Weber extends his analysis to uncover the characteristics of legal auth¬ority, the forms of behaviour that best suit the maintenance and enhance¬ment of legal authority. Systems of laws, he says, may be rational or irrational, formal or substantive. In a rational system, decisions are made by following rules and procedures for classes of cases rather than seeing each case as unique and establishing ad hoc rules of judgment for every new case. Systems are substantive if they appeal to rules or beliefs outside the system of law itself (for example, religion); they are formal to the extent that the definitions and beliefs involved in making judgments are defined by law itself (Cotterrell 1984). A formally rational system of criminal law, then, would have a set of definitions of crimes and a set of rules of adjudi¬cation, and a formally rational penal code would complement this with a prescribed set of penalties. Weber sees formal rationality as the best prin-ciple for the formulation and operation of law (and other subsystems of authority and government) in modern capitalist societies. The character¬istics of formally rational systems, of proceeding according to rules, of authority being vested in roles rather than persons qua persons he calls bureaucratic rationality, and he sees this as an essential feature of an efficient, legitimately governed, modern state.