“‘But what, if the safety of our life consisted in the choice of even and odd, when more ought properly to be chosen, and when less, each with reference to itself, or one with reference to the other, whether they might be near or distant, what, in this case, would preserve our life? Would it not be a science? and would it not be one of mensuration, since it is an art of excess and defect? But since it has relation to even and odd, can it be any other than arithmetic?’ Would the men grant us this, or not?” It appeared also to Protagoras that they would. “‘Be it so, my friends; but since the safety of our life has appeared to consist in the right choice of pleasure and pain, and of more and fewer, greater and smaller, more distant and nearer; does it not first of all appear to be an art of mensuration, since it is a consideration of excess and defect and equality of these with respect to each other?’ ‘Necessarily so.’ ‘But since it has to do with mensuration, it must of necessity be an art and a science.’ 115. They will assent to this. What then this art and science may be, we will consider hereafter; but that it is a science is sufficient for the proof of that which Protagoras and I had to make good in answer to the question you asked us. You asked, if you remember, when we agreed with each other that nothing is more powerful than knowledge, but that it always gets the mastery, wherever it may be, both of pleasure and every thing else; but you said that pleasure often gets the mastery, even of a man possessed of knowledge, and when we did not agree with you, you thereupon asked us, ‘Protagoras and Socrates, if this affection is not the being overcome by pleasure, what is it then, and what do you say it is? tell us.’ 116. If, then, we had immediately said to you, that it is ignorance, you would have laughed at us. But now if you laugh at us, you will also laugh at yourselves. For you have admitted that they err through want of knowledge, who err in the choice of pleasures and pains; but these are things good and evil; and not only through want of knowledge, but as you afterwards further admitted, a knowledge of mensuration. Now an erroneous action done without knowledge, as you must yourselves know, is done through ignorance: so that to be overcome by pleasure is the greatest ignorance; of which Protagoras here says he is a physician, and so do Prodicus and Hippias. But you, because you think it is something else than ignorance, neither go yourselves, nor send your children to the teachers of these things, the sophists, as if this knowledge could not be taught, but by saving your money, and not giving it to these men, you fare badly, both in private and public. 117. Such is the answer we should give to the many. But I ask you, Hippias and Prodicus, as well as Protagoras, for let the conversation be common to you all, whether I appear to you to speak the truth, or to speak falsely?” What had been said appeared to all to be eminently true.