In his practical philosophy, Kant employs a number of conceptions of community among moral agents, the meanings of which and the relations among which are contested. The realm of ends that Kant introduces in his third formulation of the categorical imperative in the Groundwork for the Metaphysics of Morals is clearly a conception of a community of moral agents of some sort: a realm is “a systematic union of various beings through common laws,” and a realm of ends is a “whole of all ends in systematic connection (a whole both of rational beings as ends in themselves and of the ends of his own that each may set himself” (G, 4:433). The highest good, which Kant discusses in each of the three Critiques (1781/1787, 1788, and 1790) as well as in Religion within the Boundaries of Mere Reason (1793) and in the essay “On the Common Saying: ‘That May Be Correct in Theory, but It Is of No Use in Practice’” (1793), is clearly a condition of a community of moral agents of some sort, at least in some of Kant's versions of this concept, as when he defines it as “universal happiness combined with and in conformity with the purest morality throughout the world” (TP, 8:279).