Socrates SOC. And all the rest—hard and hot and so forth—must be regarded in the same way: we must assume, 157a we said before, that nothing exists in itself, but all things of all sorts arise out of motion by intercourse with each other; for it is, as they say, impossible to form a firm conception of the active or the passive element as being anything separately; for there is no active element until there is a union with the passive element, nor is there a passive element until there is a union with the active; and that which unites with one thing is active and appears again as passive when it comes in contact with something else. And so it results from all this, as we said in the beginning, that nothing exists as invariably one, itself by itself, but everything is always becoming in relation to something, and “being” should be altogether abolished, 157b though we have often—and even just now—been compelled by custom and ignorance to use the word. But we ought not, the wise men say, to permit the use of “something” or “somebody’s” or “mine” or “this” or “that” or any other word that implies making things stand still, but in accordance with nature we should speak of things as “becoming” and “being made” and “being destroyed” and “changing”; for anyone who by his mode of speech makes things stand still is easily refuted. And we must use such expressions in relation both to particular objects and collective designations, among which are 157c “mankind” and “stone” and the names of every animal and class. Do these doctrines seem pleasant to you, Theaetetus, and do you find their taste agreeable?

Theaetetus THEAET. I don’t know, Socrates; besides, I can’t tell about you, either, whether you are preaching them because you believe them or to test me.

Socrates SOC. You forget, my friend, that I myself know nothing about such things, and claim none of them as mine, but am incapable of bearing them and am merely acting as a midwife to you, and for that reason am uttering incantations and giving you a taste of each of the philosophical theories, 157d until I may help to bring your own opinion to light. And when it is brought to light, I will examine it and see whether it is a mere wind-egg or a real offspring. So be brave and patient, and in good and manly fashion tell what you think in reply to my questions.

Theaetetus THEAET. Very well; ask them.

Socrates SOC. Then say once more whether the doctrine pleases you that nothing is, but is always becoming—good or beautiful or any of the other qualities we were just enumerating.

Theaetetus THEAET. Why, when I hear you telling about it as you did, it seems to me that it is wonderfully reasonable and ought to be accepted as you have presented it.

Socrates SOC. Let us, then, not neglect a point in which it is defective. The defect is found in connection with dreams and diseases, including insanity, and everything else that is said to cause illusions of sight and hearing and the other senses. For of course you know that in all these the doctrine we were just presenting seems admittedly to be refuted, because 158a in them we certainly have false perceptions, and it is by no means true that everything is to each man which appears to him; on the contrary, nothing is which appears.

Theaetetus THEAET. What you say is very true, Socrates.

Socrates SOC. What argument is left, then, my boy, for the man who says that perception is knowledge and that in each case the things which appear are to the one to whom they appear?

Theaetetus THEAET. I hesitate to say, Socrates, that I have no reply to make, because you scolded me just now when I said that. 158b But really I cannot dispute that those who are insane or dreaming have false opinions, when some of them think they are gods and others fancy in their sleep that they have wings and are flying.

Socrates SOC. Don’t you remember, either, the similar dispute about these errors, especially about sleeping and waking?

Theaetetus THEAET. What dispute?

Socrates SOC. One which I fancy you have often heard. The question is asked, what proof you could give if anyone should ask us now, at the present moment, whether we are asleep and our thoughts are a dream, or whether we are awake 158c and talking with each other in a waking condition.

Theaetetus THEAET. Really, Socrates, I don’t see what proof can be given; for there is an exact correspondence in all particulars, as between the strophe and antistrophe of a choral song. Take, for instance, the conversation we have just had: there is nothing to prevent us from imagining in our sleep also that we are carrying on this conversation with each other, and when in a dream we imagine that we are relating dreams, the likeness between the one talk and the other is remarkable.

