Complete Works

by Plato, Cooper, John M. , Hutchinson, D. S.

  THEAETETUS: That’s true.

  SOCRATES: Then as regards the things we don’t know, we often don’t perceive them either, but often we only perceive them.

  THEAETETUS: That is so, also.

  [193] SOCRATES: Now see if you can follow me a little better. Supposing Socrates knows both Theodorus and Theaetetus, but is not seeing either of them, or having any other perception about them: he could never in that case judge within himself that Theaetetus was Theodorus. Is that sense or not?

  THEAETETUS: Yes, that’s quite true.

  SOCRATES: This, then, was the first of the cases I was speaking of.

  THEAETETUS: It was.

  SOCRATES: Secondly then. Supposing I am acquainted with one of you and not the other, and am perceiving neither of you: in that case, I could never think the one I do know to be the one I don’t know.

  THEAETETUS: That is so.

  [b] SOCRATES: Thirdly, supposing I am not acquainted with either of you, and am not perceiving either of you: I could not possibly think that one of you, whom I don’t know, is another of you whom I don’t know. Now will you please take it that you have heard all over again in succession the other cases described before—the cases in which I shall never judge falsely about you and Theodorus, either when I am familiar or when I am unfamiliar with both of you; or when I know one and not the other. And similarly with perceptions, you follow me.

  THEAETETUS: I follow.

  SOCRATES: So there remains the possibility of false judgment in this case. [c] I know both you and Theodorus; I have your signs upon that block of wax, like the imprints of rings. Then I see you both in the distance, but cannot see you well enough; but I am in a hurry to refer the proper sign to the proper visual perception, and so get this fitted into the trace of itself, that recognition may take place. This I fail to do; I get them out of line, applying the visual perception of the one to the sign of the other. It is like people putting their shoes on the wrong feet, or like what happens when [d] we look at things in mirrors, when left and right change places. It is then that ‘heterodoxy’ or false judgment arises.

  THEAETETUS: Yes, that seems very likely, Socrates; it is an awfully good description of what happens to the judgment.

  SOCRATES: Then, again, supposing I know both of you, and am also perceiving one of you, and not the other, but am not keeping my knowledge of the former in line with my perception—that’s the expression I used before and you didn’t understand me then.

  THEAETETUS: No, I certainly didn’t.

  SOCRATES: Well, I was saying that if you know one man and perceive [e] him as well, and keep your knowledge of him in line with your perception, you will never take him for some other person whom you know and are perceiving, and the knowledge of whom you are holding straight with the perception. Wasn’t that so?

  THEAETETUS: Yes.

  SOCRATES: There remained, I take it, the case we have just mentioned where false judgment arises in the following manner: you know both men [194] and you are looking at both, or having some other perception of them; and you don’t hold the two signs each in line with its own perception, but like a bad archer you shoot beside the mark and miss—which is precisely what we call falsehood.

  THEAETETUS: Naturally so.

  SOCRATES: And when for one of the signs there is also a present perception but there is not for the other, and you try to fit to the present perception the sign belonging to the absent perception, in all such cases thought is in error.

  We may sum up thus: it seems that in the case of things we do not [b] know and have never perceived, there is no possibility of error or of false judgment, if what we are saying is at all sound; it is in cases where we both know things and are perceiving them that judgment is erratic and varies between truth and falsity. When it brings together the proper stamps and records directly and in straight lines, it is true; when it does so obliquely and crosswise, it is false.

  THEAETETUS: Well, isn’t that beautiful, Socrates?

  SOCRATES: Ah, when you’ve heard what is coming next, you will say so [c] all the more. For true judgment is beautiful, right enough, and error is ugly.

  THEAETETUS: No doubt about that.

  SOCRATES: Well, this, then, they say, is why the two things occur. In some men, the wax in the soul is deep and abundant, smooth and worked to the proper consistency; and when the things that come through the senses are imprinted upon this ‘heart’ of the soul—as Homer calls it, hinting at the likeness to the wax36—the signs that are made in it are lasting, because [d] they are clear and have sufficient depth. Men with such souls learn easily and remember what they learn; they do not get the signs out of line with the perceptions, but judge truly. As the signs are distinct and there is plenty of room for them, they quickly assign each thing to its own impress in the wax—the things in question being, of course, what we call the things that are and these people being the ones we call wise.

