Aristotle on Non-Contradiction: Philosophers vs. Non-Philosophers

Abstract

Aristotle's principle of non-contradiction (PNC) has been interpreted by Łukasiewicz through three distinct formulations, namely ontological, logical, and psychological. Many have criticized Łukasiewicz's position, but they still maintain that Aristotle defends distinct formulations. In contrast, this paper shows that Aristotle suggests only one formulation of the PNC. This unique formulation belongs to philosophy as the first science, so that the philosophers think of the PNC as a necessarily true principle, owing to their meta-physical cognition of the nature of things. Yet, there is another way to understand this formulation. Indeed, the non-philosophers believe in the PNC, without being able to understand its necessary truth, due to their ignorance of philosophy. Thus, Aristotle has to convince them that the PNC is the most certain opinion of all, and his dialectical justifications are purposely weak, as they are only concerned with the defense of a common opinion. 1 We shall use the acronym PNC as a useful convention, but the expression 'principle of non-contradiction' (for which PNC stands) is nowhere to be found in Aristotle's works. 2 All translations in this paper are my own, unless otherwise indicated. The two main English translations of Metaphysics Gamma are Ross (1924) and Kirwan (1993).