  He then considered adding a demon, and applied the same argument to the combined system of engine and demon. Now he concluded work can be extracted leaving the molecule in a macrostate occupying the entire box, but only by leaving the demon indeterministically in one of a number of macrostates. The additional statistical entropy of the probability distribution over the demon's macrostates compensates for the entropy reduction in the heat bath. Eliminating the statistical distribution over the demon's states is possible only with the cost of an entropy increase in the heat bath.