I’m not sure that comparison works. I can pick any initial universe-configuration and time-evolve it under Newtonian gravitation; a solution will always exist. But if I time-evolve initial conditions under laws that allow backwards time travel, it’s not clear to me that there necessarily exist any solutions. Maybe the Deutsch law forces the superposition to be 50-50, but the other physical laws force it to be 80-20. It may be that the Deutsch law is just a logical consequence of the other physical laws, in which case I think you’d be right. (This all with the caveat that I don’t really know physics, so I’m likely completely wrong.)
I can’t really think about this without having some idea of how it’s chosen which universes are real.
I’m not sure that comparison works. I can pick any initial universe-configuration and time-evolve it under Newtonian gravitation; a solution will always exist. But if I time-evolve initial conditions under laws that allow backwards time travel, it’s not clear to me that there necessarily exist any solutions. Maybe the Deutsch law forces the superposition to be 50-50, but the other physical laws force it to be 80-20. It may be that the Deutsch law is just a logical consequence of the other physical laws, in which case I think you’d be right. (This all with the caveat that I don’t really know physics, so I’m likely completely wrong.)
I can’t really think about this without having some idea of how it’s chosen which universes are real.