One way of making mere belief approach the status of knowledge would be to accompany one's judgment with an explanation (or reason) of why one holds this or that belief. Such a reason (logos) would then serve to ground the belief, it would provide a foundation for the judgment, This seems to be the further buttressing that mere belief needs, and the dialogue now begins to move in this direction.
Theaetetus and Socrates approach the problem by investigating various modes of explanation The first, strangely enough, is presented through the image of a dream which Socrates had once had (3323- 3346). It seems that in Socrates' dream he had heard of a theory which held that all things are essentially complexes made up of many simple elements, For example, we can say that a broom is a complex thing made up of (the simpler elements of) a long wooden handle and straw bristles. This theory then goes on to say that the broom's handle would itself be made of simpler elements (it is, for instance, both wooden and long), and that, in fact, these elements get simpler and simpler until we reach the simplest possible elements. These primary elements would then be described as the ultimate (conceptual) building blocks of the complex entity called the broom.
Now, from within this dream image, it seems possible to give an account of knowledge. We may be said to know a thing when we are able to explain it in terms of its simple elements. Once we analyze a complex object down to its constituent parts, we may then be said to have arrived at a full explanation of the object-and we may then be said to have arrived at a knowledge of the object.
Theaetetus is at first favorably inclined to accept this view, but Socrates is uncertain. The problem is that, within the dream itself, there is the belief that these simple elements are so simple that they cannot even be described. In fact, these ultimate simples seem "unknowable" (3368), This is the theory’s fatal flaw. When we attempt to arrive at a knowledge of something (by analyzing it into its simplest elements) we eventually arrive at something unknowable. Yet how can that which is unknowable serve as a foundation for knowledge? What does it mean to make complexes knowable (for example, a word) while at the same time to make its elements (viz., the syllables) unknowable (3379-3665)? It seems as if Socrates and Theaetetus really have been dreaming. If we are going to give an explanation of a thing in terms of its elements, then these elements must at least be capable of being known.
Awake now from the dream, both Socrates and Theaetetus return to the problem of explanation. Together, they will explore three possible meanings of the phrase "to give an account."
But what would a mere listing of the individual parts contribute to a knowledge of what the wagon really is? We might well know all the parts of a wagon and still not know what a wagon is (for instance, what a wagon is used for, how to ride it, etc.). To know the parts is different from knowing what the thing is; to know the parts of Theaetetus' name is not to know Theaetetus.
Plato is making us feel the need for something more in our description of things. In this case, what is missing is the "Form'' or essence of the wagon, and this is something distinct from the mere enumeration of the parts (elements). So even if one claims that the elements are knowable, one still cannot arrive at a "knowledge of X" from an "analysis (of the parts) of X," This second account fails, and Theaetetus and Socrates go on to their final attempt to arrive at an understanding of knowledge.
(3) To give an account means to know what distinguishes an object from other objects (3828-3889). In a sense, if I know what makes Theaetetus different from everyone else, then I know Theaetetus. The problem becomes one of locating distinguishing marks. For instance, what distinguishes a wagon from a tree is that the former has wheels, is drawn by a horse, etc.
But Socrates immediately sees a fatal circularity in this approach. (3882) How can I know what differentiates one object from another unless I already know precisely what that object is? One must know Theaetetus in order to say what makes him different. This final account quite simply begs the question.
The dialogue closes (3894-3940), Socrates has been unable to assist Theaetetus in the birth of an adequate account of knowledge, In the spirit of a true Socratic encounter, both men are now more aware of their ignorance in the areas discussed. Yet such an awareness separates them immeasurably from those who have never attempted such questions. Perhaps Theaetetus' embryonic thoughts will be better as a consequence of Socrates' midwifery. Be this as it may, Socrates must now go to the portico of King Archon to meet an indictment which a man named Meletus has drawn against him. He bids Theodorus and Theaetetus farewell, and entreats them to join him tomorrow, when they can again take up the problem of knowledge.
This proposed conversation makes up the dialogue called the Sophist, and it is in this dialogue that Plato will feel free to introduce his own account of the nature of knowledge. The Theaetetus has served its purpose, It has attempted to arrive at an understanding of knowledge without any appeal to the world of the Forms, and it has failed at every turn.
