Archive for the 'Don Patinkin' Category

The Neoclassical Synthesis and the Mind-Body Problem

The neoclassical synthesis that emerged in the early postwar period aimed at reconciling the macroeconomic (IS-LM) analysis derived from Keynes via Hicks and others with the neoclassical microeconomic analysis of general equilibrium derived from Walras. The macroeconomic analysis was focused on an equilibrium of income and expenditure flows while the Walrasian analysis was focused on the equilibrium between supply and demand in individual markets. The two types of analysis seemed to be incommensurate inasmuch as the conditions for equilibrium in the two analysis did not seem to match up against each other. How does an analysis focused on the equality of aggregate flows of income and expenditure get translated into an analysis focused on the equality of supply and demand in individual markets? The two languages seem to be different, so it is not obvious how a statement formulated in one language gets translated into the other. And even if a translation is possible, does the translation hold under all, or only under some, conditions? And if so, what are those conditions?

The original neoclassical synthesis did not aim to provide a definitive answer to those questions, but it was understood to assert that if the equality of income and expenditure was assured at a level consistent with full employment, one could safely assume that market forces would take care of the allocation of resources, so that markets would be cleared and the conditions of microeconomic general equilibrium satisfied, at least as a first approximation. This version of the neoclassical synthesis was obviously ad hoc and an unsatisfactory resolution of the incommensurability of the two levels of analysis. Don Patinkin sought to provide a rigorous reconciliation of the two levels of analysis in his treatise Money, Interest and Prices. But for all its virtues – and they are numerous – Patinkin’s treatise failed to bridge the gap between the two levels of analysis.

As I mentioned recently in a post on Romer and Lucas, Kenneth Arrow in a 1967 review of Samuelson’s Collected Works commented disparagingly on the neoclassical synthesis of which Samuelson was a leading proponent. The widely shared dissatisfaction expressed by Arrow motivated much of the work that soon followed on the microfoundations of macroeconomics exemplified in the famous 1970 Phelps volume. But the motivation for the search for microfoundations was then (before the rational expectations revolution) to specify the crucial deviations from the assumptions underlying the standard Walrasian general-equilibrium model that would generate actual or seeming price rigidities, which a straightforward – some might say superficial — understanding of neoclassical microeconomic theory suggested were necessary to explain why, after a macro-disturbance, equilibrium was not rapidly restored by price adjustments. Two sorts of explanations emerged from the early microfoundations literature: a) search and matching theories assuming that workers and employers must expend time and resources to find appropriate matches; b) institutional theories of efficiency wages or implicit contracts that explain why employers and workers prefer layoffs to wage cuts in response to negative demand shocks.

Forty years on, the search and matching theories do not seem capable of accounting for the magnitude of observed fluctuations in employment or the cyclical variation in layoffs, and the institutional theories are still difficult to reconcile with the standard neoclassical assumptions, remaining an ad hoc appendage to New Keynesian models that otherwise adhere to the neoclassical paradigm. Thus, although the original neoclassical synthesis in which the Keynesian income-expenditure model was seen as a pre-condition for the validity of the neoclassical model was rejected within a decade of Arrow’s dismissive comment about the neoclassical synthesis, Tom Sargent has observed in a recent review of Robert Lucas’s Collected Papers on Monetary Theory that Lucas has implicitly adopted a new version of the neoclassical synthesis dominated by an intertemporal neoclassical general-equilibrium model, but with the proviso that substantial shocks to aggregate demand and the price level are prevented by monetary policy, thereby making the neoclassical model a reasonable approximation to reality.

Ok, so you are probably asking what does all this have to do with the mind-body problem? A lot, I think in that both the neoclassical synthesis and the mind-body problem involve a disconnect between two kinds – two levels – of explanation. The neoclassical synthesis asserts some sort of connection – but a problematic one — between the explanatory apparatus – macroeconomics — used to understand the cyclical fluctuations of what we are used to think of as the aggregate economy and the explanatory apparatus – microeconomics — used to understand the constituent elements of the aggregate economy — households and firms — and how those elements are related to, and interact with, each other.

