THEO. Do so, for it is not I, Socrates, but rather

 
Callias the son of Hipponicus, who is the guardian of his children. As for me, I turned rather too soon from abstract speculations to geometry. However, I shall be grateful to you if you come to his assistance. SOC. Good, Theodorus! Now see how I shall help him; for a man might find himself involved in still worse inconsistencies than those in which we found ourselves just now, if he did not pay attention to the terms which we generally use in assent and denial. Shall I explain this to you, or only to Theaetetus? THEO. To both of us, but let the younger answer; 
 
for he will be less disgraced if he is discomfited. SOC. Very well; now I am going to ask the most frightfully difficult question of all. It runs, I believe, something like this: Is it possible for a person, if he knows a thing, at the same time not to know that which he knows? THEO. Now, then, what shall we answer, Theaetetus? THEAET. It is impossible, I should think. SOC. Not if you make seeing and knowing identical. For what will you do with a question from which there is no escape, by which you are, as the saying is, caught in a pit, when your adversary, unabashed, puts his hand over one of your eyes and asks
 
if you see his cloak with the eye that is covered? THEAET. I shall say, I think, Not with that eye, but with the other. SOC. Then you see and do not see the same thing at the same time? THEAET. After a fashion. SOC. That, he will reply, is not at all what I want, and I did not ask about the fashion, but whether you both know and do not know the same thing. Now manifestly you see that which you do not see. But you have agreed that seeing is knowing and not seeing is not knowing. Very well; from all this, reckon out what the result is. THEAET. Well, I reckon out that the result is the contrary of my hypothesis. SOC. And perhaps, my fine fellow, more troubles of the same sort might have come upon you, if anyone asked you further questions—whether it is possible to know the same thing both sharply and dully, to know close at hand but not at a distance, to know both violently and gently, and countless other questions, such as a nimble fighter, fighting for pay in the war of words, might have lain in wait and asked you, when you said that knowledge and perception were the same thing; he would have charged down upon hearing and smelling and such senses,
 
and would have argued persistently and unceasingly until you were filled with admiration of his greatly desired wisdom and were taken in his toils, and then, after subduing and binding you he would at once proceed to bargain with you for such ransom as might be agreed upon between you. What argument, then, you might ask, will Protagoras produce to strengthen his forces? Shall we try to carry on the discussion? THEAET. By all means.