Complete Works

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

  THEAETETUS: Yes; that is reasonable, now.

  SOCRATES: But when he gets hold of the one he is trying to get hold of, then he is free from error; when he does that, he is judging what is. In [c] this way, both true and false judgment exist; and the things that worried us before no longer stand in our way. I daresay you’ll agree with me? Or, if not, what line will you take?

  THEAETETUS: I agree.

  SOCRATES: Yes; we have now got rid of this ‘not knowing what one knows’. For we now find that at no point does it happen that we do not possess what we possess, whether we are in error about anything or not. But it looks to me as if something else more alarming is by way of coming upon us.

  THEAETETUS: What’s that?

  SOCRATES: I mean, what is involved if false judgment is going to become a matter of an interchange of pieces of knowledge.

  THEAETETUS: What do you mean?

  SOCRATES: To begin with, it follows that a man who has knowledge of [d] something is ignorant of this very thing not through want of knowledge but actually in virtue of his knowledge. Secondly, he judges that this is something else and that the other thing is it. Now surely this is utterly unreasonable; it means that the soul, when knowledge becomes present to it, knows nothing and is wholly ignorant. According to this argument, there is no reason why an accession of ignorance should not make one know something, or of blindness make one see something, if knowledge is ever going to make a man ignorant.

  THEAETETUS: Well, perhaps, Socrates, it wasn’t a happy thought to make [e] the birds only pieces of knowledge. Perhaps we ought to have supposed that there are pieces of ignorance also flying about in the soul along with them, and what happens is that the hunter sometimes catches a piece of knowledge and sometimes a piece of ignorance concerning the same thing; and the ignorance makes him judge falsely, while the knowledge makes him judge truly.

  SOCRATES: I can hardly refrain from expressing my admiration of you, Theaetetus; but do think again about that. Let us suppose it is as you say: then, you maintain, the man who catches a piece of ignorance will judge [200] falsely. Is that it?

  THEAETETUS: Yes.

  SOCRATES: But presumably he will not think he is judging falsely?

  THEAETETUS: No, of course he won’t.

  SOCRATES: He will think he is judging what is true; and his attitude towards the things about which he is in error will be as if he knew them.

  THEAETETUS: Of course.

  SOCRATES: He will think he has hunted down and ‘has’ a piece of knowledge and not a piece of ignorance.

  THEAETETUS: Yes, that’s clear.

  SOCRATES: So, after going a long way round, we are back at our original difficulty. Our friend the expert in refutation will laugh. ‘My very good [b] people,’ he will say, ‘do you mean that a man who knows both knowledge and ignorance is thinking that one of them which he knows is the other which he knows? Or is it that he knows neither, and judges the one he doesn’t know to be the other which he doesn’t know? Or is it that he knows one and not the other, and judges that the one he knows is the one he doesn’t know? Or does he think that the one he doesn’t know is the one he does? Or are you going to start all over again and tell me that there’s another set of pieces of knowledge concerning pieces of knowledge and ignorance, which a man may possess shut up in some other ridiculous aviaries or waxen devices, which he knows so long as he possesses them [c] though he may not have them ready to hand in his soul—and in this way end up forced to come running round to the same place over and over again and never get any further?’ What are we going to say to that, Theaetetus?

  THEAETETUS: Oh, dear me, Socrates, I don’t know what one ought to say.

  SOCRATES: Then don’t you think, my boy, that the argument is perhaps dealing out a little proper chastisement, and showing us that we were [d] wrong to leave the question about knowledge and proceed to inquire into false judgment first? While as a matter of fact it’s impossible to know this until we have an adequate grasp of what knowledge is.

  THEAETETUS: Well, at the moment, Socrates, I feel bound to believe you.

  SOCRATES: Then, to go back to the beginning, what are we going to say knowledge is?—We are not, I suppose, going to give up yet?

  THEAETETUS: Certainly not, unless you give up yourself.

  SOCRATES: Tell me, then, how could we define it with the least risk of contradicting ourselves?