  Or do you feel any doubts about this?

  THEAETETUS: No, I find it extraordinarily convincing.

  SOCRATES: But it is a different matter when a man’s ‘heart’ is ‘shaggy’ [e] (the kind of heart our marvellously knowing poet praises), or when it is dirty and of impure wax; or when it is very soft or hard. Persons in whom the wax is soft are quick to learn but quick to forget; when the wax is hard, the opposite happens. Those in whom it is ‘shaggy’ and rugged, a stony thing with earth or filth mixed all through it, have indistinct impressions. So too if the wax is hard, for then the impressions have no depth; similarly they are indistinct if the wax is soft, because they quickly run [195] together and are blurred. If, in addition to all this, the impresses in the wax are crowded upon each other for lack of space, because it is only some little scrap of a soul, they are even more indistinct. All such people are liable to false judgment. When they see or hear or think of anything, they can’t quickly allot each thing to each impress; they are slow and allot things to impresses which do not belong to them, misseeing, mishearing and misthinking most of them—and these in turn are the ones we describe as in error about the things that are and ignorant.

  [b] THEAETETUS: That’s exactly it, Socrates; no man could improve on your account.

  SOCRATES: Then are we to say that false judgments do exist in us?

  THEAETETUS: Yes, most emphatically.

  SOCRATES: And true ones, of course?

  THEAETETUS: And true ones.

  SOCRATES: And we think we have now reached a satisfactory agreement, when we say that these two kinds of judgment certainly exist?

  THEAETETUS: There’s no earthly doubt about it, Socrates.

  SOCRATES: Theaetetus, I’m afraid a garrulous man is really an awful nuisance.

  THEAETETUS: Why, what are you talking about?

  [c] SOCRATES: I’m annoyed at my own stupidity—my own true garrulousness. What else could you call it when a man will keep dragging arguments up and down, because he is too slow-witted to reach any conviction, and will not be pulled off any of them?

  THEAETETUS: But why should you be annoyed?

  SOCRATES: I am not only annoyed; I am alarmed. I am afraid of what I may say if someone asks me: ‘So, Socrates, you’ve discovered false judgment, have you? You have found that it arises not in the relation of [d] perceptions to one another, or of thoughts to one another, but in the connecting of perception with thought?’ I believe I am very likely to say ‘Yes’, with an air of flattering myself upon our having made some beautiful discovery.

  THEAETETUS: Well, Socrates, what you have just shown us looks to me quite a presentable thing anyway.

  SOCRATES: ‘You mean’, he goes on, ‘that we would never suppose that a man we are merely thinking of but not seeing is a horse which again we are not seeing or touching, but just thinking of and not perceiving anything else about it?’ I suppose I shall agree that we do mean this.

  THEAETETUS: Yes, and quite rightly.

  [e] SOCRATES: ‘Well then,’ he goes on, ‘doesn’t it follow from this theory that a m
an couldn’t possibly suppose that eleven, which he is merely thinking about, is twelve, which again he is merely thinking about?’ Come now, you answer.

  THEAETETUS: Well, my answer will be that someone who is seeing or touching them could suppose that eleven are twelve, but not with those that he has in his thought: he would never judge this in that way about them.

  [196] SOCRATES: Well, now, take the case where a man is considering five and seven within himself—I don’t mean seven men and five men, or anything of that sort, but five and seven themselves; the records, as we allege, in that waxen block, things among which it is not possible that there should be false judgment. Suppose he is talking to himself about them, and asking himself how many they are. Do you think that in such a case it has ever happened that one man thought they were eleven and said so, while another thought and said that they were twelve? Or do all men say and all men think that they are twelve?

  THEAETETUS: Oh, good Heavens, no; lots of people would make them [b] eleven. And with larger numbers they go wrong still more often—for I suppose what you say is intended to apply to all numbers.

  SOCRATES: Quite right. And I want you to consider whether what happens here is not just this, that a man thinks that twelve itself, the one on the waxen block, is eleven.

