Originally posted by DeepThoughtI understand all that, but I still do not understand your account of accidental necessity. According to your account, something is accidentally necessary at T if it is necessary in all members of A. In what sense is the second instance of 'necessary' to be understood here?
On the assumption that the universe isn't deterministic the future isn't set so any event in the future would not necessarily happen in all the possible worlds in A. In Plantinga's example, assume the Ants moved in earlier today (Wednesday), I can't remember if he specified the day. Paul may or may not mow his lawn on Sunday. So there's a subset of po ...[text shortened]... e other possible worlds in not having a set future. I don't know how much of a problem that is.
How is this account supposed to capture accidental necessity of the past? Consider some past state E. That past state E will of course, by definition of A, be represented in all members of A. According to your account, E is accidentally necessary if it is necessary in all members of A. If A is comprised of the actual world only, then your account boils down to saying that E is accidentally necessary if it is necessary. But that just sounds like a trivial implication, not a substantive account of what accidental necessity of the past consists in. If A has distinguishable members (differing in their future states), then your account says that E is accidentally necessary if it is necessary in all these worlds. Again, it is hard to avoid the conclusion that this is a rather trivial implication. The point of a working account of "accidental" necessity is that it should explicate how things that are otherwise contingent should be thought of as in some other sense necessary; not that it just affirms that things that are necessary are also accidentally necessary. So, I'm not getting it.
I would think a better approach to "accidental" necessity of the past would need to include counterfactual analysis. Something like Plantinga's approach but perhaps more general than his agency description. The key, I would think, is that something that has the "accidental" necessity of the past needs to be immune from the possibility of future eventuation(s), such that the nearest-by worlds wherein any of these future event occur are worlds where this past event is not represented, or some such.