Uneasy Money

The paper, forthcoming in The Review of Austrian Economics, can be read online.

Here is the abstract:

Hayek was among the first to realize that for intertemporal equilibrium to obtain all agents must have correct expectations of future prices. Before comparing four categories of intertemporal, the paper explains Hayek’s distinction between correct expectations and perfect foresight. The four equilibrium concepts considered are: (1) Perfect foresight equilibrium of which the Arrow-Debreu-McKenzie (ADM) model of equilibrium with complete markets is an alternative version, (2) Radner’s sequential equilibrium with incomplete markets, (3) Hicks’s temporary equilibrium, as extended by Bliss; (4) the Muth rational-expectations equilibrium as extended by Lucas into macroeconomics. While Hayek’s understanding closely resembles Radner’s sequential equilibrium, described by Radner as an equilibrium of plans, prices, and price expectations, Hicks’s temporary equilibrium seems to have been the natural extension of Hayek’s approach. The now dominant Lucas rational-expectations equilibrium misconceives intertemporal equilibrium, suppressing Hayek’s insights thereby retreating to a sterile perfect-foresight equilibrium.

And here is my concluding paragraph:

Four score and three years after Hayek explained how challenging the subtleties of the notion of intertemporal equilibrium and the elusiveness of any theoretical account of an empirical tendency toward intertemporal equilibrium, modern macroeconomics has now built a formidable theoretical apparatus founded on a methodological principle that rejects all the concerns that Hayek found so vexing denies that all those difficulties even exist. Many macroeconomists feel proud of what modern macroeconomics has achieved, but there is reason to think that the path trod by Hayek, Hicks and Radner could have led macroeconomics in a more fruitful direction than the one on which it has been led by Lucas and his associates.