Soc. Then does it seem to you, my friends, as Protagoras and I assert, that the only reason why these things are evil is that they end at last in pains, and deprive us of other pleasures? Would they admit this?
 We both agreed that they would.
 Then again, suppose we should ask them the opposite: You, sirs, who tell us on the other hand that good things are painful—do you not give such instances as physical training, military service, and medical treatment conducted by cautery, incision, drugs, or starvation, and say that these are good, but painful? Would they not grant it? 
 He agreed that they would.
 Then do you call them good because they produce extreme pangs and anguish for the moment, or because later on they result in health and good bodily condition, the deliverance of cities, dominion over others, and wealth? They would assent to this, I suppose.
 He agreed.
 And are these things good for any other reason than that they end at last in pleasures and relief and riddance of pains? Or have you some other end to mention, with respect to which you call them good, apart from pleasures and pains? They could not find one, I fancy.
 I too think they could not, said Protagoras.
 Then do you pursue pleasure as being a good thing, and shun pain as being a bad one?
 He agreed that we do.
 So one thing you hold to be bad—pain; and pleasure you hold to be good, since the very act of enjoying you call bad as soon as it deprives us of greater pleasures than it has in itself, or leads to greater pains than the pleasures it contains. For if it is with reference to something else that you call the act of enjoyment bad, and with a view to some other end, you might be able to tell it us but this you will be unable to do.
 I too think that they cannot, said Protagoras.
 Then is not the same thing repeated in regard to the state of being pained? You call being pained a good thing as soon as it either rids us of greater pains than those it comprises, or leads to greater pleasures than its pains. Now if you have in view some other end than those which I mention when you call being pained good, you can tell it us; but you never can.
 Truly spoken, said Protagoras.
 Once more then, I proceeded; if you were to ask me, my friends, Now why on earth do you speak at such length on this point, and in so many ways? I should reply, Forgive me: in the first place, it is not easy to conclude what it is that you mean when you say overcome by pleasures ; and secondly, on this point hang all our conclusions. Soc. But it is still quite possible to retract, if you can somehow contrive to say that the good is different from pleasure, or the bad from pain. Is it enough for you to live out your life pleasantly, without pain? If it is, and you are unable to tell us of any other good or evil that does not end in pleasure or pain, listen to what I have to say next. I tell you that if this is so, the argument becomes absurd, when you say that it is often the case that a man, knowing the evil to be evil, nevertheless commits it, when he might avoid it, because he is driven and dazed by his pleasures; while on the other hand you say that a man, knowing the good, refuses to do good because of the momentary pleasures by which he is overcome.
 The absurdity of all this will be manifest if we refrain from using a number of terms at once, such as pleasant, painful, good, and bad; and as there appeared to be two things, let us call them by two names—first, good and evil, and then later on, pleasant and painful. Let us then lay it down as our statement, that a man does evil in spite of knowing the evil of it. Now if someone asks us: Why? we shall answer: Because he is overcome. By what? the questioner will ask us and this time we shall be unable to reply: By pleasure—for this has exchanged its name for the good. So we must answer only with the words: Because he is overcome. By what? says the questioner. The good—must surely be our reply. Now if our questioner chance to be an arrogant person he will laugh and exclaim: What a ridiculous statement, that a man does evil, knowing it to be evil, and not having to do it, because he is overcome by the good! Is this, he will ask, because the good is not worthy of conquering the evil in you, or because it is worthy? Clearly we must reply: Because it is not worthy; otherwise he whom we speak of as overcome by pleasures would not have offended. But in what sense, he might ask us, is the good unworthy of the bad, or the bad of the good? This can only be when the one is greater and the other smaller, or when there are more on the one side and fewer on the other. We shall not find any other reason to give; So it is clear, he will say, that by being overcome you mean getting the greater evil in exchange for the lesser good. That must be agreed. Soc. Then let us apply the terms pleasant and painful to these things instead, and say that a man does what we previously called evil, but now call painful, knowing it to be painful, because he is overcome by the pleasant, which is obviously unworthy to conquer. What unworthiness can there be in pleasure as against pain, save an excess or defect of one compared with the other? That is, when one becomes greater and the other smaller, or when there are more on one side and fewer on the other, or here a greater degree and there a less. For if you should say: But, Socrates, the immediately pleasant differs widely from the subsequently pleasant or painful, I should reply: Do they differ in anything but pleasure and pain? That is the only distinction. Like a practised weigher, put pleasant things and painful in the scales, and with them the nearness and the remoteness, and tell me which count for more. For if you weigh pleasant things against pleasant, the greater and the more are always to be preferred: if painful against painful, then always the fewer and smaller. If you weigh pleasant against painful, and find that the painful are outbalanced by the pleasant—whether the near by the remote or the remote by the near—you must take that course of action to which the pleasant are attached; but not that course if the pleasant are outweighed by the painful. Can the case be otherwise, I should ask, than thus, my friends? I am certain they could state no alternative.
 To this he too assented.
