Previously I noted that Polemarchus breaks into the conversation, not because he is interested in the definition of justice, but to defend his father from what he takes to be an attack by Socrates. Now let’s look at how the intervention of Polemarchus begins to show a profound difference between Polemarchus and his father in terms of their conceptions of justice.

Cephalus’s conception of justice appears purely formal: “give back what you owe and tell the truth.” He does not express any concern about the persons toward whom one is to be just. It appears that his motivation for being just is entirely based in self-interest. His is motivated entirely by fear — fear that he will be punished by the gods after death.

What about Polemarchus? We have observed that his motivation for re-entering the conversation is to defend his father. He is not so much interested in defending his father’s thesis. He is interested in defending his father. In contrast to Cephalus, who seems to be entirely self-interested, Polemarchus seems to be primarily motivated by a concern for the well-being of another person. Before Polemarchus has expressed his conception of justice in words, we see in the behavior of Polemarchus an example of what Thrasymachus says so contemptuously about justice, that it is not one's own good but somebody else's good. But not just anybody else's good, since we will see that Polemarchus limits the positive obligatnions of justice to people who share a particular relationship to oneself, namely friends including family, which for many people is an extension of oneself. So we will see that for Polemarchus justice turns out to be a kind of enlarged self-interest.

Comparison of Socrates’ motivation and that of Polemarchus:

I have been saying that Socrates has been the victim of an injustice (being involuntarily detained) and because his captors don’t understand this as an injustice, he has an interest in teaching them about justice insofar as that will influence them to treat him justly — but I have been saying as well that, contrary to the assumption of many commentators who assume that Socrates is primarily interested in a theoretical inquiry into the nature of justice, Socrates is only interested in the question of justice to the extent that it will help him to achieve justice for himself.

Is Polemarchus interested in having a theoretical conversation about justice? No! As we have noted, Polemarchus is only interested in defending his father. Like Socrates, he is motivated to re-enter the conversation only because he wants to correct or prevent an injustice from being done to his father, and, like Socrates, Polemarchus has no theoretical interest in justice.

Lance