Why not deism?

[GrandizerII]

It's one alternative possible explanation, and I don't see how it must go beyond naturalism. It is possible for natural reality to be all there is and for its existence to be a logical/metaphysical necessity. You seem to be defining nature in a way that does not go beyond the observable subset of reality, but that doesn't necessarily make what's outside of this subset of reality spiritual or of a qualitatively different kind of reality.

The modal realist postulation should be seen as an extension of what we see, rather than a "beyond nature" kind of thing.

ETA: The point is you don't know whether nature is metaphysically contingent or not, and you shouldn't confidently make a statement like that.

What you seem to be defining as naturalism is what I've understood as monism: there is one kind of reality. Naturalism, as I understand it, is the belief that our space-time continuum — the physical phenomena and laws that we know in this world, as they are in location and sequence — are the extent of existence.

Whatever you wish to call it, it is not theism/deism of any sort.

If physics is the same in every logically possible world — that it's like physical copies of this universe with all logically possible outcomes in location and sequence — then I think we're equivocating logical and physical possibility. It is conceivable there are other worlds that have the same physics as ours, but a different space-time, like a set of mirrors of how things in our own world could have been. My understanding is that what constitutes nature in our world, the physical matter and laws, could logically be entirely different in other worlds. In that case, what is natural there is not natural here.

I do agree I should be more careful when I say "logically possible" because what I mean by "logically possible" is really more like "physically/metaphysically possible". Something that is conceivable does not necessarily mean it's physically/metaphysically possible.

Yes, I'm aware there's also a distinction between physical and metaphysical possibility, but my point is that according to the version of modal realism I'm talking about, whatever world that can be actualized in this reality is actualized. I'm not suggesting a David Lewis kind of modal realism, but more of a modernized Max Tegmark type (though I'm not sure about the whole Platonic mathematical structure bit). Either way, this is a good alternative to theism and actually, even better than theism if you wish to go beyond the PSR and argue that every "unactualized" world must have a sufficient reason for it not being actualized.

Or it may very well be, that this actual world we're in is the only world that could ever be actual, hence this is what we have. It may be that the only way for existence to actualize is to actualize as the "maximal world of some sort" (something similar to how Leibniz, if I remember correctly, argued this world is the best of all possible worlds). Or this world just somehow is (even if it's not satisfactory, we can't logically rule this out). So who knows at the end of the day? Using the power of imagination, you can come up with plenty of alternative explanations that doesn't require God. Theism/deism is, in fact, extraneous compared to some of these more naturalistic alternatives.