Limits of Logic in Moism

We are trying to answer the following question, using the distinctions of contemporary logic: why did the Moists stop at some points on their otherwise remarkable way to logic? We argue that they did not explicitly discover negation because of their insistence on linguistic parallelism; they did not recognize logical conjunction nor logical disjunction because of juxtaposition or prefixation; they did not identify the notion of sufficient condition; negation of quantifiers was treated as a problem of extension; their notion of proposi-tion was limited; they discovered some intensionality phenomena but did not explore them very deeply; they insisted more on argumentation than on logic. However our exploration of these limitations shows that the Moists had discovered many logical phenomena and that their attention to the structure of the proposition and to their parallelism reveals a real interest in formal methods.