I have previously discussed Sraffa's review of Prices and Production, Hayek's reply, and Sraffa's rejoinder. I thought I would bring up today a couple of other aspects of that debate.
2.0 Hayek Changes His Notion Of Equilibrium
The traditional neoclassical equilibrium concept, in the period roughly from 1870 to 1930, is roughly of a stationary state. Neoclassical economists in this period erroneously thought that one could define such an equilibrium, given tastes, technology, and endowments, including the endowment of capital, by some or another definition of capital. As Walras recognized, such an equilibrium can never be expected to be established. At most, actual capitalist economies can be expected to be tending towards this kind of equilibrium at any point in time.
This was Hayek's equilibrium concept in Prices and Production. He put forth another equilibrium concept in The Theory of Capital, a concept he had been developing for some time. (Hayek is very clear on this in Chapter 2.) This equilibrium concept is of plan compatibility, a concept formally equivalent in some sense to the Arrow-Debreu model of intertemporal equilibrium.
Given spot prices, a monetary interest rate, and the past history of an economy, entrepreneurs, based on their economic theories, form expectations about future prices and the expectations and plans of others. They form their plans based on these expectations. Equilibrium exists if all these plans are mutually compatible. Under this equilibrium concept, no need exists for entrepreneurs to plan to produce the same quantities period after period. Likewise, consumers might plan to consume different quantities in different periods. Furthermore, entrepreneurs and consumers will generally expect spot prices to vary over time.
Hayek's equilibrium concept of plan compatibility, as I understand it, cannot be used to ground Austrian Business Cycle Theory.
3.0 Austrian Business Cycle Theory Outside Of Historical Time
Sraffa destroyed Hayek's version of Austrian Business Cycle Theory, as Robert Skidelsky notes.
I am amused in noting part of Sraffa's critique. Keynes sets his General Theory in historical time, not logical time. I read Sraffa as pointing out that Hayek's theory, like neoclassical theory on Keynes's reading, is set in logical time:
"That the position reached as the result of 'voluntary saving' will be one of equilibrium... is clear enough; though the conclusion is not strengthened by the curious reason he gives for it.13And again:
But equally stable would be that position if brought about by inflation; and Dr. Hayek fails to prove the contrary. In the case of inflation, just as in that of saving, the accumulation of capital takes place through a reduction in consumption. 'But now this sacrifice is not voluntary, and is not made by those who will reap the benefit from the new investments... There can be no doubt that, if their money receipts should rise again [and this rise is bound to happen as Dr. Hayek promises to prove] they would immediately attempt to expand consumption to the usual proportion', that is to say, capital will be reduced to its former amount; 'such a transition to less capitalistic method of production necessarily takes the form of an economic crisis'...
As a moment's reflection will show, 'there can be no doubt' that nothing of the sort will happen. One class has, for a time, robbed another class of a part of their incomes; and has saved the plunder. When the robbery comes to an end, it is clear that the victims cannot possibly consume the capital which is now well out of their reach. If they are wage-earners, who have all the time consumed every penny of their income, they have no wherewithal to expand consumption. And if they are capitalists, who have not shared in the plunder, they may indeed be induced to consume now a part of their capital by the fall in the rate of interest; but not more so than if the rate had been lowered by the 'voluntary savings' of other people.
13The reason given is that 'since, after the change had been completed, these persons [i.e., the savers] would get a greater proportion of the total real income, they would have no reason' to consume the newly acquired capital... But it is not necessarily true that these persons will get a greater proportion of the total real income, and if the fall in the rate of interest is large enough they will get a smaller proportion; and anyhow it is difficult to see how the proportion of total income which falls to them can be relevant to the 'decisions of individuals'. Dr. Hayek, who extols the imaginary achievements of the 'subjective method' in economics, often succeeds in making patent nonsense of it." -- Piero Sraffa (March 1932)
"The first question is whether, as Dr. Hayek asserts, the capital accumulated by 'forced saving' will be, 'at least party' dissipated as soon as inflation comes to an end: 'It is upon the truth of this point that my [Dr. H's] theory stands or falls'. My simple-minded objection was that forced saving being a misnomer for spoliation, if those who had gained by the inflation chose to save the spoils, they had no reason at a later stage to revise the decision; and at any rate those on whom forced saving had been inflicted would have no say in the matter. This appeal to common sense has not shaken Dr. Hayek: he describes it as 'surprisingly superficial', though unfortunately he forgets to tell me where it is wrong." -- Piero Sraffa (June 1932)The distribution of endowments - who owns what - is a datum for traditional neoclassical theory. Disequilibria employment, production, and purchases will change this data. So one cannot expect, contrary to Hayek, the previous equilibra corresponding to previous data to be restored after the economy is on some disequilibrium path for some extended time.
Sraffa, like later Post Keynesians, suggested a coherent economic theory must be set in historic time.
- P. Garegnani (1976) "On a Change in the Notion of Equilibrium in Recent Work on Value and Distribution", reprinted in Keynes's Economics and Theory of Value and Distribution (edited by J. L. Eatwell and M. Milgate, 1983), Oxford University Press.
- F. A. Hayek (1935) Prices and Production, 2nd. Edition, Routledge and Sons.
- F. A. Hayek (June 1932) "Money and Capital: A Reply", Economic Journal, V. 42: 237-249.
- F. A. Hayek (1941) The Pure Theory of Capital, University of Chicago Press.
- M. Milgate (1979) "On the Origin of the Notion of 'Intertemporal Equilibrium'", Economica, V. 46, N. 1: 1-10.
- P. Sraffa (March 1932) "Dr. Hayek on Money and Capital" Economic Journal, V. 42: 42-53.
- P. Sraffa (June 1932). "A Rejoinder", Economic Journal, V. 42: 249-251.