Christians, what is your VERY BEST arguments for the existence of God?

[BioLogos]

Intuition is a priori. The Ontological argument has other holes, and I'm not aware of any prominent religious philosophers who still consider it a valid argument; certainly not a proof.

It essentially says "if we can conceive of a being such as God, he must exist" by reasoning that to exist in reality is greater than to just exist in the mind, and God is a perfect being, so he must exist in reality. It's a circular argument brought about by the fact that you are using the definition of an idea to conclude that the idea is existent in reality, which doesn't work. Ideas only have a basis in the mind; they do not have to be true manifestations in physical reality.

I should probably point out the famous parody of this argument, the ontological argument for the non-existence of God.

1. The creation of everything in existence is the most marvelous achievement imaginable.
2. The merit of an achievement is the product of (a) its intrinsic quality, and (b) the ability of its creator.
3. The greater the disability (or handicap) of the creator, the more impressive the achievement.
4. The most formidable handicap for a creator would be non-existence.
5. Therefore if we suppose that everything is the product of an existent creator, we can conceive a greater being — namely, one who created everything while not existing.
6. Therefore, God does not exist.

It doesn't work of course, since it relies on the same faulty logic as the original, but that is the point of a parody. You can reason anything into existence (or non-existence) this way...you just have to rely on bad logic.

You think this is a serious response to the Ontological Argument? The argument is logically incoherent.

You need to read some more philosophers of religion if you think no prominent philosophers consider it a valid argument - eg, Plantinga with his modal argument comes to mind. The problem with the argument is that the possibility premise is very difficult to get a handle on. However the argument is useful in showing that a maximally great being's existence is either necessary or impossible.