 Some have suggested that they need not be. John Rawls argued that questions about the system of ownership are secondary or derivative questions, to be dealt with pragmatically rather than as issues in political philosophy (Rawls 1999, pp. 235–42). Although every society has to decide whether the economy will be organized on the basis of markets and private ownership or on the basis of central collective control, there was little that philosophers could contribute to these debates. Philosophers, Rawls said, are better off discussing the abstract principles of justice that should constrain the establishment of any social institutions, than trying to settle a priori questions of social and economic strategy. His own suggestions favoring the institutions of ‘a property-owning democracy’ are put forward more as intermediate principles than as fundamentals of justice.