Bryson of Heraclea and Polyxenus have received little attention from scholars. Sources on these philosophers are few and difficult to interpret. However, they present interesting dialectical arguments that concern some of Plato’s and Aristotle’s most important theoretical elaborations: Bryson’s arguments on the issue of semantic ambiguity were explicitly discussed by Aristotle, and Polyxenus is credited with a particular version of the Third Man argument. My purpose in this paper is to reconstruct the historical background of these two philosophers and to (...) analyze the philosophical implications of the arguments that the ancient tradition ascribes to them. (shrink)