  THEAETETUS: It certainly looks as if he does.

  SOCRATES: Then haven’t we come back to the things we were saying at the outset? You see, anyone to whom this happens is thinking that one thing he knows is another thing he knows. And this we said was impossible; in fact, it was just this consideration which led us to exclude the possibility of false judgment, because, if admitted, it would mean that the same man [c] must, at one and the same time, both know and not know the same objects.

  THEAETETUS: That’s perfectly true.

  SOCRATES: Then we shall have to say that false judgment is something other than a misapplication of thought to perception; because if this were so, we could never be in error so long as we remained within our thoughts themselves. But as the matter now stands, either there is no such thing as false judgment; or a man may not know what he knows. Which do you choose?

  THEAETETUS: You are offering me an impossible choice, Socrates.

  SOCRATES: But I’m afraid the argument will not permit both. Still—[d] we must stop at nothing; supposing now we were to set about being quite shameless?

  THEAETETUS: How?

  SOCRATES: By consenting to say what knowing is like.

  THEAETETUS: And why should that be shameless?

  SOCRATES: You don’t seem to realize that our whole discussion from the beginning has been an inquiry about knowledge, on the assumption that we do not yet know what it is.

  THEAETETUS: Oh but I do.

  SOCRATES: Well, then, don’t you think it is a shameless thing that we, who don’t know what knowledge is, should pronounce on what knowing [e] is like? But as a matter of fact, Theaetetus, for some time past our whole method of discussion has been tainted. Time and again we have said ‘we are acquainted with’ and ‘we are not acquainted with’, ‘we know’ and ‘we do not know’, as if we could to some extent understand one another while we are still ignorant of what knowledge is. Or here’s another example, if you like: at this very moment, we have again used the words ‘to be ignorant of’, and ‘to understand’, as if these were quite proper expressions for us when we are deprived of knowledge.

  THEAETETUS: But how are you going to carry on the discussion at all, Socrates, if you keep off these words?

  [197] SOCRATES: Quite impossible, for a man like me; but if I were one of the experts in contradiction, I might be able to. If one of those gentlemen were present, he would have commanded us to refrain from them, and would keep coming down upon us heavily for the faults I’m referring to. But since we are no good anyway, why don’t I make bold to tell you what knowing is like? It seems to me that this might be of some help.

  THEAETETUS: Then do be bold, please. And if you don’t keep from using these words, we’ll forgive you all right.

  SOCRATES: Well, then, have you heard what people are saying nowadays that knowing is?

  THEAETETUS: I dare say I have; but I don’t remember it at the moment.

  [b] SOCRATES: Well, they say, of course, that it is ‘the having of knowledge’.

  THEAETETUS: Oh, yes, that’s true.

  SOCRATES: Let us make a slight change; let us say ‘the possession of knowledge’.

  THEAETETUS: And how would you say that was different from the first way of putting it?

  SOCRATES: Perhaps it isn’t at all; but I will tell you what I think the difference is, and then you must help me to examine it.

  THEAETETUS: All right—if I can.

  SOCRATES: Well, then, to ‘possess’ doesn’t seem to me to be the same as to ‘have’. For instance, suppose a man has bought a coat and it is at his disposal but he is not wearing it; we would not say that he ‘has’ it on, but we would say he ‘possesses’ it.

  THEAETETUS: Yes, that would be correct.

  [c] SOCRATES: Now look here: is it possible in this way to possess knowledge and not ‘have’ it? Suppose a man were to hunt wild birds, pigeons or something, and make an aviary for them at his house and look after them there; then, in a sense, I suppose, we might say he ‘has’ them all the time, because of course he possesses them. Isn’t that so?

  THEAETETUS: Yes.

  SOCRATES: But in another sense he ‘has’ none of them; it is only that he has acquired a certain power in respect of them, because he has got them [d] under his control in an enclosure of his own. That is to say, he has the power to hunt for any one he likes at any time, and take and ‘have’ it whenever he chooses, and let it go again; and this he can do as often as he likes.

  THEAETETUS: That is so.

