Lesson Plan - Ontological Argument for Year 12

The Ontological Argument

The Ontological argument goes as follows:

The concept of God is the concept of a being than which nothing greater can be conceived.

To exist is greater than to not exist

So if God did not exist, one could conceive of a greater being (i.e. an existent God)

Therefore, God exists.

Questions

A valid argument is one in which, if the premises are true, it logically entails that the conclusion is true.

e.g. If A, then B
A
Therefore B

An argument is sound if all of its premises are true and it is valid.


1) Is the argument valid? Is it sound? If not, what premises do you think can be questioned?


Immanuel Kant raised the following objection:

“Being is evidently not a real predicate, that is, a conception of something which is added to the conception of some other thing … Now if I take the subject (God) with all its predicates (omnipotence being one), and say, God is, or There is a God, I add no new predicate to the conception of God, I merely posit or affirm the existence of the subject with all its predicates - I posit the object in relation to my conception.”

2) Do you agree with Kant that existence is not a property?

Some philosophers have tried to rescue the argument from Kant’s objection by arguing that necessary existence is a property, and that this is a more perfect property than non-existence.

3) Do you think this reply helps save the original argument?

4) Does anything strike you as odd about using the properties of God in order to prove his existence?

5) Can you think of any way to save this argument? Do you think the attempt to prove the existence of God ‘a priori’ is a good approach in the first place?