do not use 'p is (metaphysically) possible' to mean 'p is not ruled out by the laws of physics'. If they did, then they wouldn't understand anthropic arguments that presuppose the contingency of the physical laws themselves.

If that is meant to indicate there is some specific sense of possible that is used instead, I doubt that. Consider the following:

• A: "Are perpertual motions machines possible?"

• B: "I don;t see why not"

• A: "Ah, but theyre against the laws of thermodynamics <explains them>"

• B: "Ok, they.re impossible".

• A: "But could the laws of phsyics have been different..?"

• B: "I suppse so. I don't know what makes them thew way they are".

AFAICS, B has gone through as many of 3 different notions of possibility there.

But you still haven't explained what a 'merely possible' thing is.

I don't think there is "mere" possibility, if it means subtracting the X from "something is X-ly possible if it is allowed by X-ical laws".

If logical and nomological possibility are metaphysical, then you owe us an account of what kinds of beings or thingies these possibilia are. On the other hand, if you reduce logical and nomological possibility to epistemic possibility

What they are would depend on the value of X. Family resemblance.