Page:Popular Science Monthly Volume 78.djvu/53

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49
KANT AND EVOLUTION

has learned that the admission of a common descent of different organic species is not necessarily inconsistent either with his hypothesis of "purposive predispositions" or with those doctrines of the completely teleological character of organisms, and of their independence of all merely external causes of modification, which that hypothesis was designed to safeguard. He no longer condemns transformism on a priori grounds as a philosophical monstrosity. Its truth or falsity becomes a question to be settled by empirical evidence. But he also appears to say as plainly as possible that all the known empirical evidence is against the theory. No contemporary of Kant's, reading this passage in the "Kritik of Judgment" as a whole, was likely to find in it encouragement to risk that "bold adventure of the reason" of which it speaks. Moreover, in the next section of the "Kritik of Judgment" (§ 81) Kant, in discussing various embryological hypotheses, unmistakably gives his own endorsement to the opinion that "the Supreme Cause of the world. . . would, in the original products of its wisdom, have supplied merely the predispositions by which an organic being produces another of like kind and the species perpetually maintains itself." Throughout the remarks upon embryology contained in this section Kant seems to take the constancy of specific forms for granted.[1]

The chief topic of this second or biological part of the "Kritik of Judgment" is, of course, that question which had been present to Kant's mind ever since his adoption of a theory of the evolution of the inorganic world "according to mechanical laws." Could organisms also be mechanistically "explained," or only teleologically? It would require too much space to set forth and discuss adequately Kanf s extremely diverse utterances on this question in his last important treatise. But when all those utterances are considered together, they do not seem to indicate any essential departure from the position which we have found him all along maintaining. It is true that he now insists with the utmost emphasis that without the conception of mechanism there is no such thing as science. "It is infinitely important for reason, in its explanation of Nature's processes of production. . . not to pass beyond the mechanism of Nature" (§ 78). He even declares that "apart from causality according to mechanical laws organisms would not be products of Nature at all" (§ 81). But he also continues with equal emphasis to insist that "absolutely no human reason (in

  1. Brock in commenting upon § 80 of the "Kritik of Judgment" observes that Kant takes cognizance directly only of the hypothesis of saltatory mutation, and is silent concerning the possibility of transformation through the summation of slight individual variations. This remark seems to me scarcely justified by Kant's language. By generatio heteronima he means the change of one species "little by little" (nach und nach) into another; though he evidently had only vague ideas of the rate at which, and the mode in which, this change might be supposed by the partisans of transformism to take place. (Cf. Brock in Biol. Centralblatt, Bd. 8, p. 644.)