Descartes’ Proofs for God’s Existence
The Existence of God
Descartes needs God to ensure truth and eliminate the evil genius hypothesis. But how to prove God’s existence? In Descartes’ system, only arguments based on the idea of God or the self are possible.
Arguments Based on the Idea of God
Anselm’s Argument
Descartes accepts the ontological argument but believes it lacks a prior assumption: if we perceive clearly and distinctly that the concept of a property P belongs to the concept of something X, then X has that property P. If we perceive clearly and distinctly that the concept of existence belongs to the concept of God, then God exists in reality. Descartes catches Anselm’s presupposition that concepts can be applied to the world, but how do we know this presupposition is valid? The problem is that the criterion of clarity and distinction cannot be introduced until there is proof of God’s existence and the elimination of the evil genius, as Descartes argues against the premises of his own system.
Cartesian Argument for God’s Existence
Descartes believes that ideas in our minds differ because some have more content than others. There are two types of ideas: finite beings and God. The idea of God differs as it is the only idea of an infinite being. Descartes defines God as the being who meets all perfections in the highest degree. Applying the theory of causality, the idea of God in our mind must have a cause. The theory of proportionality states that there must be neither more nor less content in the effect than in the cause. The cause of the idea of God cannot be the finite human mind, which cannot form the idea of an infinite being. Denying properties of a finite being results in negatives, while God’s properties are positive. If this idea is in our mind and we haven’t formed it, who placed it there? If a finite mind did, it must have been caused by another infinite mind. Only God can cause the idea of God, therefore God exists.
Assumptions:
- The idea of God is unique and valid. Descartes doesn’t question Christian ideas when challenging all others.
- The principle of causality: God exists and therefore has a cause. We don’t know if this principle is valid.
- The principle of proportionality: there must be a proportion between cause and effect. We don’t know if this principle is valid.
- The idea of God has infinite content and cannot create a finite mind. Descartes confuses the content of the idea with its referent, God. God is infinite, but the idea is finite.
Argument Based on the Existence of the Self
I am a finite being with finite qualities, but I have ideas of infinity and perfections I lack. If I caused myself, I wouldn’t be perfect. The cause of my existence must be another being, possibly finite, but with another cause, leading to an infinite cause. This argument rests on the principle of causality, which we don’t know is valid.
In the Meditations, Descartes recounts a personal experience of seeing a wonderful, dazzling light that brought great happiness. This light is either God or comes from God and contains all knowledge, offering a way to extract and rebuild knowledge and philosophy.
Descartes believes he has demonstrated God’s existence, ensuring truth and eliminating the evil genius. God is defined as good, omniscient, and omnipotent. The evil genius cannot exist as it is incompatible with God. All beings are logically compatible.
Why do we err? Descartes believed error is not due to finite reason, as that would make God responsible. Error is caused by the misuse of reason. We are responsible for our mistakes. Error occurs when the will affects reason, leading us to perceive beyond clear and distinct ideas. To avoid error, we must limit the will to the realm of clear and distinct ideas. The method provides rules to limit the will. Descartes says without a method, it is better not to seek truth.