  Peirce felt that the teridentity relation was in some way more primitive logically and thus more fundamental than the usual dyadic identity relation x = y, which he derived from two instances of the triadic identity relation by two applications of the relative product operation of de Morgan. Peirce also felt that de Morgan’s relative product operation was logically a more primitive and fundamental operation than, say, the Boolean product or the Boolean sum. The full philosophical import of his Reduction Thesis, and the philosophical importance of his triadism insofar as this triadism rests on his Reduction Thesis, cannot be ascertained without a prior understanding of his non-typical theory of identity and his special view of the fundamental nature of the relative product operation.