An Analysis of the Debate Between al-Tūsī and al-Kātibī on Infinite Regress

Abstract

This study presents an analysis of the written debate between Najm al-Dīn al-K ā tibī and Nasīr al-Dīn al-Ṭ ūsī on the possi bilit y/imp ossib ility of infinite regress. This debate addressed three of the most famous arguments put forward by Islamic philosophers, regarding the impossibility of infinite regress in the classical period. These arguments are known as burh ā n al-arshi, burh ā n al-tatbīq, and burh ā n al-tazayuf in the classical Islamic thought. Al-K ā tibī wrote a letter to his teacher al-Ṭ ūsī to raise his objections against these arguments. In this letter, he first presented the arguments about the impossibility of infinite regress and then voiced his objections against them. However, al-Ṭ ūsī offered quite satisfactory and convincing answers to al-K ā tibī's objections. Convinced by his teacher’s explanations, al-K ā tibī accepted the validity of these arguments, which were offered in the classical period regarding the impossibility of infinite regress, and expressed this acceptance by writing a final letter of confession. The debate ended with the last letter that al-Ṭ ūsī wrote, in response to this confession, to express his gratitude and appreciation.