Greece & Rome · c. 490–420 BCE
Protagoras
The most famous sophist, who taught virtue for a fee
Declared that “man is the measure of all things”, so that things are for each person as they appear to that person. He was agnostic about the gods, saying the question is obscure and human life is short.
Life and thought
Protagoras came from Abdera in northern Greece and spent some forty years travelling as a teacher, often in Athens, where Pericles reportedly asked him to draft laws for the new colony of Thurii in 444 BCE. He was the first to charge fees for teaching “virtue”, meaning the skills of managing a household and taking part in public life. Later stories that his books were burned and he was expelled for impiety are doubtful.
His most famous sentence opened his book Truth: “Man is the measure of all things, of things that are, that they are, and of things that are not, that they are not.” If the wind feels cold to me and warm to you, there is no further fact about the wind itself; each perception is true for the perceiver. About the gods he said he could not know whether they exist, since the question is obscure and life is short. Plato devoted the Theaetetus to refuting him: if every belief is true for its holder, so is the belief that Protagoras is wrong.