Theaetetus (164)

SOC. We must, though, if we are to maintain our previous argument; otherwise, it is all up with it.

THEAET. I too, by Zeus, have my suspicions, but I don’t fully understand you. Tell me how it is.

SOC. This is how it is: he who sees has acquired knowledge, we say, of that which he has seen; for it is agreed that sight and perception and knowledge are all the same.

THEAET. Certainly.

SOC. But he who has seen and has acquired knowledge of what he saw, if he shuts his eyes, remembers it, but does not see it. Is that right?

THEAET. Yes.

SOC. But does not see is the same as does not know, if it is true that seeing is knowing.

THEAET. True.

SOC. Then this is our result. When a man has acquired knowledge of a thing and still remembers it, he does not know it, since he does not see it; but we said that would be a monstrous conclusion.

THEAET. Very true.

SOC. So, evidently, we reach an impossible result if we say that knowledge and perception are the same.

THEAET. So it seems.

SOC. Then we must say they are different.

THEAET. I suppose so.

SOC. Then what can knowledge be? We must, apparently, begin our discussion all over again. And yet, Theaetetus, what are we on the point of doing?

THEAET. About what?

SOC. It seems to me that we are behaving like a worthless game-cock; before winning the victory we have leapt away from our argument and begun to crow.

THEAET. How so?

SOC. We seem to be acting like professional debaters; we have based our agreements on the mere similarity of words and are satisfied to have got the better of the argument in such a way, and we do not see that we, who claim to be, not contestants for a prize, but lovers of wisdom, are doing just what those ingenious persons do.

THEAET. I do not yet understand what you mean.

SOC. Well, I will try to make my thought clear. We asked, you recollect, whether a man who has learned something and remembers it does not know it. We showed first that the one who has seen and then shuts his eyes remembers, although he does not see, and then we showed that he does not know, although at the same time he remembers; but this, we said, was impossible. And so the Protagorean tale was brought to naught, and yours also about the identity of knowledge and perception.

THEAET. Evidently.

SOC. It would not be so, I fancy, my friend, if the father of the first of the two tales were alive; he would have had a good deal to say in its defence. But he is dead, and we are abusing the orphan. Why, even the guardians whom Protagoras left—one of whom is Theodorus here—are unwilling to come to the child’s assistance. So it seems that we shall have to do it ourselves, assisting him in the name of justice.