tention and study,
is uninformed, and speedily forgets whatever she has learned?

THEAETETUS: True.

SOCRATES: Then motion is a good, and rest an evil, to the soul as well
as to the body?

THEAETETUS: Clearly.

SOCRATES: 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.

THEAETETUS: I believe, Socrates, that you have truly explained his
meaning.

SOCRATES: 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.

THEAETETUS: Then what is colour?

SOCRATES: 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?

THEAETETUS: Far from it.

SOCRATES: 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?

THEAETETUS: The latter.

SOCRATES: 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 wonderf