F = the fraction of possible worlds in which a statement is true. F can be exactly 0 or 1.
If “possible world” means “any imaginable world history which is consistent with our knowledge”, F and B will probably collapse into one concept.
If it means “any world history which is consistent with logic, some specified set of physical laws and initial conditions given in one moment”, and if we expect the laws to be deterministic, then F1 would also be 0 or 1 and not 0.5.
I would like to see your definition of “possible world”.
If “possible world” means “any imaginable world history which is consistent with our knowledge”, F and B will probably collapse into one concept.
If it means “any world history which is consistent with logic, some specified set of physical laws and initial conditions given in one moment”, and if we expect the laws to be deterministic, then F1 would also be 0 or 1 and not 0.5.
I would like to see your definition of “possible world”.