Am I not right?
Quite right, he replied.
But is the art of medicine or any other art faulty or deficient in any quality in the same way that the eye may be deficient in sight or the ear fail of hearing, and therefore requires another art to provide for the interests of seeing and hearing--has art in itself, I say, any similar liability to fault or defect, and does every art require another supplementary art to provide for its interests, and that another and another without end?
Or have the arts to look only after their own interests?
Or have they no need either of themselves or of another ?--having no faults or defects, they have no need to correct them, either by the exercise of their own art or of any other; they have only to consider the interest of their subject-matter.

For every art remains pure and faultless while remaining true--that is to say, while perfect and unimpaired.

Take the words in your precise sense, and tell me whether I am not right." Yes, clearly.
Then medicine does not consider the interest of medicine, but the interest of the body?
True, he said.
Nor does the art of horsemanship consider the interests of the art of horsemanship, but the interests of the horse; neither do any other arts care for themselves, for they have no needs; they care only for that which is the subject of their art?
True, he said.
But surely, Thrasymachus, the arts are the superiors and rulers of their own subjects?
To this he assented with a good deal of reluctance.
Then, I said, no science or art considers or enjoins the interest of the stronger or superior, but only the interest of the subject and weaker?
He made an attempt to contest this proposition also, but finally acquiesced.
Then, I continued, no physician, in so far as he is a physician, considers his own good in what he prescribes, but the good of his patient; for the true physician is also a ruler having the human body as a subject, and is not a mere money-maker; that has been admitted?
Yes.
And the pilot likewise, in the strict sense of the term, is a ruler of sailors and not a mere sailor?
That has been admitted.
And such a pilot and ruler will provide and prescribe for the interest of the sailor who is under him, and not for his own or the ruler's interest?
He gave a reluctant 'Yes.' Then, I said, Thrasymachus, there is no one in any rule who, in so far as he is a ruler, considers or enjoins what is for his own interest, but always what is for the interest of his subject or suitable to his art; to that he looks, and that alone he considers in everything which he says and does.
When we had got to this point in the argument, and every one saw that the definition of justice had been completely upset, Thrasymachus, instead of replying to me, said: Tell me, Socrates, have you got a nurse?
Why do you ask such a question, I said, when you ought rather to be answering?
Because she leaves you to snivel, and never wipes your nose: she has not even taught you to know the shepherd from the sheep.
What makes you say that?
I replied.
Because you fancy that the shepherd or neatherd fattens of tends the sheep or oxen with a view to their own good and not to the good of himself or his master; and you further imagine that the rulers of states, if they are true rulers, never think of their subjects as sheep, and that they are not studying their own advantage day and night.

Oh, no; and so entirely astray are you in your ideas about the just and unjust as not even to know that justice and the just are in reality another's good; that is to say, the interest of the ruler and stronger, and the loss of the subject and servant; and injustice the opposite; for the unjust is lord over the truly simple and just: he is the stronger, and his subjects do what is for his interest, and minister to his happiness, which is very far from being their own.
Consider further, most foolish Socrates, that the just is always a loser in comparison with the unjust.

First of all, in private contracts: wherever the unjust is the partner of the just you will find that, when the partnership is dissolved, the unjust man has always more and the just less.