The principle of sufficient reason in the kalam tradition

Foundational ideas of the kalām tradition are still to be studied. The Principle of Sufficient Reason (PSR) as an ontological principle is one of the most potent principles for metaphysics. Many philosophical discussions in Islamic literature refer to this principle. Moreover, the mutakallims, for their divine goal of building a solid theology consistent with the Qurʾān and the Ḥadīṯ, utilize it extensively. To better understand the metaphysics of the overall kalām tradition, this study investigates how the muhaqqiqīn explained the foundations of a specific variant of the PSR and utilized it: Tarajjuḥ bilā murajjih bāṭil. The aim is a general but complete picture. Hence, primarily major works of the muhaqqiqīn are examined and clarification of an accepted view had priority over the conveyance of different opinions. Comparisons to the contemporary philosophical debates enabled us to see how a possible defense by the mutakallims would start. The mutakallims claim a type of modalism based on a nonmodal account of essentialism, and there is a nonrealist truth theory behind everything. After addressing these metaphysical foundations, the explananda and the explanantia were restricted. As a result, a well-rounded variant of the PSR led to a theory of causality. The causal theory introduced a voluntary type of causation: a willing powerful agent who decides without any external reason. The utilization of these findings and their effect on some metaphysical issues were explained. Finally, some supposedly eligible objections are discussed. The results show that the PSR is central to the kalām tradition. Main arguments for the existence of God and important maxims about the divine attributes are based on it. Restrictions on it are based on elaborations in the modal theory rather than pragmatic modifications. This variant of the PSR avoids the objections and is on par with contemporary solutions, if not better than them.