SO. So also do those whose wax is hard; for the imprints lack depth. And imprints in soft wax are also indistinct, because

 
they melt together and quickly become blurred; but if besides all this they are crowded upon one another through lack of room, in some mean little soul, they are still more indistinct. So all these men are likely to have false opinions. For when they see or hear or think of anything, they cannot quickly assign things to the right imprints, but are slow about it, and because they assign them wrongly they usually see and hear and think amiss. These men, in turn, are accordingly said to be deceived about realities and ignorant. THEAET. You are right as right could be, Socrates. SOC. Shall we, then, say that false opinions exist in us? THEAET. Assuredly. SOC. And true opinions, no doubt? THEAET. And true ones also. SOC. Then now at last we think we have reached a valid agreement, that these two kinds of opinion incontestably exist? THEAET. Most emphatically. SOC. Truly, Theaetetus, a garrulous man is a strange and unpleasant creature! THEAET. Eh? What makes you say that? SOC. Vexation at my own stupidity and genuine garrulity. For what else could you call it when a man drags his arguments up and down because he is so stupid that he cannot be convinced, and is hardly to be induced to give up any one of them? THEAET. But you, why are you vexed? SOC. I am not merely vexed, I am actually afraid; for I do not know what answer to make if anyone asks me: Socrates, have you found out, I wonder, that false opinion exists neither in the relations of the perceptions to one another nor in the thoughts,
 
but in the combination of perception with thought? I shall say yes, I suppose, and put on airs, as if we had made a fine discovery. THEAET. It seems to me, Socrates, that the result we have now brought out is not half bad. SOC. Do you go on and assert, then, he will say, that we never could imagine that the man whom we merely think of, but do not see, is a horse which also we do not see or touch or perceive by any other sense, but merely think of? I suppose I shall say that I do make that assertion. THEAET. Yes, and you will be right. SOC. Then, he will say, according to that, could we ever imagine that the number eleven which is merely thought of, is the number twelve which also is merely thought of? Come now, it is for you to answer. THEAET. Well, my answer will be that a man might imagine the eleven that he sees or touches to be twelve, but that he could never have that opinion concerning the eleven that he has in his mind. SOC. Well, then, do you think that anyone ever considered in his own mind five and seven,—

 
I do not mean by setting before his eyes seven men and five men and considering them, or anything of that sort, but seven and five in the abstract, which we say are imprints in the block of wax, and in regard to which we deny the possibility of forming false opinions—taking these by themselves, do you imagine that anybody in the world has ever considered them, talking to himself and asking himself what their sum is, and that one person has said and thought eleven, and another twelve, or do all say and think that it is twelve? THEAET. No, by Zeus; many say eleven,
 
and if you take a larger number for consideration, there is greater likelihood of error. For I suppose you are speaking of any number rather than of these only. SOC. You are right in supposing so; and consider whether in that instance the abstract twelve in the block of wax is not itself imagined to be eleven. THEAET. It seems so. SOC. Have we not, then, come back again to the beginning of our talk? For the man who is affected in this way imagines that one thing which he knows is another thing which he knows. This we said was impossible, and
 
by this very argument we were forcing false opinion out of existence, that the same man might not be forced to know and not know the same things at the same time. THEAET. Very true. SOC. Then we must show that forming false opinion is something or other different from the interchange of thought and perception. For if it were that, we should never be deceived in abstract thoughts. But as the case now stands, either there is no false opinion or it is possible for a man not to know that which he knows. Which alternative will you choose? THEAET. There is no possible choice, Socrates. SOC. And yet the argument is not likely to admit both. But still, since we must not shrink from any risk, what if we should try to do a shameless deed? THEAET. What is it? SOC. To undertake to tell what it really is to know. THEAET. And why is that shameless? SOC. You seem not to remember that our whole talk from the beginning has been a search for knowledge, because we did not know what it is. THEAET. Oh yes, I remember. SOC. Then is it not shameless to proclaim what it is to know, when we are ignorant of knowledge? 
 
