Theod. He was a friend of mine, Socrates, as you were saying, and therefore I cannot have him refuted by my lips, nor can I oppose you when I agree with you ; please, then, to take Theaetetus again ; he seemed to answer very nicely.
Soc. If you were to go into a Lacedaemonian palestra, Theodorus, would you have a right to look on at the naked wrestlers, some of them making a poor figure, if you did not strip and give them an opportunity of judging of your own person ?
Theod. Why not, Socrates, if they would allow me, as I think you will in consideration of my age and stiffness ; let some more supple youth try a fall with you, and do not drag me into the gymnasium.
Soc. Your will is my will, Theodorus, as the proverbial philosophers say, and therefore I will return to the sage Theaetetus : Tell me, Theaetetus, in reference to what I was saying, are you not lost in wonder, like myself, when you find that all of a sudden you are raised to the level of the wisest of men, or indeed of the gods ? — for you would assume the measure of Protagoras to apply to the gods as well as men ?
Theaet. Certainly I should, and I confess to you that I am lost in wonder. At first hearing, I was quite satisfied with the doctrine, that whatever appears is to each one, but now the face of things has changed.
Soc. Why, my dear boy, you are young, and therefore your ear is quickly caught and your mind influenced by popular arguments. Protagoras, or some one speaking on his behalf, will doubtless say in reply, good people, young and old, you meet and harangue, and bring in the gods, whose existence of non-existence I banish from writing and speech, or you talk about the reason of man being degraded to the level of the brutes, which is a telling argument with the multitude, but not one word of proof or demonstration do you offer. All is probability with you, and yet surely you and Theodorus had better reflect whether you are disposed to admit of probability and figures of speech in matters of such importance. He or any other mathematician who argued from probabilities and likelihoods in geometry, would not be worth an ace.
Theaet. But neither you nor we, Socrates, would be satisfied with such arguments.
Soc. Then you and Theodorus mean to say that we must look at the matter in some other way ?
Theaet. Yes, in quite another way.
Soc. And the way will be to ask whether perception is or is not the same as knowledge ; for this was the real point of our argument, and with a view to this we raised (did we not ?) those many strange questions.
Theaet. Certainly.
Soc. Shall we say that we know every thing which we see and hear ? for example, shall we say that not having learned, we do not hear the language of foreigners when they speak to us ? or shall we say that we not only hear, but know what they are saying ? Or again, if we see letters which we do not understand, shall we say that we do not see them ? or shall we aver that, seeing them, we must know them ?
Theaet. We shall say, Socrates, that we know what we actually see and hear of them — that is to say, we see and know the figure and colour of the letters, and we hear and know the elevation or depression of the sound of them ; but we do not perceive by sight and hearing, or know, that which grammarians and interpreters teach about them.
Soc. Capital, Theaetetus ; and about this there shall be no dispute, because I want you to grow ; but there is another difficulty coming, which you will also have to repulse.
Theaet. What is it ?
Soc. Some one will say, Can a man who has ever known anything, and still has and preserves a memory of that which he knows, not know that which he remembers at the time when he remembers ? I have, I fear, a tedious way of putting a simple question, which is only, whether a man who has learned, and remembers, can fail to know ?
Theaet. Impossible, Socrates ; the supposition is monstrous.
Soc. Am I talking nonsense, then ? Think : is not seeing perceiving, and is not sight perception ?
Theaet. True.
Soc. And if our recent definition holds, every man knows that which he has seen ?
Theaet. Yes.
Soc. And you would admit that there is such a thing as memory ?
Theaet. Yes.
Soc. And is memory of something or of nothing ?
Theaet. Of something, surely.
Soc. Of things learned and perceived, that is ?
Theaet. Certainly.
Soc. Often a man remembers that which he has seen ?
Theaet. True.
Soc. And if he closed his eyes, would he forget ?
Theaet. Who, Socrates, would dare to say so ?
Soc. But we must say so, if the previous argument is to be maintained.
Theaet. What do you mean ? I am not quite sure that I understand you, though I have a strong suspicion that you are right.
Soc. As thus : he who sees knows, as we say, that which he sees ; for perception and sight and knowledge are admitted to be the same.
