What makes people irrational thinkers?

[LadyForCamus]

I’m curious; why do you believe that the question of the necessity or contingency of physical  reality is a purely philosophical one that science cannot have anything to say about?

How would science go about establishing that physical reality is necessary or contingent? Not saying it's not possible, but it seems like the best we can do is to rely on intuition as to what would do for something to be metaphysically necessary or contingent.

Sure, and likewise, I’m not asserting that it is possible. Rather, I’m pointing out what seems to be an inconsistency in the fact that Hart makes very specific claims about the nature of physical reality in his arguments while simultaneously insisting science can say nothing of these details one way or the other. It seems like the set-up of an escape hatch of sorts so that he can make sweeping assertions about physical reality without having to support them. 

A physical reality comprising of only one universe doesn't feel like a necessary reality because you can reasonably ask yourself the question "why this universe rather than an alternate universe?" or "why one seemingly arbitrary universe instead of multiple universes?" This is the case even under theism. If God is the reason for this one particular physical reality, why this rather than an alternate?*

It seems like the most intuitive way to argue for a metaphysically necessary physical reality is if you postulate that it comprises a network of all metaphysically possible universes or something like that. Then the question of "why this rather than that" starts to feel forced and less reasonable to ask.

If I understand you correctly, that’s more along the lines of what I’m thinking; that there is no alternative to existence, or stuff existing, because non-existence, by definition, cannot exist as an alternative state of affairs. A Necessary physical existence could encompass all possible physical realities. Or at least, I don’t see why it couldn’t.