Socrates and Thrasymachus

Republic I.353d-354a

Thrasymachus admits that "injustice is never more profitable than justice."


1.  Justice is the virtue of the soul.
2.  If (1) is true, then just lives are happier than unjust lives.
3.  If just lives are happier than unjust lives, then injustice is never more profitable than justice.
4.  Injustice is never more profitable than justice.


1. So, for example, in this way of thinking, part of the "virtue" of a knife is having a blade suitable for easy cutting.

  "The soul (ψυχῆς), has it a work (ἔργον) which you couldn't accomplish with anything else in the world, as for example, management, rule, deliberation, and the like (ἐπιμελεῖσθαι καὶ ἄρχειν καὶ βουλεύεσθαι καὶ τὰ τοιαῦτα πάντα), is there anything else than soul to which you could rightly assign these and say that they were its peculiar work?
  Nothing else.
  And again life (ζῆν)? Shall we say that too is the function of the soul?
  Most certainly.
  And do we not also say that there is a virtue (ἀρετήν) of the soul?
  We do.
  Will the soul ever accomplish its own work well if deprived of its own virtue, or is this impossible?
  It is impossible.
  Of necessity, then, a bad soul will govern and manage things badly while the good soul will in all these things do well.
  Of necessity.
  And did we not agree that the excellence or virtue of soul is justice (δικαιοσύνην) and its defect injustice?
  Yes, we did" (Republic I.353d).
Socrates supposes that things that have functions have virtues. Having the virtue is how the thing performs its function well. In the case of the human soul, the function is "managing things, rule, deliberation, and the like." A line later Socrates adds that "life" is part of the function. the soul is that in terms of which a human being makes decisions about what to do as he lives out his life. The virtue is the quality that allows the soul to carry out this function well.

"'Then the just man has turned out on our hands to be good and wise and the unjust man bad and ignorant. Thrasymachus made all these admissions, not as I now lightly narrate them, but with much baulking and reluctance and prodigious sweating, it being summer, and it was then I beheld what I had never seen before—Thrasymachus blushing. But when we did reach our conclusion that justice is virtue and wisdom and injustice vice and ignorance, 'Good,' said I, 'let this be taken as established'" (Republic I.350c)

Socrates narrates in the Republic, as in the Charmides and Lysis. If possible, I eliminate this narration from the translation.
Earlier in the conversations, at Republic I.350c, Socrates gets Thrasymachus to agree that justice is this virtue of the soul. The discussion in this passage is not completely clear, but Thrasymachus seems to agree that a just human being is wise and hence knows what decisions to make to "manage" things so that his life goes as well as possible in the circumstances.

2. Since the just manage their lives better, their lives are happier. They are good at living well. They make decisions that result in more happiness. The unjust are bad at living well. Because they lack knowledge, the unjust make decisions that result in less happiness.

  "The just soul and the just man then will live well and the unjust ill?
  So it appears by your reasoning.
  But furthermore, he who lives well is blessed and happy (μακάριός τε καὶ εὐδαίμων), and he who does not the contrary.
  Of course.
  Then the just is happy and the unjust miserable.
  So be it, Socrates" (Republic I.353e).

3. Since just lives are happier than unjust lives, injustice is never more profitable than justice. Even the least happy just life is better than the most happy unjust life.

  "But it surely does not pay to be miserable, but to be happy.
  Of course not.
  Never, then, my blessed Thrasymachus, can injustice be more profitable than justice.   Let this complete your entertainment, Socrates, at the festival of Bendis" (Republic I.354a).
The festival is in honor the Thracian god Bendis, featuring processions, races, and other celebrations.

  “Do you mean to say that you haven't heard that there is to be a torchlight race this evening on horseback in honor of the Goddess?
  On horseback, Adeimantus? That is a new idea. Polemarchus, will they carry torches and pass them along to one another as they race with the horses, or how do you mean?
  That's the way of it, Socrates, and, besides, there is to be a night festival which will be worth seeing" (Republic I.327c).


The argument appears to be an instance of a valid argument form. If the premises are true, the conclusion looks to follow. The question is whether the premises are true.

1. The first premise needs considerable more justification if it is to be plausible. Even if the soul has a function and so is understood as a sort of cognitive mechanism in which the agent (= the human being with the soul) evaluates the circumstances and tries to arrange things so that he is living a good life and is happy, it is unclear that justice is the state that allows the soul to do this well.

Socrates seems to think that justice in the soul brings wisdom with it, that wisdom includes knowledge, and that this knowledge is of what is good and what is bad in the circumstances. This conception of justice as a state in the soul is unusual. That a human being is just seems to be the much weaker claim he is in the habit of doing what is right in his dealings with others.

  "[N]either of them will ever be happier (εὐδαιμονέστερος) than the other—neither he who has unjustly compassed the despotic power, nor he who pays the penalty; for of two wretched persons neither can be happier; but still more wretched is he who goes scot-free and establishes himself as despot What is that I see, Polus? You are laughing? Here we have yet another form of refutation—when a statement is made, to laugh it down, instead of disproving it!
  Do you not think yourself utterly refuted, Socrates, when you make such statements as nobody in the world would assent to" (Gorgias 473d)?
2. The truth of the second premise is not obvious either. The problem is that Socrates has not made clear what contributes to and detracts from the happiness of a life. In the absence of this explanation, it seems possible for a person to be just and thus to manage his life well but still have a life that is not as happy as the life of someone who is unjust and does not manage his life well.

3. The third premise is the most plausible of the three. If the least happy just life is happier than the happiest unjust life, then it seems to follow that injustice is never more profitable than justice. It seems to follow that a human being who is just must become less happy and more miserable if he ever resorts to injustice and thus abandons the just life for an unjust one.

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