Theaetetus (166)

SOC. He will, I fancy, say all that we have said in his defence and then will close with us, saying contemptuously, Our estimable Socrates here frightened a little boy by asking if it was possible for one and the same person to remember and at the same time not to know one and the same thing, and when the child in his fright said no, because he could not foresee what would result, Socrates made poor me a laughing-stock in his talk. But, you slovenly Socrates, the facts stand thus: when you examine any doctrine of mine by the method of questioning, if the person who is questioned makes such replies as I should make and comes to grief, then I am refuted, but if his replies are quite different, then the person questioned is refuted, not I. Take this example. Do you suppose you could get anybody to admit that the memory a man has of a past feeling he no longer feels is anything like the feeling at the time when he was feeling it? Far from it. Or that he would refuse to admit that it is possible for one and the same person to know and not to know one and the same thing? Or if he were afraid to admit this, would he ever admit that a person who has become unlike is the same as before he became unlike? In fact, if we are to be on our guard against such verbal entanglements, would he admit that a person is one at all, and not many, who become infinite in number, if the process of becoming different continues? But, my dear fellow, he will say, attack my real doctrines in a more generous manner, and prove, if you can, that perceptions, when they come, or become, to each of us, are not individual, or that, if they are individual, what appears to each one would not, for all that, become to that one alone—or, if you prefer to say be, would not be—to whom it appears. But when you talk of pigs and dog-faced baboons, you not only act like a pig yourself, but you persuade your hearers to act so toward my writings, and that is not right. For I maintain that the truth is as I have written; each one of us is the measure of the things that are and those that are not; but each person differs immeasurably from every other in just this, that to one person some things appear and are, and to another person other things. And I do not by any means say that wisdom and the wise man do not exist; on the contrary, I say that if bad things appear and are to any one of us, precisely that man is wise who causes a change and makes good things appear and be to him. And, moreover, do not lay too much stress upon the words of my argument, but get a clearer understanding of my meaning from what I am going to say. Recall to your mind what was said before, that his food appears and is bitter to the sick man, but appears and is the opposite of bitter to the man in health.