Ontological argumentsfor God’s existence:

Derived from the Greek terms ontos (being) and logos(reason or rational account)

First developed by Saint Anselm of Canterbury, the argument takes a variety of forms

The common theme among them is that they begin a priori – proceeding from the mere concept of God – and conclude that God must exist

1. Everyone is able to understand by the term “God” a being than which none greater can be conceived

2. So, a being than which none greater can be conceived exists in the mind (the understanding) when one hears about such a being

3. We can conceive of a being than which none greater can be conceived which exists both in the mind and in reality

4. To exist in reality is better than to exist in the mind alone

5. If, therefore, a being than which none greater can be conceived exists in the mind alone and not in reality, it is not a being than which none greater can be conceived

6. Therefore, a being than which none greater can be conceived exists in reality.

1. Everyone is able to understand by the term “Perfect Island” the greatest possible island(GPI).

2. So, a GPI exists in the mind3. We can conceive of a GPI that exists in the

mind and reality4. Existence in reality is greater than existence in

the mind alone5. If a GPI exists in the mind alone, then it is not

the GPI6. Thus, a GPI exists in reality7. But since a GPI does not exist in reality, the

argument structure (which Anselm also utilizes) must be flawed

Existence is not a predicate such that it is a property which can be affirmed of a thing

Existence does not add to the concept of a thing; rather, existence is the instantiation of a thing

The example of a black, existing cat

1. It is possible that a being exists which is maximally great (a being we can call God)

2. So, there is a possible world in which a maximally great being exists

3. A maximally great being is necessarily maximally excellent in every possible world(by definition)

4. Since a maximally great being is necessarily maximally excellent in every possible world, that being is necessarily maximally excellent in the actual world

5. Therefore, a maximally great being exists in the actual world

God’s existence is a logical or metaphysical impossibility

Possible worlds and the semantics they employ are problematic

Fairies, ghosts, gremlins and unicorns can be made “plausible” through the same argumentation (similar to “Perfect Island”)

1. It is possible that a special fairy exists2. So, there is a possible world in which a

special fairy exists3. A special fairy is necessarily a tiny

woodland creature with magical powers in every possible world

4. Since a special fairy is necessarily a tiny woodland creature with magical powers in every possible world, that fairy is necessarily a tiny woodland creature with magical powers in the actual world

5. Therefore, a special fairy exists in the actual world

Is it greater to exist than to not exist, as Anselm claimed? How does your answer affect Anselm’s argument?

Can you conceive of God’s non-existence? If so, what follows from this regarding the ontological argument?

How does the ontological argument differ from other classic arguments for the existence of God?