Predicates: characteristics
A posteriori argument is based on experience or evidence
A priori arguments are based on logic
Logical fallacy: logical problem
Anselm’s ontological argument (Chapter 2)
, - His book is called “Proslogion”
- Chapter 2 = show that God exists
- ‘Something which nothing greater can be thought’.
1. God is defined as the greatest being imaginable.
2. A being that exists both in the mind and in reality, is greater than one that exists
only in the mind.
3. If God only existed in the mind, then we could imagine something greater (a God
that exists in reality).
4. Therefore, God must exist, because otherwise, He wouldn't be the greatest being.
Anselm’s ontological argument (Chapter 3)
In Proslogion (Chapter 3), Anselm argues:
1. God is a being that cannot be thought not to exist (necessary existence).
2. If God could be thought not to exist, He wouldn’t be the greatest being.
3. Therefore, God must exist necessarily—He cannot not exist.
He uses Aristotle’s four categories possible to be, possible not to be, not possible to be,
not possible to not be. He argues that God is a necessary being so comes into not
possible not to be. Which shows God cannot be thought not to exist.
Gaunilo's Criticism
- Was against Anselm.
- He argued it was wishful thinking as not everything can be thought into existence
and that his argument isn’t logical.
- He uses the example of a perfect island, just because it exists doesn't mean it’s
real as we can’t imagine things into existence.
Anselm’s response
- Anselm says the island is contingent (depends on other things for its existence)
- God is a necessary being so doesn’t depend on anything.
Aquinas’ criticisms
- Believed God’s existence could be proved with prosteriori arguments and not priori
alone. We cannot understand the means to what God exists as we don’t have full
knowledge/ limited. So, we don’t know God is the greatest conceived thing
Descartes ontological argument
In his book ‘meditations’ he reformed the ontological argument