On the influence and effects on policies of economic ideas and theories
In this volume we have been concerned primarily with the influences and forces shaping economic theories and the major changes and choices in them, that is, with the origins, sources, or even 'causes', of changes and revolutions in economic theories, rather than with the influence and effects of such theories and ideas on policies. But these complex forces and influences are to some extent mutually interdependent; and what effects, in turn, economic theories are thought to be having, or going to have, on policies, has some part in the shaping and changing of these theories. So before summing up some conclusions in the next chapter we would like to look very briefly at the question as to how far economic ideas and theories may be said to have influenced and shaped policies. Various sweeping, but contrasting, generalisations have been put forward regarding this latter relationship.
Historians of ideas and of science, on the one hand, and economic historians on the other, will, as such, start with different interests and approaches regarding the history of economic thought and its relation with and effects on economic policies: for the historian of ideas, or of science, the history of 'economic thought', in any sense of that term, is not necessarily dependent for its value or interest on the existence, or on a belief in the existence, of any close or significant relationship between economic thought and policy, or on the determination, or partial determination, of policies by 'thought'. The historian of ideas can simply be satisfied with, for example, Clerk Maxwell's claim that: 'The history of the development, whether normal or abnormal, of ideas is of all subjects that in which we, as thinking men, take the deepest interest.'
Certainly the effect that many or most economists want, or try, to exercise on policy, or which they think, or claim, they are exercising or have exercised, may add an intriguing dimension to the interest in 'economic thought' of the historian of ideas. But it is not necessary for his interest for him to believe that economists actually have had any significant influence on policies.