Theaetetus THEAET. That would not be right, Socrates; neither you nor we would think so.

Socrates SOC. Apparently, then, you and Theodorus mean we must look at the matter in a different way.

Theaetetus THEAET. Yes, certainly in a different way.

Socrates SOC. Well, then, let us look at it in this way, raising the question whether knowledge is after all the same as perception, or different. For that is the object of all our discussion, and it was to answer that question than we stirred up all these strange doctrines, was it not?

Theaetetus THEAET. Most assuredly.

Socrates SOC. Shall we then agree that all that we perceive by sight or hearing we know? For instance, shall we say that before having learned the language of foreigners we do not hear them when they speak, or that we both hear and know what they say? And again, if we do not know the letters, shall we maintain that we do not see them when we look at them or that if we really see them we know them?

Theaetetus THEAET. We shall say, Socrates, that we know just so much of them as we hear or see: in the case of the letters, we both see and know the form and color, 163c and in the spoken language we both hear and at the same time know the higher and lower notes of the voice; but we do not perceive through sight or hearing, and we do not know, what the grammarians and interpreters teach about them.

Socrates SOC. First-rate, Theaetetus! and it is a pity to dispute that, for I want you to grow. But look out for another trouble that is yonder coming towards us, and see how we can repel it.

Theaetetus THEAET. What is it?

Socrates SOC. It is like this: If anyone should ask, “Is it possible, if a man has ever known a thing and still has 163d and preserves a memory of that thing, that he does not, at the time when he remembers, know that very thing which he remembers?” I seem to be pretty long winded; but I merely want to ask if a man who has learned a thing does not know it when he remembers it.

Theaetetus THEAET. Of course he does, Socrates; for what you suggest would be monstrous.

Socrates SOC. Am I crazy, then? Look here. Do you not say that seeing is perceiving and that sight is perception?

Theaetetus THEAET. I do.

Socrates SOC. Then, according to what we have just said, the man who has seen a thing has acquired knowledge 163e of that which he has seen?

Theaetetus THEAET. Yes.

Socrates SOC. Well, then, do you not admit that there is such a thing as memory?

Theaetetus THEAET. Yes.

Socrates SOC. Memory of nothing or of something?

Theaetetus THEAET. Of something, surely.

Socrates SOC. Of things he has learned and perceived—that sort of things?

Theaetetus THEAET. Of course.

Socrates SOC. A man sometimes remembers what he has seen, does he not?

Theaetetus THEAET. He does.

Socrates SOC. Even when he shuts his eyes, or does he forget if he does that?

Theaetetus THEAET. It would be absurd to say that, Socrates.

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

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

Socrates 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.

Theaetetus THEAET. Certainly.

Socrates 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?

Theaetetus THEAET. Yes.

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

Theaetetus THEAET. True.

Socrates 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.

Theaetetus THEAET. Very true.

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

Theaetetus THEAET. So it seems.

Socrates SOC. Then we must say they are different.

Theaetetus THEAET. I suppose so.

Socrates 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?

Theaetetus THEAET. About what?

Socrates 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.

Theaetetus THEAET. How so?

Socrates 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, 164d are doing just what those ingenious persons do.

Theaetetus THEAET. I do not yet understand what you mean.

Socrates 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.

Theaetetus THEAET. Evidently.

Socrates 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.

Theodorus THEO. Do so, for it is not I, Socrates, but rather 165a Callias the son of Hipponicus, who is the guardian of his children. As for me, I turned rather too soon from abstract speculations to geometry. However, I shall be grateful to you if you come to his assistance.

Socrates SOC. Good, Theodorus! Now see how I shall help him; for a man might find himself involved in still worse inconsistencies than those in which we found ourselves just now, if he did not pay attention to the terms which we generally use in assent and denial. Shall I explain this to you, or only to Theaetetus?

Theodorus THEO. To both of us, but let the younger answer; 165b for he will be less disgraced if he is discomfited.

Socrates SOC. Very well; now I am going to ask the most frightfully difficult question of all. It runs, I believe, something like this: Is it possible for a person, if he knows a thing, at the same time not to know that which he knows?

Theodorus THEO. Now, then, what shall we answer, Theaetetus?

Theaetetus THEAET. It is impossible, I should think.

Socrates SOC. Not if you make seeing and knowing identical. For what will you do with a question from which there is no escape, by which you are, as the saying is, caught in a pit, when your adversary, unabashed, puts his hand over one of your eyes and asks 165c if you see his cloak with the eye that is covered?

Theaetetus THEAET. I shall say, I think, “Not with that eye, but with the other.”

Socrates SOC. Then you see and do not see the same thing at the same time?

Theaetetus THEAET. After a fashion.

Socrates SOC. “That,” he will reply, “is not at all what I want, and I did not ask about the fashion, but whether you both know and do not know the same thing. Now manifestly you see that which you do not see. But you have agreed that seeing is knowing and not seeing is not knowing. Very well; from all this, reckon out what the result is.”

Theaetetus THEAET. Well, I reckon out that the result is the contrary of my hypothesis.

Socrates SOC. And perhaps, my fine fellow, more troubles of the same sort might have come upon you, if anyone asked you further questions—whether it is possible to know the same thing both sharply and dully, to know close at hand but not at a distance, to know both violently and gently, and countless other questions, such as a nimble fighter, fighting for pay in the war of words, might have lain in wait and asked you, when you said that knowledge and perception were the same thing; he would have charged down upon hearing and smelling and such senses, 165e and would have argued persistently and unceasingly until you were filled with admiration of his greatly desired wisdom and were taken in his toils, and then, after subduing and binding you he would at once proceed to bargain with you for such ransom as might be agreed upon between you. What argument, then, you might ask, will Protagoras produce to strengthen his forces? Shall we try to carry on the discussion?

Theaetetus THEAET. By all means.