The notion of community (Gemeinschaft), or mutual interaction (Wechselwirkung), has experienced a rather ambivalent reception in the scholarly literature devoted to Kant's thought. On the one hand, one must acknowledge that it is a central principle of Kant's entire Critical project. It is a pure concept of the understanding, or category, that he uses, along with the other categories (B109), to confer a distinctive formal structure onto both his theoretical and his practical philosophy in the Critique of Pure Reason, Metaphysical Foundations of Natural Science, and Critique of the Power of Judgment, as well as in the Critique of Practical Reason and Metaphysics of Morals. It also plays an obvious and crucial role in the content of his moral philosophy, since the kingdom of ends referred to in one prominent formulation of the Categorical Imperative is nothing other than a particular kind of moral community (whose members are related by means of mutual love and respect); and it is not difficult to see, at least in principle, that it can take on a parallel function in his theoretical philosophy insofar as the world of experience, whose conditions he is exploring in the Critique of Pure Reason, is simply a world of mutually interacting objects (e.g., in the guise of Newtonian universal gravitation). It must therefore be admitted that an adequate understanding of Kant’s philosophy requires a proper appreciation of the category of community as one of the fundamental concepts that he deploys in a comprehensive and systematic way throughout his Critical philosophy.