The dialogue thus leaves us with a sense that something is lacking. As long as we stay "on the earth," with our sensations and our opinions, we will fail to come to an understanding of the nature of knowledge. Plato has used the Theaetetus to create a felt need within the reader's mind to move beyond the limitations imposed on these first attempts. There is a desire kindled to transcend the world of the Theaetetus. The reader is thus prepared for the movement of the Sophist-a movement which leads upward toward the realm of the Forms.
the house, and the dialogue is read to them by a servant.
EUCLID: Have you only just arrived from the country, Terpsion?
TERPSION: No, I came some time ago: and I have been in the Agora looking
for you, and wondering that I could not find you.
EUCLID: But I was not in the city.
TERPSION: Where then?
EUCLID: As I was going down to the harbour, I met Theaetetus--he was being
carried up to Athens from the army at Corinth.
TERPSION: Was he alive or dead?
EUCLID: He was scarcely alive, for he has been badly wounded; but he was
suffering even more from the sickness which has broken out in the army.
TERPSION: The dysentery, you mean?
TERPSION: Alas! what a loss he will be!
EUCLID: Yes, Terpsion, he is a noble fellow; only to-day I heard some
people highly praising his behaviour in this very battle.
TERPSION: No wonder; I should rather be surprised at hearing anything else
of him. But why did he go on, instead of stopping at Megara?
EUCLID: He wanted to get home: although I entreated and advised him to
remain, he would not listen to me; so I set him on his way, and turned
back, and then I remembered what Socrates had said of him, and thought how
remarkably this, like all his predictions, had been fulfilled. I believe
that he had seen him a little before his own death, when Theaetetus was a
youth, and he had a memorable conversation with him, which he repeated to
me when I came to Athens; he was full of admiration of his genius, and said
that he would most certainly be a great man, if he lived.
TERPSION: The prophecy has certainly been fulfilled; but what was the
conversation? can you tell me?
EUCLID: No, indeed, not offhand; but I took notes of it as soon as I got
home; these I filled up from memory, writing them out at leisure; and
whenever I went to Athens, I asked Socrates about any point which I had
forgotten, and on my return I made corrections; thus I have nearly the
whole conversation written down.
TERPSION: I remember--you told me; and I have always been intending to ask
you to show me the writing, but have put off doing so; and now, why should
we not read it through?--having just come from the country, I should
greatly like to rest.
EUCLID: I too shall be very glad of a rest, for I went with Theaetetus as
far as Erineum. Let us go in, then, and, while we are reposing, the
servant shall read to us.
TERPSION: Very good.
EUCLID: Here is the roll, Terpsion; I may observe that I have introduced
Socrates, not as narrating to me, but as actually conversing with the
persons whom he mentioned--these were, Theodorus the geometrician (of
Cyrene), and Theaetetus. I have omitted, for the sake of convenience, the
interlocutory words 'I said,' 'I remarked,' which he used when he spoke of
himself, and again, 'he agreed,' or 'disagreed,' in the answer, lest the
repetition of them should be troublesome.
TERPSION: Quite right, Euclid.
EUCLID: And now, boy, you may take the roll and read.
EUCLID'S SERVANT READS.
SOCRATES: If I cared enough about the Cyrenians, Theodorus, I would ask
you whether there are any rising geometricians or philosophers in that part
of the world. But I am more interested in our own Athenian youth, and I
would rather know who among them are likely to do well. I observe them as
far as I can myself, and I enquire of any one whom they follow, and I see
that a great many of them follow you, in which they are quite right,
considering your eminence in geometry and in other ways. Tell me then, if
you have met with any one who is good for anything.
THEODORUS: Yes, Socrates, I have become acquainted with one very
remarkable Athenian youth, whom I commend to you as well worthy of your
attention. If he had been a beauty I should have been afraid to praise
him, lest you should suppose that I was in love with him; but he is no
beauty, and you must not be offended if I say that he is very like you; for
he has a snub nose and projecting eyes, although these features are less
marked in him than in you. Seeing, then, that he has no personal
attractions, I may freely say, that in all my acquaintance, which is very
large, I never knew any one who was his equal in natural gifts: for he has
a quickness of apprehension which is almost unrivalled, and he is
exceedingly gentle, and also the most courageous of men; there is a union
of qualities in him such as I have never seen in any other, and should
scarcely have thought possible; for those who, like him, have quick and
ready and retentive wits, have generally also quick tempers; they are ships
without ballast, and go darting about, and are mad rather than courageous;
and the steadier sort, when they have to face study, prove stupid and
cannot remember. Whereas he moves surely and smoothly and successfully in
the path of knowledge and enquiry; and he is full of gentleness, flowing on
silently like a river of oil; at his age, it is wonderful.
