A little over a year ago, I posted a series of posts (here, here, here, here, and here) that came together as a paper (“Hayek and Three Equilibrium Concepts: Sequential, Temporary and Rational-Expectations”) that I presented at the History of Economics Society in Toronto in June 2017. After further revisions I posted the introductory section and the concluding section in April before presenting the paper at the Colloquium on Market Institutions and Economic Processes at NYU.
I have since been making further revisions and tweaks to the paper as well as adding the names of Hicks and Radner to the title, and I have just posted the current version on SSRN where it is available for download.
Here is the abstract:
Along with Erik Lindahl and Gunnar Myrdal, F. A. Hayek was among the first to realize that the necessary conditions for intertemporal, as opposed to stationary, equilibrium could be expressed in terms of correct expectations of future prices, often referred to as perfect foresight. Subsequently, J. R. Hicks further elaborated the concept of intertemporal equilibrium in Value and Capital in which he also developed the related concept of a temporary equilibrium in which future prices are not correctly foreseen. This paper attempts to compare three important subsequent developments of that idea with Hayek’s 1937 refinement of his original 1928 paper on intertemporal equilibrium. As a preliminary, the paper explains the significance of Hayek’s 1937 distinction between correct expectations and perfect foresight. In non-chronological order, the three developments of interest are: (1) Roy Radner’s model of sequential equilibrium with incomplete markets as an alternative to the Arrow-Debreu-McKenzie model of full equilibrium with complete markets; (2) Hicks’s temporary equilibrium model, and an important extension of that model by C. J. Bliss; (3) the Muth rational-expectations model and its illegitimate extension by Lucas from its original microeconomic application into macroeconomics. While Hayek’s 1937 treatment most closely resembles Radner’s sequential equilibrium model, which Radner, echoing Hayek, describes as an equilibrium of plans, prices, and price expectations, Hicks’s temporary equilibrium model would seem to have been the natural development of Hayek’s approach. The now dominant Lucas rational-expectations approach misconceives intertemporal equilibrium and ignores the fundamental Hayekian insights about the meaning of intertemporal equilibrium.
Uneasy Money 