This study presents a comparative analysis of the role and function of intellect (ʿaql) in two prominent Qur’anic commentaries: al-Kashshāf by al-Zamakhsharī (a Muʿtazilite exegete) and al-Ṣāfī by Fayḍ al-Kāshānī (an Imāmī exegete). The central problem is to elucidate the epistemological status of reason, its methodological functions, and the hierarchical relationship between reason (ʿaql) and revelation/tradition (naql) in these two works. Employing a descriptive-analytical and comparative approach, the research utilizes content analysis of the exegetical texts.

The findings reveal that al-Zamakhsharī adopts a “theological rationalism” (ʿaql-centric) orientation, wherein reason serves as an independent source governing transmitted evidence; within this framework, the exegete serves reason, and reason constitutes the ultimate criterion in resolving conflicts with the outward literal sense of transmitted texts. Conversely, Fayḍ al-Kāshānī pursues “measured rationality within the framework of transmission,” defining reason not in opposition to narrations, but as an instrument serving a deeper understanding of the Ahl al-Bayt’s (a) Sunnah.

Al-Zamakhsharī in al-Kashshāf, by going to extremes in employing “source-based reason” (ʿaql-i manbaʿī), has paid less regard to other contextual and textual evidence, thereby conforming texts to Muʿtazilite theological premises; whereas Fayḍ al-Kāshānī in al-Ṣāfī, adopting a moderate stance, utilizes the instrumental and illuminative (miṣbāḥī) functions of reason.

The key divergences between the two exegetes are articulated along three axes: the status of reason (sovereign vs. servant), the approach to conflicts between reason and transmission (the priority of rational interpretation [taʾwīl] vs. the priority of rational reconciliation), and the theological boundaries of applying reason (Muʿtazilite principles vs. Imāmī theology). Although both commentators converge in rejecting rigid literalism and utilizing literary disciplines, their fundamental divergence lies in the hierarchical primacy of reason and transmission. Consequently, al-Kashshāf exemplifies the “interpreting intellect” (sovereign and independent exegetical reason), while al-Ṣāfī embodies the “interpreter of intellect” (an exegete dedicating analytical rigor to elucidating revelatory rationality).