Equilibrium and uncertainty

This chapter discusses the troublesome relation between equilibrium and uncertainty because these two words are closely related to both the method of The General Theory and the work of Victoria Chick. The issue is this: why use a static concept like equilibrium if the aim of theory is to say something useful about the real world, which is inherently dynamic? There are pragmatic reasons for theorising in terms of static relationships such as the argument that static theories are easier to understand than dynamic ones. Kohn (1986) argues that pragmatism of this kind explains why Keynes substituted the essentially static framework of The General Theory for the dynamic method that underpinned his Treatise on Money (Keynes [1930] 1973). But pragmatism is too simple an explanation for what essentially is a methodological choice. Adopting equilibrium must have added value in terms of explanatory value or descriptive accuracy to warrant the cost of causing a conflict between the assumptions of the theoretical realm (static) and the economic reality which it purports to explain (dynamic). This chapter focuses on the added value of the equilibrium method in Keynesian theory but also in other schools of thought.