Archive for the 'coordination failure' Category

A New Version of my Paper “Between Walras and Marshall: Menger’s Third Way” Is Now Available on SSRN

Published January 29, 2023 Alfred Marshall , Carl Menger , coordination failure , Franklin Fisher , general equilibrium , partial equilibrium , stability of general equilibrium , Walrasian equilibrium Leave a Comment

Last week I reposted a revised version of a blogpost from last November, which was a revised section from my paper “Between Walras and Marshall: Menger’s Third Way.” That paper was presented at a conference in September 2021 marking the 100th anniversary of Menger’s death. I have now completed my revision of the entire paper, and the new version is now posted on SSRN.

Here is the link to the new version, and here is the abstract of the paper:

Neoclassical economics is bifurcated between Marshall’s partial-equilibrium and Walras’s general-equilibrium. Neoclassical theory having failed to explain the Great Depression, Keynes proposed a theory of involuntary unemployment, later subsumed under the neoclassical synthesis of Keynesian and Walrasian theories. Lacking suitable microfoundations, that synthesis collapsed. But Walrasian theory provides no account of how equilibrium is achieved. Marshallian partial-equilibrium analysis offered a more plausible account of how general equilibrium is reached. But presuming that all markets, but the one being analyzed, are already in equilibrium, Marshallian partial equilibrium, like Walrasian general equilibrium, begs the question of how equilibrium is attained. A Mengerian approach to circumvent this conceptual impasse, relying in part on a critique of Franklin Fisher’s analysis of the stability of general equilibrium, is proposed.

Commnets, criticisms and suggestions are welcomed and encouraged.

Axel Leijonhufvud and Modern Macroeconomics

Published June 20, 2022 Alchian , Axel Leijonfuvud , common knowledge , coordination failure , Earl Thompson , Hayek , IS-LM , J. R. Hicks , Keynes , microfoundations , Milton Friedman , neoclassical synthesis , New Classical macroeconomics , New Keynesians , rational expectations , rational expectations equilibrium , Robert Clower , Robert Lucas , search theories , sticky prices , sticky wages , tatonnement , temporary equilibrium , Thomas Sargent , Walrasian equilibrium 10 Comments

For many baby boomers like me growing up in Los Angeles, UCLA was an almost inevitable choice for college. As an incoming freshman, I was undecided whether to major in political science or economics. PoliSci 1 didn’t impress me, but Econ 1 did. More than my Econ 1 professor, it was the assigned textbook, University Economics, 1st edition, by Alchian and Allen that impressed me. That’s how my career in economics started.

After taking introductory micro and macro as a freshman, I started the intermediate theory sequence of micro (utility and cost theory, econ 101a), (general equilibrium theory, 101b), and (macro theory, 102) as a sophomore. It was in the winter 1968 quarter that I encountered Axel Leijonhufvud. This was about a year before his famous book – his doctoral dissertation – Keynesian Economics and the Economics of Keynes was published in the fall of 1968 to instant acclaim. Although it must have been known in the department that the book, which he’d been working on for several years, would soon appear, I doubt that its remarkable impact on the economics profession could have been anticipated, turning Axel almost overnight from an obscure untenured assistant professor into a tenured professor at one of the top economics departments in the world and a kind of academic rock star widely sought after to lecture and appear at conferences around the globe. I offer the following scattered recollections of him, drawn from memories at least a half-century old, to those interested in his writings, and some reflections on his rise to the top of the profession, followed by a gradual loss of influence as theoretical marcroeconomics, fell under the influence of Robert Lucas and the rational-expectations movement in its various forms (New Classical, Real Business-Cycle, New-Keynesian).

Axel, then in his early to mid-thirties, was an imposing figure, very tall and gaunt with a short beard and a shock of wavy blondish hair, but his attire reflecting the lowly position he then occupied in the academic hierarchy. He spoke perfect English with a distinct Swedish lilt, frequently leavening his lectures and responses to students’ questions with wry and witty comments and asides.  

Axel’s presentation of general-equilibrium theory was, as then still the norm, at least at UCLA, mostly graphical, supplemented occasionally by some algebra and elementary calculus. The Edgeworth box was his principal technique for analyzing both bilateral trade and production in the simple two-output, two-input case, and he used it to elucidate concepts like Pareto optimality, general-equilibrium prices, and the two welfare theorems, an exposition which I, at least, found deeply satisfying. The assigned readings were the classic paper by F. M. Bator, “The Simple Analytics of Welfare-Maximization,” which I relied on heavily to gain a working grasp of the basics of general-equilibrium theory, and as a supplementary text, Peter Newman’s The Theory of Exchange, much of which was too advanced for me to comprehend more than superficially. Axel also introduced us to the concept of tâtonnement and highlighting its importance as an explanation of sorts of how the equilibrium price vector might, at least in theory, be found, an issue whose profound significance I then only vaguely comprehended, if at all. Another assigned text was Modern Capital Theory by Donald Dewey, providing an introduction to the role of capital, time, and the rate of interest in monetary and macroeconomic theory and a bridge to the intermediate macro course that he would teach the following quarter.

