Naṣīr al-Dīn al-Ṭūsī’s innovative version of proof of the truthful (Burhān-i ṣiddīqīn) and its reception in Islamic kalām

Among the arguments for God's Existence in the Islamic philosophy and kalam, the proof of the truthful (Burhān-i ṣiddīqīn) due to its merits has a unique position. invented by Avicenna (Ibn Sīnā), soon received a noticeable reception from his followers who tried to present new versions of the proof. Among the post-Avicennian Imāmī theologians, Naṣīr al-Dīn al-Ṭūsī (d. 672/1274) set forth an important, new version of the proof of the truthful in his theological treatise entitled Fūṣūl, which is known by some of later Imāmī theologians as an innovative version of the proof. The gist of his argument is that since contingent beings are not beings by itself, nor can be by itself the cause for something to exist, there must be a necessary existence among the beings of the universe. Naṣīr al-Dīn al-Ṭūsī’s innovative version of proof of the truthful and its effects and reception in the later theological and philosophical works has not received much attention in the recent researches so far. In the present article, having discussed and analyzed al-Ṭūsī’s innovative version of the proof, point out that some of the Imāmī theologians showed considerable attention to it and set out various versions of the proof in their writings.