He has heard from priests and priestesses, and from the poet Pindar, of an immortal soul which is born again and again in successive periods of existence, returning into this world when she has paid the penalty of ancient crime, and, having wandered over all places of the upper and under world, and seen and known all things at one time or other, is by association out of one thing capable of recovering all. For nature is of one kindred; and every soul has a seed or germ which may be developed into all 82 knowledge. The existence of this latent knowledge is further proved by the interrogation of one of Meno’s slaves, who, in the skilful hands of Socrates, is made to acknowledge some elementary relations of geometrical figures. The theorem that the square of the diagonal is double the square of the side—that 83-85 famous discovery of primitive mathematics, in honour of which the legendary Pythagoras is said to have sacrificed a hecatomb—is elicited from him. The first step in the process of teaching has made him conscious of his own ignorance. He has had the ‘torpedo’s shock’ given him, and is the better for the operation. But whence had the uneducated man this knowledge? He had 86 never learnt geometry in this world; nor was it born with him; he must therefore have had it when he was not a man. And as he always either was or was not a man, he must have always had it. (Cp. Phaedo, 73 B.) After Socrates has given this specimen of the true nature of teaching, the original question of the teachableness of virtue is renewed. Again he professes a desire to know ‘what virtue is’ first. But he is willing to argue the question, as mathematicians 87 say, under an hypothesis. He will assume that if virtue is knowledge, then virtue can be taught. (This was the stage of the 88 argument at which the Protagoras concluded.) [Sidenote: _Analysis 93-100._]