  The idea of using an elenchus is at first sight very puzzling. The person claiming to reject PNC is not being consistent and apparently does not want to be. Aristotle is not trying to catch the opponent in a formal contradiction. The opponent purportedly does not care about that, and it would be begging the question. Instead, Aristotle’s trick is to draw the opponent into saying something, without making a complete statement, that shows that he does accept that x is F and is not at the same time not F, in spite of the words he previously said. In other words, Aristotle needs to show that his opponent is committed to at least one thing that is not contradictory. The Socratic method is turned on its head.