Phi202

Plato on JusticeandSelf-interest (in the Republic)

1. Polemarchusand the conventional view ofjustice

Polemarchus asked to define: dike (state of justice)

dikeisine (the virtue of being just)

Answers: it is a matter of giving every man his due.

Fits in with an idea of cosmic hierarchy or order - everything has a place where it is meant to be.

Justice is giving everything what its entitled to in virtue of its place in the cosmic order.
Socrates wonders what this amounts to: Quote 1
Socrates will deny that a just act can do harm, contrary to what Polemarchus argues. He asks Polemarchus to consider justice as a skill. Quote 3.

Polemarchus thinks of justice as the skill of helping friends and harming enemies. Archi tectonic in some way (lol?). What if your friends are bad andyourenemies good? Surely justice cannot be used to harm thegood! Or, says Polemarchus, I meantthat justice is a matter of helping the friends, those who are good and harming genuine enemies, those who are bad. Well, says Socrates, if justice is a skill it can't be used to harm even the bad. Justice can only help, even when it is applied to the bad. (Doesn't rule out punishment, if the effect is to reform).

Justice is also revealed not to be a departmental skill, but an architedonic one. (socrates tries to get Polemarchus to tell him what benefit justice produces - none it seems.

2. Thrasymachus

Thrasymachus was a sophist

Holds that justice is a matter of convention or custom rather than nature. To say that justice or politeness is a matter is not to deny that there is a fact of the matter about what's polite or just here and now. It is to say that what is just or polite is arbitrary and contingent.

(It is not impolite to discuss real estate at dinner, but it could have been the height of rudeness.)

In contrast, that potatoes are nourishing rather than poisonous is a matter of nature. It isn't contingent on arbitrary human decision.