Theaetetus

THEAETETUS: Therefore, it is impossible for it to have anything the same either in power or in any other respect whatsoever, when it is altogether different. SOCRATES: Must we not, then, also agree that such a thing is unlike? THEAETETUS: So it seems to me. SOCRATES: If, then, it happens that something becomes like or unlike something, whether to itself or to another, shall we say that when it is made like it becomes the same, and when it is made unlike it becomes different? THEAETETUS: Inevitably. SOCRATES: Did we not say before that the active factors are many and infinite, and likewise also the passive factors? THEAETETUS: Yes. SOCRATES: And further, that one thing mingling with one thing, and with another, will generate not the same but different things? THEAETETUS: Absolutely so. SOCRATES: Let us now speak of me and you and other things according to the same argument, of Socrates in health and Socrates, on the other hand, in illness. Shall we say this one is like or unlike that one? THEAETETUS: Do you mean the ill Socrates, this whole, compared to that whole, the Socrates in health? SOCRATES: You understood perfectly; that is exactly what I mean. THEAETETUS: Unlike, surely. SOCRATES: And therefore different, just as it is unlike? THEAETETUS: Inevitably. SOCRATES: And will you say the same of him when sleeping, and of all the states we just now went through? THEAETETUS: I certainly will. SOCRATES: Then each of the things whose nature it is to act on something, when it finds Socrates in health, will treat me as one distinct thing, and when it finds him in illness, as another? THEAETETUS: How could it not? SOCRATES: And so I, the passive factor, and that active factor will generate different things in each of the two cases? THEAETETUS: Of course. SOCRATES: When, then, I drink wine being in health, does it appear pleasant and sweet to me? THEAETETUS: Yes. SOCRATES: For indeed, according to our previous agreements, the active and the passive factors generated sweetness and perception, both moving together; and while the perception, being on the side of the passive factor, made the tongue perceiving, the sweetness, being on the side of the wine and moving around it, made the wine both be and appear sweet to the healthy tongue. THEAETETUS: Absolutely so; our previous agreements were to that effect. SOCRATES: But when it finds me in illness, does it not, in the first place, in truth find a different person? For it has approached one who is unlike. THEAETETUS: Yes. SOCRATES: And so, in turn, this sort of Socrates and the drinking of the wine generated different things: on the side of the tongue a perception of bitterness, and on the side of the wine a bitterness arising and moving around it, making the wine not bitterness itself but bitter, and me not perception itself but perceiving? THEAETETUS: Most assuredly.

​SOCRATES: Therefore, neither shall I ever become thus perceiving of any other thing; for a perception of another thing is another perception, and it makes the perceiver different and another; nor will that active factor, by coming together with another, ever generate the same and become such as it is now; for by generating another thing from another subject, it will become different. THEAETETUS: That is so. SOCRATES: Nor indeed shall I, by myself, become such as I am to myself, nor will that, by itself, become such as it is to itself. THEAETETUS: No, indeed. SOCRATES: But it is necessary that I should become perceiving of something when I become perceiving; for it is impossible to become perceiving but perceiving of nothing; and that it should become sweet or bitter or something of the sort to someone; for it is impossible to become sweet, but sweet to no one. THEAETETUS: Absolutely so. SOCRATES: It remains then, I think, for us to be bound to one another, whether we are or whether we become, since necessity binds our essence together indeed, but binds it to none of the other things, nor again to ourselves. It remains, therefore, that we are bound to one another. So that if anyone names something as being, he must say that it is for someone, or of someone, or in relation to something, and likewise if he names it as becoming; but that anything is or becomes itself by itself, he must neither say himself nor accept it when someone else says so, as the argument we have gone through indicates. THEAETETUS: Absolutely so, Socrates. SOCRATES: Therefore, when that which acts on me is for me and not for another, do I also perceive it, while another does not? THEAETETUS: Of course. SOCRATES: True, therefore, to me is my perception—for it is always of my essence—and I am, according to Protagoras, the judge of the things that are for me, that they are, and of the things that are not, that they are not. THEAETETUS: So it seems. SOCRATES: How then, being unerring and not stumbling in my mind concerning the things that are or become, could I fail to be a knower of those very things of which I am a perceiver? THEAETETUS: In no way is it possible that you should not. SOCRATES: Most beautifully, then, has it been said by you that knowledge is nothing other than perception; and it has converged into the same result: according to Homer and Heraclitus and all that tribe, that all things move like streams, and according to Protagoras, the wisest of all, that man is the measure of all things, and according to Theaetetus, since these things are so, that perception becomes knowledge. Is it not so, Theaetetus? Shall we say that this is, as it were, your newborn child, and my delivery? Or how do you say? THEAETETUS: It must be so, Socrates.