One of the sources and references in Quranic exegesis is reason.The interpreters from both Islamic religious sects have not absolutely denied the application of reason in interpreting the holy Qur’an.
They have given three definitions of reasons. The scholars of both religious sects accept that reason acts as a means for understanding the self-evident concepts, a source for constituting logical analogy and a source for inference from Quranic verses using the intertextual and nonintertextual data. However, despite the difference in source of and results they draw only Shiites and Mutazilites recognize reason as an independent source in apperception of virtues and vices of any deeds and in legislation of Ashariah rules (ahkam) . In a sharp contrast to some scholars’ viewpoint, Shiites are not influenced by Mutazilites; rather it has influenced the Mutazilites theology and exegesis.