SOC. Let us, then, take them up and examine them, or rather, let us examine ourselves and see whether it was in accordance with this theory, or not, that we learned letters. First then, the syllables have a rational explanation, but the letters have not? THEAET. I suppose so. SOC. I think so, too, decidedly. Now if anyone should ask about the first syllable of Socrates; Theaetetus, tell me, what is SO? What would you reply? THEAET. I should say S and O. SOC. This, then, is your explanation of the syllable? THEAET. Yes. SOC. Come now, in the same manner give me the explanation of the S. THEAET. How can one give any elements of an element? For really, Socrates, the S is a voiceless letter, The distinction here made is that which we make between vowels and consonants. The seven Greek vowels are α, ε, η, ι, ο, υ, ω called φωνήεντα . a mere noise, as of the tongue hissing; B again has neither voice nor noise, nor have most of the other letters; and so it is quite right to say that they have no explanation, seeing that the most distinct of them, the seven vowels, have only voice, but no explanation whatsoever. SOC. In this point, then, my friend, it would seem that we have reached a right conclusion about knowledge. THEAET. I think we have. SOC. But have we been right in laying down the principle that whereas the letter is unknowable, yet the syllable is knowable? THEAET. Probably. SOC. Well then, shall we say that the syllable is the two letters, or, if there be more than two, all of them, or is it a single concept that has arisen from their combination? THEAET. I think we mean all the letters it contains. SOC. Now take the case of two, S and O. The two together are the first syllable of my name. He who knows it knows the two letters, does he not? THEAET. Of course. SOC. He knows, that is, the S and the O. THEAET. Yes. SOC. How is that? He is ignorant of each, and knowing neither of them he knows them both? THEAET. That is monstrous and absurd, Socrates. SOC. And yet if a knowledge of each letter is necessary before one can know both, he who is ever to know a syllable must certainly know the letters first, and so our fine theory will have run away and vanished! THEAET. And very suddenly, too. SOC. Yes, for we are not watching it carefully. Perhaps we ought to have said that the syllable is not the letters, but a single concept that has arisen from them, having a single form of its own, different from the letters. THEAET. Certainly; and perhaps that will be better than the other way. SOC. Let us look into that; we must not give up in such unmanly fashion a great and impressive theory. THEAET. No, we must not. SOC. Let it be, then, as we say now, that the syllable or combination is a single form arising out of the several conjoined elements, and that it is the same in words and in all other things. THEAET. Certainly. SOC. Therefore there must be no parts of it. THEAET. How so? SOC. Because if there are parts of anything, the whole must inevitably be all the parts; or do you assert also that the whole that has arisen out of the parts is a single concept different from all the parts? THEAET. Yes, I do. SOC. Do you then say that all and the whole are the same,
 
or that each of the two is different from the other? THEAET. I am not sure; but you tell me to answer boldly, so I take the risk and say that they are different. SOC. Your boldness, Theaetetus, is right; but whether your answer is so remains to be seen. THEAET. Yes, certainly, we must see about that. SOC. The whole, then, according to our present view, would differ from all? THEAET. Yes. SOC. How about this? Is there any difference between all in the plural and all in the singular? For instance, if we say one, two, three,
 
four, five, six, or twice three, or three times two, or four and two, or three and two and one, are we in all these forms speaking of the same or of different numbers? THEAET. Of the same. SOC. That is, of six? THEAET. Yes. SOC. Then in each form of speech we have spoken of all the six? THEAET. Yes. SOC. And again do we not speak of one thing when we speak of them all? THEAET. Assuredly. SOC. That is, of six? THEAET. Yes. SOC. Then in all things that are made up of number, we apply the same term to all in the plural and all in the singular? THEAET. Apparently. SOC. Here is another way of approaching the matter. The number of the fathom and the fathom are the same, are they not? THEAET. Yes. SOC. And of the furlong likewise. THEAET. Yes. SOC. And the number of the army is the same as the army, and all such cases are alike? In each of them all the number is all the thing. THEAET. Yes. SOC. And is the number of each anything but
 
