It seems like “equally probable MWI microstates” is doing a lot of work here. If we have some way of determining how probable a microstate is, then we are already assuming the Born probabilities. So it doesn’t work as a method of deriving them.
Well, microstates come before probabilities. They are just there, while probabilities are in the model that describes macrostates (emergence). This is similar to how one calculates entropy with the Boltzmann equation, assigning microstates to (emergent) macrostates, S= k ln W. But yes, there is no known argument that would derive the Born rule from just counting microstates. Anything like that would be a major breakthrough.
It seems like “equally probable MWI microstates” is doing a lot of work here. If we have some way of determining how probable a microstate is, then we are already assuming the Born probabilities. So it doesn’t work as a method of deriving them.
Well, microstates come before probabilities. They are just there, while probabilities are in the model that describes macrostates (emergence). This is similar to how one calculates entropy with the Boltzmann equation, assigning microstates to (emergent) macrostates, S= k ln W. But yes, there is no known argument that would derive the Born rule from just counting microstates. Anything like that would be a major breakthrough.