The direct evidence in favor of the kineto genetic mode of evolution is greatly strength ened by the discovery of Ameghino in the Tertiary beds of the Argentina of one-toed ungulates with two splint bones, and with teeth strikingly like those of the horse, though the animal belongs to a quite different order. The similarity or divergence in shape of the parts is due to the action of similar mechanical con ditions in two quite unrelated groups. The same results of strains involved in are seen in the fore legs of the fossorial edentates, in the mole, as well as in the mole cricket. Thus as Cope concludes, *in biologic evolution, as in ordinary mechanics, identical causes pro duce identical results.' It is to be observed, however, that °ordi nary mechanics° does not state that °identical causes produce identical results.' The truth appears to be that in the great paleontologist, Cope, we have another instance of a man's thought being much wider and richer than his system. M. Bergson has recently made a point aganst a mechanical mode of intellectual appropriation and just because he understood the law of causality in the sense mentioned by Cope. The principle, °identical cause, identical effect,' which is sometimes said to be the prin ciple of causality, is much narrower in its scope than the principle which really occurs in physics and chemistry,— in science in gen eral. Indeed, the principle °identical cause, identical effect,* strictly interpreted, has no scope at all in ordinary mechanics, since the same cause never recurs exactly. Both Cope
and Bergson state the law of causation too narrowly. The law does not state merely that, if the same cause is repeated, the identical effect will be repeated. It states rather that there is a constant relation between causes of certain kinds and effects of certain kinds. What is constant in a truly causal law is not the object or objects given, nor yet the object inferred, both of which may vary within wide limits, but the relation between what is given and what is inferred. It is not asserted here that the great naturalist was unconscious of the significance of the principle. On the contrary we feel that it was plainly operative in his thought world. But in view of the great ado nowadays over teleology and aetiology as modes of intellectual appropriation of the subject called life, it appears that science cannot too often remind itself that freedom is the postulate of teleology, and determinism (causation) the postulate of science. Further, it is not so much required to deny teleology in the domain of organized nature as to purify and sift our views of teleology. There is a kind of teleology which does not stand in contradiction to the causation of efficient causes so called. The kind of causation in question has just been mentioned. Consult Cope, E. D., 'The Pri mary Factors of Organic Evolution' (Ch:cago 1896) ; Wyman, 'On the Cancellated Structure of Some of the Bones of the Human Body' (in Journal of the Boston Society of Natural History, Vol. VI, Boston 1857).