Theaetetus
question with which we begin. What do they mean when they say that all
things are in motion? Is there only one kind of motion, or, as I rather
incline to think, two? I should like to have your opinion upon this
point in addition to my own, that I may err, if I must err, in your
company; tell me, then, when a thing changes from one place to another,
or goes round in the same place, is not that what is called motion?
THEODORUS: Yes.
SOCRATES: Here then we have one kind of motion. But when a thing,
remaining on the same spot, grows old, or becomes black from being
white, or hard from being soft, or undergoes any other change, may not
this be properly called motion of another kind?
THEODORUS: I think so.
SOCRATES: Say rather that it must be so. Of motion then there are these
two kinds, 'change,' and 'motion in place.'
THEODORUS: You are right.
SOCRATES: And now, having made this distinction, let us address
ourselves to those who say that all is motion, and ask them whether all
things according to them have the two kinds of motion, and are changed
as well as move in place, or is one thing moved in both ways, and
another in one only?
THEODORUS: Indeed, I do not know what to answer; but I think they would
say that all things are moved in both ways.
SOCRATES: Yes, comrade; for, if not, they would have to say that the
same things are in motion and at rest, and there would be no more truth
in saying that all things are in motion, than that all things are at
rest.
THEODORUS: To be sure.
SOCRATES: And if they are to be in motion, and nothing is to be devoid
of motion, all things must always have every sort of motion?
THEODORUS: Most true.
SOCRATES: Consider a further point: did we not understand them to
explain the generation of heat, whiteness, or anything else, in some
such manner as the following:--were they not saying that each of them
is moving between the agent and the patient, together with a perception,
and that the patient ceases to be a perceiving power and becomes a
percipient, and the agent a quale instead of a quality? I suspect that
quality may appear a strange and uncouth term to you, and that you
do not understand the abstract expression. Then I will take concrete
instances: I mean to say that the producing power or agent becomes
neither heat nor whiteness but hot and white, and the like of other
things. For I must repeat what I said before, that neither the agent
nor patient have any absolute existence, but when they come together
and generate sensations and their objects, the one becomes a thing of a
certain quality, and the other a percipient. You remember?
THEODORUS: Of course.
SOCRATES: We may leave the details of their theory unexamined, but
we must not forget to ask them the only question with which we are
concerned: Are all things in motion and flux?
THEODORUS: Yes, they will reply.
SOCRATES: And they are moved in both those ways which we distinguished,
that is to say, they move in place and are also changed?
THEODORUS: Of course, if the motion is to be perfect.
SOCRATES: If they only moved in place and were not changed, we should
be able to say what is the nature of the things which are in motion and
flux?
THEODORUS: Exactly.
SOCRATES: But now, since not even white continues to flow white, and
whiteness itself is a flux or change which is passing into another
colour, and is never to be caught standing still, can the name of any
colour be rightly used at all?
THEODORUS: How is that possible, Socrates, either in the case of this
or of any other quality--if while we are using the word the object is
escaping in the flux?
SOCRATES: And what would you say of perceptions, such as sight and
hearing, or any other kind of perception? Is there any stopping in the
act of seeing and hearing?
THEODORUS: Certainly not, if all things are in motion.
SOCRATES: Then we must not speak of seeing any more than of not-seeing,
nor of any other perception more than of any non-perception, if all
things partake of every kind of motion?
THEODORUS: Certainly not.
SOCRATES: Yet perception is knowledge: so at least Theaetetus and I were
saying.
THEODORUS: Very true.
SOCRATES: Then when we were asked what is knowledge, we no more answered
what is knowledge than what is not knowledge?
THEODORUS: I suppose not.
SOCRATES: Here, then, is a fine result: we corrected our first answer
in our eagerness to prove that nothing is at rest. But if nothing is at
rest, every answer upon whatever subject is equally right: you may say
that a thing is or is not thus; or, if you prefer, 'becomes' thus; and
if we say 'becomes,' we shall not then hamper them with words expressive
of rest.
THEODORUS: Quite true.
SOCRATES: Yes, Theodorus, except in saying 'thus' and 'not thus.' But
you ought not to use the word 'thus,' for there is no motion in 'thus'
or in 'not thus.' The maintainers of the doctrine have as yet no words
in which to express themselves, and must get a new language. I know of
no word that will suit them, except perhaps 'no how,' which is perfectly
indefinite.
THEODORUS: Yes, that is a manner of speaking in which they will be quite
at home.
SOCRATES: And so, Theodorus, we have got rid of your friend without
assenting to his doctrine, that every man is the measure of all
things--a wise man only is a measure; neither can we allow that
knowledge is perception, certainly not on the hypothesis of a perpetual
flux, unless perchance our friend Theaetetus is able to convince us that
it is.
THEODORUS: Very good, Socrates; and now that the argument about the
doctrine of Protagoras has been completed, I am absolved from answering;
for this was the agreement.
THEAETETUS: Not, Theodorus, until you and Socrates have discussed the
doctrine of those who say that all things are at rest, as you were
proposing.
