Assuming this, let us go on to say that a man does evil knowing that he does evil. But some one will ask, Why? Because he is overcome, is the first answer. And by what is he overcome? the enquirer will proceed to ask. And we shall not be able to reply "By pleasure," for the name of pleasure has been exchanged for that of good. In our answer, then, we shall only say that he is overcome. "By what?" he will reiterate. By the good, we shall have to reply; indeed we shall. Nay, but our questioner will rejoin with a laugh, if he be one of the swaggering sort, "That is too ridiculous, that a man should do what he knows to be evil when he ought not, because he is overcome by good. Is that, he will ask, because the good was worthy or not worthy of conquering the evil?" And in answer to that we shall clearly reply, Because it was not worthy; for if it had been worthy, then he who, as we say, was overcome by pleasure, would not have been wrong. "But how," he will reply, "can the good be unworthy of the evil, or the evil of the good?" Is not the real explanation that they are out of proportion to one another, either as greater and smaller, or more and fewer? This we cannot deny. And when you speak of being overcome-"what do you mean," he will say, "but that you choose the greater evil in exchange for the lesser good?" Admitted. And now substitute the names of pleasure and pain for good and evil, and say, not as before, that a man does what is evil knowingly, but that he does what is painful knowingly, and because he is overcome by pleasure, which is unworthy to overcome. What measure is there of the relations of pleasure to pain other than excess and defect, which means that they become greater and smaller, and more and fewer, and differ in degree? For if any one says: "Yes, Socrates, but immediate pleasure differs widely from future pleasure and pain"-To that I should reply: And do they differ in anything but in pleasure and pain? There can be no other measure of them. And do you, like a skilful weigher, put into the balance the pleasures and the pains, and their nearness and distance, and weigh them, and then say which outweighs the other. If you weigh pleasures against pleasures, you of course take the more and greater; or if you weigh pains against pains, you take the fewer and the less; or if pleasures against pains, then you choose that course of action in which the painful is exceeded by the pleasant, whether the distant by the near or the near by the distant; and you avoid that course of action in which the pleasant is exceeded by the painful. Would you not admit, my friends, that this is true? I am confident that they cannot deny this.
He agreed with me.
Well then, I shall say, if you agree so far, be so good as to answer me a question: Do not the same magnitudes appear larger to your sight when near, and smaller when at a distance? They will acknowledge that. And the same holds of thickness and number; also sounds, which are in themselves equal, are greater when near, and lesser when at a distance. They will grant that also. Now suppose happiness to consist in doing or choosing the greater, and in not doing or in avoiding the less, what would be the saving principle of human life?
Would not the art of measuring be the saving principle; or would the power of appearance? Is not the latter that deceiving art which makes us wander up and down and take the things at one time of which we repent at another, both in our actions and in our choice of things great and small? But the art of measurement would do away with the effect of appearances, and, showing the truth, would fain teach the soul at last to find rest in the truth, and would thus save our life. Would not mankind generally acknowledge that the art which accomplishes this result is the art of measurement?
Yes, he said, the art of measurement.
Suppose, again, the salvation of human life to depend on the choice of odd and even, and on the knowledge of when a man ought to choose the greater or less, either in reference to themselves or to each other, and whether near or at a distance; what would be the saving principle of our lives? Would not knowledge?-a knowledge of measuring, when the question is one of excess and defect, and a knowledge of number, when the question is of odd and even? The world will assent, will they not?
Protagoras himself thought that they would.
Well then, my friends, I say to them; seeing that the salvation of human life has been found to consist in the right choice of pleasures and pains,-in the choice of the more and the fewer, and the greater and the less, and the nearer and remoter, must not this measuring be a consideration of their excess and defect and equality in relation to each other?
This is undeniably true.
And this, as possessing measure, must undeniably also be an art and science?
They will agree, he said.