1. IN SUPPORT OF THE ONTOLOGICAL ARGUMENT
If God is the greatest he must exist in reality as this is better than just existing in understanding
Necessary existence is greater than contingent existence – God must necessarily exist
An imperfect being could not have thought of a perfect being on its own
A perfect God that did not exist would be meaningless
Could be subjectively true statements – language game
Liebniz
Anti - Realism
IN OPPOSITION TO THE ONTOLOGICAL ARGUMENT
Cannot define something into existence - Gaunilo
Just because a subject has a predicate it does not mean they both exist
Existence is not a real predicate because it does not describe the subject
Existence means occupies space in the world
Necessary existence is an incoherent concept
Hume

2. WHO SAID THIS… Anselm Aquinas Kant Malcolm Moore Descartes Liebniz1
God is that which nothing greater can be conceived
Anselm 2
Transitional error
Aquinas 3
Existence is obviously not a real predicate
Kant 4
A necessary being cannot not exist
Malcolm 5
Some tame tigers do not growl, some tame tigers exist
Moore 6
Humans are imperfect, therefore they could not have thought of a perfect being by themselves
Descartes 7
A perfect God that did not exist would be meaningless
Liebniz 8
The analogy of the perfect island
Gaunilo 9
Necessary existence is an incoherent concept
Hume 10
We should be suspicious of arguments that ‘lack a single piece of data from the real world’
Dawkins

3. THE ONTOLOGICAL ARGUMENT
KEY IDEA
You cannot define something into existence, you need evidence
God is that which nothing greater can be conceived – God is the best thing
It is better to exist in reality and understanding than in understanding alone – for God to be the best, he must exist in both
Gaunilo
Inseparable predicates do not prove existence, they only tell us what something would be like if it did exist
Necessary and Contingent
Kant 1
WHY DOES THE ARGUMENT COLLAPSE?
Necessary existence is better than contingent existence – God must have necessary existence and a necessary being cannot not exist
If existence is not a real predicate then it is not analytically true that a ‘perfect’ God must exist
Kant 2
Existence is not a real predicate of perfection or anything else