STRANGER: When we speak of things which are not, are we not attributing plurality to not-being?
THEAETETUS: Certainly.
STRANGER: But, on the other hand, when we say 'what is not,' do we not attribute unity?
THEAETETUS: Manifestly.
STRANGER: Nevertheless, we maintain that you may not and ought not to attribute being to not-being?
THEAETETUS: Most true.
STRANGER: Do you see, then, that not-being in itself can neither be spoken, uttered, or thought, but that it is unthinkable, unutterable, unspeakable, indescribable?
THEAETETUS: Quite true.
STRANGER: But, if so, I was wrong in telling you just now that the difficulty which was coming is the greatest of all.
THEAETETUS: What! is there a greater still behind?