Soc. Well, but do you think that no one ever put before his own mind five and seven, — I do not mean five or seven men or horses, but five or seven in the abstract, which, as we say, are recorded on the waxen block, and in which false opinion is held to be impossible ; did no man ever ask himself how many these numbers make when added together, and answer that they are eleven, while another thinks that they are twelve, or would all agree in thinking and saying that they are twelve ?
Theaet. Certainly not ; many would think that they are eleven, and in the higher numbers the chance of error is greater still ; for I assume you to be speaking of numbers in general.
Soc. Exactly ; and I want you to consider whether this does not imply that the twelve in the waxen block are supposed to be eleven ?
Theaet. Yes, that seems to be the case.
Soc. Then do we not come back to the old difficulty ? For he who makes such a mistake does think one thing which he knows to be another thing which he knows ; but this, as we said, was impossible, and afforded an irresistible proof of the non-existence of false opinion, because otherwise the same person would inevitably know and not know the same thing at the same time.
Theaet. Most true.
Soc. Then false opinion cannot be explained as a confusion of thought and sense, for in that case we could not have been mistaken about pure conceptions of thought ; and thus we are obliged to say, either that false opinion does not exist, or that a man may not know that which he knows ; — which alternative do you prefer ?
Theaet. It is hard to determine, Socrates.
Soc. And yet the argument will scarcely admit of both. But, as we are at our wits’ end, suppose that we do a shameless thing ?
Theaet. What is it ?
Soc. Let us attempt to explain the verb “to know.”
Theaet. And why should that be shameless ?
Soc. You seem not to be aware that the whole of our discussion from the very beginning has been a search after knowledge, of which we are assumed not to know the nature.
Theaet. Nay, but I am well aware.
Soc. And is it not shameless when we do not know what knowledge is, to be explaining the verb “to know” ? The truth is, Theaetetus, that we have long been infected with logical impurity. Thousands of times have we repeated the words “we know,” and “do not know,” and “we have or have not science or knowledge,” as if we could understand what we are saying to one another, so long as we remain ignorant about knowledge ; and at this moment we are using the words “we understand,” “we are ignorant,” as though we could still employ them when deprived of knowledge or science.
Theaet. But if you avoid these expressions, Socrates, how will you ever argue at all ?
Soc. I could not, being the man I am. The case would be different if I were a true hero of dialectic : and O that such an one were present ! for he would have told us to avoid the use of these terms ; at the same time he would not have spared in you and me the faults which I have noted. But, seeing that we are no great wits, shall I venture to say what knowing is ? for I think that the attempt may be worth making.
Theaet. Then by all means venture, and no one shall find fault with you for using the forbidden terms.
Soc. You have heard the common explanation of the verb “to know” ?
Theaet. I think so, but I do not remember it at the moment.
Soc. They explain the word “to know” as meaning “to have knowledge.”
Theaet. True.
Soc. I should like to make a slight change, and say “to possess” knowledge.
Theaet. How do the two expressions differ ?
Soc. Perhaps there may be no difference ; but still I should like you to hear my view, that you may help me to test it.
Theaet. I will, if I can.
Soc. I should distinguish “having” from “possessing” : for example, a man may buy and keep under his control a garment which he does not wear ; and then we should say, not that he has, but that he possesses the garment.
Theaet. It would be the correct expression.
Soc. Well, may not a man “possess” and yet not “have” knowledge in the sense of which I am speaking ? As you may suppose a man to have caught wild birds — doves or any other birds — and to be keeping them in an aviary which he has constructed at home ; we might say of him in one sense, that he always has them because he possesses them, might we not ?
Theaet. Yes.
Soc. And yet, in another sense, he has none of them ; but they are in his power, and he has got them under his hand in an enclosure of his own, and can take and have them whenever he likes ; — he can catch any which he likes, and let the bird go again, and he may do so as often as he pleases.
Theaet. True.
Soc. Once more, then, as in what preceded we made a sort of waxen figment in the mind, so let us now suppose that in the mind of each man there is an aviary of all sorts of birds — some flocking together apart from the rest, others in small groups, others solitary, flying anywhere and everywhere.
Theaet. Let us imagine such an aviary — and what is to follow ?
Soc. We may suppose that the birds are kinds of knowledge, and that when we were children, this receptacle was empty ; whenever a man has gotten and detained in the enclosure a kind of knowledge, he may be said to have learned or discovered the thing which is the subject of the knowledge : and this is to know.
Theaet. Granted.
Soc. And further, when any one wishes to catch any of these knowledges or sciences, and having taken, to hold it, and again to let them go, how will he express himself ? — will he describe the “catching” of them and the original “possession” in the same words ? I will make my meaning clearer by an example : — You admit that there is an art of arithmetic ?
Theaet. To be sure.
Soc. Conceive this under the form of a hunt after the science of odd and even in general.
Theaet. I follow.
Soc. Having the use of the art, the arithmetician, if I am not mistaken, has the conceptions of number under his hand, and can transmit them to another.
Theaet. Yes.
