adynaton / ἀδύνατον

ἀδύνατον: incapable, impossible

In the case of a distorted view, one knows, and does not   know, one and the same thing! However, Theaetetus promptly says that such a thing is impossible, ἀδύνατον. If this is so, what remains? One might presume: he knows neither. Then having a distorted view would mean that one takes something one does not know for something else one likewise does not know. Then someone who knew neither Theaetetus nor Socrates   could intend both while taking Socrates for Theaetetus or Theaetetus for Socrates. That is obviously impossible! The distorted view, consequently, cannot exist at all. The guiding principle, and what followed from it, remain valid: it is impossible that someone who knows something also does not know it, and vice versa. [GA34  ]