Socrates and Glaucon are in the midst of discussing the nature of justice at Cephalus’ house in the Piraeus, the navel port of Athens, which is playing host to a festival dedicated to the goddess Bendis. The question of what constitutes justice was first raised in book I when Cephalus tells Socrates that aged men such as he, when faced with the end of life, are forced to consider how their choices in life may effect their position in the afterlife. Each interlocutor introduces a definition of justice to the company to help answer how one goes about living a just life.

Cephalus says that to be ‘just’ one must “pay their debts and tell the truth.” His son, Polemarchus, says that it is just to “do good to your friends and harm to your enemies.” Thrasymachus boldly claims that “justice is in the interest of the stronger” (might makes right). Socrates presents strong arguments against all three of these prevailing forms of “justice” and advances his own: justice is a virtue of the soul necessary for living well. Unsatisfied with Socrates’ answer, Glaucon recovers the argument from Thrasymachus and plays devil’s advocate for injustice, forcing Socrates to defend his thesis and ultimately launching us into the creation of Plato’s Republic.