The ring of Gyges, and the city built in speech

Glaucon is unsatisfied. Thrasymachus was beaten in argument, but he was not really refuted; the cynical case for injustice has only been pushed underground. Glaucon wants to make it more strongly than Thrasymachus did — to put it as well as possible — and then have Socrates answer it. He divides goods into three kinds: those wanted for themselves, those wanted for their consequences, those wanted for both. Where does justice belong? Most people, he says, treat it as a necessary evil — good only because of what it gets you. Socrates places it in the third category, the highest. Glaucon then argues the popular case at full strength.

He retells the myth of the ring of Gyges. A shepherd finds a ring on the corpse of a giant and discovers it makes him invisible. He uses it to seduce the queen, murder the king, and take the throne. Glaucon's challenge is exact: imagine two such rings, one given to a just man and one to an unjust man. If the just man behaves the same as the unjust — and Glaucon thinks he would — then justice is not chosen for itself, only because we cannot get away with breaking it. Adeimantus follows up: even our religion teaches that justice is for the rewards. Prove that the just life is better than the unjust, even if the just man is reviled and the unjust honored. Prove it without appeal to consequences.

Socrates accepts the challenge. But he proposes a method. Justice in a single soul is small and hard to see; justice in a city is the same shape, only larger. Let us build a city in speech, he says, and find justice in it; then we will know what to look for in the soul. They begin. A first village forms — farmers, weavers, builders. It grows into a luxurious city with armies and physicians. The army needs special education. By the end of Book Two they are debating what the soldiers should be told about the gods, and the long detour through education has begun.