SOCRATES: That is good news; whose son is he?
THEODORUS: The name of his father I have forgotten, but the youth himself
is the middle one of those who are approaching us; he and his companions
have been anointing themselves in the outer court, and now they seem to
have finished, and are coming towards us. Look and see whether you know
SOCRATES: I know the youth, but I do not know his name; he is the son of
Euphronius the Sunian, who was himself an eminent man, and such another as
his son is, according to your account of him; I believe that he left a
THEODORUS: Theaetetus, Socrates, is his name; but I rather think that the
property disappeared in the hands of trustees; notwithstanding which he is
SOCRATES: He must be a fine fellow; tell him to come and sit by me.
THEODORUS: I will. Come hither, Theaetetus, and sit by Socrates.
SOCRATES: By all means, Theaetetus, in order that I may see the reflection
of myself in your face, for Theodorus says that we are alike; and yet if
each of us held in his hands a lyre, and he said that they were tuned
alike, should we at once take his word, or should we ask whether he who
said so was or was not a musician?
THEAETETUS: We should ask.
SOCRATES: And if we found that he was, we should take his word; and if
SOCRATES: And if this supposed likeness of our faces is a matter of any
interest to us, we should enquire whether he who says that we are alike is
a painter or not?
THEAETETUS: Certainly we should.
SOCRATES: And is Theodorus a painter?
THEAETETUS: I never heard that he was.
SOCRATES: Is he a geometrician?
THEAETETUS: Of course he is, Socrates.
SOCRATES: And is he an astronomer and calculator and musician, and in
general an educated man?
THEAETETUS: I think so.
SOCRATES: If, then, he remarks on a similarity in our persons, either by
way of praise or blame, there is no particular reason why we should attend
THEAETETUS: I should say not.
SOCRATES: But if he praises the virtue or wisdom which are the mental
endowments of either of us, then he who hears the praises will naturally
desire to examine him who is praised: and he again should be willing to
THEAETETUS: Very true, Socrates.
SOCRATES: Then now is the time, my dear Theaetetus, for me to examine, and
for you to exhibit; since although Theodorus has praised many a citizen and
stranger in my hearing, never did I hear him praise any one as he has been
THEAETETUS: I am glad to hear it, Socrates; but what if he was only in
SOCRATES: Nay, Theodorus is not given to jesting; and I cannot allow you
to retract your consent on any such pretence as that. If you do, he will
have to swear to his words; and we are perfectly sure that no one will be
found to impugn him. Do not be shy then, but stand to your word.
THEAETETUS: I suppose I must, if you wish it.
SOCRATES: In the first place, I should like to ask what you learn of
Theodorus: something of geometry, perhaps?
SOCRATES: And astronomy and harmony and calculation?
THEAETETUS: I do my best.
SOCRATES: Yes, my boy, and so do I; and my desire is to learn of him, or
of anybody who seems to understand these things. And I get on pretty well
in general; but there is a little difficulty which I want you and the
company to aid me in investigating. Will you answer me a question: 'Is
not learning growing wiser about that which you learn?'
THEAETETUS: Of course.
SOCRATES: And by wisdom the wise are wise?
SOCRATES: And is that different in any way from knowledge?
SOCRATES: Wisdom; are not men wise in that which they know?
THEAETETUS: Certainly they are.
SOCRATES: Then wisdom and knowledge are the same?
SOCRATES: Herein lies the difficulty which I can never solve to my
satisfaction--What is knowledge? Can we answer that question? What say
you? which of us will speak first? whoever misses shall sit down, as at a
game of ball, and shall be donkey, as the boys say; he who lasts out his
competitors in the game without missing, shall be our king, and shall have
the right of putting to us any questions which he pleases...Why is there no
reply? I hope, Theodorus, that I am not betrayed into rudeness by my love
of conversation? I only want to make us talk and be friendly and sociable.
THEODORUS: The reverse of rudeness, Socrates: but I would rather that you
would ask one of the young fellows; for the truth is, that I am unused to
your game of question and answer, and I am too old to learn; the young will
be more suitable, and they will improve more than I shall, for youth is
always able to improve. And so having made a beginning with Theaetetus, I
would advise you to go on with him and not let him off.
