to possess'
knowledge.

THEAETETUS: How do the two expressions differ?

SOCRATES: Perhaps there may be no difference; but still I should like
you to hear my view, that you may help me to test it.

THEAETETUS: I will, if I can.

SOCRATES: I should distinguish 'having' from 'possessing': for example,
a man may buy and keep under his control a garment which he does not
wear; and then we should say, not that he has, but that he possesses the
garment.

THEAETETUS: It would be the correct expression.

SOCRATES: Well, may not a man 'possess' and yet not 'have' knowledge
in the sense of which I am speaking? As you may suppose a man to have
caught wild birds--doves or any other birds--and to be keeping them in
an aviary which he has constructed at home; we might say of him in one
sense, that he always has them because he possesses them, might we not?

THEAETETUS: Yes.

SOCRATES: And yet, in another sense, he has none of them; but they are
in his power, and he has got them under his hand in an enclosure of his
own, and can take and have them whenever he likes;--he can catch any
which he likes, and let the bird go again, and he may do so as often as
he pleases.

THEAETETUS: True.

SOCRATES: Once more, then, as in what preceded we made a sort of waxen
figment in the mind, so let us now suppose that in the mind of each man
there is an aviary of all sorts of birds--some flocking together apart
from the rest, others in small groups, others solitary, flying anywhere
and everywhere.

THEAETETUS: Let us imagine such an aviary--and what is to follow?

SOCRATES: We may suppose that the birds are kinds of knowledge, and that
when we were children, this receptacle was empty; whenever a man has
gotten and detained in the enclosure a kind of knowledge, he may be
said to have learned or discovered the thing which is the subject of the
knowledge: and this is to know.

THEAETETUS: Granted.

SOCRATES: And further, when any one wishes to catch any of these
knowledges or sciences, and having taken, to hold it, and again to let
them go, how will he express himself?--will he describe the 'catching'
of them and the original 'possession' in the same words? I will make
my meaning clearer by an example:--You admit that there is an art of
arithmetic?

THEAETETUS: To be sure.

SOCRATES: Conceive this under the form of a hunt after the science of
odd and even in general.

THEAETETUS: I follow.

SOCRATES: Having the use of the art, t