Page:Popular Science Monthly Volume 78.djvu/48

44 clearly perceived this implication; but in his essay "On the Use of Teleological Principles in Philosophy," 1788, he expressly draws the inference.

It is a conventional practise, especially among German writers on philosophy, to speak in a tone of reverent admiration of Kant's profound insight into the spirit and methods of empirical science. The reader, therefore, will do well to note the precise logical character of Kant's procedure in framing and supporting these hypotheses, which constitute his special contribution to biology. In the first place, he assumes, with no evidence at all, that two species incapable of producing fertile offspring when mated, thereby testify that they can have had no common ancestors. He thus, with a single dogmatic phrase, "there can be only one cause of this" infertility, begs the entire question of the transformation of species, which had been already raised in his time by writers of the first eminence, whose work was well known to him. Further, in order to reconcile his doctrine of the impossibility of any real modification of nature's "original model" for each species with his doctrine of the descent of widely divergent races and varieties from a single species, he invented the hypothesis of the latent preexistence of "germs" anticipatory of the subsequent changes of milieu which the species was to undergo, and destined to take command of the reproductive process when the proper occasions arrive, while the other germs obligingly retire into inactivity. This, which remained to the end of his days one of Kant's most cherished notions, had most of the faults of which a scientific hypothesis is capable; and it had not even the ambiguous merit of serving the purpose for which it was designed. It was intended as a support to the anti-evolutionistic dogma which Kant had made his own: "every natural kind remains true to its original nature "; yet it was admittedly consistent with an