64 PLATO
“And what about a helmsman? Is the one who’s a helmsman in the correct way a
ruler of sailors or a sailor?”
“A ruler of sailors.”
“I assume there’s no need to take into account that he does sail in the ship, and
no need for him to be called a sailor, since it’s not on account of sailing that he’s
called a helmsman, but on account of his art and his ruling position among the
sailors.”
“That’s true,” he said.
“Then for each of the latter there’s something advantageous?”
“Certainly.”
“And isn’t art by its nature for this,” I said, “for seeking and providing what’s
advantageous in each case?”
“For that,” he said.
“Then is there any advantage for each of the arts other than to be as complete as
possible?”
“In what sense are you asking this?”
“In the same sense,” I said, “as, if you were to ask me whether it’s sufficient for a
body to be a body or whether it needs something extra, I’d say ‘Absolutely it needs some-
thing extra, and it’s for that reason that the medical art has now been discovered, because a
body is inadequate and isn’t sufficient to itself to be the sort of thing it is. So it’s for this rea-
son, in order that it might provide the things that are advantageous for the body, that the art
was devised.’ Would I seem to you to be speaking correctly in saying this,” I said, “or not?”
“It’s correct,” he said.
“What then? Is the medical art itself—or any other art—inadequate, and is it
the case that it has need of some extra virtue? Just as eyes need sight and ears need
hearing and for these reasons there is need of some art applied to them that will con-
sider and provide what’s advantageous for these things, is there then in the art itself
some inadequacy in it too, and a need for each art to have another art that will con-
sider what’s advantageous for it, and for the one that will consider that to have
another art in turn of that kind, and this is unending? Or will it consider what’s
advantageous for itself? Or is there no additional need either for it or for any other
art to consider what’s advantageous for its inadequacy, because there is no inade-
quacy or mistake present in any art, nor is it appropriate for an art to look out for the
advantage of anything other than that with which the art is concerned, but it itself is
without defect and without impurity since it is correct as long as each is the whole
precise art that it is. Consider it in that precise speech now: is that the way it is, or is
it some other way?”
“That way,” he said, “as it appears.”
“So then,” I said, “the medical art considers what’s advantageous not for the med-
ical art but for a body.”
“Yes,” he said.
“And horsemanship considers what’s advantageous not for horsemanship but for
horses, and neither does any other art consider what’s advantageous for itself, since
there’s no extra need for that, but for that with which the art is concerned.”
“So it appears,” he said.
“But surely, Thrasymachus, the arts rule over and have power over that with
which they’re concerned.”
He went along with that too, very grudgingly.de342a
bc