STRANGER: 'Theaetetus, with whom I am now speaking, is flying.' THEAETETUS: That also is a sentence which will be admitted by every one to speak of me, and to apply to me. STRANGER: We agreed that every sentence must necessarily have a certain quality. THEAETETUS: Yes. STRANGER: And what is the quality of each of these two sentences? THEAETETUS: The one, as I imagine, is false, and the other true. STRANGER: The true says what is true about you? THEAETETUS: Yes. STRANGER: And the false says what is other than true? THEAETETUS: Yes. STRANGER: And therefore speaks of things which are not as if they were? THEAETETUS: True. STRANGER: And say that things are real of you which are not; for, as we were saying, in regard to each thing or person, there is much that is and much that is not. THEAETETUS: Quite true. STRANGER: The second of the two sentences which related to you was first of all an example of the shortest form consistent with our definition. THEAETETUS: Yes, this was implied in recent admission. STRANGER: And, in the second place, it related to a subject? THEAETETUS: Yes. STRANGER: Who must be you, and can be nobody else? THEAETETUS: Unquestionably. STRANGER: And it would be no sentence at all if there were no subject, for, as we proved, a sentence which has no subject is impossible. THEAETETUS: Quite true. STRANGER: When other, then, is asserted of you as the same, and not-being as being, such a combination of nouns and verbs is really and truly false discourse. THEAETETUS: Most true. STRANGER: And therefore thought, opinion, and imagination are now proved to exist in our minds both as true and false. THEAETETUS: How so? STRANGER: You will know better if you first gain a knowledge of what they are, and in what they severally differ from one another. THEAETETUS: Give me the knowledge which you would wish me to gain. STRANGER: Are not thought and speech the same, with this exception, that what is called thought is the unuttered conversation of the soul with herself? THEAETETUS: Quite true. STRANGER: But the stream of thought which flows through the lips and is audible is called speech? THEAETETUS: True. STRANGER: And we know that there exists in speech... THEAETETUS: What exists? STRANGER: Affirmation. THEAETETUS: Yes, we know it. STRANGER: When the affirmation or denial takes Place in silence and in the mind only, have you any other name by which to call it but opinion? THEAETETUS: There can be no other name. STRANGER: And when opinion is presented, not simply, but in some form of sense, would you not call it imagination? THEAETETUS: Certainly. STRANGER: And seeing that language is true and false, and that thought is the conversation of the soul with herself, and opinion is the end of thinking, and imagination or phantasy is the union of sense and opinion, the inference is that some of them, since they are akin to language, should have an element of falsehood as well as of truth?