Stranger: My dear friend, we are engaged in a very difficult speculation—there can be no doubt of that; for how a thing can appear and seem, and not be, or how a man can say a thing which is not true, has always been and still remains a very perplexing question. Can anyone say or think that falsehood really exists, and avoid being caught in a contradiction? Indeed, Theaetetus, the task is a difficult one.
Theaetetus: Why?
Stranger: He who says that falsehood exists has the audacity to assert the being of not-being; for this is implied in the possibility of falsehood. But, my boy, in the days when I was a boy, the great Parmenides protested against this doctrine, and to the end of his life he continued to inculcate the same lesson—always repeating both in verse and out of verse:
“Keep your mind from this way of enquiry, for never will you show that not-being is.”
Such is his testimony, which is confirmed by the very expression when sifted a little. Would you object to begin with the consideration of the words themselves?
Theaetetus: Never mind about me; I am only desirous that you should carry on the argument in the best way, and that you should take me with you.
Stranger: Very good; and now say, do we venture to utter the forbidden word “not-being”?
Theaetetus: Certainly we do.
Stranger: Let us be serious then, and consider the question neither in strife nor play: suppose that one of the hearers of Parmenides was asked, “To what is the term ‘not-being’ to be applied?”—do you know what sort of object he would single out in reply, and what answer he would make to the enquirer?
Theaetetus: That is a difficult question, and one not to be answered at all by a person like myself.
Stranger: There is at any rate no difficulty in seeing that the predicate “not-being” is not applicable to any being.
Theaetetus: None, certainly.
Stranger: And if not to being, then not to something.
Theaetetus: Of course not.
Stranger: It is also plain, that in speaking of something we speak of being, for to speak of an abstract something naked and isolated from all being is impossible.
Theaetetus: Impossible.
Stranger: You mean by assenting to imply that he who says something must say some one thing?
Theaetetus: Yes.
Stranger: Some in the singular (τὶ) you would say is the sign of one, some in the dual (τινὲ) of two, some in the plural (τινὲς) of many?
Theaetetus: Exactly.
Stranger: Then he who says “not something” must say absolutely nothing.
Theaetetus: Most assuredly.
Stranger: And as we cannot admit that a man speaks and says nothing, he who says “not-being” does not speak at all.
Theaetetus: The difficulty of the argument can no further go.
Stranger: Not yet, my friend, is the time for such a word; for there still remains of all perplexities the first and greatest, touching the very foundation of the matter.