  The formal topic of the Cratylus is ‘correctness of names’, a hot topic in the late fifth century BC when the dialogue has its dramatic setting. Sophists like Prodicus offered training courses in this subject, sometimes perhaps meaning by it little more than lessons in correct diction. But that practical issue spawned the theoretical question, what criteria determine the correct choice of name for any given object? And in the Cratylus Socrates’ two primary interlocutors, Hermogenes and Cratylus (the latter of whom is reported by Aristotle to have been an early philosophical influence on Plato), represent two diametrically opposed answers to that question.