The mind-body problem concerns the relationship between the mental – our direct experience of a conscious inner life of thoughts, emotions, memories, decisions, hopes and regrets — and the physical – matter, atoms, neurons. A basic postulate of science is that all phenomena have material causes. So the existence of conscious states that seem to us, by way of our direct experience, to be independent of material causes is also highly problematic. There are a few strategies for handling the problem. One is to assert that the mind truly is independent of the body, which is to say that consciousness is not the result of physical causes. A second is to say that mind is not independent of the body; we just don’t understand the nature of the relationship. There are two possible versions of this strategy: a) that although the nature of the relationship is unknown to us now, advances in neuroscience could reveal to us the way in which consciousness is caused by the operation of the brain; b) although our minds are somehow related to the operation of our brains, the nature of this relationship is beyond the capacity of our minds or brains to comprehend owing to considerations analogous to Godel’s incompleteness theorem (a view espoused by the philosopher Colin McGinn among others); in other words, the mind-body problem is inherently beyond human understanding. And the third strategy is to deny the existence of consciousness, because a conscious state is identical with the physical state of a brain, so that consciousness is just an epiphenomenon of a brain state; we in our naivete may think that our conscious states have a separate existence, but those states are strictly identical with corresponding brain states, so that whatever conscious state that we think we are experiencing has been entirely produced by the physical forces that determine the behavior of our brains and the configuration of its physical constituents.

The first, and probably the last, thing that one needs to understand about the third strategy is that, as explained by Colin McGinn (see e.g., here), its validity has not been demonstrated by neuroscience or by any other branch of science; it is, no less than any of the other strategies, strictly a metaphysical position. The mind-body problem is a problem precisely because science has not even come close to demonstrating how mental states are caused by, let alone that they are identical to, brain states, despite some spurious misinterpretations of research that purport to show such an identity.

Analogous to the scientific principle that all phenomena have material or physical causes, there is in economics and social science a principle called methodological individualism, which roughly states that explanations of social outcomes should be derived from theories about the conduct of individuals, not from theories about abstract social entities that exist independently of their constituent elements. The underlying motivation for methodological individualism (as opposed to political individualism with which it is related but from which it is distinct) was to counter certain ideas popular in the nineteenth and twentieth centuries asserting the existence of metaphysical social entities like “history” that are somehow distinct from yet impinge upon individual human beings, and that there are laws of history or social development from which future states of the world can be predicted, as Hegel, Marx and others tried to do. This notion gave rise to a two famous books by Popper: The Open Society and its Enemies and The Poverty of Historicism. Methodological individualism as articulated by Popper was thus primarily an attack on the attribution of special powers to determine the course of future events to abstract metaphysical or mystical entities like history or society that are supposedly things or beings in themselves distinct from the individual human beings of which they are constituted. Methodological individualism does not deny the existence of collective entities like society; it simply denies that such collective entities exist as objective facts that can be observed as such. Our apprehension of these entities must be built up from more basic elements — individuals and their plans, beliefs and expectations — that we can apprehend directly.

However, methodological individualism is not the same as reductionism; methodological individualism teaches us to look for explanations of higher-level phenomena, e.g., a pattern of social relationships like the business cycle, in terms of the basic constituents forming the pattern: households, business firms, banks, central banks and governments. It does not assert identity between the pattern of relationships and the constituent elements; it says that the pattern can be understood in terms of interactions between the elements. Thus, a methodologically individualistic explanation of the business cycle in terms of the interactions between agents – households, businesses, etc. — would be analogous to an explanation of consciousness in terms of the brain if an explanation of consciousness existed. A methodologically individualistic explanation of the business cycle would not be analogous to an assertion that consciousness exists only as an epiphenomenon of brain states. The assertion that consciousness is nothing but the epiphenomenon of a corresponding brain state is reductionist; it asserts an identity between consciousness and brain states without explaining how consciousness is caused by brain states.

In business-cycle theory, the analogue of such a reductionist assertion of identity between higher-level and lower level phenomena is the assertion that the business cycle is not the product of the interaction of individual agents, but is simply the optimal plan of a representative agent. On this account, the business cycle becomes an epiphenomenon; apparent fluctuations being nothing more than the optimal choices of the representative agent. Of course, everyone knows that the representative agent is merely a convenient modeling device in terms of which a business-cycle theorist tries to account for the observed fluctuations. But that is precisely the point. The whole exercise is a sham; the representative agent is an as-if device that does not ground business-cycle fluctuations in the conduct of individual agents and their interactions, but simply asserts an identity between those interactions and the supposed decisions of the fictitious representative agent. The optimality conditions in terms of which the model is solved completely disregard the interactions between individuals that might cause an unintended pattern of relationships between those individuals. The distinctive feature of methodological individualism is precisely the idea that the interactions between individuals can lead to unintended consequences; it is by way of those unintended consequences that a higher-level pattern might emerge from interactions among individuals. And those individual interactions are exactly what is suppressed by representative-agent models.

