Soc. In the name of the Graces, what an almighty wise man Protagoras must have been ! He spoke these things in a parable to the common herd, like you and me, but told the truth, his Truth, in secret to his own disciples.
Theaet. What do you mean, Socrates ?
Soc. I am about to speak of a high argument, in which all things are said to be relative ; you cannot rightly call anything by any name, such as great or small, heavy or light, for the great will be small and the heavy light — there is no single thing or quality, but out of motion and change and admixture all things are becoming relatively to one another, which “becoming” is by us incorrectly called being, but is really becoming, for nothing ever is, but all things are becoming. Summon all philosophers — Protagoras, Heracleitus, Empedocles, and the rest of them, one after another, and with the exception of Parmenides they will agree with you in this. Summon the great masters of either kind of poetry — Epicharmus, the prince of Comedy, and Homer of Tragedy ; when the latter sings of
Ocean whence sprang the gods, and mother Tethys,
does he not mean that all things are the offspring, of flux and motion ?
Theaet. I think so.
Soc. And who could take up arms against such a great army having Homer for its general, and not appear ridiculous ?
Theaet. Who indeed, Socrates ?
Soc. Yes, Theaetetus ; and there are plenty of other proofs which will show that motion is the source of what is called being and becoming, and inactivity of not-being and destruction ; for fire and warmth, which are supposed to be the parent and guardian of all other things, are born of movement and friction, which is a kind of motion ; — is not this the origin of fire ?
Theaet. It is.
Soc. And the race of animals is generated in the same way ?
Theaet. Certainly.
Soc. And is not the bodily habit spoiled by rest and idleness, but preserved for a long time by motion and exercise ?
Theaet. True.
Soc. And what of the mental habit ? Is not the soul informed, and improved, and preserved by study and attention, which are motions ; but when at rest, which in the soul only means want of attention and study, is uninformed, and speedily forgets whatever she has learned ?
Theaet. True.
Soc. Then motion is a good, and rest an evil, to the soul as well as to the body ?
Theaet. Clearly.
Soc. I may add, that breathless calm, stillness and the like waste and impair, while wind and storm preserve ; and the palmary argument of all, which I strongly urge, is the golden chain in Homer, by which he means the sun, thereby indicating that so long as the sun and the heavens go round in their orbits, all things human and divine are and are preserved, but if they were chained up and their motions ceased, then all things would be destroyed, and, as the saying is, turned upside down.
Theaet. I believe, Socrates, that you have truly explained his meaning.
Soc. Then now apply his doctrine to perception, my good friend, and first of all to vision ; that which you call white colour is not in your eyes, and is not a distinct thing which exists out of them. And you must not assign any place to it : for if it had position it would be, and be at rest, and there would be no process of becoming.
Theaet. Then what is colour ?
Soc. Let us carry the principle which has just been affirmed, that nothing is self-existent, and then we shall see that white, black, and every other colour, arises out of the eye meeting the appropriate motion, and that what we call a colour is in each case neither the active nor the passive element, but something which passes between them, and is peculiar to each percipient ; are you quite certain that the several colours appear to a dog or to any animal whatever as they appear to you ?
Theaet. Far from it.
Soc. Or that anything appears the same to you as to another man ? Are you so profoundly convinced of this ? Rather would it not be true that it never appears exactly the same to you, because you are never exactly the same ?
Theaet. The latter.
Soc. And if that with which I compare myself in size, or which I apprehend by touch, were great or white or hot, it could not become different by mere contact with another unless it actually changed ; nor again, if the comparing or apprehending subject were great or white or hot, could this, when unchanged from within become changed by any approximation or affection of any other thing. The fact is that in our ordinary way of speaking we allow ourselves to be driven into most ridiculous and wonderful contradictions, as Protagoras and all who take his line of argument would remark.
Theaet. How ? and of what sort do you mean ?
Soc. A little instance will sufficiently explain my meaning : Here are six dice, which are more by a half when compared with four, and fewer by a half than twelve — they are more and also fewer. How can you or any one maintain the contrary ?
Theaet. Very true.
Soc. Well, then, suppose that Protagoras or some one asks whether anything can become greater or more if not by increasing, how would you answer him, Theaetetus ?
Theaet. I should say “No,” Socrates, if I were to speak my mind in reference to this last question, and if I were not afraid of contradicting my former answer.
Soc. Capital excellent ! spoken like an oracle, my boy ! And if you reply “Yes,” there will be a case for Euripides ; for our tongue will be unconvinced, but not our mind.
Theaet. Very true.
Soc. The thoroughbred Sophists, who know all that can be known about the mind, and argue only out of the superfluity of their wits, would have had a regular sparring-match over this, and would — have knocked their arguments together finely. But you and I, who have no professional aims, only desire to see what is the mutual relation of these principles — whether they are consistent with each or not.
Theaet. Yes, that would be my desire.
Soc. And mine too. But since this is our feeling, and there is plenty of time, why should we not calmly and patiently review our own thoughts, and thoroughly examine and see what these appearances in us really are ? If I am not mistaken, they will be described by us as follows : — first, that nothing can become greater or less, either in number or magnitude, while remaining equal to itself — you would agree ?
Theaet. Yes.
Soc. Secondly, that without addition or subtraction there is no increase or diminution of anything, but only equality.
Theaet. Quite true.
Soc. Thirdly, that what was not before cannot be afterwards, without becoming and having become.
Theaet. Yes, truly.
Soc. These three axioms, if I am not mistaken, are fighting with one another in our minds in the case of the dice, or, again, in such a case as this — if I were to say that I, who am of a certain height and taller than you, may within a year, without gaining or losing in height, be not so tall — not that I should have lost, but that you would have increased. In such a case, I am afterwards what I once was not, and yet I have not become ; for I could not have become without becoming, neither could I have become less without losing somewhat of my height ; and I could give you ten thousand examples of similar contradictions, if we admit them at all. I believe that you follow me, Theaetetus ; for I suspect that you have thought of these questions before now.
Theaet. Yes, Socrates, and I am amazed when I think of them ; by the Gods I am ! and I want to know what on earth they mean ; and there are times when my head quite swims with the contemplation of them.