Non-contradiction and excluded middle: Avicenna and the first principle of metaphysics

Abstract

In his paraphasis of Aristotle’s Metaphysics, Avicenna seems to adopt afirst principle distintc form the one adopted by the Greek philosopher for thisscience. In fact, some interpreters consider him as prefering the principle of thirdexcluded instead of the principle of non contradiction. Since I desagree with thisthesis, I propose to analyse here Avicenna’s formulation of the first principle. Inorder to do that, I propose, first, to clarify the meaning of the first principle bylooking to one of the most important modern critics: Jan Lukasiewicz. To put itbriefly, the question I will try to answer is: how Avicenna and Aristotle justify thenature of the logical relations. The article finishes with make some generalremarks on Avicenna’s defense of the first principle.