René Descartes is another philosopher who used the Ontological argument to prove the existence of God. Like Anselm, God is a perfect being. If existence is perfection and God is a perfect being, then God must exist. Descartes uses the idea of triangles and mountains as a metaphor: God has existence like triangles have 3 sides and angles adding up to 180o and like mountains must have valleys. It is a predicate of God.
Norman Malcolm was a modern philosopher and though he disliked Anselm’s Proslogion 2 and Descartes’ argument, he sympathised with Anselm’s Proslogion 3. Malcolm’s version of TWNGCBC was ‘God is an unlimited being’. Then if something caused God to exist then God would be limited. So, God is either impossible or has necessary existence. However, there is always a possibility of such a being existing so God exists and has necessary existence. Plantinga also used necessary existence, but unlike Anselm and Descartes, both he and Malcolm didn’t use it as a predicate. In a possible world God exists, but God has necessary existence so God must exist in all possible worlds. If God exists in all possible worlds then God must exist in this world therefore God exists.
Kant’s Argument Has Finished All Ontological Arguments
Kant’s objection to the Ontological argument can be seen by some to have finished the Ontological argument and it can be seen as irrelevant to others.
Immanuel Kant is a theist philosopher who is well known for criticising many different arguments for the existence of God. Kant disliked both Anselm’s and Descartes’ Ontological argument. To Kant existence is not a predicate – which was the key argument in Proslogion 2 and Descartes’ argument. Kant used the example of thalers (currency in Europe during the 1800s when Kant was alive) to prove his point. Kant said that if you add existence to a list of other predicates no one would think any differently about thalers. Since nothing in our minds change when we use existence as a predicate, existence cannot be a predicate. Furthermore, existence adds nothing to the idea of God so, according to Kant, the Ontological argument fails to prove the existence of God.
However, scholars like Alvin Plantinga disagree with Kant’s argument. Plantinga argues that Kant’s criticism is not even relevant to Anselm’s Ontological argument. This is because God is a necessary being, not contingent. If Anselm added existence to a contingent being then Kant’s argument may have been able to work. But, God is necessary and a necessary being comes with existence.
Gareth Matthews also thinks Kant has misunderstood Anselm’s argument. Gareth argues that Anselm was not adding the concept of existence to God, but Anselm was merely comparing a being that exists in reality and a being that exists in mind.
Evaluating Matthews and Plantinga and Kant has led me to the conclusion that Alvin Plantinga has proved that Kant’s attack on Anselm was not effective. This is because Kant has misunderstood the Ontological argument. Matthews’s argument is not as strong because he was just simplifying the argument without actually explaining why Kant was wrong.
Kant’s argument was originally aimed at Descartes Ontological argument. In Descartes argument he said that God possessed all perfections and existence is one of those attributes. To Kant, existence is not a predicate like omnipotence or Omni-benevolence is. This is because existence is not a quality that adds to the nature of God like omnipotence does. And so, Descartes Ontological argument was proved incorrect by Kant.
Though Descartes may have been proved wrong, there are still many Ontological arguments that do not use existence as a predicate and are still strong today. For example, Alvin Plantinga is a modern philosopher who used a multiverse theory to prove the existence of God. This argument does not use existence as a predicate. In the argument there is a possible world where God exists necessarily. This means God must exist in all possible worlds necessarily and as a result God exists in our world.
I think this shows that Kant has not finished all Ontological arguments because Kant’s argument was based on existence not being a predicate. However, Alvin Plantinga’s argument was not based off existence being a predicate at all. This means that Kant’s argument is irrelevant when using Plantinga’s argument for Gods existence.
In addition, Malcolm also created his version of the Ontological argument. His argument does not use existence as a predicate either. Instead Malcolm uses deduction to have God end up as an unlimited, necessary being or as impossible to exist. Since there is always a possibility of such a being to exist, God must exist. Since Malcolm’s argument has no relevance to Kant’s criticism based on existence not being a predicate, Malcolm’s argument has not been finished.
Overall, I believe that Kant’s argument has not finished the Ontological argument because clearly Kant has misunderstood Anselm’s argument. Also, his argument has no relevance to Plantinga or Malcolm. His argument may have finished Descartes argument but the others are still strong. So, Kant’s argument that existence is not a predicate is not strong enough to finish all the Ontological arguments.