WHY EQUILIBRIUM STATISTICAL-MECHANICS WORKS - UNIVERSALITY AND THE RENORMALIZATION-GROUP

Discussions of the foundations of Classical Equilibrium Statistical Me chanics (SM) typically focus on the problem of justifying the use of a certain probability measure (the microcanonical measure) to compute a verage values of certain functions. One would like to be able to expla in why the equilibrium behavior of a wide variety of distinct systems (different sorts of molecules interacting with different potentials) c an be described by the same averaging procedure. A standard approach i s to appeal to ergodic theory to justify this choice of measure. A dif ferent approach, eschewing ergodicity, was initiated by A. I. Khinchin . Both explanatory programs have been subjected to severe criticisms. This paper argues that the Khinchin type program deserves further atte ntion in light of relatively recent results in understanding the physi cs of universal behavior.