  [e] THEAETETUS: In the way we were attempting before, Socrates; I can’t think of any other.

  SOCRATES: In what way do you mean?

  THEAETETUS: By saying that knowledge is true judgment. Judging truly is at least something free of mistakes, I take it, and everything that results from it is admirable and good.

  SOCRATES: Well, Theaetetus, as the man who was leading the way across [201] the river said, ‘It will show you.’37 If we go on and track this down, perhaps we may stumble on what we are looking for; if we stay where we are, nothing will come clear.

  THEAETETUS: You’re right; let’s go on and consider it.

  SOCRATES: Well, this won’t take long to consider, anyway; there is a whole art indicating to you that knowledge is not what you say.

  THEAETETUS: How’s that? What art do you mean?

  SOCRATES: The art of the greatest representatives of wisdom—the men called orators and lawyers. These men, I take it, use their art to produce conviction not by teaching people, but by making them judge whatever they themselves choose. Or do you think there are any teachers so clever [b] that within the short time allowed by the clock they can teach adequately to people who were not eye-witnesses the truth of what happened to people who have been robbed or assaulted?

  THEAETETUS: No, I don’t think they possibly could; but they might be able to persuade them.

  SOCRATES: And by ‘persuading them’, you mean ‘causing them to judge’, don’t you?

  THEAETETUS: Of course.

  SOCRATES: Then suppose a jury has been justly persuaded of some matter which only an eye-witness could know, and which cannot otherwise be known; suppose they come to their decision upon hearsay, forming a [c] true judgment: then they have decided the case without knowledge, but, granted they did their job well, being correctly persuaded?

  THEAETETUS: Yes, certainly.

  SOCRATES: But, my dear lad, they couldn’t have done that if true judgment is the same thing as knowledge; in that case the best juryman in the world couldn’t form a correct judgment without knowledge. So it seems they must be different things.

  THEAETETUS: Oh, yes, Socrates, that’s just what I once heard a man say; I had forgotten, but now it’s coming back to me. He said that it is true [d] judgment with an account38 that is knowledge; true judgment without an account falls outside of knowledge. And he said that the things of which there is no account are not knowable (yes, he actually called them that),39 while those which have an account are knowable.

  SOCRATES: Very good indeed. Now tell me, how did he distinguish these knowables and unknowables? I want to see if you and I have heard the same version.

  THEAETETUS: I don’t know if I can find that out; but I think I could follow if someone explained it.

  SOCRATES: Listen then to a dream in return for a dream. In my dream, too, I thought I was listening to people saying that the primary elements, [e] as it were, of which we and everything else are composed, have no account. Each of them, in itself, can only be named; it is not possible to say anything else of it, either that it is or that it is not. That would mean that we were [202] adding being or not-being to it; whereas we must not attach anything, if we are to speak of that thing itself alone. Indeed we ought not to apply to it even such words as ‘itself’ or ‘that’, ‘each’, ‘alone’, or ‘this’, or any other of the many words of this kind; for these go the round and are applied to all things alike, being other than the things to which they are added, whereas if it were possible to express the element itself and it had its own proprietary account, it would have to be expressed without any other thing. As
it is, however, it is impossible that any of the primaries [b] should be expressed in an account; it can only be named, for a name is all that it has. But with the things composed of these, it is another matter. Here, just in the same way as the elements themselves are woven together, so their names may be woven together and become an account of something—an account being essentially a complex of names. Thus the elements are unaccountable and unknowable, but they are perceivable, whereas the complexes are both knowable and expressible and can be the objects of true judgment.

  [c] Now when a man gets a true judgment about something without an account, his soul is in a state of truth as regards that thing, but he does not know it; for someone who cannot give and take an account of a thing is ignorant about it. But when he has also got an account of it, he is capable of all this and is made perfect in knowledge. Was the dream you heard the same as this or a different one?

  THEAETETUS: No, it was the same in every respect.

