Boltzmann and Gibbs: An attempted reconciliation

Abstract There are three levels of description in classical statistical mechanics, the microscopic/dynamic, the macroscopic/statistical and the thermodynamic. At one end there is a well-used concept of equilibrium in thermodynamics and at the other dynamic equilibrium does not exist in measure-preserving reversible dynamic systems. Statistical mechanics attempts to situate equilibrium at the macroscopic level in the Boltzmann approach and at the statistical level in the Gibbs approach. The aim of this work is to propose a reconciliation between these approaches and to do so we need to reconsider the concept of equilibrium. Our proposal is that the binary property of the system being or not being in equilibrium is replaced by a continuous property of commonness .