I would agree that there are different variations on the multiverse theory, more than the ones you listed, and that they will give different answers. Of course, within our sufficiently narrowly defined “universe” we like to believe that there are universal laws (including even some constants) that apply everywhere, although we do not know that for sure.
Regarding gravity more particularly, yes the examples I gave involved surface applications. I regularly tell students that the fact that a helium balloon floats upward does not prove that the law of gravity is false.
However, there is a higher level problem, that general relativity, and especially its parts dealing with gravity, remain unreconciled clearly with other parts of apparent physical law, notably quantum mechanics, with the clearest surface manifestation of the problem being the continued inability to “unite” gravity with the other three basic forces (which have been pretty much shown to be “unitable” within existing frameworks). Of course this is what string theory, quantum loop theory, and some other candidates have been trying to achieve, but the failure to clearly find such a GUT leaves a certain level of doubt at a very fundamental level regarding the complete universality of the “law of gravity” in its general relativistic conceptualization.
Eliezer,
I would agree that there are different variations on the multiverse theory, more than the ones you listed, and that they will give different answers. Of course, within our sufficiently narrowly defined “universe” we like to believe that there are universal laws (including even some constants) that apply everywhere, although we do not know that for sure.
Regarding gravity more particularly, yes the examples I gave involved surface applications. I regularly tell students that the fact that a helium balloon floats upward does not prove that the law of gravity is false.
However, there is a higher level problem, that general relativity, and especially its parts dealing with gravity, remain unreconciled clearly with other parts of apparent physical law, notably quantum mechanics, with the clearest surface manifestation of the problem being the continued inability to “unite” gravity with the other three basic forces (which have been pretty much shown to be “unitable” within existing frameworks). Of course this is what string theory, quantum loop theory, and some other candidates have been trying to achieve, but the failure to clearly find such a GUT leaves a certain level of doubt at a very fundamental level regarding the complete universality of the “law of gravity” in its general relativistic conceptualization.