Mainstream historians in recent decades have often treated formal categories and rules as something to be 'used' by individuals, as one might use a stick or stone, and the gains of an earlier legal history are often needlessly set aside. Anthropologists, meanwhile, have treated rules as analytic errors and categories as an imposition by outside powers or by analysts, leaving a very thin notion of 'practice' as the stuff of social life. Philosophy of an older vintage, as well as the work of scholars such as Charles Taylor, provides fresh approaches when applied imaginatively to cases beyond...