Definitions

Ontological: From the Greek "ontos" meaning being. Relating to existence or being.

A priori: Knowledge that comes from reason alone, without needing experience.

Analytic: A statement that is true by definition.

Necessary existence: Existence that cannot not exist.

The Argument

The ontological argument tries to prove God exists using pure logic and the definition of God. It says:

  1. God is defined as the greatest possible being
  2. A being that exists is greater than one that doesn't exist
  3. Therefore, God must exist
Pure Logic

This argument doesn't rely on evidence or observation. It claims to prove God's existence through pure logical reasoning.

Anselm's Version

The Definition

Anselm defined God as "that than which nothing greater can be conceived."

The Logic

If we can conceive of God existing, then God must exist, because:

  • A God that exists is greater than a God that doesn't exist
  • If God didn't exist, we could conceive of something greater
  • But God is the greatest conceivable being
  • Therefore, God must exist
Why is this argument appealing?

Problems with the Argument

Existence is Not a Property

Kant argued that existence is not a property that makes something "greater." Saying something exists doesn't add to its qualities.

What does this mean?
The Island Example

Gaunilo used the example of a perfect island. If we can conceive of the most perfect island, does that mean it must exist?

How does this refute the argument?
Begging the Question

The argument assumes what it's trying to prove. It defines God in a way that includes existence.

What is begging the question?

Conclusion

The ontological argument is clever but flawed. It tries to prove God's existence through pure logic, but most philosophers think it fails because it assumes what it's trying to prove.

The Bottom Line

While the argument is intellectually interesting, it doesn't successfully prove God's existence. It's more of a thought experiment than a solid proof.