Frege's Ontological Argument

Notes on Joan Weiner's Frege Explained (p.159-161):

1. The ontological argument for the existence of God:

2." God is omniscient", "God exists"...

3. existence is not a property. The predicate 'exists' is actually a natural language expression for a quantifier.

4. To say that a cat exists is not to predicate existence of a particular cat but rather, to say that there exists an X such that X is a cat.

5. To say that God exists is not to predicate a property of God.

6. It is, rather to say something about the concept most perfect being that can be conceived; existence statements are about concepts.

7. There is no property of existence that can be predicated of an object. Thus the argument does not go through.

I first encountered this argument when I read Anscombe. But Weiner 's explanation is more clear and concise.