Gorgias, Rhetoric and the Nomos–Physis Debate

Gorgias of Leontini in Sicily (c. 483–c. 375 BCE) dazzled Athens when he arrived as an ambassador in 427 BCE, and he became the most celebrated teacher of rhetoric. In his Encomium of Helen, he argued that speech is a powerful drug that can move emotions, so Helen of Troy might be blameless if she was persuaded. In a provocative treatise he even argued that nothing exists, and that if it did it could not be known or communicated.

The Sophistic age also produced the debate between nomos (law or custom) and physis (nature). Some thinkers argued that laws are human conventions that vary from place to place; others, like the character Callicles in Plato's Gorgias, claimed that by nature the strong should rule the weak. These questions about whether morality is natural or invented set the agenda for Socrates and Plato.