The Ontological Argument

Ontological argument - Arguments for the existence of God beginning with the concept of God and making claims about the world based on it. Based on a priori reasoning. 

Anselm

• God is 'that than which nothing greater can be conceived'
• Even the fool who says 'God doesn't exist'
• Existence must be a part of God's greatness, therefore...

God Must Exist

1. GOD IS: That which nothing greater can be conceived

2. GOD: Exists in the mind

3. GOD: Exists in reality

4. If a concept in your mind could be real it could be greater

5. Suppose God only exists in the mind

6. GOD: Could have been greater than he is

7. A greater being than God is possible

8. A greater being than that than which nothing greater can be conceived is possible?

9. CONTRADICTION!!!

10. FALSE: That God exists in the mind

11. GOD: Exists in reality

Gaunilo

"Imagine an island of which no greater could be conceived"

Contingency - Dependant/Doesn't have to be true

Vs

Necessity - Necessary for God to exist because there must be a greatest possible being

Descartes

"Existence can no more be separated from the essence of God than can its having 3 angles equal to 2 right angles be separated from the essence of a triangle"

• To think of a triangle you have to think of 3 sides and 3 angles.
• But this is irrelevant to whether they exist or not.
• Existence can be added to them, but their concept is the same.

God is perfect and if he did not exist he would lack perfection.

Therefore existence is a property of a perfect being.

Kant argues...

Existence is not a part of God's concept. To say that 'God…