Plato’s questions about justice Notes for September 10

Main points

Book I tells us about Plato’s motivations for writing The Republic. He was worried that failure to reflect on questions about justice left his society open to ideas such as those expressed by Thrasymachus.

Glaucon formulated the official challenge that the work as a whole seeks to address at the beginning of Book II. We were especially concerned with how Glaucon’s challenge was related to Thrasymachus’s, what it means to value something “for its own sake,” and Glaucon’s description of the perfectly just person.

What is the question?

The problem that Plato will try to resolve is set out by Glaucon and Adeimantus: showing that justice is worth valuing for its own sake rather than a second-best alternative. Adeimantus puts the challenge in a way that tells us a lot about how Plato will try to meet it: “No one has ever adequately described what each [justice and injustice] does of its own power by its presence in the soul of the person who possesses it, even if it remains hidden from gods and humans” (366e). The question, in other words, is about how being just or unjust effects the soul of the just or unjust person. Plato’s answer will be that the just person’s soul is ordered while the unjust person’s is not. We will have to ask whether that is enough to show that it is better to be just than unjust.

Things you should know

Here is a list of key terms, ideas, and parts of the text. These are things that you should be able to explain after today’s class.

  1. Thrasymachus’s attack on justice
  2. Glaucon’s understanding of justice
  3. Glaucon’s division of goods
  4. The Ring of Gyges

And for fun

Glaucon’s point in three panels.

This page was written by Michael Green for Social & Political Philosophy, Philosophy 33, Fall 2012. It was posted September 10, 2012.
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