The Function of Logic in Tahāfut at-Tahāfut: Ibn Rushd on Demonstration, Causality and the Principle of Non-Contradiction

Abstract

This article reads Ibn Rushd's Tahāfut at-Tahāfut not as a theological rejoinder but as a work whose organising centre is logic. Its central claim is that the weight of Ibn Rushd's objections falls not on the falsity of particular theological theses but on the misidentification of the evidential class of the reasoning on which those theses rest. For Ibn Rushd, the denial of causal necessity does not merely reject isolated propositions; it withdraws the condition under which demonstrative syllogism is possible, since once the middle term loses its causal function the kind of knowledge Aristotle defines in the Posterior Analytics collapses with it. Existing scholarship has examined the defence of causality largely within metaphysics and natural philosophy, leaving its systematic connection to demonstrative theory underexplored. This article aims to fill this gap by aligning the text of Tahāfut at-Tahāfut with the technical analyses in the Talkhīṣ Kitāb al-Burhān at the level of terminology. Drawing on Ibn Rushd's threefold division of demonstration (burhān al-lima, burhān al-anna, absolute demonstration) and on his theory of essential predication (bi'dh-dhāt), the article argues that causality functions as a condition of syllogistic inference before it functions as a cosmological thesis. It then examines the treatment of the principle of non-contradiction as an indemonstrable first principle and confronts the reflexive objection that Ibn Rushd's own argument is dialectical, showing that its structure is instead transcendental.