Socrates SOC. I will tell you if I can. Assume that I have right opinion about you; if I add the explanation or definition of you, then I have knowledge of you, otherwise I have merely opinion.

Theaetetus THEAET. Yes.

Socrates SOC. But explanation was, we agreed, the interpretation of your difference.

Theaetetus THEAET. It was.

Socrates SOC. Then so long as I had merely opinion, I did not grasp in my thought any of the points in which you differ from others?

Theaetetus THEAET. Apparently not.

Socrates SOC. Therefore I was thinking of some one of the common traits which you possess no more than other men.

Theaetetus THEAET. You must have been.

Socrates SOC. For heaven’s sake! How in the world could I in that case have any opinion about you more than about anyone else? Suppose that I thought “That is Theaetetus which is a man and has nose and eyes and mouth” and so forth, mentioning all the parts. Can this thought make me think of Theaetetus any more than of Theodorus or of the meanest of the Mysians, ¹ as the saying is?

Theaetetus THEAET. Of course not.

Socrates SOC. But if I think not only of a man with nose and eyes, 209c but of one with snub nose and protruding eyes, shall I then have an opinion of you any more than of myself and all others like me?

Theaetetus THEAET. Not at all.

Socrates SOC. No; I fancy Theaetetus will not be the object of opinion in me until this snubnosedness of yours has stamped and deposited in my mind a memorial different from those of the other examples of snubnosedness that I have seen, and the other traits that make up your personality have done the like. Then that memorial, if I meet you again tomorrow, will awaken my memory and make me have right opinion about you.

Theaetetus THEAET. Very true.

Socrates SOC. Then right opinion also would have to do with differences in any given instance?

Theaetetus THEAET. At any rate, it seems so.

Socrates SOC. Then what becomes of the addition of reason or explanation to right opinion? For if it is defined as the addition of an opinion of the way in which a given thing differs from the rest, it is an utterly absurd injunction.

Theaetetus THEAET. How so?

Socrates SOC. When we have a right opinion of the way in which certain things differ from other things, we are told to acquire a right opinion of the way in which those same things differ from other things! On this plan the twirling of a scytale ² or a pestle or anything of the sort would be as nothing 209e compared with this injunction. It might more justly be called a blind man’s giving directions; for to command us to acquire that which we already have, in order to learn that of which we already have opinion, is very like a man whose sight is mightily darkened.

Theaetetus THEAET. Tell me now, what did you intend to say when you asked the question a while ago?

Socrates SOC. If, my boy, the command to add reason or explanation means learning to know and not merely getting an opinion about the difference, our splendid definition of knowledge would be a fine affair! For learning to know is acquiring knowledge, 210a is it not?

Theaetetus THEAET. Yes.

Socrates SOC. Then, it seems, if asked, “What is knowledge?” our leader will reply that it is right opinion with the addition of a knowledge of difference; for that would, according to him, be the addition of reason or explanation.

Theaetetus THEAET. So it seems.

Socrates SOC. And it is utterly silly, when we are looking for a definition of knowledge, to say that it is right opinion with knowledge, whether of difference or of anything else whatsoever. So neither perception, Theaetetus, nor true opinion, nor reason or explanation 210b combined with true opinion could be knowledge.

Theaetetus THEAET. Apparently not.

Socrates SOC. Are we then, my friend, still pregnant and in travail with knowledge, or have we brought forth everything?

Theaetetus THEAET. Yes, we have, and, by Zeus, Socrates, with your help I have already said more than there was in me.

Socrates SOC. Then does our art of midwifery declare to us that all the offspring that have been born are mere wind-eggs and not worth rearing?

Theaetetus THEAET. It does, decidedly.

Socrates SOC. If after this you ever undertake to conceive other thoughts, Theaetetus, and do conceive, 210c you will be pregnant with better thoughts than these by reason of the present search, and if you remain barren, you will be less harsh and gentler to your associates, for you will have the wisdom not to think you know that which you do not know. So much and no more my art can accomplish; nor do I know aught of the things that are known by others, the great and wonderful men who are today and have been in the past. This art, however, both my mother and I received from God, she for women and I for young and noble men and for all who are fair. 210d And now I must go to the Porch of the King, to answer to the suit which Meletus ³ has brought against me. But in the morning, Theodorus, let us meet here again.