Conclusion Philosophers have only interpreted the world in various ways; the point is, however, to change it. (Karl Marx, Theses on Feuerbach, The German Ideology) The use of ‘top-down’, deductive, models based upon the assumption of selfinterested behaviour is generally held to have transformed the academic study of economics and given it an intellectual status approaching those of the natural sciences (but see Lawson 1997). It is therefore not surprising that economists have attempted to export their methods to the study of politics. Anthony Downs is, for example, quite explicit in his desire to emulate economics. An Economic Theory of Democracy opens with the following observation: Little progress has been made toward a generalized yet realistic behaviour rule for a rational government similar to the rules traditionally used for rational consumers and producers. As a result, government has not been successfully integrated with private decision-makers in a general equilibrium theory. This thesis is an attempt to provide such a behaviour rule for democratic government and to trace its implications. (Downs 1957: 3) Yet public choice theorists have not simply interpreted the world. They have also sought to and succeeded in changing it. In the 1960s and 70s public choice theorists challenged what they saw as a post-war orthodoxy about the need for and benefits of an ‘active’ state. They succeeded in drawing academics’ and politicians’ attention to the failings of the state.