Theaet. Certainly.
Soc. But he who saw, and has knowledge of that which he saw, remembers, when he closes his eyes, that which he no longer sees.
Theaet. True.
Soc. And seeing is knowing, and therefore not-seeing is not-knowing ?
Theaet. Very true.
Soc. Then the inference is, that a man may have attained the knowledge, of something, which he may remember and yet not know, because he does not see ; and this has been affirmed by us to be a monstrous supposition.
Theaet. Most true.
Soc. Thus, then, the assertion that knowledge and perception are one, involves a manifest impossibility ?
Theaet. Yes.
Soc. Then they must be distinguished ?
Theaet. I suppose that they must.
Soc. Once more we shall have to begin, and ask “What is knowledge ?” and yet, Theaetetus, what are we going to do ?
Theaet. About what ?
Soc. Like a good-for-nothing cock, without having won the victory, we walk away from the argument and crow.
Theaet. How do you mean ?
Soc. After the manner of disputers, we were satisfied with mere verbal consistency, and were well pleased if in this way we could gain an advantage. Although professing not to be mere Eristics, but philosophers, I suspect that we have unconsciously fallen into the error of that ingenious class of persons.
Theaet. I do not as yet understand you.
Soc. Then I will try to explain myself : just now we asked the question, whether a man who had learned and remembered could fail to know, and we showed that a person who had seen might remember when he had his eyes shut and could not see, and then he would at the same time remember and not know. But this was an impossibility. And so the Protagorean fable came to nought, and yours also, who maintained that knowledge is the same as perception.
Theaet. True.
Soc. And yet, my friend, I rather suspect that the result would have been different if Protagoras, who was the father of the first of the two-brats, had been alive ; he would have had a great deal to say on their behalf. But he is dead, and we insult over his orphan child ; and even the guardians whom he left, and of whom our friend Theodorus is one, are unwilling to give any help, and therefore I suppose that must take up his cause myself, and see justice done ?
Theod. Not I, Socrates, but rather Callias, the son of Hipponicus, is guardian of his orphans. I was too soon diverted from the abstractions of dialectic to geometry. Nevertheless, I shall be grateful to you if you assist him.
Soc. Very good, Theodorus ; you shall see how I will come to the rescue. If a person does not attend to the meaning of terms as they are commonly used in argument, he may be involved even in greater paradoxes than these. Shall I explain this matter to you or to Theaetetus ?
Theod. To both of us, and let the younger answer ; he will incur less disgrace if he is discomfited.
Soc. Then now let me ask the awful question, which is this : — Can a man know and also not know that which he knows ?
Theod. How shall we answer, Theaetetus ?
Theaet. He cannot, I should say.
Soc. He can, if you maintain that seeing is knowing. When you are imprisoned in a well, as the saying is, and the self-assured adversary closes one of your eyes with his hand, and asks whether you can see his cloak with the eye which he has closed, how will you answer the inevitable man ?
Theaet. I should answer, “Not with that eye but with the other.”
Soc. Then you see and do not see the same thing at the same time.
Theaet. Yes, in a certain sense.
Soc. None of that, he will reply ; I do not ask or bid you answer in what sense you know, but only whether you know that which you do not know. You have been proved to see that which you do not see ; and you have already admitted that seeing is knowing, and that not-seeing is not-knowing : I leave you to draw the inference.
Theaet. Yes, the inference is the contradictory of my assertion.
Soc. Yes, my marvel, and there might have been yet worse things in store for you, if an opponent had gone on to ask whether you can have a sharp and also a dull knowledge, and whether you can know near, but not at a distance, or know the same thing with more or less intensity, and so on without end. Such questions might have been put to you by a light-armed mercenary, who argued for pay. He would have lain in wait for you, and when you took up the position, that sense is knowledge, he would have made an assault upon hearing, smelling, and the other senses ; — he would have shown you no mercy ; and while you were lost in envy and admiration of his wisdom, he would have got you into his net, out of which you would not have escaped until you had come to an understanding about the sum to be paid for your release. Well, you ask, and how will Protagoras reinforce his position ? Shall I answer for him ?
Theaet. By all means.