This argument, by which Kant reasons that all men are of one Stamm, directly implies that men and other animals are not of one Stamm, i. e., are not related through any lines of natural descent. For he makes identity of species synonymous with community of descent, and diversity of species synonymous with separateness of descent. In other words, his manner of distinguishing a species from a race rests upon wholly anti-evolutionary presuppositions.
Within the limits of a species, however, Kant holds that very considerable modifications of physical character may be brought about in the course of successive generations. Now (apart from individual variations not transmitted to offspring), there seem to Kant to be two significantly different types of heritable peculiarities: those which are invariably inherited, and those which are only alternatively inherited. Thus the. colors of a negro and a white who marry are both manifested in the offspring; children of such marriages are always mulattoes. But the complexions of the children of a dark man and a blonde woman are not necessarily a compromise between the complexions of their parents. Some or all of the children may resemble one parent only, and show (with respect to any given character) no marks of their descent from the other. By means of this distinction Kant differentiates a "race" from a "variety." Those members of a single species which also possess in common characters of the invariably hereditary sort belong to the same race; those which possess in common (and, so long as they mate with their own like, transmit to their offspring) characters that, upon cross-breeding with other types, are only alternatively hereditary, constitute only "varieties."
These definitions of "species" and "race," it is true, involve—as Kant recognizes—some revision of the classifications of the systematists.
- It is for this reason that, in translating Kant's expositions of his own doctrines, I have, so far as possible, rendered both Art and Gattung by "species." The citation is from the "Conception of Race," § 6, n.
offspring. But where the generation of such offspring is possible, the utmost diversity of external appearance is no obstacle to regarding the parents as having a common descent. For if they can, in spite of this diversity, produce offspring that exhibit the characters of both parents, then they may be classified as belonging to two races of a single stock, which originally had latent within itself the characters that were to be developed in each separately."