Some of the laws of physics could change from universe to universe, but there must be some laws that remain invariant across the entire multiverse because without rules it would behave chaotically and if the multiverse behaved that way so would all the universes in it, including ours. However there is order in our universe, but what is fundamental and what is not? I think we probably all agree that purely mathematical things like pi or e would remain constant in all universes, but consider some of the physical things that might change:
The Planck constant. The speed of light. The gravitational (big G) constant. The mass of the electron, proton, and neutron. The electrical charge on the proton and electron.
The inverse square law of gravity and electromagnetism. The conservation of Mass-energy, momentum, angular momentum, spin and electrical charge.The relative strength of the 4 forces of nature. The number of large dimensions in a universe.
The Hubble constant.
The ratio of baryonic matter to dark matter and dark energy.
It seems to me that the speed of light and Planck’s constant may be more fundamental than other “constants” and the basic structure of the laws of physics may be more fundamental than the constants they use. But I could be wrong, perhaps the things that always remain the same are none of the above and we haven’t even discovered them yet.
Some of the laws of physics could change from universe to universe
I will assume that by “universe” here you mean “Everett branch”.
I agree that they could (with low probability), just as they could slowly change over time or be different billions of light years away. This is a possibility because our reality has a property that physicists call locality. What I object to is the belief, which more than a handful of LW and SL4 participants hold, that there is something about many worlds (or about quantum mechanics for that matter) that increases the probability of stuff like that happening above what it would be if our reality had this locality property but no Everett branching.
should increase the probability we assign to stuff like that happening.
Some of the laws of physics could change from universe to universe, but there must be some laws that remain invariant across the entire multiverse because without rules it would behave chaotically and if the multiverse behaved that way so would all the universes in it, including ours. However there is order in our universe, but what is fundamental and what is not? I think we probably all agree that purely mathematical things like pi or e would remain constant in all universes, but consider some of the physical things that might change:
The Planck constant. The speed of light. The gravitational (big G) constant. The mass of the electron, proton, and neutron. The electrical charge on the proton and electron. The inverse square law of gravity and electromagnetism. The conservation of Mass-energy, momentum, angular momentum, spin and electrical charge.The relative strength of the 4 forces of nature. The number of large dimensions in a universe. The Hubble constant. The ratio of baryonic matter to dark matter and dark energy.
It seems to me that the speed of light and Planck’s constant may be more fundamental than other “constants” and the basic structure of the laws of physics may be more fundamental than the constants they use. But I could be wrong, perhaps the things that always remain the same are none of the above and we haven’t even discovered them yet.
John K Clark
I will assume that by “universe” here you mean “Everett branch”.
I agree that they could (with low probability), just as they could slowly change over time or be different billions of light years away. This is a possibility because our reality has a property that physicists call locality. What I object to is the belief, which more than a handful of LW and SL4 participants hold, that there is something about many worlds (or about quantum mechanics for that matter) that increases the probability of stuff like that happening above what it would be if our reality had this locality property but no Everett branching.
should increase the probability we assign to stuff like that happening.
There is also the