 Beyond these superficial similarities with the basic logical notions of contemporary formal-theoretical systems, there is a great deal of material in the Mohist Canons that is indisputably concerned with articulating logical principles, but whose interpretation is still highly debatable. Scholars have extrapolated from Mohists texts versions of principles common to Western systems of symbolic logic, such as basic rules of inference (modus ponens, modus tollens, hypothetical syllogism), necessary and sufficient conditions, the laws of non-contradiction and excluded middle, and reductio ad absurdum. Intriguingly, we also find what appears to be a formulation of the liar paradox, first attributed in the West to Eubulides in the 4th century BCE: “To claim that all saying contradicts itself is self-contradictory. Explained by: what he says himself” (B71). It is hard to believe that the Mohists had anything in mind here but a precise notion of logical inconsistency.