The ontological argument is the argument that God exists because he is a necessity, a being in which nothing greater can be thought of. There are several different philosophers who have adapted the ontological argument: from Anselm who agrees that God is the greatest being possible. To the Cartesian argument, which was a version of the ontological argument from Rene Descartes, who famously said, “I think therefore I am”. However, there are also many philosophers who disagree with this argument – one of them being Immanuel Kant, and his disagreement with the fact that existence is not a predicate – a predicate is something that tells us about an object.
Kant says, “Existence is not a predicate” this is his counter argument to Descartes argument that says, “I think, therefore I am”. Descartes accepts that where a triangle is, there are three sides and three angles but it doesn’t mean the triangle exists but there is a definition there, He also says how it is possible to define a winged horse but thinking about it doesn’t mean it exists because it doesn’t have the predicate of existence. Where as Kant says to add the “predicate” of existence adds nothing to the overall picture of the object – it only tells us about the world, the object remains unchanged. Descartes goes on to say that if existence is perfect then if God is perfect, then it is a defining predicate