Relativism and Pure Reason

One of Kant's Categories, an expression of Pure Reason, in the mode of the Understanding, is Community, or, equivalently, Reciprocity.  His two extended applications of the Category are to Newton's Third Law, and to the concept of Deservedness.  But, he does not consider its relevance to the experiential context itself.  He thus misses that it grounds the Perception of an Object as a frame of reference to which the Subject might be referred. Likewise, it grounds the cardinal features of his Moral doctrine--the treatment of others as Ends, and the Kingdom of Ends--more elegantly than does his strained attempts to derive them from the Principle of Contradiction.  Plus, it re-casts 'the existence of others' as an a priori, rather than an Emprical, concept, thereby easily resolving this perennial Philosophical problem.  Thus, this category of Community/Reciprocity provides Relativism with a Rational basis.