SOCRATES: Do you hear, Theaetetus, what Theodorus says? The philosopher,
whom you would not like to disobey, and whose word ought to be a command to
a young man, bids me interrogate you. Take courage, then, and nobly say
what you think that knowledge is.
THEAETETUS: Well, Socrates, I will answer as you and he bid me; and if I
make a mistake, you will doubtless correct me.
SOCRATES: We will, if we can.
THEAETETUS: Then, I think that the sciences which I learn from Theodorus--
geometry, and those which you just now mentioned--are knowledge; and I
would include the art of the cobbler and other craftsmen; these, each and
all of, them, are knowledge.
SOCRATES: Too much, Theaetetus, too much; the nobility and liberality of
your nature make you give many and diverse things, when I am asking for one
THEAETETUS: What do you mean, Socrates?
SOCRATES: Perhaps nothing. I will endeavour, however, to explain what I
believe to be my meaning: When you speak of cobbling, you mean the art or
science of making shoes?
THEAETETUS: Just so.
SOCRATES: And when you speak of carpentering, you mean the art of making
THEAETETUS: I do.
SOCRATES: In both cases you define the subject matter of each of the two
SOCRATES: But that, Theaetetus, was not the point of my question: we
wanted to know not the subjects, nor yet the number of the arts or
sciences, for we were not going to count them, but we wanted to know the
nature of knowledge in the abstract. Am I not right?
THEAETETUS: Perfectly right.
SOCRATES: Let me offer an illustration: Suppose that a person were to ask
about some very trivial and obvious thing--for example, What is clay? and
we were to reply, that there is a clay of potters, there is a clay of oven-
makers, there is a clay of brick-makers; would not the answer be
SOCRATES: In the first place, there would be an absurdity in assuming that
he who asked the question would understand from our answer the nature of
'clay,' merely because we added 'of the image-makers,' or of any other
workers. How can a man understand the name of anything, when he does not
know the nature of it?
THEAETETUS: He cannot.
SOCRATES: Then he who does not know what science or knowledge is, has no
knowledge of the art or science of making shoes?
SOCRATES: Nor of any other science?
SOCRATES: And when a man is asked what science or knowledge is, to give in
answer the name of some art or science is ridiculous; for the question is,
'What is knowledge?' and he replies, 'A knowledge of this or that.'
SOCRATES: Moreover, he might answer shortly and simply, but he makes an
enormous circuit. For example, when asked about the clay, he might have
said simply, that clay is moistened earth--what sort of clay is not to the
THEAETETUS: Yes, Socrates, there is no difficulty as you put the question.
You mean, if I am not mistaken, something like what occurred to me and to
my friend here, your namesake Socrates, in a recent discussion.
SOCRATES: What was that, Theaetetus?
THEAETETUS: Theodorus was writing out for us something about roots, such
as the roots of three or five, showing that they are incommensurable by the
unit: he selected other examples up to seventeen --there he stopped. Now
as there are innumerable roots, the notion occurred to us of attempting to
include them all under one name or class.
SOCRATES: And did you find such a class?
THEAETETUS: I think that we did; but I should like to have your opinion.
SOCRATES: Let me hear.
THEAETETUS: We divided all numbers into two classes: those which are made
up of equal factors multiplying into one another, which we compared to
square figures and called square or equilateral numbers;--that was one
SOCRATES: Very good.
THEAETETUS: The intermediate numbers, such as three and five, and every
other number which is made up of unequal factors, either of a greater
multiplied by a less, or of a less multiplied by a greater, and when
regarded as a figure, is contained in unequal sides;--all these we compared
to oblong figures, and called them oblong numbers.
SOCRATES: Capital; and what followed?
THEAETETUS: The lines, or sides, which have for their squares the
equilateral plane numbers, were called by us lengths or magnitudes; and the
lines which are the roots of (or whose squares are equal to) the oblong
numbers, were called powers or roots; the reason of this latter name being,
that they are commensurable with the former [i.e., with the so-called
lengths or magnitudes] not in linear measurement, but in the value of the
superficial content of their squares; and the same about solids.
SOCRATES: Excellent, my boys; I think that you fully justify the praises
of Theodorus, and that he will not be found guilty of false witness.
THEAETETUS: But I am unable, Socrates, to give you a similar answer about
knowledge, which is what you appear to want; and therefore Theodorus is a