From Divine Illumination to the Clearing of Being: Heidegger’s Ontological Turn in the Grounding of Truth Beyond Aquinas

The problem of truth-grounding occupies a central position in the history of metaphysics. Aquinas synthesizes Aristotelian epistemology with the Augustinian doctrine of illumination, establishing a comprehensive system in which participation in the divine intellect, expressed through the illuminative function of the agent intellect, serves as the foundational principle. Heidegger, through a critical transformation of this system, opens an alternative path to the ontological grounding of truth. Rather than standing in simple opposition, the two thinkers stand in a relation of critical engagement. Heidegger preserves the phenomenological validity of the illumination metaphor, acknowledging the fundamental structure of truth as manifestation, while simultaneously dismantling the theological framework that undergirds its transcendent guarantee. In its place, he advances the ontological concepts of the clearing (Lichtung) and appropriation (Ereignis). This conceptual transformation marks a decisive shift in the grounding of truth: from dependence on the eternal assurance of a transcendent being to the historical self-disclosure inherent in Dasein itself.