He agreed with me.
Well then, I shall say, if you admit that, 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 supposing that happiness consisted in making and taking large things, what would be the saving principle of human life? Would 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 is that which 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 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 men ought to choose the greater or less, either in reference to themselves or to each other whether near or at a distance; what would be the saving principles 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 acknowledge that, will they not?
Protagoras admitted that they would.
Well then, I say to them, my friends, 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 excess and defect and equality in relation to one another?
That is undeniably true.
And this, as possessing measure, must undeniably also be an art and science?
They will agree to that....
Then you agree, I said, that the pleasant is the good, and the painful evil. And here I would beg my friend Prodicus not to introduce his distinction of names, whether he is disposed to say pleasurable, delightful, joyful. However and in whatever way he rejoices to name them, I will ask you, most excellent Prodicus, to answer this in my sense.