The Ontological argument

A priori- not based on experience

Anselm:

♥1st Argument:To the Fool (Psalm 14)

♥Concept of God "that than which nothing greater can be conceived"

♥It is greater to exist in the mind and reality than just in the mind

♥Therefore God exists in reality, because existence is a predicate of perfection

♥2nd Argument: argument from necessity and contingency:

♥Argument doesn't apply to anything but God as they are all contingent whereas God is a necessary being (eternal and transcendent, outside time and space but able to act and create within it)

♥The greatest conceivable being must have necessary existence (it cannot be thought not to exist)

♥A logically necessary being is one whose non-existence is impossible

♥God necessarily exists

(If God exists, he cannot come into existence, nor can his existence cease to be)

Descartes: existence is a perfection that God cannot lack

♥God is defined as a supremely perfect being

Existence is a predicate (attribute/quality/essence) of a perfect being

♥God therefore exists

♥If God didn't exist he would be self-contradictory as he would be imperfect and therefore not God

♥Trying to imagine a God who doesn't exist is illogical as existence is inseperable from "God"

(It is similar to a triangle that has 3 sides and 180 degrees is the sum of the internal angles. These predicates are necessary to the definition of a triangle)

○Gaunilo: Analogy of the Island on behalf of the fool:

We can conceive a perfect Island, than which no greater can be conceived. The "perfect island" could not just exist in the mind, to be "perfect" it must exist in both mind and reality. Reductio ad absurdum- you can conceive things which may not exist in reality. The fool is right to demand proof that God is real in fact, not just by definition as the greatest conceivable being.

However, Gaunilo didn't take into account the difference between contingent and necessary beings

○Kant: Existence is not a predicate as it is not a property or attribute, it is to do with the subkect and existence is a thing including all its attributes.

Strengths

•Logical and decutive- infers existence through definition. Uses reason

•A priori- no physical evidence required

•It uses logical premises people are likely to accept

•Plantinga criticized Gaunilo by saying that Islands have no intrinsic maximum- you could always add more trees/beaches. Also God is maximal greatness meaning he exists in any possible worlds. In a possible world, the maximally great being could exist, and for it to exist, it would have to exist in all possible worlds so it must exist in this world as it is one of many possible worlds.

Weaknesses:

•Kant, Gaunilo

•Hume: not possible to take an idea out of the mind and apply to pure logical and reach a conclusion external to the universe. It comes from a perspective of prior belief. All existential propositions are synthetic (true or false based on experience) and can't be predicates.

•Bishop Berkely: if we dismiss the predicate (Existence) and the subject (God) then there is no contradiction