Plato, Charmides

I daresay, I said; but I am afraid I am still my old self: I still do not see how knowing what one knows and does not know is the same as the other.

How do you mean? he asked.

In this way, I replied: will a science of science, if such exists, be able to do more than determine that one of two things is science, and the other is not science?

No, only that. [170b] Now, is science or lack of science of health the same as science or lack of science of justice?

By no means.

For the one, I suppose, is medicine, and the other politics, while the thing in question is merely science.

Yes, to be sure.

And if a man has no added knowledge of health and justice, but knows only science, as having science of that alone, he will probably know that he has a certain piece of scientific knowledge about himself and about other people, will he not?

Yes. [170c] But how will this science help him to know what he knows? For of course he knows health by means of medicine, not temperance, and harmony by means of music, not temperance, and building by means of the builder's art, not temperance; and so it will be in every case, will it not?

Apparently.

And how will temperance, supposing it is only a science of sciences, help him to know that he knows health, or that he knows building?

By no means.

Then he who is ignorant of all this will not know what he knows, but only that he knows.

So it seems. [170d] Then being temperate, or temperance, will not be this knowledge of what one knows or does not know, but, it would seem, merely knowing that one knows or does not know.

It looks like it.

Then such a person will also be unable to examine another man's claim to some knowledge, and make out whether he knows or does not know what he says he knows: he will merely know, it would seem, that he has a certain knowledge; but of what it is, temperance will not cause him to know.

Apparently not. [170e] So he will be able to distinguish neither the man who pretends to be a doctor, but is none, from the man who really is one, nor any other man who has knowledge from him who has none. But let us consider it another way: if the temperate man or anybody else would discriminate between the true doctor and the false, he will go to work thus, will he not? He will surely not talk to him about medicine; for, as we were saying, the doctor understands nothing else but health and disease. Is not that so?

Yes, it is.

But about science he knows nothing, for that, you know, we assigned to temperance alone.

Yes.

So the medical man knows nothing about medicine either, since