The Ontological Argument for the Existence of God

[Angrboda]

As is readily evident, each version of the ontological argument rests on the assumption that the concept of God, as it is described in the argument, is self-consistent. Both versions of Anselm's argument rely on the claim that the idea of God (that is, a being than which none greater can be conceived) "exists as an idea in the understanding." Similarly, Plantinga's version relies on the more transparent claim that the concept of maximal greatness is self-consistent.

But many philosophers are skeptical about the underlying assumption, as Leibniz describes it, "that this idea of the all-great or all-perfect being is possible and implies no contradiction."

http://www.iep.utm.edu/ont-arg/  

Additionally, I would make the same objection to Plantinga that I make to Godel's version, namely:

The proof is fatally flawed because it assumes the possible objective existence of positive and negative properties. Properties themselves exist, but they are neither objectively positive or negative. In short, there is no objective, natural ordering of any set of properties such that for any P(i) and P(j) in the set, under all possible worlds, P(i) is more positive than P(j), or vice versa. You can say nothing about the ordering of properties in all possible worlds, therefore it is impossible to postulate a being that is essentially positive (using the definition of "essence" given in the Wikipedia article).

https://atheistforums.org/thread-23216-p...#pid578986

Therefore the concept of a maximally great being that exists in a possible world is either incoherent (my take), or one would have to say there are as many maximally great beings as there are properties, which seems like an absurd result. There would indeed then be a maximally great being whose greatness consisted solely of being the most smelly being.