The relation of causal necessity with free will has been a source of great debate in the history of philosophy and theology. However, in recent years, it has also been discussed in the science of Usul al-Fiqh. After explaining the compatibility of causal necessity with free will, Ākhūnd Khurāsānī speaks of the 'shattering of his pen.' Two interpretations have been given for this statement. Muḥaqqiq Iṣfahānī considers the theory of compatibility that Khurāsānī presented as being correct. However, he interprets the 'shattering of the pen' to be a reference to another matter, i.e., the problem of the recompense of an agent in the case where causal necessity is accepted. His explanation of the aforementioned compatibility and the permissibility of the recompense of sinners has been evaluated in this article. On the contrary, Muḥaqqiq Na'ini considers the 'shattering of the pen' to be a reference to the problem of the conflict between causal necessity and free will. He says that aside from the popular preliminaries of free will, such as knowledge and intention (which are the products of causal necessity), there is a need for something that he calls 'talab'-a noetic action that stems from the governance of the soul. He considers this talab to fall outside the scope of causal necessity. This paper seeks to examine the views of these two illustrious students of Ākhūnd Khurāsānī so that the various Usuli dimensions of this discussion can be clarified.
