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.