The Republic

In Republic Book One, Socrates is drawn into a debate at Cephalus's house where successive definitions of justice - paying debts, helping friends and harming enemies, and Thrasymachus's "justice is the interest of the stronger" - are each tested and dismantled, leaving Socrates having won every argument but still without a positive definition of justice.

In this chapter, Glaucon and Adeimantus challenge Socrates to prove justice is good in itself, not just for its rewards, using the Ring of Gyges to ask whether anyone would stay honest if invisible; Socrates responds by proposing to study justice "writ large" in an imaginary city, whose growth from simplicity into luxury leads to war and the need for guardians with a paradoxical fierce-yet-gentle nature.

In Book III of The Republic, Socrates argues that stories, lies, and performances don't just reflect character, they actively shape it - so he censors Homer's depictions of grief and the afterlife to build courage, proposes a "noble lie" founding myth to justify the city's social order, and restricts which roles guardians may imitate so they don't become what they perform.