Why not deism?

[Inqwizitor]

So, there is no sufficient reason for all possible worlds? I must be missing something. How does that pass the PSR? If we expand all possible worlds to some "megaverse" — what is the reason it exists? I feel like we need some starting point in any case.

I'm not sure if you're understanding my view correctly. If you replace "megaverse" with "God", what is the reason "God" exists? Whatever that reasoning you use to answer that question can probably be applied to the "megaverse" as well, unless you resort to special pleading that is.

The way I look at it is:

If you remove all things in existence, you're left with absolute nothingness which somehow ... exists. Can we make sense out of that? I don't think so, so it would be better to say that something is necessary to exist. But then the next question would be: what form must this something take? Why can't it take another form instead?

In answer to that question, I feel modal realism addresses it satisfactorily by positing that all possible worlds must be actual. So it isn't that there is a concrete reason we can pinpoint at and say that's why this exists. Rather, if we get rid of the "megaverse", then why do we have some worlds actual but not others? The more complete the answer, the better. The PSR perhaps may never be fully satisfied per the wording of the principle (if we're going with the most stringent possible), but if you have some respect for the PSR nevertheless, what more satisfactory answer is there?

Some naturalists are fine with the universe just is, and that's fine. They don't care about the PSR. You and I, on the other hand, do.

I think I get it. So the megaverse is actually metaphysically necessary?

I need to do some more reading.