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? Theatetus: Quite true. Stranger: But the stream of thought which flows through the lips and is audible is called speech? Theatetus: True. Stranger: And we know that there exists in speech… Theatetus: What exists? Stranger: Affirmation Theatetus: Yes, we know it.