Gorgias of Leontini was a Sophist who arrived in Athens as an ambassador in 427 BC and stayed to teach rhetoric, reportedly living past a hundred.

The three theses

His work On Nature, or On the Non-Existent argues a sequence:

  • Nothing exists.
  • If anything did exist, it could not be known.
  • If it could be known, it could not be communicated to anyone else.

Whether this is serious metaphysics, a parody of Parmenides, or a demonstration that rhetoric can argue anything has been debated since antiquity. The parody reading is strong: Parmenides had used similar reasoning to prove that only being exists, and Gorgias runs the machinery in reverse.

The third thesis is the one that survives independently. Language is not the thing it refers to, so what passes between speakers is words rather than experiences — a point about communication that does not depend on the first two.

Rhetoric as power

His Encomium of Helen defends Helen of Troy against blame, arguing she acted under compulsion — by the gods, by force, by love, or by speech. The inclusion of speech is the point: Gorgias treats persuasion as a force comparable to physical compulsion, which makes the speaker responsible in the way a wrongdoer is.

He describes speech as a powerful master able to produce fear, remove grief and increase pity. Coming from a teacher of rhetoric, it is a claim about what he was selling.

Plato's reply

Plato's dialogue named for him puts the charge directly: rhetoric is not an art but a knack, like cookery, producing gratification rather than health, and indifferent to whether what it persuades people of is true.

That characterization of rhetoric has stuck for two and a half thousand years, and it comes from a hostile source — as almost everything about the Sophists does.