Descartes on the Existence of God

Descartes' Proofs for God's Existence

It is necessary to prove the existence of God without reference to the outside world, only from the analysis of my ideas.

Arguments from the Idea of God

The "cogito ergo sum" gives us the assurance that there are ideas in my mind but does not give us certainty if the objects they represent remain in external reality or not.

The ideas are not different if considered from the point of view of their subjective reality, but when considered from the objective point of view, they are very different from each other.

All these ideas are "caused," and "it is clear that there must be at least as much reality in the cause as in the effect."

The ideas that represent other people or natural things contain nothing so perfect that it cannot be produced by me.

But as regards the idea of God, it is difficult for me to have created it myself. "By the word 'God' I understand a substance that is infinite, eternal, omniscient, independent, powerful..." and these ideas could not have been produced by myself.

The idea of God is the only one in which there is something that could not come from myself, and I do not possess any of the perfections which are represented in this idea.

The simple presence in me of the idea of God proves I am not alone in the world; it demonstrates the existence of God.

According to Descartes, because I doubt, I am finite. The "cogito ergo sum" necessarily relates man to the idea of perfection, and the cause of this idea is God. The idea of the infinite must be prior to the finite.

Descartes in the "Meditation 3" asks how could I know that I doubt and I wish if I had not an idea of something more perfect than myself?

He claims that "the notion of infinity is, somehow, prior to the notion of the finite, that is, the notion of God is prior to that of myself."

The affirmation of my self as doubting (flawed) is the affirmation of God (perfection), but the consciousness of the latter is later than the consciousness of myself. The very consciousness of myself as being cogitative "means" God consciousness.

Challenges and Further Arguments

He wonders if the Cartesian proofs for the existence of God involve the use of certain principles such as the "principle of causality," since the existence of God has not been demonstrated until the conclusion of the proof. The proof must demonstrate the existence of a non-deceiving God.

Arnauld says that the only sure reason to believe that what we perceive clearly and distinctly is true is the fact that God exists, but in turn, we can only be sure that God exists because we perceive things clearly and distinctly. Therefore, before being certain that God exists, we must be certain that everything we perceive clearly and distinctly is true.

But Descartes doubts 'clear and distinct' ideas with the hypothesis of the "Evil Genius."

The Ontological Argument

A scholastic proof sought to move from the simple idea of God to the existence of God, and Descartes endorsed this by presenting it as a demonstration and mathematical proof. But can I show the existence of God by considering the perfection contained in the idea of God? Existence is one of the perfections of God and belongs to the divine essence. A supremely perfect being cannot be conceived as devoid of the perfection that is existence.

The divine essence, being the utmost perfection, includes existence. Hence, one cannot conceive God except as existing. It is not in my power to think of God as not existing, i.e., think of a supremely perfect being devoid of a supreme perfection (existence).

For Descartes, when we understand what the word 'God' means, we understand that God exists in reality and not only in the mind.

The Role of God in Descartes' Philosophy

The fundamental role that Descartes recognizes in God is as a guarantee of all truth, and the Cartesian concept of God is largely devoid of traditional religious character.