Plato's Republic

Socrates believes he has answered Thrasymachus and is done with the discussion of justice.

Socrates' young companions, Glaucon and Adeimantus, continue the argument of Thrasymachus for the sake of furthering the discussion. Glaucon gives a lecture in which he argues first that the origin of justice was in social contracts aimed at preventing one from suffering injustice and being unable to take revenge, second that all those who practice justice do so unwillingly and out of fear of punishment, and third that the life of the unjust man is far more blessed than that of the just man. Glaucon would like Socrates to prove that justice is not only desirable, but that it belongs to the highest class of desirable things: those desired both for their own sake and their consequences. To demonstrate the problem, he tells the story of Gyges, who – with the help of a ring that turns him invisible – achieves great advantages for himself by committing injustices.

After Glaucon's speech, Adeimantus adds that, in this thought experiment, the unjust should not fear any sort of divine judgement in the afterlife, since the very poets who wrote about such judgment also wrote that the gods would grant forgiveness to those humans who made ample religious sacrifice. Adeimantus demonstrates his reason by drawing two detailed portraits that the unjust man could grow wealthy by injustice, devoting a percentage of this gain to religious losses, thus rendering him innocent in the eyes of the gods.

Socrates suggests that they look for justice in a city rather than in an individual man. After attributing the origin of society to the individual not being self-sufficient and having many needs which he cannot supply himself, they go on to describe the development of the city. Socrates first describes the "healthy state", but Glaucon asks him to describe "a city of pigs", as he finds little difference between the two. He then goes on to describe the luxurious city, which he calls "a fevered state". This requires a guardian class to defend and attack on its account. This begins a discussion concerning the type of education that ought to be given to these guardians in their early years, including the topic of what kind of stories are appropriate. They conclude that stories that ascribe evil to the gods are untrue and should not be taught.