Two crises, two ideas and one question

Specific ideas about the Fisher relation between real and nominal interest rates and more general ideas about the nature of the central bank's duty to support the financial system in times of crisis were important to the Monetarist re-assessment of the causes of the Great Depression and what this event implied about the inherent stability of the market economy. Aspects of the evolution of these ideas since the Depression and the role that they have played in recent debates about the Great Recession are discussed, and some tentative conclusions about the validity of Monetarist ideas are drawn.