1. The Ontological Argument
Must God logically exist?

2. The Ontological Argument
Four main contributors to the argument
Anselm
Descartes
Gaunilo
Kant

3. The Ontological Argument
An a priori argument
Based on innate knowledge
logic
Attempts to prove existence of God from the meaning of the word ‘God’
Depends on a particular understanding of God

4. St Anselm of Canterbury
Book – Proslogion

5. Classical concept of God
Omnipotent
All powerful
Can do anything
Omniscient
Knows all things, past, present and future
Omnipresent
Present at every place at same time

6. Anselm’s first argument
Anselm defined God as:
‘that than which nothing greater can be conceived’
Everyone must have a definition of God
Even the atheist
Therefore God exists in the mind
Just as dragons exist in the mind
And therefore:
God must exist in reality because He is:

7. Gaunilo’s objection If I were to describe the most perfect Island
Then state that it must exist because of its perfection
You would be a fool to believe me

8. Criticism of Gaunilo Not comparing Like with Like Anselm talks of
‘that than which nothing greater can be conceived’
A greater Island can always be conceived

9. Anselm’s second argument
Must be more to God than fact that He exists
That would make him similar to us
Therefore God must be ‘necessary’
That is there is no possibility of Him not existing

10. Anselm’s second argument
It can be conceived that something exists that cannot be thought not to exist
God must be such a thing if He is
‘that than which nothing greater can be conceived’
This is because something that can be thought not to exist would be inferior to that which cannot

11. Descartes

12. Descartes argument God is a supremely perfect being
Existence is a predicate of a perfect being
PREDICATE - the part of a sentence in which something is said about the subject
Trying to image God without the predicate of existence is illogical
Like a triangle without 3 sides

13. Kant

14. Kant’s objection Opposed Descartes Triangles
If you dismiss the idea of 3 sides (predicate)
And you dismiss the idea of the triangle (subject)
There is no contradiction
You can define a thing as you think fit
But that does not mean it exists

15. Kant’s objection Opposed Anselm Existence is not a predicate
To say that X exists tells you nothing about X
A predicate must say something about X
‘X is’ does not tell us anything about X
If ‘X exists’ tells us about a property of X then ‘X does not exist’ must tell us what X lacks
However, how can something that does not exist lack anything?

16. Putting it together
Write bullet points that show how you would go about answering the following exam question:
(a) Explain the traditional forms of the ontological argument put forward by Anselm and Descartes (33)
(b) ‘The criticisms presented by Gaunilo and Kant successfully reject these arguments.’ Discuss (17)