Theaetetus
SOCRATES: Then, my friend, there is such a thing as right opinion united
with definition or explanation, which does not as yet attain to the
exactness of knowledge.
THEAETETUS: It would seem so.
SOCRATES: And what we fancied to be a perfect definition of knowledge
is a dream only. But perhaps we had better not say so as yet, for were
there not three explanations of knowledge, one of which must, as we
said, be adopted by him who maintains knowledge to be true opinion
combined with rational explanation? And very likely there may be found
some one who will not prefer this but the third.
THEAETETUS: You are quite right; there is still one remaining. The first
was the image or expression of the mind in speech; the second, which has
just been mentioned, is a way of reaching the whole by an enumeration of
the elements. But what is the third definition?
SOCRATES: There is, further, the popular notion of telling the mark or
sign of difference which distinguishes the thing in question from all
others.
THEAETETUS: Can you give me any example of such a definition?
SOCRATES: As, for example, in the case of the sun, I think that you
would be contented with the statement that the sun is the brightest of
the heavenly bodies which revolve about the earth.
THEAETETUS: Certainly.
SOCRATES: Understand why:--the reason is, as I was just now saying, that
if you get at the difference and distinguishing characteristic of each
thing, then, as many persons affirm, you will get at the definition or
explanation of it; but while you lay hold only of the common and not of
the characteristic notion, you will only have the definition of those
things to which this common quality belongs.
THEAETETUS: I understand you, and your account of definition is in my
judgment correct.
SOCRATES: But he, who having right opinion about anything, can find out
the difference which distinguishes it from other things will know that
of which before he had only an opinion.
THEAETETUS: Yes; that is what we are maintaining.
SOCRATES: Nevertheless, Theaetetus, on a nearer view, I find myself
quite disappointed; the picture, which at a distance was not so bad, has
now become altogether unintelligible.
THEAETETUS: What do you mean?
SOCRATES: I will endeavour to explain: I will suppose myself to have
true opinion of you, and if to this I add your definition, then I have
knowledge, but if not, opinion only.
THEAETETUS: Yes.
SOCRATES: The definition was assumed to be the interpretation of your
difference.
THEAETETUS: True.
SOCRATES: But when I had only opinion, I had no conception of your
distinguishing characteristics.
THEAETETUS: I suppose not.
SOCRATES: Then I must have conceived of some general or common nature
which no more belonged to you than to another.
THEAETETUS: True.
SOCRATES: Tell me, now--How in that case could I have formed a judgment
of you any more than of any one else? Suppose that I imagine Theaetetus
to be a man who has nose, eyes, and mouth, and every other member
complete; how would that enable me to distinguish Theaetetus from
Theodorus, or from some outer barbarian?
THEAETETUS: How could it?
SOCRATES: Or if I had further conceived of you, not only as having nose
and eyes, but as having a snub nose and prominent eyes, should I have
any more notion of you than of myself and others who resemble me?
THEAETETUS: Certainly not.
SOCRATES: Surely I can have no conception of Theaetetus until your
snub-nosedness has left an impression on my mind different from the
snub-nosedness of all others whom I have ever seen, and until your other
peculiarities have a like distinctness; and so when I meet you to-morrow
the right opinion will be re-called?
THEAETETUS: Most true.
SOCRATES: Then right opinion implies the perception of differences?
THEAETETUS: Clearly.
SOCRATES: What, then, shall we say of adding reason or explanation to
right opinion? If the meaning is, that we should form an opinion of
the way in which something differs from another thing, the proposal is
ridiculous.
THEAETETUS: How so?
SOCRATES: We are supposed to acquire a right opinion of the differences
which distinguish one thing from another when we have already a right
opinion of them, and so we go round and round:--the revolution of the
scytal, or pestle, or any other rotatory machine, in the same circles,
is as nothing compared with such a requirement; and we may be truly
described as the blind directing the blind; for to add those things
which we already have, in order that we may learn what we already think,
is like a soul utterly benighted.
THEAETETUS: Tell me; what were you going to say just now, when you asked
the question?
SOCRATES: If, my boy, the argument, in speaking of adding the
definition, had used the word to 'know,' and not merely 'have an
opinion' of the difference, this which is the most promising of all the
definitions of knowledge would have come to a pretty end, for to know is
surely to acquire knowledge.
THEAETETUS: True.
SOCRATES: And so, when the question is asked, What is knowledge? this
fair argument will answer 'Right opinion with knowledge,'--knowledge,
that is, of difference, for this, as the said argument maintains, is
adding the definition.
THEAETETUS: That seems to be true.
SOCRATES: But how utterly foolish, when we are asking what is knowledge,
that the reply should only be, right opinion with knowledge of
difference or of anything! And so, Theaetetus, knowledge is neither
sensation nor true opinion, nor yet definition and explanation
accompanying and added to true opinion?
THEAETETUS: I suppose not.
SOCRATES: And are you still in labour and travail, my dear friend, or
have you brought all that you have to say about knowledge to the birth?
THEAETETUS: I am sure, Socrates, that you have elicited from me a good
deal more than ever was in me.
SOCRATES: And does not my art show that you have brought forth wind, and
that the offspring of your brain are not worth bringing up?
THEAETETUS: Very true.
SOCRATES: But if, Theaetetus, you should ever conceive afresh, you will
be all the better for the present investigation, and if not, you will be
soberer and humbler and gentler to other men, and will be too modest
to fancy that you know what you do not know. These are the limits of my
art; I can no further go, nor do I know aught of the things which great
and famous men know or have known in this or former ages. The office
of a midwife I, like my mother, have received from God; she delivered
women, I deliver men; but they must be young and noble and fair.
And now I have to go to the porch of the King Archon, where I am to meet
Meletus and his indictment. To-morrow morning, Theodorus, I shall hope
to see you again at this place.