 This charge is less acute than it appears at first glance. First, it is important to emphasise that it is not the sheer number of applications that make a physical concept important, but whether there are some important systems that are ergodic. And there are examples of such systems. For example, so-called ‘hard-ball systems’ (and some more sophisticated variants of them) are effective idealizations of the dynamics of gas molecules, and these systems seem to be ergodic;for details, see Berkovitz, Frigg and Kronz 2006, Section 3.2, Vranas (1998) and Frigg and Werndl (2011).