192–193
Theaetetus
THEAET. What cases are they? I hope they may help me to understand better; for now I cannot follow you.
Socrates
SOC. The cases in which he may think that things which he knows are some other things which he knows and perceives; or which he does not know, but perceives; or that things which he knows and perceives are other things which he knows and perceives.
Theaetetus
THEAET. Now I am even more out of the running than before.
Socrates
SOC. Then let me repeat it in a different way. I know Theodorus and remember within myself what sort of a person he is, and just so I know Theaetetus, but sometimes I see them, and sometimes I do not, sometimes I touch them, sometimes not, sometimes I hear them or perceive them through some other sense, and sometimes I have no perception of you at all, but I remember you none the less and know you in my own mind. Is it not so?
5
Theaetetus
THEAET. Certainly.
Socrates
SOC. This, then, is the first of the points which I wish to make clear. Note that one may perceive or not perceive that which one knows.
Theaetetus
THEAET. That is true.
Socrates
SOC. So, too, with that which he does not know—he may often not even perceive it, and often he may merely perceive it?
Theaetetus
THEAET. That too is possible.
10
Socrates
SOC. See if you follow me better now. If Socrates knows Theodorus and Theaetetus, but sees neither of them and has no other perception of them, he never could have the opinion within himself that Theaetetus is Theodorus. Am I right or wrong?
Theaetetus
THEAET. You are right.
Socrates
SOC. Now that was the first of the cases of which I spoke.
