where "kB" is Boltzmann's constant, and "ln" is the natural logarithm. "W" is "Wahrscheinlichkeit", a German word meaning the probability of occurrence of a macrostate or, more precisely, the number of possible microstates corresponding to the macroscopic state of a system — the number of (unobservable) "ways" in the (observable) thermodynamic state of a system that can be realized by assigning different positions and momenta to the various molecules. Boltzmann's paradigm was an ideal gas of "N" "identical" particles, of which "N""i" are in the "i"th microscopic condition (range) of position and momentum. "W" can be counted using the formula for permutations