is many-histories?”) The bottom or maximally divided level consists of
microstates which can be counted by the formula W = exp (S/k), where S = entropy, k = Boltzmann’s constant (approx 10^-23 Joules/Kelvin) and W = number of worlds or macrostates. The number of coarser grained worlds is lower, but still increasing with entropy by the same ratio, ie the number of worlds a single world splits into at the site of an irreversible event, entropy dS, is exp(dS/k). Because k is very small a great many worlds split off at each macroscopic event.
