Socrates (c. 469–399 BC)

Athenian philosopher. He wrote nothing but was immortalized in the dialogues of his pupil Plato. In his desire to combat the scepticism of the sophists, Socrates asserted the possibility of genuine knowledge. In ethics, he put forward the view that the good person never knowingly does wrong. True knowledge emerges through dialogue and systematic questioning and an abandoning of uncritical claims to knowledge.

The effect of Socrates' teaching was disruptive since he opposed tyranny. Accused in 399 on charges of impiety and corruption of youth, he was condemned by the Athenian authorities to die by drinking hemlock, which he is said to have taken willingly.