Soc. And when transmitting them he may be said to teach them, and when receiving to learn them, and when receiving to learn them, and when having them in possession in the aforesaid aviary he may be said to know them.
Theaet. Exactly.
Soc. Attend to what follows : must not the perfect arithmetician know all numbers, for he has the science of all numbers in his mind ?
Theaet. True.
Soc. And he can reckon abstract numbers in his head, or things about him which are numerable ?
Theaet. Of course he can.
Soc. And to reckon is simply to consider how much such and such a number amounts to ?
Theaet. Very true.
Soc. And so he appears to be searching into something which he knows, as if he did not know it, for we have already admitted that he knows all numbers ; — you have heard these perplexing questions raised ?
Theaet. I have.
Soc. May we not pursue the image of the doves, and say that the chase after knowledge is of two kinds ? one kind is prior to possession and for the sake of possession, and the other for the sake of taking and holding in the hands that which is possessed already. And thus, when a man has learned and known something long ago, he may resume and get hold of the knowledge which he has long possessed, but has not at hand in his mind.
Theaet. True.
Soc. That was my reason for asking how we ought to speak when an arithmetician sets about numbering, or a grammarian about reading ? Shall we say, that although he knows, he comes back to himself to learn what he already knows ?
Theaet. It would be too absurd, Socrates.
Soc. Shall we say then that he is going to read or number what he does not know, although we have admitted that he knows all letters and all numbers ?
Theaet. That, again, would be an absurdity.
Soc. Then shall we say that about names we care nothing ? — any one may twist and turn the words “knowing” and “learning” in any way which he likes, but since we have determined that the possession of knowledge is not the having or using it, we do assert that a man cannot not possess that which he possesses ; and, therefore, in no case can a man not know that which he knows, but he may get a false opinion about it ; for he may have the knowledge, not of this particular thing, but of some other ; — when the various numbers and forms of knowledge are flying about in the aviary, and wishing to capture a certain sort of knowledge out of the general store, he takes the wrong one by mistake, that is to say, when he thought eleven to be twelve, he got hold of the ringdove which he had in his mind, when he wanted the pigeon.
Theaet. A very rational explanation.
Soc. But when he catches the one which he wants, then he is not deceived, and has an opinion of what is, and thus false and true opinion may exist, and the difficulties which were previously raised disappear. I dare say that you agree with me, do you not ?
Theaet. Yes.
Soc. And so we are rid of the difficulty of a man’s not knowing what he knows, for we are not driven to the inference that he does not possess what he possesses, whether he be or be not deceived. And yet I fear that a greater difficulty is looking in at the window.
Theaet. What is it ?
Soc. How can the exchange of one knowledge for another ever become false opinion ?
Theaet. What do you mean ?
Soc. In the first place, how can a man who has the knowledge of anything be ignorant of that which he knows, not by reason of ignorance, but by reason of his own knowledge ? And, again, is it not an extreme absurdity that he should suppose another thing to be this, and this to be another thing ; — that, having knowledge present with him in his mind, he should still know nothing and be ignorant of all things ? — you might as well argue that ignorance may make a man know, and blindness make him see, as that knowledge can make him ignorant.
Theaet. Perhaps, Socrates, we may have been wrong in making only forms of knowledge our birds : whereas there ought to have been forms of ignorance as well, flying about together in the mind, and then he who sought to take one of them might sometimes catch a form of knowledge, and sometimes a form of ignorance ; and thus he would have a false opinion from ignorance, but a true one from knowledge, about the same thing.
Soc. I cannot help praising you, Theaetetus, and yet I must beg you to reconsider your words. Let us grant what you say — then, according to you, he who takes ignorance will have a false opinion — am I right ?
Theaet. Yes.
Soc. He will certainly not think that he has a false opinion ?
Theaet. Of course not.
Soc. He will think that his opinion is true, and he will fancy that he knows the things about which he has been deceived ?
Theaet. Certainly.
Soc. Then he will think that he has captured knowledge and not ignorance ?
Theaet. Clearly.
Soc. And thus, after going a long way round, we are once more face to face with our original difficulty. The hero of dialectic will retort upon us : — “O my excellent friends, he will say, laughing, if a man knows the form of ignorance and the form of knowledge, can he think that one of them which he knows is the other which he knows ? or, if he knows neither of them, can he think that the one which he knows not is another which he knows not ? or, if he knows one and not the other, can he think the one which he knows to be the one which he does not know ? or the one which he does not know to be the one which he knows ? or will you tell me that there are other forms of knowledge which distinguish the right and wrong birds, and which the owner keeps in some other aviaries or graven on waxen blocks according to your foolish images, and which he may be said to know while he possesses them, even though he have them not at hand in his mind ? And thus, in a perpetual circle, you will be compelled to go round and round, and you will make no progress.” What are we to say in reply, Theaetetus ?
Theaet. Indeed, Socrates, I do not know what we are to say.
Soc. Are not his reproaches just, and does not the argument truly show that we are wrong in seeking for false opinion until we know what knowledge is ; that must be first ascertained ; then, the nature of false opinion ?
Theaet. I cannot but agree with you, Socrates, so far as we have yet gone.