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, the arithmetician, if I am not mistaken, has the conceptions of number under his hand, and can transmit them to another.
THEAETETUS: Yes.
SOCRATES: And when transmitting them he may be said to teach them, and when receiving to learn them, and when receiving to learn them, and when having them in possession in the aforesaid aviary he may be said to know them.
THEAETETUS: Exactly.