A most excellent end to Book I

And the end or use of a horse or of anything would be that which could not be accomplished, or not so well accomplished, by any other thing? ... And that to which an end is appointed has also an excellence? ... And the same is true of all other things; they have each of them an end and a special excellence? ... I might say the same of the ears; when deprived of their own proper excellence they cannot fulfill their end?

Well; and has not the soul an end which nothing else can fulfill? for example, to super-intend and command and deliberate and the like. Are not these functions proper to the soul, and can they rightly be assigned to any other? ... And is not life to be reckoned among the ends of the soul? ... And has not the soul an excellence also? ... And can she or can she not fulfill her own ends when deprived of that excellence? ... And we have admitted that justice is the excellence of the soul, and injustice the defect of the soul?

- Socrates, The Republic, Book I, by Plato. Translation by Benjamin Jowett

I gotta say, the Socratic Method makes putting together a meaningful quote much more difficult, but following the argument is more fun when Socrates makes a fool out of his opponent. Sistafriend takes Thrasymachus and puts that queen in her place. Thrasymachus just gives up eventually and just goes along with whatever Socrates asserts.

There's this bit where Socrates claims that an unjust society would soon be filled with thieves and robbers, and everyone would be so distrustful of everyone else that nothing would ever be accomplished and the society would soon fall apart. He concludes that justice provides people with good lives.

Then he goes off on another tangent to that explain things have excellences and ends, that is, what the object or action does and why they do it. If you can't perform your excellence, Socrates explains, then you can't reach your desired end. For example, you go down to the mall and buy yo'self an outfit that makes your ass look great and you so certain you gonna hook up when you go out clubbing tonight. Well, the outfit's excellence is making you look good, and its end is to get you laid. If the outfit keeps you from looking good, then it's harder to get laid.

So what's the soul's end? Socrates would hope that a happy and healthy life would be the desired end of the soul's influence, and the excellence that provides that is justice. But by this point, Socrates realizes that he has gone off topic, and it's time now to return to the question at hand: What is justice?