly, as I wish to call attention to some differences in the aspect of the proofs by which two such different hypotheses are established. First, however, as the point will not hereafter come up for consideration in this paper, it may be well to notice the theological objection which has been urged against Mr. Darwin, as it was once urged against Newton, and to show briefly why, as above hinted, it cannot be regarded as properly relevant to the discussion of the scientific hypothesis. The theological objection to natural selection, which has weight with many minds, is precisely the same objection that Leibnitz made to gravitation,—that the action of physical forces appears to be substituted for the direct action of the Deity. This has, indeed, been a very common objection to theories which enlarge and define what is called the action of secondary causes, but it has been peculiarly unfortunate in this respect, that with the progress of inquiry it has invariably been overruled without practical detriment to theism. It regularly happens that the so-called atheistical theory becomes accepted as part and parcel of science, and yet men remain as firm theists as ever. The objection is, therefore, evidently fallacious, and the fallacy is not difficult to point out. It lies in a metaphysical misconception of the words "force" and "cause." "Force" is implicitly regarded as a sort of entity or dæmon which has a mode of action distinguishable from that of universal Deity; otherwise it is meaningless to speak of substituting the one for the other. But such a personification of "force" is a remnant of barbaric thought, and is in no wise sanctioned by physical science. When astronomy speaks of two planets as attracting each other with a "force" which varies directly as their masses and inversely as the squares of their distances apart, it simply uses the phrase as a convenient metaphor by which to describe the manner in which the observed movements of the two bodies occur. It explains that in presence of each other the two bodies. are observed to change their positions in a certain specified way, and this is all that it means. This is all that a strictly scientific hypothesis can possibly allege, and this is all that observation can possibly prove. Whatever goes beyond this and imagines or asserts a kind of "pull" between the two bodies, is not science, but metaphysics. An atheistic metaphysics may imagine such a "pull" and may interpret it as the "action" of something that is not |