A critical examination of the charge of self-refutation, particularly as leveled by orthodoxy-defending philosophers against those maintaining epistemologically unorthodox, especially relativistic or skeptical, views. Beginning with an analysis of its classic illustration in Plato’s *Theaetetus* as leveled against Protagoras’s “Man is the measure ...,” I consider various aspects of the charge, including logical, rhetorical, pedagogic, affective, and cognitive.