the parts of each? THEAET. No. SOC. Everything that has parts, accordingly, consists of parts, does it not? THEAET. Evidently. SOC. But we are agreed that the all must be all the parts if all the number is to be the all. Cf. Plat. Theaet. 204b THEAET. Yes. SOC. Then the whole does not consist of parts, for if it consisted of all the parts it would be the all. THEAET. That seems to be true. SOC. But is a part a part of anything in the world but the whole? THEAET. Yes, of the all. SOC. You are putting up a brave fight, Theaetetus. But is not the all precisely that of which nothing is wanting? THEAET. Necessarily. SOC. And is not just this same thing, from which nothing whatsoever is lacking, a whole? For that from which anything is lacking is neither a whole nor all, which have become identical simultaneously and for the same reason. THEAET. I think now that there is no difference between all and whole. SOC. We were saying, were we not, that if there are parts of anything, the whole and all of it will be all the parts? THEAET. Certainly. SOC. Once more, then, as I was trying to say just now, if the syllable is not the letters, does it not follow necessarily
 
that it contains the letters, not as parts of it, or else that being the same as the letters, it is equally knowable with them? THEAET. It does. SOC. And it was in order to avoid this that we assumed that it was different from them? THEAET. Yes. SOC. Well then, if the letters are not parts of the syllable, can you mention any other things which are parts of it, but are not the letters The reader is reminded that words στοιχεῖον and συλλαβή have the meanings element and combination as well as letter and syllable. of it? THEAET. Certainly not. For if I grant that there are parts of the syllable, it would be ridiculous to give up the letters and look for other things as parts. SOC. Without question, then, Theaetetus, the syllable would be, according to our present view, some indivisible concept. THEAET. I agree. SOC. Do you remember, then, my friend, that we admitted a little while ago, on what we considered good grounds, that there can be no rational explanation of the primary elements of which other things are composed, because each of them, when taken by itself, is not composite, and we could not properly apply to such an element even the expression be or this, because these terms are different and alien, and for this reason it is irrational and unknowable? THEAET. I remember. SOC. And is not this the sole reason why it is single in form and indivisible? I can see no other. THEAET. There is no other to be seen. SOC. Then the syllable falls into the same class with the letter, if it has no parts and is a single form? THEAET. Yes, unquestionably. SOC. If, then, the syllable is a plurality of letters and is a whole of which the letters are parts, the syllables and the letters are equally knowable and expressible, if all the parts were found to be the same as the whole. THEAET. Certainly. SOC. But if one and indivisible, then syllable and likewise letter are equally irrational and unknowable; for the same cause will make them so. THEAET. I cannot dispute it. SOC. Then we must not accept the statement of any one who says that the syllable is knowable and expressible, but the letter is not. THEAET. No, not if we are convinced by our argument. SOC. But would you not rather accept the opposite belief, judging by your own experience when you were learning to read? THEAET. What experience? SOC. In learning, you were merely constantly trying to distinguish between the letters both by sight and by hearing, keeping each of them distinct from the rest, that you might not be disturbed by their sequence when they were spoken or written. THEAET. That is very true. SOC. And in the music school was not perfect attainment
 
the ability to follow each note and tell which string produced it; and everyone would agree that the notes are the elements of music? THEAET. Yes, that is all true. SOC. Then if we are to argue from the elements and combinations in which we ourselves have experience to other things in general, we shall say that the elements as a class admit of a much clearer knowledge than the compounds and of a knowledge that is much more important for the complete attainment of each branch of learning, and if anyone says that the compound is by its nature knowable and the element unknowable, we shall consider that he is, intentionally or unintentionally, joking. THEAET. Certainly. SOC. Still other proofs of this might be brought out, I think; but let us not on that account lose sight of the question before us, which is: What is meant by the doctrine that the most perfect knowledge arises from the addition of rational explanation to true opinion? THEAET. No, we must not. SOC. Now what are we intended to understand by rational explanation ? I think it means one of three things. THEAET. What are they? SOC. The first would be making one’s own thought clear through speech by means of verbs and nouns, imaging the opinion in the stream that flows through the lips, as in a mirror or water. Do you not think the rational explanation is something of that sort? THEAET. Yes, I do. At any rate, we say that he who does that speaks or explains. SOC. Well, that is a thing that anyone can do sooner or later; he can show what he thinks about anything, unless he is deaf or dumb from the first; and so
 
all who have any right opinion will be found to have it with the addition of rational explanation, and there will henceforth be no possibility of right opinion apart from knowledge. THEAET. True.