ures 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.