[vinceguidry]

Anselm defined God as "that which nothing greater can be thought." Introducing a devil into this mix doesn't change this reasoning, and basically boils down to "is evil greater than good?", which I don't think anyone can reasonably argue.

It's not the most interesting argument for God I've encountered, but it's not trivially invalidated by elevating evil to the same status as good. That hasn't been a serious element of any real theology since long before the ancient Hebrews.

Theology is the art of imagination, the same way that politics is the art of the possible. Imagining absolute evil is only interesting when you want to attack the idea of absolute good. Absolute good remains interesting without a foil. So therefore people will be willing to believe in it.

[goto11]

The point is that if the ontological argument is valid then you can define all kinds of things into existence also. The devil is just an example, it could also be The Most Perfect Island, The Real Santa Claus and so on. So it is a reductio ad absurdum.

[vinceguidry]

I'm not saying the ontological argument is correct, just that your reasoning doesn't sufficiently refute it.

[goto11]

It doesn't refute it per se. It just shows that The Real Santa Claus also exists by the same token. Which is not really a logical contradiction so if you want to believe that, more power to you.

[vinceguidry]

More generally, you can't attack the reasoning with any amount of imaginary horrors or delights. This is because the ontological argument doesn't try to argue imaginary things that are not God exist. Just that the imagination we have of God does exist, as the greatest thing ever. This is because of God's special property, that of being the greatest thing ever, that any imagination greater would just become the new God.

This property is not shared by things that are not God, such as Santa Claus. So you can't use the ontological argument for God to also show that Santa Claus exists. Santa Claus isn't the greatest thing ever, so Santa Claus isn't bound by the rules of logic to exist.

[vinceguidry]

The real Santa Claus did exist, the one the current myth is based on.

[goto11]

Fair enough, but that is totally beside the point.

[vinceguidry]

Maybe sibling comment is more to your liking.