So the notion that any analysis premised on a representative agent provides microfoundations for macroeconomic theory seems to be a travesty built on a total misunderstanding of the principle of methodological individualism that it purports to affirm.

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Sumner Sticks with Friedman

Scott Sumner won’t let go. Scott had another post today trying to show that the Cambridge Theory of the demand for money was already in place before Keynes arrived on the scene. He quotes from Hicks’s classic article “Mr. Keynes and the Classics” to dispute the quotation from another classic article by Hicks, “A Suggestions for Simplifying the Theory of Money,” which I presented in a post last week, demonstrating that Hicks credited Keynes with an important contribution to the demand for money that went beyond what Pigou, and even Lavington, had provided in their discussions of the demand for money.

In this battle of dueling quotations, I will now call upon Mark Blaug, perhaps the greatest historian of economics since Schumpeter, who in his book Economic Theory in Retrospect devotes an entire chapter (15) to the neoclassical theory of money, interest and prices. I quote from pp. 636-37 (4th edition).

Marshall and his followers went some way to move the theory of the demand for money in the direction of ordinary demand analysis, first, by relating money to net output or national income rather than the broader category of total transactions, and, second, by shifting from money’s rate of turnover to the proportion of annual income that the public wishes to hold in the form of money. In purely formal terms, there I nothing to choose between the Fisherian transaction approach and the Cambridge cash-balance approach, but the Cambridge formulation held out the potential of a genuine portfolio theory of the demand for money, which potential, however, was never fully exploited. . . .

The Cambridge formulation implies a demand for money equation, D_m = kPY, which contains no variable to represent the opportunity costs of holding cash, namely the rate of interest or the yield of alternative non-money assets, analogous to the relative price arguments of ordinary demand functions.
Yet a straight-forward application of utility-maximizing principles would have suggested that a rise in interest rates is likely to induce a fall in k as people strive to substitute interest-earning assets for passive money balances in their asset portfolios. Similarly, a fall in interest rates, by lowering the opportunity cost of holding money, is likely to cause a rise in k. Strangely enough, however, the Cambridge monetary theory never explicitly recognized the functional dependence of k on either the rate of interest or the rate on all non-monetary assets. After constructing a framework highly suggestive of a study of all the factors influencing cash-holding decisions, the Cambridge writers tended to lapse back to a list of the determinants of k that differed in no important respects from the list of institutional factors that Fisher had cited in his discussion of V. One can find references in Marshall, Pigou and particularly Lavington to a representative individual striking a balance between the costs of cash holdings in terms of interest foregone (minus the brokerage costs that would have been incurred by the movement into stocks and bonds) and their returns in terms of convenience and security against default but such passages were never systematically integrated with the cash-balance equation. As late as 1923, we find the young Keynes in A Tract on Monetary Reform interpreting k as a stable constant, representing an invariant link in the transmission mechanism connecting money to prices. If only Keynes at that date had read Wicksell instead of Marshall, he might have arrived at a money demand function that incorporates variations in the interest rate years before The General Theory (1936).

Moving to pp. 645-46, we find the following under the heading “The Demand for Money after Keynes.”

In giving explicit consideration to the yields on assets that compete with money, Keynes became one of the founders of the portfolio balance approach to monetary analysis. However, it is Hicks rather than Keynes who ought to be regarded as the founder of the view that the demand for money is simply an aspect of the problem of choosing an optimum portfolio of assets. In a remarkable paper published a year before the appearance of the General Theory, modestly entitled “A Suggestion for Simplifying the Theory of Money,” Hicks argued that money held at least partly as a store of value must be considered a type of capital asset. Hence the demand for money equation must include total wealth and expected rates of return on non-monetary assets as explanatory variables. Because individuals can choose to hold their entire wealth portfolios in the form of cash, the wealth variable represents the budget constraint on money holdings. The yield variables, on the other hand, represent both the opportunity costs of holding money and the substitutions effects of changes in relative rates of return. Individuals optimize their portfolio balances by comparing these yields with the imputed yield in terms of convenience and security of holding money. By these means, Hicks in effect treated the demand for money as a problem of balance sheet equilibrium analyzed along the same lines as those employed in ordinary demand theory.

