Is justice better than injustice?

Book 9 gives three arguments for the conclusion that the just life is better than the unjust one. We spent a lot of time on the first two and rushed through the third at the end.

First, tyrants are fearful addicts

Plato’s first argument continues a theme from book 8: the tyrant, a.k.a. the completely unjust man, is an addict. They tyrant does all sorts of self-defeating things because he is controlled by his appetites. Consequently, he is unhappy, lacks control over his behavior, and lives in fear of others.

The argument is not based on generalizations about actual tyrants. (Would it be true if it were?) In making it, Plato reverts to the analogy between the city and the soul. Slave owners in the city have to fear their slaves and so the tyrant would live in fear of his appetites (see 579). That is not the most persuasive use of the analogy, in my opinion.

Our most important question about the argument took us back to our old friends Thrasymachus and Glaucon (see the handout). It looks to me as though Plato’s characterization of the tyrant is aimed at the character Thrasymachus described as the completely unjust man. It is less clear to Semassa and me that it is relevant to the more stealthy character that Glaucon describes.

Second, the philosophers’ experience

We entered into Plato’s second argument with a remark by Jiwon. She observed that the philosopher would pity someone like the tyrant. The tyrant, after all, is deeply deluded about what is important, from the philosopher’s point of view. At the same time, the tyrant would not think highly of the philosopher’s life. This raises the question of whose point of view is more accurate.

Plato maintained that the philosophers have the best point of view on what kinds of pleasures are valuable. The philosophers have experienced the pleasures of satisfying their appetites, winning honors, and knowing things. Of the three, they rank knowledge as the best. Assuming that those who have experienced different kinds of pleasure are in the best position to judge which of them is best, Plato concludes that the pleasures of knowledge are the best.

We practiced putting this into a numbered argument and especially looking for the unstated premise that is needed to make the argument work.

Samuel questioned whether there is even an answer to the question. Why is it obvious that there is a best kind of pleasure rather than just three (or more) different kinds that can’t be compared with one another? And Helena expressed doubts about whether the philosophers really have experienced the pleasures of the other ways of life.

Third, the nature of pleasure

Plato’s third argument is the most difficult to assess. He starts with the assumption that pleasure involves filling a kind of void. Then he maintains that the kinds of things the philosophers take pleasure in are more real than the kinds of things others take pleasure in. (Numbers, for instance, are unchanging and perfect while the stuff of the earth is neither.) Assuming that what is more real is more filling than what is less real, Plato concluded that the philosopher’s pleasures are superior to the pleasures that the other kinds of people pursue.

We did not have much time to go into this. Two points will have to suffice.

First, even if you concede that numbers (and the other objects of knowledge that, according to Plato, are all like numbers) are unchanging, it does not follow that they are more real much less that thinking about them is more filling than, say, eating a good sandwich.

Second, I don’t see how Plato can get from this argument to the conclusion that everyone is better off “when the entire soul follows the philosophic part” (586d).

Key points

  1. The argument that the most unjust man is an unhappy addict.
  2. The argument that the philosophers have experience of all kinds of pleasure and so know which ones are best.


There was a handout for this class: 06.PlatoAnswerGlaucon.handout.pdf