Logical Thought in Mohism and Later Mohism

Abstract

This chapter describes the rich logical contributions of Mohism. Early Mohism does not yet consider logic as an object of independent study, but already uses a lot of explicit arguments and implicit logical reasonings. Later Mohism, on the other hand, is mostly devoted to a conscious discussion of genuine logical notions. The present chapter analyzes in modern terms the Mohist notions of “names,” “standards,” “criteria” and gives some interpretations of the key notion of “lei” (equivalence class or class or sort or…) and of the problem of compound names. It explains in what sense the Later Mohists had already a theory of propositions and of their semantics, a theory of reasonings, how they had anticipated notions such as a priori, necessary and sufficient conditions, quantifiers, paradoxes, and the like. Besides discussing logical notions, their texts were remarkably organized and written in quite precise technical terms, making them the foremost contributors of pre-Qin philosophers to the study of logic.