Cartesian Arguments for God's Existence

Descartes' Proofs for God's Existence

René Descartes, starting from the doubt in his own mind, which indicates imperfection, raises questions about the origin of the idea of perfection within him. He doubts everything except his own existence, recognizing his imperfection. Thus, since this idea cannot come from nothing or from himself (being imperfect), Descartes concludes that it must come from a perfect being, God, who has "put us in as the seal of the architect."

The Argument from the Idea of Perfection

This is the first demonstration of God's existence: the idea of perfection must be given by a perfect being. Since we, as imperfect beings, possess this idea but do not embody perfection, the idea must originate from God.

God as Guarantor of Truth

With this argument, Descartes refutes the possibility of a deceitful God, thereby validating his method. If God is perfect, God lacks malice and would not deceive us. Therefore, whatever we conceive clearly and distinctly must be true. The initial hypothesis of a "deceitful God" is replaced by God as a guarantor of the truth of the evidence acquired by the res cogitans (thinking thing).

The Ontological Argument

Another demonstration presented by Descartes, similar to one made earlier by St. Anselm of Canterbury, is the ontological argument. It posits that if God is the most perfect being conceivable, existence must be a perfection, and therefore God must necessarily exist.

The Contingency Argument

Finally, the third argument resembles St. Thomas Aquinas's third way (the argument from contingency). It posits that contingent beings require a necessary being for their existence. This argument necessarily leads to the existence of a being who caused everything else to exist – the thinking subject itself and all other finite beings. This necessary being is God.

God's Necessity in Cartesian Philosophy

Influenced by the scholastic tradition, Descartes attempts to account for God's existence. The figure of a perfect God is also necessary for his philosophical system, which is based on the cogito, ergo sum ("I think, therefore I am"). Without God, Descartes' methodical doubt would lead to subjective solipsism – the state of having certainty only about one's own subjective consciousness. From this isolated position, it would be impossible to prove the existence of other minds or the external world.

Avoiding Subjective Solipsism

The concept of a perfect, non-deceiving God allows Descartes to move beyond the certainty of his own existence and validate the reality of the external world and other minds, based on clear and distinct perceptions.

God as Guarantor of Rational Knowledge

In short, God becomes the guarantor of rational knowledge, ensuring the truth of whatever can be conceived clearly and distinctly.