  SOCRATES: Well a little while ago we were equipping souls with I don’t know what sort of a waxen device. Now let us make in each soul a sort of aviary of all kinds of birds; some in flocks separate from the others, some in small groups, and others flying about singly here and there among all the rest.

  THEAETETUS: All right, let us suppose it made. What then? [e]

  SOCRATES: Then we must say that when we are children this receptacle is empty; and by the birds we must understand pieces of knowledge. When anyone takes possession of a piece of knowledge and shuts it up in the pen, we should say that he has learned or has found out the thing of which this is the knowledge; and knowing, we should say, is this.

  THEAETETUS: That’s given, then.

  SOCRATES: Now think: when he hunts again for any one of the pieces of [198] knowledge that he chooses, and takes it and ‘has’ it, then lets it go again, what words are appropriate here? The same as before, when he took possession of the knowledge, or different ones?—You will see my point more clearly in this way. There is an art you call arithmetic, isn’t there?

  THEAETETUS: Yes.

  SOCRATES: Now I want you to think of this as a hunt for pieces of knowledge concerning everything odd and even.

  THEAETETUS: All right, I will.

  SOCRATES: It is by virtue of this art, I suppose, that a man both has under [b] his control pieces of knowledge concerning numbers and also hands them over to others?

  THEAETETUS: Yes.

  SOCRATES: And we call it ‘teaching’ when a man hands them over to others, and ‘learning’ when he gets them handed over to him; and when he ‘has’ them through possessing them in this aviary of ours, we call that ‘knowing’.

  THEAETETUS: Yes, certainly.

  SOCRATES: Now you must give your attention to what is coming next. It must surely be true that a man who has completely mastered arithmetic knows all numbers? Because there are pieces of knowledge covering all numbers in his soul.

  THEAETETUS: Of course.

  SOCRATES: And a man so trained may proceed to do some counting, [c] either counting to himself the numbers themselves, or counting something else, one of the external things which have number?

  THEAETETUS: Ye
s, surely.

  SOCRATES: And counting we shall take to be simply a matter of considering how large a number actually is?

  THEAETETUS: Yes.

  SOCRATES: Then it looks as if this man were considering something which he knows as if he did not know it (for we have granted that he knows all numbers). I’ve no doubt you’ve had such puzzles put to you.

  THEAETETUS: I have, yes.

  SOCRATES: Then using our image of possessing and hunting for the pigeons, [d] we shall say that there are two phases of hunting; one before you have possession in order to get possession, and another when you already possess in order to catch and have in your hands what you previously acquired. And in this way even with things you learned and got the knowledge of long ago and have known ever since, it is possible to learn them—these same things—all over again. You can take up again and ‘have’ that knowledge of each of them which you acquired long ago but had not ready to hand in your thought, can’t you?

  THEAETETUS: True.

  [e] SOCRATES: Now this is what I meant by my question a moment ago. What terms ought we to use about them when we speak of what the arithmetician does when he proceeds to count, or the scholar when he proceeds to read something? Here, it seems, a man who knows something is setting out to learn again from himself things which he already knows.

  THEAETETUS: But that would be a very odd thing, Socrates.

  SOCRATES: But are we to say that it is things which he does not know [199] that such a man is going to read and count—remembering that we have granted him knowledge of all letters and all numbers?

  THEAETETUS: That wouldn’t be reasonable, either.

  SOCRATES: Then would you like us to take this line? Suppose we say we do not mind at all about the names; let people drag around the terms ‘knowing’ and ‘learning’ to their heart’s content. We have determined that to ‘possess’ knowledge is one thing and to ‘have’ it is another; accordingly we maintain that it is impossible for anyone not to possess that which he has possession of, and thus, it never happens that he does not know something he knows. But he may yet make a false judgment about it. This [b] is because it is possible for him to ‘have’, not the knowledge of this thing, but another piece of knowledge instead. When he is hunting for one piece of knowledge, it may happen, as they fly about, that he makes a mistake and gets hold of one instead of another. It was this that happened when he thought eleven was twelve. He got hold of the knowledge of eleven that was in him, instead of the knowledge of twelve, as you might catch a ring-dove instead of a pigeon.