Abstract

I come not to clarify Aristotle’s defence of the principle of non-contradiction, but to put it in its proper context. I argue that remarks in Metaphysics IV.3 together with the argument of IV.4, 1006a11-31 show that Aristotle practises Plato’s method of dialectic in his defence of PNC. I mean this in the strong sense that he uses the very methodology described in the middle books of the Republic and, I claim, illustrated in such dialogues as Parmenides, Sophist and Theaetetus.