Theaetetus

​SOCRATES: And indeed I do. Since this is so, shall we not quietly examine again, as if having plenty of leisure, not being peevish but truly testing ourselves, what on earth these appearances in us are? In inspecting them, we shall say first, as I think, that nothing could ever become greater or smaller, either in bulk or in number, as long as it remains equal to itself. Is it not so? THEAETETUS: Yes. SOCRATES: And secondly, that to which nothing is added and from which nothing is subtracted, this neither ever increases nor decreases, but is always equal. THEAETETUS: Absolutely. SOCRATES: And thirdly, is it not also the case that what was not previously, but is later, cannot possibly be so without having become and becoming? THEAETETUS: It certainly seems so. SOCRATES: These three admissions, I think, fight with one another in our soul when we speak of the dice, or when we say that I, being of this age, having neither increased nor undergone the opposite, within a year am now larger than you, who are young, and later will be smaller, though nothing of my bulk has been taken away, but you have increased. For I am later what I was not previously, without having become so; for without becoming, it is impossible to have become, and since I lost nothing of my bulk, I could never have been becoming smaller. And ten thousand other things in ten thousand ways are like this, if we are to accept these points. For you follow, I suppose, Theaetetus; at least you seem to me not to be inexperienced in such matters. THEAETETUS: By the gods, Socrates, I wonder exceedingly what these things are, and sometimes, when looking at them, I truly get dizzy. SOCRATES: For Theodorus, my friend, seems not to have guessed badly about your nature. For this feeling, wondering, is very much that of a philosopher; for there is no other beginning of philosophy than this, and he who said that Iris is the offspring of Thaumas seems not to have genealogized badly. But do you already understand why these things are so from what we say Protagoras means, or not yet? THEAETETUS: I do not think so yet. SOCRATES: Will you be grateful to me, then, if I search out with you the hidden truth of the thought of a man, or rather of famous men? THEAETETUS: How should I not be grateful, and very much so indeed? SOCRATES: Look around then, lest some of the uninitiated should overhear. These are those who think nothing else exists except what they can grasp tightly with their hands, but actions and generations and all that is invisible they do not accept as having a share in reality.

​THEAETETUS: Indeed, Socrates, you speak of hard and resistant men. SOCRATES: For they are, my boy, very much without the Muses. But there are others far more clever, whose mysteries I am about to tell you. Their principle, upon which all the things we just mentioned are suspended, is this: that the universe is motion, and there is nothing else besides this; and of motion there are two kinds, each infinite in number, but one having the power to act, and the other to be acted upon. And from the intercourse and friction of these with one another, offspring are generated, infinite in number but twins, the one being the perceived, and the other perception, which always erupts and is born along with the perceived. Now the perceptions have such names for us: sight, hearing, smell, cold and heat, pleasures and pains, desires and fears, and others, the nameless ones being infinite, and the named ones being very many. And on the other hand, the class of perceived things is of the same birth as each of these, colors of all kinds for sights of all kinds, and voices in the same way for hearings, and the other perceived things becoming akin to the other perceptions. What then, Theaetetus, does this myth mean for us in relation to the former points? Do you understand? THEAETETUS: Not quite, Socrates. SOCRATES: But watch if somehow it may be completed. For it means to say that all these things, as we say, are in motion, and there is speed and slowness in their motion. Now, as much of it as is slow keeps its motion in the same place and in relation to what is near and thus generates, but the things generated in this way are faster. For their motion is carried and natural in locomotion. Whenever, therefore, an eye and some other of the things commensurate with it come near and generate whiteness and the perception connate with it, which would never have occurred if either of them had gone to anything else, then, while they are moving in the intermediate space, sight from the eyes and whiteness from the thing that co-begets the color, the eye becomes full of sight and then sees and becomes not sight itself, but a seeing eye, and the thing that co-begat the color is filled with whiteness and becomes not whiteness itself, but white, whether it be wood or stone or whatever object happened to be colored with such a color.