GORGIAS of Leontini, in Sicily, a rhetorician and sophist of whose personal history nothing is known beyond the facts that in 427, when already a comparatively old man, he was sent by his fellow-citizens at the head of an embassy to ask Athenian protection against the aggression of the Syracusans; that he then settled in Athens, and supported himself by the practice of oratory and by teaching rhetoric; and that he ended his days at Larissa, in Thessaly. His birth and death may be approximately dated respectively at 483 and 375 b.c. He was the author of a lost work On Nature or the Non-existent (πepl τov μη orτoς η 7r∈pt φt'σeως), the substance of which may be gathered from the writings of Sextus Empiricus, and also from the treatise (ascribed to Theophrastus) De Melisso, Xenophane, Gorgia. His philosophical opinions may be summed up in three propositions, which stand in direct relation to the teachings of the Eleatic school. He held (1) that there is nothing which has any real existence; (2) that, even if anything did really exist, it could not be known; and (3) that, supposing real existence to be knowable, the knowledge would be incommunicable. On the first point his argument was that a real existence must either have come into being or have been eternal. But the first alternative would require it to have been produced, either from the existent or from the non-existent; the second alternative would require us to identify it with the infinite, but the infinite exists nowhere (for that would involve the absurdity of its existing either within itself or within something else), but what exists nowhere is nothing. In support of the second proposition he argued that, if existence could be known, then thought would be existence, and the non-existent would be ...