  SOCRATES: Do you like this then, and do you suggest that knowledge is true judgment with an account?

  THEAETETUS: Yes, certainly.

  [d] SOCRATES: Theaetetus, can it be that all in a moment, you and I have today laid hands upon something which many a wise man has searched for in the past—and gone gray before he found it?

  THEAETETUS: Well, it does seem to me anyway, Socrates, that what has just been said puts the matter very well.

  SOCRATES: And it seems likely enough that the matter is really so; for what knowledge could there be apart from an account and correct judgment? But there is one of the things said which I don’t like.

  THEAETETUS: And what’s that?

  SOCRATES: What looks like the subtlest point of all—that the elements [e] are unknowable and the complexes knowable.

  THEAETETUS: And won’t that do?

  SOCRATES: We must make sure; because, you see, we do have as hostages for this theory the original models that were used when all these statements were made.

  THEAETETUS: What models?

  SOCRATES: Letters—the elements of language—and syllables.40 It must have been these, mustn’t it, that the author of our theory had in view—it couldn’t have been anything else?

  THEAETETUS: No, he must have been thinking of letters and syllables.

  [203] SOCRATES: Let’s take and examine them then. Or rather let us examine ourselves, and ask ourselves whether we really learned our letters in this way or not. Now, to begin with, one can give an account of the syllables but not of the letters—is that it?

  THEAETETUS: Well, perhaps.

  SOCRATES: It most certainly looks like that to me. At any rate, supposing you were asked about the first syllable of ‘Socrates’: ‘Tell me, Theaetetus, what is SO?’ What would you answer to that?

  THEAETETUS: That it’s S and O.

  SOCRATES: And there you have an account of the syllable?

  THEAETETUS: Yes.

  SOCRATES: Come along then, and let us have the account of S in the [b] same way.

  THEAETETUS: How can anyone give the letters of a letter? S is just one of the voiceless letters, Socrates, a mere sound like a hissing of the tongue. B again has neither voice nor sound, and that’s true of most letters. So the statement that they themselves are unaccountable holds perfectly good. Even the seven clearest have only voice; no sort of account whatever can be given of them.41

  SOCRATES: So here, my friend, we have established a point about knowledge.

  THEAETETUS: We do appear to have done so.

  SOCRATES: Well then: we have shown that the syllable is knowable but [c] not the letter—is that all right?

  THEAETETUS: It seems the natural conclusion, anyway.

  SOCRATES: Look here, what do we mean by ‘the syllable’? The two letters (or if there are more, all the letters)? Or do we mean some single form produced by their combination?

  THEAETETUS: I think we mean all the letters.

  SOCRATES: Then take the case of the two letters, S and O; these two are the first syllable of my name. If a man knows the syllable, he must know both the letters?

  THEAETETUS: Of course. [d]

  SOCRATES: So he knows S and O.

  THEAETETUS: Yes.

  SOCRATES: But can it be that he is ignorant of each one, and knows the two of them without knowing either?

  THEAETETUS: That would be a strange and unaccountable thing, Socrates.

  SOCRATES: And yet, supposing it is necessary to know each in order to know both, then it is absolutely necessary that anyone who is ever to know a syllable must first get to know the letters. And in admitting this, we shall find that our beautiful theory has taken to its heels and got clean away from us.

  THEAETETUS: And very suddenly too. [e]

  SOCRATES: Yes; we are not keeping a proper watch on it. Perhaps we ought not to have supposed the syllable to be the letters; perhaps we ought to have made it some single form produced out of them, having its own single nature—something different from the letters.

  THEAETETUS: Yes, certainly; that might be more like it.

  SOCRATES: We must look into the matter; we have no right to betray a great and imposing theory in this faint-hearted manner.

  THEAETETUS: Certainly not.

  [204] SOCRATES: Then let it be as we are now suggesting. Let the complex be a single form resulting from the combination of the several elements when they fit together; and let this hold both of language and of things in general.

  THEAETETUS: Yes, certainly.

