Despite Conger’s classic view that one can find very little of the microcosmic doctrine in any of the Idealists, the paper argues that Kant develops several little known microcosmic doctrines over the course of his development from his first Critique to his second Critiqueto his Opus Postumum and that these are intimately connected with his various notions of “transcendental” philosophy. First, the roots of the microcosmic doctrine in Plato are explored. Second, Kant’s most basic microcosmic doctrine and its connection with (...) his “faculty psychology” notion of transcendental philosophy in the first Critique are explored. Third, it is explained why, contrary to Conger, the Idealist tradition is a natural home for microcosmic doctrines. Fourth, Kant’s moral microcosmic doctrine, which is implicit in the “starry heavens” remark in the conclusion to second Critique and related remarks in the Opus Postumum, is discussed in some detail. This includes a discussion of the microcosmic doctrines in the Stoics. Fifth, it is shown how Kant’s various microcosmic doctrines shed considerable light on his evolving conception of transcendental philosophy from his first Critique to his final statement in the Opus Postumum. (shrink)