Does God exist?
Descartes’ fifth Meditation argument for God's existence relies on an untenable notion that existence is a perfection and that it can be predicated of God. I shall first explain what Descartes’ argument for God's existence is, and then present his argument in propositional form. I will then attempt to support the argument that existence is neither a perfection nor a predicate of God. In our thoughts we apprehend ideas of things. These ideas may reside entirely within our thoughts or they may exist independent of our considerations of them. Descartes argues that the idea of God is that He is infinite substance "eternal, immutable, independent, all-knowing, all-powerful" to which nothing more perfect can be imagined. Descartes defines the more perfect as "that which contains in itself more reality" so that there are gradations of perfection beginning with the subjective phantasms, such as a chimera, and culminating with the most perfect being in God Himself. Thus, because our idea of God is one of absolute perfection, and existence contains more reality than nonexistent thoughts alone, God exists. Descartes’ argument can be represented logically as: (1) in our thoughts we experience an idea of the most perfect being. (2) Existence in reality is more perfect than existence in our thoughts alone. Therefore, (3) the most perfect being exists in reality.
The ontological argument is the only a priori justification for God’s existence: that is, it does not depend upon our experience of the world to be verified, but instead relies upon purely logical inferences from the concept of God. It was adapted by Descartes in Meditation 5 and has been reformulated in recent times. The classical version comes from Anselm who addresses it to the fool in Psalm 14 who says in his heart, there is no God: ... “this very fool, when he hears of this being of which I speak – a being than which nothing greater can be conceived – understands what he hears, and what he understands is in his understanding; although he does not understand it to exist. For, it is one thing for an object to be in the understanding, and another to understand that the object exists... Hence, even the fool is convinced that something exists in the understanding, at least, than which nothing greater can be conceived... And assuredly that, than which nothing greater can be conceived, cannot exist in the understanding alone. For, suppose it exists in the understanding alone: then it can be conceived to exist in reality; which is greater. Therefore, if that, than which nothing greater can be conceived, exists in the understanding alone, the very being, than which nothing greater can be conceived, is one, than which a greater can be conceived. But obviously this is impossible. Hence, there is no doubt that there exists a being, than which nothing greater can be conceived, and it exists both in the understanding and in reality.”
The argument starts from the definition of God as ‘a being than which nothing greater can be conceived’. The fool understands this concept but believes that such a being does not exist. If it did exist, however, it would be greater than the concept alone: an existing being is greater than a mere idea. Therefore the fool is contradicting himself as he can conceive of a being greater than ‘a being than which nothing greater can be conceived’, one that actually exists. Anselm’s argument assumes the premise that God does not exist leads to a contradiction. Therefore, God must exist. Another way of putting this is to say that God necessarily exists. If God is ‘a being than which nothing greater can be conceived’, then he must exist by necessity as such a being is greater than a merely contingent one. Since the concept ‘God’ contains the notion of necessary existence, then the proposition ‘God exists’ must be analytic, in the same way that ‘bachelors are unmarried’ is analytic: the predicate (exists, unmarried) is already…