STRANGER: When we say that he deceives us with an illusion, and that

his art is illusory, do we mean that our soul is led by his art to think

falsely, or what do we mean?

THEAETETUS: There is nothing else to be said.

STRANGER: Again, false opinion is that form of opinion which thinks the

opposite of the truth:--You would assent?

THEAETETUS: Certainly.

STRANGER: You mean to say that false opinion thinks what is not?

THEAETETUS: Of course.

STRANGER: Does false opinion think that things which are not are not, or

that in a certain sense they are?

THEAETETUS: Things that are not must be imagined to exist in a certain

sense, if any degree of falsehood is to be possible.

STRANGER: And does not false opinion also think that things which most

certainly exist do not exist at all?

THEAETETUS: Yes.

Sophist