Richard Cartwright on Logic and the Trinity

Abstract

It is often maintained that the doctrine of the Holy Trinity implies a contradiction. It is sometimes maintained that if the doctrine is formulated in a way consonant with the thesis that “identity is always relative to a sortal term,” it can be shown that it does not involve a contradiction. Richard Cartwright has contended that an appeal to “the relativity of identity” cannot change the fact that the doctrine of the Trinity is inconsistent with a principle that is “evident to the natural light of reason,” namely If every A is a B, then there cannot be fewer B’s than A’s. The purpose of this essay is to examine and evaluate that contention.