IT is not surprising that classical Political Economy should have stirred its age, and exerted an influence which was revolutionary both to traditional notions and to traditional practice. In the history of thought in the social sciences its arrival was epoch-making because it created the concept of economic society as a deterministic system : a system in the sense that it was ruled by laws of its own, on the basis of which calculation and forecast of events could be made. For the first time a determinism of law in the affairs of men was demonstrated to exist, comparable to the determination of law in nature.