THEODORUS: You, Theaetetus, who are a young rogue, must not instigate
your elders to a breach of faith, but should prepare to answer Socrates
in the remainder of the argument.
THEAETETUS: Yes, if he wishes; but I would rather have heard about the
doctrine of rest.
THEODORUS: Invite Socrates to an argument--invite horsemen to the open
plain; do but ask him, and he will answer.
SOCRATES: Nevertheless, Theodorus, I am afraid that I shall not be able
to comply with the request of Theaetetus.
THEODORUS: Not comply! for what reason?
SOCRATES: My reason is that I have a kind of reverence; not so much for
Melissus and the others, who say that 'All is one and at rest,' as for
the great leader himself, Parmenides, venerable and awful, as in Homeric
language he may be called;--him I should be ashamed to approach in a
spirit unworthy of him. I met him when he was an old man, and I was a
mere youth, and he appeared to me to have a glorious depth of mind.
And I am afraid that we may not understand his words, and may be still
further from understanding his meaning; above all I fear that the nature
of knowledge, which is the main subject of our discussion, may be thrust
out of sight by the unbidden guests who will come pouring in upon our
feast of discourse, if we let them in--besides, the question which is
now stirring is of immense extent, and will be treated unfairly if only
considered by the way; or if treated adequately and at length, will put
into the shade the other question of knowledge. Neither the one nor the
other can be allowed; but I must try by my art of midwifery to deliver
Theaetetus of his conceptions about knowledge.
THEAETETUS: Very well; do so if you will.
SOCRATES: Then now, Theaetetus, take another view of the subject: you
answered that knowledge is perception?
THEAETETUS: I did.
SOCRATES: And if any one were to ask you: With what does a man see black
and white colours? and with what does he hear high and low sounds?--you
would say, if I am not mistaken, 'With the eyes and with the ears.'
THEAETETUS: I should.
SOCRATES: The free use of words and phrases, rather than minute
precision, is generally characteristic of a liberal education, and
the opposite is pedantic; but sometimes precision is necessary, and I
believe that the answer which you have just given is open to the charge
of incorrectness; for which is more correct, to say that we see or hear
with the eyes and with the ears, or through the eyes and through the
ears.
THEAETETUS: I should say 'through,' Socrates, rather than 'with.'
SOCRATES: Yes, my boy, for no one can suppose that in each of us, as
in a sort of Trojan horse, there are perched a number of unconnected
senses, which do not all meet in some one nature, the mind, or whatever
we please to call it, of which they are the instruments, and with which
through them we perceive objects of sense.
THEAETETUS: I agree with you in that opinion.
SOCRATES: The reason why I am thus precise is, because I want to know
whether, when we perceive black and white through the eyes, and again,
other qualities through other organs, we do not perceive them with one
and the same part of ourselves, and, if you were asked, you might refer
all such perceptions to the body. Perhaps, however, I had better allow
you to answer for yourself and not interfere. Tell me, then, are not
the organs through which you perceive warm and hard and light and sweet,
organs of the body?
THEAETETUS: Of the body, certainly.
SOCRATES: And you would admit that what you perceive through one
faculty you cannot perceive through another; the objects of hearing,
for example, cannot be perceived through sight, or the objects of sight
through hearing?
THEAETETUS: Of course not.
SOCRATES: If you have any thought about both of them, this common
perception cannot come to you, either through the one or the other
organ?
THEAETETUS: It cannot.
SOCRATES: How about sounds and colours: in the first place you would
admit that they both exist?
THEAETETUS: Yes.
SOCRATES: And that either of them is different from the other, and the
same with itself?
THEAETETUS: Certainly.
SOCRATES: And that both are two and each of them one?
THEAETETUS: Yes.
SOCRATES: You can further observe whether they are like or unlike one
another?
THEAETETUS: I dare say.
SOCRATES: But through what do you perceive all this about them? for
neither through hearing nor yet through seeing can you apprehend that
which they have in common. Let me give you an illustration of the
point at issue:--If there were any meaning in asking whether sounds and
colours are saline or not, you would be able to tell me what faculty
would consider the question. It would not be sight or hearing, but some
other.
THEAETETUS: Certainly; the faculty of taste.
SOCRATES: Very good; and now tell me what is the power which discerns,
not only in sensible objects, but in all things, universal notions, such
as those which are called being and not-being, and those others
about which we were just asking--what organs will you assign for the
perception of these notions?
THEAETETUS: You are thinking of being and not being, likeness and
unlikeness, sameness and difference, and also of unity and other numbers
which are applied to objects of sense; and you mean to ask, through
what bodily organ the soul perceives odd and even numbers and other
arithmetical conceptions.
SOCRATES: You follow me excellently, Theaetetus; that is precisely what
I am asking.
THEAETETUS: Indeed, Socrates, I cannot answer; my only notion is, that
these, unlike objects of sense, have no separate organ, but that the
mind, by a power of her own, contemplates the universals in all things.
SOCRATES: You are a beauty, Theaetetus, and not ugly, as Theodorus was
saying; for he who utters the beautiful is himself beautiful and good.
And besides being beautiful, you have done me a kindness in releasing me