Justice in the City

We set out to answer a question about individual people: why should someone be just? But immediately after formulating the question, Plato takes up what appears to be a different subject: justice in a city.

Plato’s assumption is that justice is the same in the city and the individual soul, such that a description of justice in the city would help us to answer our original question about justice in the individual.

So Plato is going to try to answer four questions.

  1. What is a just city?
  2. Why is it good for a city to be just?
  3. What is a just person (individual or soul)?
  4. Why is it good for a person to be just?

And he is going to try to answer these questions while also maintaining this assumption:

  1. Justice in the city is the same as it is in the individual soul.

Can he keep all five balls in the air? He comes surprisingly close. Plato is awesome.

In today’s class, I summarized the readings from Books II and III. Then we discussed the first part of Book IV.

Wisdom and courage

The good city would have the four virtues of wisdom, courage, moderation, and justice. It has the first two virtues because of the roles played by the different classes. For instance, the city is wise because it is ruled by the class that knows the most about what is good and is the most dedicated to the city: the guardians. And it is courageous because the auxiliaries are in charge of their defense.

Note that the city is not courageous because everyone is courageous; it’s only the auxiliaries who are courageous (see 429b). Nor is the city wise because everyone is wise (428e). The city has these qualities because a particular class plays its role: the guardians run the city and the auxiliaries defend it. Plato did not think the members of the productive class were especially wise or courageous.


In order to describe moderation in the city, Plato swings to the individual. Moderate individuals control their desires such that the “naturally better part” of the soul “is in control of the worse” (431a). With that account of moderation in the individual in hand, he turns back to the city. The city is moderate if “the desires of the inferior many are controlled by the wisdom and desires of the superior few” (431d).

It appears as though moderation is going to follow the same pattern as wisdom and courage: the city has a virtue V (such as moderation, wisdom, courage) if and only if a part of the city has that virtue and that part plays an appropriate role in the city. In this case, the story seems to be that the city is moderate so long as the guardians are moderate and they govern the other, immoderate classes.

However, that is not what Plato says. In a good city, “moderation spreads throughout the whole” producing “agreement between the naturally worse and the naturally better as to which of the two is to rule” (432a). By contrast, there is no thought that everyone could be wise or courageous even in the best city.

I said that I thought there was some tension between these two things that Plato says about moderation in the city:

  1. The city is moderate because the superior guardians control the desires of the inferior many.
  2. The city is moderate because moderation “spreads throughout the whole” producing agreement about who should rule.

Plato himself did not go into enough detail about how this would work, so we are going to have to try to think about how he might have reconciled these ideas on our own.

For example, Audrey said that she thought the idea was that the members of the productive class can recognize their inferiority and so do what the guardians tell them. They are incapable of regulating their desires on their own, but they are capable of recognizing that they should listen to someone else. That seems promising to me; we will have occasion to talk about it and other possible solutions on Thursday.


According to Plato, “the city was thought to be just when each of the three natural classes within it did its own work” (435b). We are going to talk about justice on Thursday, so I will just make a couple remarks.

First, it is not easy to see how justice and moderation differ from each other.

Second, it is not obvious to me why Plato thinks this makes the city just. I can see how Plato thought he had shown why the city he is describing is good: the people in a just city all do what they are best at and that has to be better than their doing what they are not so good at. But why is it a just city?

Everyone in the just city keeps to their place. So they won’t try to overthrow the government of the guardians. That is at least part of what I would recognize as just behavior. But does that mean they will do the things mentioned in Books I and II as examples of justice: telling the truth, performing their contracts, and so on?

Key terms

  1. The parts of the city
  2. The parts of the soul
  3. The virtues of city and soul
  4. The difference between wisdom and courage, on the one hand, and moderation and justice, on the other hand, as virtues of the city


Plato. 1992. Republic. Translated by G.M.A. Grube and C.D.C. Reeve. Indianapolis: Hackett.


There was a handout for this class: 03.PlatoJusticeCity.handout.pdf