  SOCRATES: Then it must have no parts.

  THEAETETUS: Why is that, now?

  SOCRATES: Because when a thing has parts, the whole is necessarily all the parts. Or do you mean by ‘the whole’ also a single form arising out of the parts, yet different from all the parts?

  THEAETETUS: I do.

  [b] SOCRATES: Now do you call ‘sum’42 and ‘whole’ the same thing or different things?

  THEAETETUS: I don’t feel at all certain; but as you keep telling me to answer up with a good will, I will take a risk and say they are different.

  SOCRATES: Your good will, Theaetetus, is all that it should be. Now we must see if your answer is too.

  THEAETETUS: We must, of course.

  SOCRATES: As the argument stands at present, the whole will be different from the sum?

  THEAETETUS: Yes.

  SOCRATES: Well now, is there any difference between all the things and [c] the sum? For instance, when we say ‘one, two, three, four, five, six’; or, ‘twice three’, or ‘three times two’, ‘four and two’, ‘three and two and one’; are we speaking of the same thing in all these cases or different things?

  THEAETETUS: The same thing.

  SOCRATES: That is, six?

  THEAETETUS: Precisely.

  SOCRATES: Then with each expression have we not spoken of all the six?

  THEAETETUS: Yes.

  SOCRATES: And when we speak of them all, aren’t we speaking of a sum?

  THEAETETUS: We must be.

  SOCRATES: That is, six?

  THEAETETUS: Precisely.

  [d] SOCRATES: Then in all things made up of number, at any rate, by ‘the sum’ and ‘all of them’ we mean the same thing?

  THEAETETUS: So it seems.

  SOCRATES: Now let us talk about them in this way. The number of an acre is the same thing as an acre, isn’t it?

  THEAETETUS: Yes.

  SOCRATES: Similarly with a mile.

  THEAETETUS: Yes.

  SOCRATES: And the number of an army is the same as the army? And so always with things of this sort; their total number is the sum that each of them is.

  THEAETETUS: Yes.

  SOCRATES: But is the number of each anything other than its parts? [e]

  THEAETETUS: No.

  SOCRATES: Now things which have parts consist of parts?

  THEAETETUS: That seems true.

  SOCRATES: And it is agreed that all the parts are the sum, seeing that the total number is to be the sum.

  THEAETETUS: That is so
.

  SOCRATES: Then the whole does not consist of parts. For if it did, it would be all the parts and so would be a sum.

  THEAETETUS: It looks as if it doesn’t.

  SOCRATES: But can a part, as such, be a part of anything but the whole?

  THEAETETUS: Yes; of the sum.

  SOCRATES: You are putting up a good fight anyway, Theaetetus. But this [205] sum now—isn’t it just when there is nothing lacking that it is a sum?

  THEAETETUS: Yes, necessarily.

  SOCRATES: And won’t this very same thing—that from which nothing anywhere is lacking—be a whole? While a thing from which something is absent is neither a whole nor a sum—the same consequence having followed from the same condition in both cases at once?

  THEAETETUS: Well, it doesn’t seem to me now that there can be any difference between whole and sum.

  SOCRATES: Very well. Now were we not saying43 that in the case of a thing that has parts, both the whole and the sum will be all the parts?

  THEAETETUS: Yes, certainly.

  SOCRATES: Now come back to the thing I was trying to get at just now.44 Supposing the syllable is not just its letters, doesn’t it follow that it cannot [b] contain the letters as parts of itself? Alternatively, if it is the same as the letters, it must be equally knowable with them?

  THEAETETUS: That is so.

  SOCRATES: Well, wasn’t it just in order to avoid this result that we supposed it different from the letters?

  THEAETETUS: Yes.

  SOCRATES: Well then, if the letters are not parts of the syllable, can you tell me of any other things, not its letters, which are?

  THEAETETUS: No, indeed. If I were to admit that it had component parts, Socrates, it would be ridiculous, of course, to set aside the letters and look for other components.