This article is a study of the Later Mohists' 'Lesser Selection (Xiǎoqǔ Chinese Source)', which, more than any other early Chinese text, seems to engage in the study of logic. I focus on a procedure that the Mohists called móu Chinese Source. Arguments by móu are grounded in linguistic parallelism, implying perhaps that the Mohists were on the way to a formal analysis of argumentation. However, their main aim was to head off arguments by móu that targeted their own doctrines, and if their argument succeeds then it entails that linguistic parallelism can never ground a cogent argument. In a way, this committed them to the view that formal logic cannot work, but the fact that they did not pursue this line of investigation was by no means inev...