Phi202

For Thrasymachus, to be virtuous is to be excellent and to be excellent is to be a winner. An excellence is something that helps to achieve the goal of being the best. So a virtue can be being unjust.

What Socrates does is that he turns these ideas back on themselves. In terms of that telos (above), being a lion among men, a wolf among men, is not going to achieve that goal. It's not a genuine thing. Justice IS a virtue.

Henceforth, he then takes a different tack and argues that justice doesn't pay. Moreover, he has it that justice is not a virtue, i.e. not an excellence. How can this be?

For Thrasymachus, the human telos is rather like that of a beast of prey. It consists in dominating and imposing your will. For that end, justice may well not be an affective means. But a thing is excellent if and only if it has qualities that help it fulfil its end. So forth the just man won't have such qualities, i.e. won't be excellent.

Socrates responds to this by arguing for a different telos. Roughly, humans are social and human excellence consists for Socrates at least partly in having qualities that render you able to interact well socially - justice plausibly is one of these qualities.

Is there anything that Socrates can say to argue Thrasymachus out of his view as to what the human telos is?

One argument is that no one man can dominate all the people all the time. So even on his own terms Thrasymachus has to admit that the man who acts like a beast of prey will not succeed.