 Since that is the case, then, I shall say, please answer me this: Does not the same size appear larger to your sight when near, and smaller when distant? They will admit this. And it is the same with thickness and number? And sounds of equal strength are greater when near, and smaller when distant? They would agree to this. Now if our welfare consisted in doing and choosing things of large dimensions, and avoiding and not doing those of small, what would be our salvation in life? Would it be the art of measurement, or the power of appearance? Is it not the latter that leads us astray, as we saw, and many a time causes us to take things topsy-turvy and to have to change our minds both in our conduct and in our choice of great or small? Whereas the art of measurement would have made this appearance ineffective, and by showing us the truth would have brought our soul into the repose of abiding by the truth, and so would have saved our life. Would men acknowledge, in view of all this, that the art which saves our life is measurement, or some other?
 It is measurement, he agreed. Soc. Well now, if the saving of our life depended on the choice of odd or even, and on knowing when to make a right choice of the greater and when of the less—taking each by itself or comparing it with the other, and whether near or distant—what would save our life? Would it not be knowledge; a knowledge of measurement, since the art here is concerned with excess and defect, and of numeration, as it has to do with odd and even? People would admit this, would they not?
 Protagoras agreed that they would.
 Well then, my friends, since we have found that the salvation of our life depends on making a right choice of pleasure and pain—of the more and the fewer, the greater and the smaller, and the nearer and the remoter—is it not evident, in the first place, that measurement is a study of their excess and defect and equality in relation to each other?
 This must needs be so. 
 And being measurement, I presume it must be an art or science?
 They will assent to this. 
 Well, the nature of this art or science we shall consider some other time The intellectual control of our sense-perceptions, which differ as to the size or number of the same things when near and when distant, etc., has an important part in the educational scheme of the Republic . The measuring art is further considered in the Politicus (283 ff.). ; but the mere fact of its being a science will suffice for the proof which Protagoras and I are required to give in answer to the question you have put to us. You asked it, if you remember, when we were agreeing cf. Plat. Prot. 352b ff . that there is nothing stronger than knowledge, and that knowledge, wherever it may be found, has always the upper hand of pleasure or anything else; and then you said that pleasure often masters even the man of knowledge, and on our refusing to agree with you, you went on to ask us: Protagoras and Socrates, if this experience is not being overcome by pleasure, whatever can it be, and what do you call it? Tell us. If on the spur of the moment we had replied, Ignorance, you would have laughed us to scorn: but now if you laugh at us you will be laughing at yourselves as well. For you have admitted that it is from defect of knowledge that men err, when they do err, in their choice of pleasures and pains—that is, in the choice of good and evil; and from defect not merely of knowledge but of the knowledge which you have now admitted also to be that of measurement. And surely you know well enough for yourselves that the erring act committed without knowledge is done through ignorance. Accordingly to be overcome by pleasure means just this—ignorance in the highest degree, which Protagoras here and Prodicus and Hippias profess to cure. But you, through supposing it to be something else than ignorance, will neither go yourselves nor send your children to these sophists, who are the teachers of those things—you say it cannot be taught; you are chary of your money and will give them none, and so you fare badly both in private and in public life. Soc. Such would have been our answer to the world at large. And I ask you now, Hippias and Prodicus, as well as Protagoras—for I would have you make a joint reply—whether you think what I say is true or false.
 They all thought what I had said was absolutely true.
 Then you agree, I continued, that the pleasant is good and the painful bad. And let me entreat my friend Prodicus to spare me his distinction of terms: for whether you say pleasant or delightful or enjoyable, my excellent Prodicus, or in whatever style or manner you may be pleased to name these things, pray reply to the sense of my question.
 At this Prodicus laughed and consented, as did the rest.
 Well now, my friends, I said, what of this? All actions aimed at living painlessly and pleasantly are honorable, are they not? And the honorable work is both good and useful?
 They agreed.
 Then if, I proceeded, the pleasant is good, no one who has knowledge or thought of other actions as better than those he is doing, and as possible, will do as he proposes if he is free to do the better ones; and this yielding to oneself is nothing but ignorance, and mastery of Yielding to oneself and mastery of oneself are here put instead of being overcome by pleasure and the opposite state. The conflict between the better and worse self is discussed in Plat. Rep. 4.430e ff . oneself is as certainly wisdom.
 They all agreed.
 Well then, by ignorance do you mean having a false opinion and being deceived about matters of importance?
 They all agreed to this also.
 Then surely, I went on, no one willingly goes after evil or what he thinks to be evil; it is not in human nature, apparently, to do so—to wish to go after what one thinks to be evil in preference to the good; and when compelled to choose one of two evils, nobody will choose the greater when he may the lesser.
 All this met with the assent of everyone.
 Well, I said, is there something you call dread, or fear? And is it—I address myself to you, Prodicus —the same as I have in mind—something I describe as an expectation of evil, whether you call it fear or dread?
 Protagoras and Hippias agreed to this description of dread or fear; but Prodicus thought this was dread, not fear.
 No matter, Prodicus, I said, but my point is this: if our former statements are true, will any man wish to go after what he dreads, when he may pursue what he does not? Surely this is impossible after what we have admitted—that he regards as evil that which he dreads? And what is regarded as evil is neither pursued nor accepted willingly, we saw, by anyone. 
 
 
 Here also they were all in agreement.