The interaction between “intra-religious” and “extra-religious” sources constitutes a methodological tension within Islamic political thought. This tension has hindered the formulation of a “state theory” in the Islamic Republic of Iran, a problem that can be traced, for instance, in the “Theory of Agency for Individual Owners of Undivided Property.” This research aims to evaluate the methodological rigor of the aforementioned theory in its dual reliance on scriptural (naqlī) and rational (aqlī) sources. Therefore, by employing the “qualitative content analysis” method within the framework of “convergence theory,” and by identifying Haeri’s intra-textual justifications and extra-textual arguments, we address the primary question: In the Theory of Agency for Individual Owners of Undivided Property, what relationship is established between scriptural evidence and rational arguments? The findings indicate that despite his attempt to establish a logical correspondence between these two sources, his rational arguments have determined his interpretation of the scriptural text (naṣṣ) without having fully met the conditions for certainty. In contrast to the existing philosophical and theological critiques of the “Theory of Agency,” the results of this study reveal the consequences that a “lack of a philosophy of method” in Islamic political thought has for the guidance of indigenous state-building.