Theaetetus

SOCRATES: Then we may fairly argue against your master, that he must admit one man to be wiser than another, and that the wiser is a measure: but I, who know nothing, am not at all obliged to accept the honour which the advocate of Protagoras was just now forcing upon me, whether I would or not, of being a measure of anything.

THEODORUS: That is the best refutation of him, Socrates; although he is also caught when he ascribes truth to the opinions of others, who give the lie direct to his own opinion.

SOCRATES: There are many ways, Theodorus, in which the doctrine that every opinion of every man is true may be refuted; but there is more difficulty in proving that states of feeling, which are present to a man, and out of which arise sensations and opinions in accordance with them, are also untrue. And very likely I have been talking nonsense about them; for they may be unassailable, and those who say that there is clear evidence of them, and that they are matters of knowledge, may probably be right; in which case our friend Theaetetus was not so far from the mark when he identified perception and knowledge. And therefore let us draw nearer, as the advocate of Protagoras desires; and give the truth of the universal flux a ring: is the theory sound or not? at any rate, no small war is raging about it, and there are combination not a few.

THEODORUS: No small, war, indeed, for in Ionia the sect makes rapid strides; the disciples of Heracleitus are most energetic upholders of the doctrine.

SOCRATES: Then we are the more bound, my dear Theodorus, to examine the question from the foundation as it is set forth by themselves.

THEODORUS: Certainly we are. About these speculations of Heracleitus, which, as you say, are as old as Homer, or even older still, the Ephesians themselves, who profess to know them, are downright mad, and you cannot talk with them on the subject. For, in accordance with their text-books, they are always in motion; but as for dwelling upon an argument or a question, and quietly asking and answering in turn, they can no more do so than they can fly; or rather, the determination of these fellows not to have a particle of rest in them is more than the utmost powers of negation can express. If you ask any of them a question, he will produce, as from a quiver, sayings brief and dark, and shoot them at you; and if you inquire the reason of what he has said, you will be hit by some other new-fangled word, and will make no way with any of them, nor they with one another; their great care is, not to allow of any settled principle either in their arguments or in their minds, conceiving, as I imagine, that any such principle would be stationary; for they are at war with the stationary, and do what they can to drive it out everywhere.

SOCRATES: I suppose, Theodorus, that you have only seen them when they were fighting, and have never stayed with them in time of peace, for they are no friends of yours; and their peace doctrines are only communicated by them at leisure, as I imagine, to those disciples of theirs whom they want to make like themselves.

THEODORUS: Disciples! my good sir, they have none; men of their sort are not one another's disciples, but they grow up at their own sweet will, and get their inspiration anywhere, each of them saying of his neighbour that he knows nothing. From these men, then, as I was going to remark, you will never get a reason, whether with their will or without their will; we must take the question out of their hands, and make the analysis ourselves, as if we were doing geometrical problem.

SOCRATES: Quite right too; but as touching the aforesaid problem, have we not heard from the ancients, who concealed their wisdom from the many in poetical figures, that Oceanus and Tethys, the origin of all things, are streams, and that nothing is at rest? And now the moderns, in their superior wisdom, have declared the same openly, that the cobbler too may hear and learn of them, and no longer foolishly imagine that some things are at rest and others in motion – having learned that all is motion, he will duly honour his teachers. I had almost forgotten the opposite doctrine, Theodorus,

'Alone Being remains unmoved, which is the name for the all.'

This is the language of Parmenides, Melissus, and their followers, who stoutly maintain that all being is one and self-contained, and has no place in which to move. What shall we do, friend, with all these people; for, advancing step by step, we have imperceptibly got between the combatants, and, unless we can protect our retreat, we shall pay the penalty of our rashness – like the players in the palaestra who are caught upon the line, and are dragged different ways by the two parties. Therefore I think that we had better begin by considering those whom we first accosted, 'the river-gods,' and, if we find any truth in them, we will help them to pull us over, and try to get away from the others. But if the partisans of 'the whole' appear to speak more truly, we will fly off from the party which would move the immovable, to them. And if I find that neither of them have anything reasonable to say, we shall be in a ridiculous position, having so great a conceit of our own poor opinion and rejecting that of ancient and famous men. O Theodorus, do you think that there is any use in proceeding when the danger is so great?

THEODORUS: Nay, Socrates, not to examine thoroughly what the two parties have to say would be quite intolerable.

SOCRATES: Then examine we must, since you, who were so reluctant to begin, are so eager to proceed. The nature of motion appears to be the question with which we begin. What do they mean when they say that all things are in motion? Is there only one kind of motion, or, as I rather incline to think, two? I should like to have your opinion upon this point in addition to my own, that I may err, if I must err, in your company; tell me, then, when a thing changes from one place to another, or goes round in the same place, is not that what is called motion?

