Jowett: saving principle

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 ? PROTAGORAS

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