ABSTRACT
Uncertainty, limited knowledge and the nature of expectations are of increasing concern to economists today. After the long decades in which a complacent orthodoxy assumed these problems away, they have rapidly re-emerged with the rise of the rational expectations hypothesis and renewed interest in the Austrian School. Theoretical work from both these camps has been used in attempts to rebut Keynes and to justify a laissez-faire approach to economic policy. Yet for Keynes too the existence of uncertainty in economic life was a central theme in The General Theory of Employment, Interest and Money. He was, however, drawn to less conservative policy conclusions. His ideas inspired the reforming consensus of the post World War II period.
