Kant and Leibniz are interested in explaining how a number of individuals can come together and form a single unified composite substance. Leibniz does not have a convincing account of how this is possible. In his pre-critical writings and in his later metaphysics lectures, Kant is committed to the claim that the idea of a world is the idea of a real whole, and hence is the idea of a composite substance. This metaphysical idea is taken over into his ethical (...) writings and becomes the idea of a realm of ends. I explain why a realm of ends, should be thought of as both a unum per se and as a real whole. A realm of ends is a whole of individuals unified by laws they have given themselves, that is, it is a community of autonomous individuals. Only such a community can be thought of as a composite individual. Such a whole will be real rather than ideal because the source of the unity of the whole is intrinsic to the whole, for what gives unity to the realm are laws and the sources of the laws are the individual members of the whole. It will be a unum per se because both the laws and the individuals constituting the realm are incomplete without one another. If this reading is correct, this requires a fundamental reevaluation of Kant’s notion of autonomy. To be autonomous is not, primarily, to be understood in terms of ruling oneself, but instead must be thought of primarily in terms of being a generative source of laws for an ideal community. (shrink)