*Quick thought. For kicks (sort of). In draft.*
Plantinga's modal ontological argument aims to demonstrate the existence of a modally ultimate being, upon which all else depends for its existence. But the argument seems to require an ontologically prior Platonic modal space, of which God's existence is a function (of its existence and structure).[1] To see this, just think about
the way in which Plantinga's ontological argument proceeds, and its ontological underpinnings. On such a view, abstract objects are fundamental, and God is an intermediary,
derivative layer of reality -- sandwiched between the layers of necessary
abstracta and contingent
concreta -- contrary to the aims of the argument (and to the Aseity-Sovereignty doctrine).
The theist might try to avoid this implication via theistic activism. But if the theist goes this route, then
the bootstrapping problem rears its ugly head, in addition to other problems (e.g.,
the Benacerraf problem for God's knowledge of abstracta, etc.). On the other hand, if the theist takes the theistic conceptualist route, then this also leads to the bootstrapping problem and other problems (e.g., concepts are concrete, non-repeatable entities, and therefore not suitable to play the role of
abstracta). On yet a third hand, if the theist goes the nominalist or fictionalist route, then
the ontological argument fails. But this exhausts the relevant possibilities for the theist regarding
abstracta: straight platonism, theistic activism, theistic conceptualism, nominalism, and fictionalism/pretense theory.[2], [3]
There is thus non-trivial pressure to think that Plantinga's ontological argument succeeds only if the being it proves to exist is not ontologically ultimate, but rather one that supervenes on an ontological foundation of platonic modal space.
[1] Rather like a modal analogue of the way in which (some
argue that) our universe is a function of the nature and structure of relativistic quantum fields.
[2] Hybrid views tend to
take on board the problems of pure views.
[3] Strictly speaking, other views are epistemic possibilities (e.g., structuralism) -- but seem to succumb to similar problems.
[4]
Such a being would be what I have elsewhere called a necessary dependent being, and the platonic modal space on which it depends would be what I have elsewhere called a necessary independent being.