Ontological Arguments

Question 1

What is Anselm’s Ontological argument?

Answer 1

P1. God is the greatest conceivable being
P2. He does not lack any perfection
IC. It is greater to consist in reality than to exist only in the mind
C. Therefore, God must exist

Question 2

What is Guanilo’s objection to Anselm’s argument?

Answer 2

1. You could prove anything why is ‘more excellent’ must exist by this argument
2. I can conceive of an island that is greater than any other island. And so, such an island must exist as it would make it less great if it didn’t. This is ridiculous and so the ontological argument must be flawed.

Question 3

What is Anselm’s reply to the objection?

Answer 3

1. Said his argument only worked with God (not the island)
2. God has a criteria (omnipotent etc.) whereas an island doesn’t.
3. An island is dependent on other things in order to exist (sea, land and so on)
4. What would make it the greatest conceivable island? Everyone has a different criteria.

Question 4

What is Descartes’ ontological argument?

Answer 4

P1. I have an idea of God
P2. The idea of God is that of a supremely perfect being.
P3. A supremely perfect being does not lack any perfection
IC. Existence is a perfection
C. Therefore, God must exist

Question 5

What is Malcolm’s ontological argument?

Answer 5

P1. For any true or false statement there are 4 possibilities; that it is contingently true, contingently false, necessarily true or necessarily false.
P2. The statement ‘God exists’ cannot be contingently true or false as this would make Him dependent on other things which is logically impossible.
P3. Therefore, it must necessarily true or false.
IC. ‘God exists’ does not have a contradiction so it cannot be necessarily false.
C. Therefore, ‘God exists’ must be necessarily true.

Question 6

What is Descartes’ trademark argument?

Answer 6

P1. The cause of anything has to be at least as perfect as its effect
P2. We, as humans, have the idea of God who is a perfect being
P3. Our ideas must have a cause
P4. We cannot cause our own ideas as we are not as perfect as it’s effect and are not perfect beings
IC. God, who is a perfect being, must have caused the perfect idea
C. Therefore, God exists.

Question 7

Outline Plantinga’s ontological argument

Answer 7

P1. If something is logically possible, there is a possible world where it is true.
P2. If something is logically impossible (e.g. a contradiction) then there is no possible world where it is true.
P3. If something is necessarily true then it must be true in all possible worlds.
P4. It is logically possible for a necessary being to exist.
P5. There is a possible world where a being necessarily exists.
IC. A necessary being must exist in all possible worlds
C. Therefore, God exists (in this world)

Question 8

What is Hume’s objection to the ontological argument?

Answer 8

1. In order for something to be necessarily true, there would be a contradiction if denied.
2. Denying that God exists does not lead to a contradiction.
3. Therefore, to say it’s necessarily true that God exists is incorrect