Scott,
I'm saying that the traditional principle of the causal closure of the physical, taken to apply generally as a principle of causal closure of any ontological domain, is neutral as to what "the universe" is. That principle, however, implicates that whatever universe we inhabit, that universe cannot be affected by nor affect any other universe. In effect, therefore, we have what I call a causally monistic universe. So, the universe could be mathematical or physical but not both.
With the proposed adjustment of the definition of the principle of causal closure, however, the eventuality of two adjoining universes of different ontological types, is consistent with the principle of causal closure. The thing, now, which is the object for scientific ontology as I define it, is to theoretically account for the possibility of an interface between two ontologically different universes (say, a mathematical universe and a physical universe). On that ontological basis, the next step - for physics - is to determine if there is an actual interface preceding the physical universe.
To answer your question as I see it a physical model cannot account for a consistent theoretical model on an ontological level. A physical model, however, could show that a specific description of an interface is physically impossible. Before that, naturally, scientific ontology must come up with such description. As I am working on one right now I take the opportunity to ask the reader for advice as how to possibly have an endorsement from an arxiv.org user to submit an article to category physics.gen-ph.