A highlight of Axel’s general-equilibrium course was the guest lecture by Bob Clower, then visiting UCLA from Northwestern, with whom Axel became friendly only after leaving Northwestern, and two of whose papers (“A Reconsideration of the Microfoundations of Monetary Theory,” and “The Keynesian Counterrevolution: A Theoretical Appraisal”) were discussed at length in his forthcoming book. (The collaboration between Clower and Leijonhufvud and their early Northwestern connection has led to the mistaken idea that Clower had been Axel’s thesis advisor. Axel’s dissertation was actually written under Meyer Burstein.) Clower himself came to UCLA economics a few years later when I was already a third-year graduate student, and my contact with him was confined to seeing him at seminars and workshops. I still have a vivid memory of Bob in his lecture explaining, with the aid of chalk and a blackboard, how ballistic theory was developed into an orbital theory by way of a conceptual experiment imagining that the distance travelled by a projectile launched from a fixed position being progressively lengthened until the projectile’s trajectory transitioned into an orbit around the earth.

Axel devoted the first part of his macro course to extending the Keynesian-cross diagram we had been taught in introductory macro into the Hicksian IS-LM model by making investment a negative function of the rate of interest and adding a money market with a fixed money stock and a demand for money that’s a negative function of the interest rate. Depending on the assumptions about elasticities, IS-LM could be an analytical vehicle that could accommodate either the extreme Keynesian-cross case, in which fiscal policy is all-powerful and monetary policy is ineffective, or the Monetarist (classical) case, in which fiscal policy is ineffective and monetary policy all-powerful, which was how macroeconomics was often framed as a debate about the elasticity of the demand for money curve with respect to interest rate. Friedman himself, in his not very successful attempt to articulate his own framework for monetary analysis, accepted that framing, one of the few rhetorical and polemical misfires of his career.

In his intermediate macro course, Axel presented the standard macro model, and I don’t remember his weighing in that much with his own criticism; he didn’t teach from a standard intermediate macro textbook, standard textbook versions of the dominant Keynesian model not being at all to his liking. Instead, he assigned early sources of what became Keynesian economics like Hicks’s 1937 exposition of the IS-LM model and Alvin Hansen’s A Guide to Keynes (1953), with Friedman’s 1956 restatement of the quantity theory serving as a counterpoint, and further developments of Keynesian thought like Patinkin’s 1948 paper on price flexibility and full employment, A. W. Phillips original derivation of the Phillips Curve, Harry Johnson on the General Theory after 25 years, and his own preview “Keynes and the Keynesians: A Suggested Interpretation” of his forthcoming book, and probably others that I’m not now remembering. Presenting the material piecemeal from original sources allowed him to underscore the weaknesses and questionable assumptions latent in the standard Keynesian model.

Of course, for most of us, it was a challenge just to reproduce the standard model and apply it to some specific problems, but we at least we got the sense that there was more going on under the hood of the model than we would have imagined had we learned its structure from a standard macro text. I have the melancholy feeling that the passage of years has dimmed my memory of his teaching too much to adequately describe how stimulating, amusing and enjoyable his lectures were to those of us just starting our journey into economic theory.

The following quarter, in the fall 1968 quarter, when his book had just appeared in print, Axel created a new advanced course called macrodynamics. He talked a lot about Wicksell and Keynes, of course, but he was then also fascinated by the work of Norbert Wiener on cybernetics, assigning Wiener’s book Cybernetics as a primary text and a key to understanding what Keynes was really trying to do. He introduced us to concepts like positive and negative feedback, servo mechanisms, stable and unstable dynamic systems and related those concepts to economic concepts like the price mechanism, stable and unstable equilibria, and to business cycles. Here’s how a put it in On Keynesian Economics and the Economics of Keynes:

Cybernetics as a formal theory, of course, began to develop only during the was and it was only with the appearance of . . . Weiner’s book in 1948 that the first results of serious work on a general theory of dynamic systems – and the term itself – reached a wider public. Even then, research in this field seemed remote from economic problems, and it is thus not surprising that the first decade or more of the Keynesian debate did not go in this direction. But it is surprising that so few monetary economists have caught on to developments in this field in the last ten or twelve years, and that the work of those who have has not triggered a more dramatic chain reaction. This, I believe, is the Keynesian Revolution that did not come off.

In conveying the essential departure of cybernetics from traditional physics, Wiener once noted:

Here there emerges a very interesting distinction between the physics of our grandfathers and that of the present day. In nineteenth-century physics, it seemed to cost nothing to get information.

In context, the reference was to Maxwell’s Demon. In its economic reincarnation as Walras’ auctioneer, the demon has not yet been exorcised. But this certainly must be what Keynes tried to do. If a single distinction is to be drawn between the Economics of Keynes and the economics of our grandfathers, this is it. It is only on this basis that Keynes’ claim to have essayed a more “general theory” can be maintained. If this distinction is not recognized as both valid and important, I believe we must conclude that Keynes’ contribution to pure theory is nil.