It was Milton Friedman who carried this Hicksian analysis of money as a capital asset to its logical conclusion. In a 1956 essay, he set out a precise and complete specification of the relevant constraints and opportunity cost variable entering a household’s money demand function. His independent variable included wealth or permanent income – the present value of expected future receipts from all sources, whether personal earning or the income from real property and financial assets – the ratio of human to non-human wealth, expected rates of return on stocks, bonds and real assets, the nominal interest rate, the actual price level, and, finally, the expected percentage change in the price level. Like Hicks, Friedman specified wealth as the appropriate budget constraint but his concept of wealth was much broader than that adopted by Hicks. Whereas Keynes had viewed bonds as the only asset competing with cash, Friedman regarded all types of wealth as potential substitutes for cash holdings in an individual’s balance sheet; thus, instead of a single interest variable in the Keynesian liquidity preference equation, we get a whole list of relative yield variables in Friedman. An additional novel feature, entirely original with Friedman, is the inclusion of the expected rate of change in P as a measure of the anticipated rate of depreciation in the purchasing power of cash balances.

This formulation of the money demand function was offered in a paper entitled “The Quantity Theory of Money: A Restatement.” Friedman claimed not only that the quantity theory of money had always been a theory about the demand for money but also that his reformulation corresponded closely to what some of the great Chicago monetary economists, such as H.C. Simons and L. W. Mints, had always meant by the quantity theory. It is clear, however, from our earlier discussion that the quantity theory of money, while embodying an implicit conception of the demand for money, had always stood first and foremost for a theory of the determination of prices and nominal income; it contained much more than a particular theory of the demand for money.

Finally, Blaug remarks in his “notes for further reading” at the end of chapter 15,

In an influential essay, “The Quantity Theory of Money – A Restatement,” . . . M. Friedman claimed that his restatement was nothing more than the University of Chicago “oral” tradition. That claim was effectively destroyed by D. Patinkin, “The Chicago Tradition, the Quantity Theory, and Friedman, JMCB, 1969 .

Well, just a couple of quick comments on Blaug. I don’t entirely agree with everything he says about Cambridge monetary theory, and about the relative importance of Hicks and Keynes in advancing the theory of the demand for money. Cambridge economists may have been a bit more aware that the demand for money was a function of the rate of interest than he admits, and I think Keynes in chapter 17, definitely formulated a theory of the demand for money in a portfolio balance context, so I think that Friedman was indebted to both Hicks and Keynes for his theory of the demand for money.

As for Scott Sumner’s quotation from Hicks’s Mr. Keynes and the Classics, I think the point of that paper was not so much the theory of the demand for money, which had already been addressed in the 1935 paper from which I quoted, as to sketch out a way of generalizing the argument of the General Theory to encompass both the liquidity trap and the non-liquidity trap cases within a single graph. From the standpoint of the IS-LM diagram, the distinctive Keynesian contribution was the case of absolute liquidity preference, that doesn’t mean that Hicks meant that nothing had been added to the theory of the demand for money since Lavington. If that were the case, Hicks would have been denying that his 1935 paper had made any contribution. I don’t think that’s what he meant to suggest.

To sum up: 1) there was no Chicago oral tradition of the demand for money; 2) Friedman’s restatement of the quantity theory owed more to Keynes (and Hicks) than he admitted; 3) Friedman adapted the Cambridge/Keynes/Hicks theory of the demand for money in novel ways that allowed him to develop an analysis of price level changes that was more straightforward than was possible in the IS-LM model, thereby de-emphasizing the link between money and interest rates, which had been a such a prominent feature of the Keynesian models. That of course is a point that Scott Sumner likes to stress. In an upcoming post, I will comment on the fact that it was not just Keynesian models which stressed the link between money and interest rates. Pre-Keynesian monetary models also stressed the connection between easy money and low interest rates and dear money and high interest rates. Friedman’s argument was thus an innovation not only relative to Keynesian models but to orthodox monetary models. What accounts for this innovation?


About Me

David Glasner
Washington, DC

I am an economist in the Washington DC area. My research and writing has been mostly on monetary economics and policy and the history of economics. In my book Free Banking and Monetary Reform, I argued for a non-Monetarist non-Keynesian approach to monetary policy, based on a theory of a competitive supply of money. Over the years, I have become increasingly impressed by the similarities between my approach and that of R. G. Hawtrey and hope to bring Hawtrey's unduly neglected contributions to the attention of a wider audience.

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