Eckard,
"Are you aware of On the So-Called Gibbs Paradox, and on the Real Paradox?"
The Author Arieh Ben-Naim briefly mentions, as a side issue, the real papradox but does not address it except to say that examples of real world discontinuity are observed.
The 'real' paradox has to do with the mathematical derivations of entropy and getting them right. is isolated in the ideal gas example that I gave. The author moves from one type of circumstance to another without connecting them. One example is when he states that "However, for ideal gases, the mixing, in itself, does not play any role in determining the value of the so-called entropy of mixing. Once we recognize that it is the expansion, not the mixing, which causes a change in the entropy, then the puzzling fact that the change in entropy is independent of the kind of molecules evaporates." He has to state clearly that all examples are of the adiabatic type.
The example of two distinguishable ideal gases, as I gave in my essay, does not cause a change in entropy whether one refers to mixing or expansion. I fail to see how he see a difference in expansion versus mixing in this same type of example. Mixing entroy cannot be dismissed as lightly as he thinks. It is an important theoretical foundation statistical mechanics and quantum theory. Its mathematical form repeats itself in derivations of entropy up to and including Shannon's information entropy.
I wondered how to respond with details of my own but couldn't see how to address all of the shortcomings that I feel exists in that article. I am thinking that I could write a few messages in my forum here that address some of the issues without direct reference to his article. There are many articles written to address the Gibb's Paradox. I could combine the major issues raised in these articles and address them myself. I think that in my essay I chose the best example for representing the paradox. It was not one chosen by the author to address in detail.
James Putnam