Theistic and Non-Theistic Ontologies in Comparison: A Critical Re-Evaluation of Comparative Studies between Mullā Ṣadrā and Heidegger

This study undertakes a sustained comparative examination of Mullā Ṣadrā’s Transcendent Philosophy (al-ḥikmah al-mutaʿāliyah) and Martin Heidegger’s analytic of Being, framed through two additional interlocutors whose positions reveal the deeper structural divergence between the two traditions: Edith Stein, whose phenomenological metaphysics unfolds the necessity of a transcendent ground of finite being, and major figures of the Kyoto School—Tanabe Hajime, Shūzō Kuki, Keiji Nishitani, Kōichi Tsujimura, and Shizuteru Ueda—whose interpretations of Heidegger’s thought advance toward a radical metaphysics of nothingness and emptiness. Although comparative studies by Alparslan Açıkgenç and Muhammad Kamal have identified noteworthy parallels between Ṣadrā and Heidegger—particularly concerning the primacy of existence, the critique of essentialism, the dynamic structure of reality, and the centrality of human existence—these analyses overlook the fundamental difference in ontological culmination that separates the two systems. This difference is not one of theological belief but of metaphysical horizon. Ṣadrā’s ontology begins without presupposing God but culminates through rational necessity in the affirmation of a transcendent Necessary Existent (wājib al-wujūd). Heidegger’s analytic, by contrast, begins with the methodological suspension of theology and culminates in the abyssal groundlessness of Being, refusing any appeal to a transcendent ground. Edith Stein’s critique of Heidegger demonstrates philosophically—rather than theologically—that finite being, by its very nature, demands an eternal ground. Her argument converges with the Sadrian metaphysics of wujūd, even though they emerge from different traditions. The Kyoto School, in contrast, deepens Heidegger’s a-theological horizon toward absolute nothingness and emptiness, thus strengthening the interpretation of Heidegger as a philosopher of groundlessness rather than grounding. Together, Stein and the Kyoto School expose the inherent tension in comparative projects that seek to harmonize Ṣadrā and Heidegger. The study concludes that the core divergence between these traditions lies not in theism versus atheism but in grounded versus groundless ontology. Ṣadrā and Stein affirm the necessity of a metaphysical ground, whereas Heidegger and the Kyoto School affirm the evental or empty disclosure of Being without ground. This interpretive framework provides the basis for a thorough critique of the comparative methodologies employed by Açıkgenç and Kamal, whose emphasis on surface parallels conceals deeper metaphysical incompatibilities. The result is an expanded and more rigorous foundation for future comparative work that recognizes the irreducible difference between theistic and non-theistic ontological horizons.