Immanent Critique of Reason: The Structural Tension between Philosophy and Theology in Avicenna

One of the fundamental issues in the history of philosophy is the tension between the rational criteria upheld by rationalist philosophers and their religious or theological commitments. This article examines this tension through the methodological lens of immanent critique, according to which a philosophical system is evaluated based on its own principles rather than from an external standpoint. The primary focus is on Avicenna’s philosophy, where rigorous criteria of knowledge, certainty, and demonstrative proof are explicitly articulated, yet his theological commitments—most notably the existence of the Necessary Existent, the Active Intellect, and prophecy—enter into tension with those criteria. A brief comparative analysis of Descartes and Kant shows that this tension constitutes a recurring pattern in the history of philosophical rationalism: self-grounding reason, when confronted with theological or moral demands, must modify or suspend its own standards. The central thesis is that when philosophy ventures into domains justified only by departing from its own principles, the internal coherence of the philosophical system is at risk, compelling philosophical reason to reconsider the legitimate limits of its intervention—without denying the social, cultural, or ethical significance of religion.