THEODORUS: Yes.

SOCRATES: Here then we have one kind of motion. But when a thing, remaining on the same spot, grows old, or becomes black from being white, or hard from being soft, or undergoes any other change, may not this be properly called motion of another kind?

THEODORUS: I think so.

SOCRATES: Say rather that it must be so. Of motion then there are these two kinds, 'change,' and 'motion in place.'

THEODORUS: You are right.

SOCRATES: And now, having made this distinction, let us address ourselves to those who say that all is motion, and ask them whether all things according to them have the two kinds of motion, and are changed as well as move in place, or is one thing moved in both ways, and another in one only?

THEODORUS: Indeed, I do not know what to answer; but I think they would say that all things are moved in both ways.

SOCRATES: Yes, comrade; for, if not, they would have to say that the same things are in motion and at rest, and there would be no more truth in saying that all things are in motion, than that all things are at rest.

THEODORUS: To be sure.

SOCRATES: And if they are to be in motion, and nothing is to be devoid of motion, all things must always have every sort of motion?

THEODORUS: Most true.

SOCRATES: Consider a further point: did we not understand them to explain the generation of heat, whiteness, or anything else, in some such manner as the following: – were they not saying that each of them is moving between the agent and the patient, together with a perception, and that the patient ceases to be a perceiving power and becomes a percipient, and the agent a quale instead of a quality? I suspect that quality may appear a strange and uncouth term to you, and that you do not understand the abstract expression. Then I will take concrete instances: I mean to say that the producing power or agent becomes neither heat nor whiteness but hot and white, and the like of other things. For I must repeat what I said before, that neither the agent nor patient have any absolute existence, but when they come together and generate sensations and their objects, the one becomes a thing of a certain quality, and the other a percipient. You remember?

THEODORUS: Of course.

SOCRATES: We may leave the details of their theory unexamined, but we must not forget to ask them the only question with which we are concerned: Are all things in motion and flux?

THEODORUS: Yes, they will reply.

SOCRATES: And they are moved in both those ways which we distinguished, that is to say, they move in place and are also changed?

THEODORUS: Of course, if the motion is to be perfect.

SOCRATES: If they only moved in place and were not changed, we should be able to say what is the nature of the things which are in motion and flux?

THEODORUS: Exactly.

SOCRATES: But now, since not even white continues to flow white, and whiteness itself is a flux or change which is passing into another colour, and is never to be caught standing still, can the name of any colour be rightly used at all?

THEODORUS: How is that possible, Socrates, either in the case of this or of any other quality – if while we are using the word the object is escaping in the flux?

SOCRATES: And what would you say of perceptions, such as sight and hearing, or any other kind of perception? Is there any stopping in the act of seeing and hearing?

THEODORUS: Certainly not, if all things are in motion.

SOCRATES: Then we must not speak of seeing any more than of not-seeing, nor of any other perception more than of any non-perception, if all things partake of every kind of motion?

THEODORUS: Certainly not.

SOCRATES: Yet perception is knowledge: so at least Theaetetus and I were saying.

THEODORUS: Very true.

SOCRATES: Then when we were asked what is knowledge, we no more answered what is knowledge than what is not knowledge?

THEODORUS: I suppose not.

SOCRATES: Here, then, is a fine result: we corrected our first answer in our eagerness to prove that nothing is at rest. But if nothing is at rest, every answer upon whatever subject is equally right: you may say that a thing is or is not thus; or, if you prefer, 'becomes' thus; and if we say 'becomes,' we shall not then hamper them with words expressive of rest.

THEODORUS: Quite true.

SOCRATES: Yes, Theodorus, except in saying 'thus' and 'not thus.' But you ought not to use the word 'thus,' for there is no motion in 'thus' or in 'not thus.' The maintainers of the doctrine have as yet no words in which to express themselves, and must get a new language. I know of no word that will suit them, except perhaps 'no how,' which is perfectly indefinite.

THEODORUS: Yes, that is a manner of speaking in which they will be quite at home.

SOCRATES: And so, Theodorus, we have got rid of your friend without assenting to his doctrine, that every man is the measure of all things – a wise man only is a measure; neither can we allow that knowledge is perception, certainly not on the hypothesis of a perpetual flux, unless perchance our friend Theaetetus is able to convince us that it is.

THEODORUS: Very good, Socrates; and now that the argument about the doctrine of Protagoras has been completed, I am absolved from answering; for this was the agreement.

THEAETETUS: Not, Theodorus, until you and Socrates have discussed the doctrine of those who say that all things are at rest, as you were proposing.

THEODORUS: You, Theaetetus, who are a young rogue, must not instigate your elders to a breach of faith, but should prepare to answer Socrates in the remainder of the argument.