Plato: The Republic

1. BOOK I (continued)

And the interest of any art is the perfection of it--this and nothing else?

What do you mean?

I mean what I may illustrate negatively by the example of the body. Suppose you were to ask me whether the body is self-sufficing or has wants, I should reply: Certainly the body has wants; for the body may be ill and require to be cured, and has therefore interests to which the art of medicine ministers; and this is the origin and intention of medicine, as you will acknowledge. 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.