Socrates SOC. So you see it is not hard to dispute the point, since it is even open to dispute whether we are awake or in a dream. 158d Now since the time during which we are asleep is equal to that during which we are awake, in each state our spirit contends that the semblances that appear to it at any time are certainly true, so that for half the time we say that this is true, and for half the time the other, and we maintain each with equal confidence.

Theaetetus THEAET. Certainly.

Socrates SOC. And may not, then, the same be said about insanity and the other diseases, except that the time is not equal?

Theaetetus THEAET. Yes.

Socrates SOC. Well, then, shall truth be determined by the length or shortness of time?

Theaetetus THEAET. That would be absurd in many ways.

Socrates SOC. But can you show clearly in any other way which of the two sets of opinions is true?

Theaetetus THEAET. I do not think I can.

Socrates SOC. Listen, then, while I tell you what would be said about them by those who maintain that what appears at any time is true for him to whom it appears. They begin, I imagine, by asking this question: “Theaetetus, can that which is wholly other have in any way the same quality as its alternative? And we must not assume that the thing in question is partially the same and partially other, but wholly other.”

Theaetetus THEAET. It is impossible for it to be the same in anything, either in quality 159a or in any other respect whatsoever, when it is wholly other.

Socrates SOC. Must we not, then, necessarily agree that such a thing is also unlike?

Theaetetus THEAET. It seems so to me.

Socrates SOC. Then if anything happens to become like or unlike anything—either itself or anything else—we shall say that when it becomes like it becomes the same, and when it becomes unlike it becomes other?

Theaetetus THEAET. We must.

Socrates SOC. Well, we said before, did we not, that the active elements were many—infinite in fact—and likewise the passive elements?

Theaetetus THEAET. Yes.

Socrates SOC. And furthermore, that any given element, by uniting at different times with different partners, will beget, not the same, but other results?

Theaetetus THEAET. Certainly.

Socrates SOC. Well, then, let us take me, or you, or anything else at hand, and apply the same principle—say Socrates in health and Socrates in illness. Shall we say the one is like the other, or unlike?

Theaetetus THEAET. When you say “Socrates in illness” do you mean to compare that Socrates as a whole with Socrates in health as a whole?

Socrates SOC. You understand perfectly; that is just what I mean.

Theaetetus THEAET. Unlike, I imagine.

Socrates SOC. And therefore other, inasmuch as unlike?

Theaetetus THEAET. Necessarily.

Socrates SOC. And you would say the same of Socrates asleep or in any of the other states 159c we enumerated just now?

Theaetetus THEAET. Yes.

Socrates SOC. Then each of those elements which by the law of their nature act upon something else, will, when it gets hold of Socrates in health, find me one object to act upon, and when it gets hold of me in illness, another?

Theaetetus THEAET. How can it help it?

Socrates SOC. And so, in the two cases, that active element and I, who am the passive element, shall each produce a different object?

Theaetetus THEAET. Of course.

Socrates SOC. So, then, when I am in health and drink wine, it seems pleasant and sweet to me?

Theaetetus THEAET. Yes.

Socrates SOC. The reason is, in fact, that according to the principles we accepted a while ago, 159d the active and passive elements produce sweetness and perception, both of which are simultaneously moving from one place to another, and the perception, which comes from the passive element, makes the tongue perceptive, and the sweetness, which comes from the wine and pervades it, passes over and makes the wine both to be and to seem sweet to the tongue that is in health.

Theaetetus THEAET. Certainly, such are the principles we accepted a while ago.

Socrates SOC. But when it gets hold of me in illness, in the first place, it really doesn’t get hold of the same man, does it? For he to whom it comes is certainly unlike.

Theaetetus THEAET. True.

Socrates SOC. Therefore the union of the Socrates who is ill and the draught of wine produces other results: in the tongue the sensation or perception of bitterness, and in the wine—a bitterness which is engendered there and passes over into the other; the wine is made, not bitterness, but bitter, and I am made, not perception, but perceptive.

Theaetetus THEAET. Certainly.