But really, Theaetetus, our talk has been badly tainted with unclearness all along; for we have said over and over again we know and we do not know and we have knowledge and we have no knowledge, as if we could understand each other, while we were still ignorant of knowledge; and at this very moment, if you please, we have again used the terms be ignorant and understand, as though we had any right to use them if we are deprived of knowledge. THEAET. But how will you converse, Socrates, if you refrain from these words? SOC. Not at all, being the man I am; but I might if I were a real reasoner; if such a man were present at this moment he would tell us to refrain from these terms, and would criticize my talk scathingly. But since we are poor creatures, shall I venture to say what the nature of knowing is? For it seems to me that would be of some advantage. THEAET. Venture it then, by Zeus. You shall have full pardon for not refraining from those terms. SOC. Have you heard what they say nowadays that knowing is? THEAET. Perhaps; however, I don’t remember just at this moment. SOC. They say it is having knowledge. THEAET. True. SOC. Let us make a slight change and say possessing knowledge. THEAET. Why, how will you claim that the one differs from the other? SOC. Perhaps it doesn’t; but first hear how it seems to me to differ, and then help me to test my view. THEAET. I will if I can. SOC. Well, then, having does not seem to me the same as possessing. For instance, if a man bought a cloak and had it under his control, but did not wear it, we should certainly say, not that he had it, but that he possessed it. THEAET. And rightly. SOC. Now see whether it is possible in the same way for one who possesses knowledge not to have it, as, for instance, if a man should catch wild birds—pigeons or the like—and should arrange an aviary at home and keep them in it, we might in a way assert that he always has them because he possesses them, might we not? THEAET. Yes. SOC. And yet in another way that he has none of them, but that he has acquired power over them, since he has brought them under his control in his own enclosure,
 
to take them and hold them whenever he likes, by catching whichever bird he pleases, and to let them go again; and he can do this as often as be sees fit. THEAET. That is true. SOC. Once more, then, just as a while ago we contrived some sort of a waxen figment in the soul, so now let us make in each soul an aviary stocked with all sorts of birds, some in flocks apart from the rest, others in small groups, and some solitary, flying hither and thither among them all. THEAET. Consider it done. What next? SOC. We must assume that while we are children this receptacle is empty, and we must understand that the birds represent the varieties of knowledge. And whatsoever kind of knowledge a person acquires and shuts up in the enclosure, we must say that he has learned or discovered the thing of which this is the knowledge, and that just this is knowing. THEAET. So be it. SOC. Consider then what expressions are needed for the process of recapturing and taking and holding and letting go again whichever he please of the kinds of knowledge, whether they are the same expressions as those needed for the original acquisition, or others. But you will understand better by an illustration. You admit that there is an art of arithmetic? THEAET. Yes. SOC. Now suppose this to be a hunt after the kinds of knowledge, or sciences, of all odd and even numbers. THEAET. I do so. SOC. Now it is by this art, I imagine, that a man has
 
the sciences of numbers under his own control and also that any man who transmits them to another does this. THEAET. Yes. SOC. And we say that when anyone transmits them he teaches, and when anyone receives them he learns, and when anyone, by having acquired them, has them in that aviary of ours, he knows them. THEAET. Certainly. SOC. Now pay attention to what follows from this. Does not the perfect arithmetician understand all numbers; for he has the sciences of all numbers in his mind? THEAET. To be sure. SOC. Then would such a man ever count anything—either any abstract numbers in his head, or any such external objects as possess number? THEAET. Of course, SOC. But we shall affirm that counting is the same thing as considering how great any number in question is. THEAET. We shall. SOC. Then he who by our previous admission knows all number is found to be considering that which he knows as if he did not know it. You have doubtless heard of such ambiguities. THEAET. Yes, I have. SOC. Continuing, then, our comparison with the acquisition
 
and hunting of the pigeons, we shall say that the hunting is of two kinds, one before the acquisition for the sake of possessing, the other carried on by the possessor for the sake of taking and holding in his hands what he had acquired long before. And just so when a man long since by learning came to possess knowledge of certain things, and knew them, he may have these very things afresh by taking up again the knowledge of each of them separately and holding it—the knowledge which he had acquired long before, but had not at hand in his mind? THEAET. That is true. SOC. This, then, was my question just now: How should we express ourselves in speaking about them when an arithmetician undertakes to count or a man of letters to read something? In such a case shall we say that although he knows he sets himself to learn again from himself that which he knows? THEAET. But that is extraordinary, Socrates.