Traditional history of philosophy regards “I think， therefore I am” as the core of Descartes’ philosophy， while the ontological argument of God’s existence is only regarded as a secondary tool. In

The History of Modern Philosophy

， Schelling puts forward the o

pposite assertion： ontological argument is the cornerstone of Descartes’ thought. He defines God as a “necessary being”， establishes the logic of the identity of existence and essence， and lays the foundation for modern rationalist metaphysics. Schelling points out that although Descartes’ argument does not prove the existence of God， it reveals its dilemma as “blind necessity” that God loses his freedom due to necessity and becomes a rigid logical object. This logic was developed by Spinoza and Leibniz and reached its peak in Hegel： Hegel integrated “I think” with ontological argument， constructed a closed system with dialectics as the core， and completely incorporated existence into the self-movement of concepts， forming a “negative philosophy”. Schelling criticized this path for obscuring the original freedom of existence， and advocated re-questioning the “unthinkable existence” beyond concepts and logic through “positive philosophy” that God as a free subject prior to necessity. The article also points out that Schelling over-focuses on the ontological argument and ignores the transcendental dimension of God as “infinite will” in Descartes’ causal argument of God’s existence. Levinas and Marion emphasize that Descartes’ God is actually the infinite “other” that overflows the human reason， implying the fundamental tension between reason and existence in his philosophy. Schelling’s interpretation not only highlights the ontological logic of modern philosophy， but also exposes its closed nature， providing a critical perspective for reflecting on the dialectical relationship between reason and freedom.