Political Philosophy Spring 2018

Glaucon’s Challenge


Plato’s goal in the Republic is to answer Glaucon’s challenge so that was what we focused on today.

The challenge itself is, apparently, straightforward: Socrates has to show that justice falls into the category of things that are valued both for their own sakes and also for what comes from them. Glaucon himself makes the case for thinking that justice belongs to a different category of things, namely, the ones that are valued only for what comes from them. Being just is like taking medicine or engaging in unpleasant physical training: if you could get the results you wanted without it, you would not do it (357).

I asked two questions about Glaucon’s challenge.

  1. Why do the participants in the dialogue all agree that what Glaucon and Thrasymachus are basically saying the same thing?

  2. How does Glaucon characterize an unjust person?

Thrasymachus and Glaucon

Thrasymachus portrays justice as a fraud. It either functions to enable the strong to exploit the weak or it is something that is venerated by the weak and foolish and ignored by the strong and clever.1

Glaucon, by contrast, describes justice as a reasonable looking deal. People found it impossible to get along without rules, so they made some rules, and that’s what we call justice.

Those two stories look quite different to me. But Plato treats them as being the same thing. Why?

Adrian and others said the right thing. The nice story Glaucon tells doesn’t really explain why you should be just when you can get away with being unjust. Skye asked whether the Republic is primarily a work on ethics (answering questions about individual behavior) or politics (answering questions about the state). As we will see, it is both. But Plato’s treatment of Glaucon’s question strongly suggests that the ethical question “why be just when you could get away with it?” is the most important one. If so, perhaps the political theory is presented in order to answer this ethical question.

That said, I still think there is an important difference between Glaucon and Thrasymachus. Suppose you came to this book as a basically good person. If you were convinced by Thrasymachus, you should be convinced that you were mistaken and that your basically good life is a sham. If you were convinced by Glaucon, you would also conclude that you were mistaken about what justice is really like. But I don’t see how coming to that conclusion would obviously lead you to reject justice altogether. You can still see the rules as good and worthy of your compliance even if they aren’t everything that they had seemed to be.

Plato doesn’t see it that way, of course. But this is a point on which I think I disagree with him.

What is an unjust person like?

I said that Glaucon characterized the unjust person in two different ways.

  1. As someone who is exclusively concerned with outdoing others and always acquiring more of anything (359c).
  2. As someone who is indifferent towards the rules of justice in pursuing his or her aims (362b-c).

At the end of the book, Plato is going to argue that the life of the first kind of person is miserable. I can see the point. That person’s life is governed by what others do or by a mindless drive to acquire things. He will make a good case for thinking that this kind of life is empty and out of control.

However I am not convinced that Plato ever comes to grips with the second way of being unjust. Since that kind of unjust life seems much more attractive to me, I think it’s the one to beat. But I also think it’s left standing at the end of the book.

Main ideas

  1. What is Glaucon’s challenge?
  2. How is it related to Thrasymachus’s attacks on justice?
  3. What is an unjust person like, according to Glaucon?


Plato. 1997. “Republic.” In Complete Works, edited by John M. Cooper, translated by G.M.A. Grube and C.D.C Reeve. Indianapolis, IN: Hackett Publishing Company.

  1. I say it is either one of those things because Thrasymachus is unclear about exactly what he thinks. More generally, you could see Thrasymachus as being genuinely outraged on behalf of the people who are exploited by the strong. Or you could see him as sardonically celebrating the way the strong flout the rules. Maybe he has both attitudes at the same time! This is something that those who make radical criticisms of a society’s social order ought to keep in mind. Anyone they convince might become a revolutionary, a reactionary, or both.