Abstract

This article considers the Gibbs paradox and its implications for three definitions of entropy in statistical mechanics: the “classical” Boltzmann entropy ; the modified Boltzmann entropy that is usually proposed in response to the paradox ; and a generalized version of the latter. It is argued that notwithstanding a recent suggestion to the contrary, the paradox does imply that SB1 is not a satisfactory definition of entropy; SB2 is undermined by “second-order” versions of the paradox; and SB2G solves the paradox but is not a satisfactory definition of entropy.