A closely related paradox to the Gibbs paradox is the mixing paradox. The Gibbs paradox is a special case of the "mixing paradox" which contains all the salient features. The difference is that the mixing paradox deals with arbitrary distinctions in the two gases, not just distinctions in particle ordering as Gibbs had considered. In this sense, it is a straightforward generalization to the argument laid out by Gibbs. Again take a box with a partition in it, with gas A on one side, gas B on the other side, and both gases are at the same temperature and pressure. If gas A and B are different gases, there is an entropy that arises once the gases are mixed, the entropy of mixing. If the gases are the same, no additional entropy is calculated. The additional entropy from mixing does not depend on the character of the gases; it only depends on the fact that the gases are different. The two gases may be arbitrarily similar, but the entropy from mixing does not disappear unless they are the same gas – a paradoxical discontinuity.