Axel’s hopes that cybernetics could provide an analytical tool with which to bring Keynes’s insights into informational scarcity on macroeconomic analysis were never fulfilled. A glance at the index to Axel’s excellent collection of essays written from the late 1960s and the late 1970s Information and Coordination reveals not a single reference either to cybernetics or to Wiener. Instead, to his chagrin and disappointment, macroeconomics took a completely different path following the path blazed by Robert Lucas and his followers of insisting on a nearly continuous state of rational-expectations equilibrium and implicitly denying that there is an intertemporal coordination problem for macroeconomics to analyze, much less to solve.

After getting my BA in economics at UCLA, I stayed put and began my graduate studies there in the next academic year, taking the graduate micro sequence given that year by Jack Hirshleifer, the graduate macro sequence with Axel and the graduate monetary theory sequence with Ben Klein, who started his career as a monetary economist before devoting himself a few years later entirely to IO and antitrust.

Not surprisingly, Axel’s macro course drew heavily on his book, which meant it drew heavily on the history of macroeconomics including, of course, Keynes himself, but also his Cambridge predecessors and collaborators, his friendly, and not so friendly, adversaries, and the Keynesians that followed him. His main point was that if you take Keynes seriously, you can’t argue, as the standard 1960s neoclassical synthesis did, that the main lesson taught by Keynes was that if the real wage in an economy is somehow stuck above the market-clearing wage, an increase in aggregate demand is necessary to allow the labor market to clear at the prevailing market wage by raising the price level to reduce the real wage down to the market-clearing level.

This interpretation of Keynes, Axel argued, trivialized Keynes by implying that he didn’t say anything that had not been said previously by his predecessors who had also blamed high unemployment on wages being kept above market-clearing levels by minimum-wage legislation or the anticompetitive conduct of trade-union monopolies.

Axel sought to reinterpret Keynes as an early precursor of search theories of unemployment subsequently developed by Armen Alchian and Edward Phelps who would soon be followed by others including Robert Lucas. Because negative shocks to aggregate demand are rarely anticipated, the immediate wage and price adjustments to a new post-shock equilibrium price vector that would maintain full employment would occur only under the imaginary tâtonnement system naively taken as the paradigm for price adjustment under competitive market conditions, Keynes believed that a deliberate countercyclical policy response was needed to avoid a potentially long-lasting or permanent decline in output and employment. The issue is not price flexibility per se, but finding the equilibrium price vector consistent with intertemporal coordination. Price flexibility that doesn’t arrive quickly (immediately?) at the equilibrium price vector achieves nothing. Trading at disequilibrium prices leads inevitably to a contraction of output and income. In an inspired turn of phrase, Axel called this cumulative process of aggregate demand shrinkage Say’s Principle, which years later led me to write my paper “Say’s Law and the Classical Theory of Depressions” included as Chapter 9 of my recent book Studies in the History of Monetary Theory.

Attention to the implications of the lack of an actual coordinating mechanism simply assumed (either in the form of Walrasian tâtonnement or the implicit Marshallian ceteris paribus assumption) by neoclassical economic theory was, in Axel’s view, the great contribution of Keynes. Axel deplored the neoclassical synthesis, because its rote acceptance of the neoclassical equilibrium paradigm trivialized Keynes’s contribution, treating unemployment as a phenomenon attributable to sticky or rigid wages without inquiring whether alternative informational assumptions could explain unemployment even with flexible wages.

The new literature on search theories of unemployment advanced by Alchian, Phelps, et al. and the success of his book gave Axel hope that a deepened version of neoclassical economic theory that paid attention to its underlying informational assumptions could lead to a meaningful reconciliation of the economics of Keynes with neoclassical theory and replace the superficial neoclassical synthesis of the 1960s. That quest for an alternative version of neoclassical economic theory was for a while subsumed under the trite heading of finding microfoundations for macroeconomics, by which was meant finding a way to explain Keynesian (involuntary) unemployment caused by deficient aggregate demand without invoking special ad hoc assumptions like rigid or sticky wages and prices. The objective was to analyze the optimizing behavior of individual agents given limitations in or imperfections of the information available to them and to identify and provide remedies for the disequilibrium conditions that characterize coordination failures.

For a short time, perhaps from the early 1970s until the early 1980s, a number of seemingly promising attempts to develop a disequilibrium theory of macroeconomics appeared, most notably by Robert Barro and Herschel Grossman in the US, and by and J. P. Benassy, J. M. Grandmont, and Edmond Malinvaud in France. Axel and Clower were largely critical of these efforts, regarding them as defective and even misguided in many respects.

But at about the same time, another, very different, approach to microfoundations was emerging, inspired by the work of Robert Lucas and Thomas Sargent and their followers, who were introducing the concept of rational expectations into macroeconomics. Axel and Clower had focused their dissatisfaction with neoclassical economics on the rise of the Walrasian paradigm which used the obviously fantastical invention of a tâtonnement process to account for the attainment of an equilibrium price vector perfectly coordinating all economic activity. They argued for an interpretation of Keynes’s contribution as an attempt to steer economics away from an untenable theoretical and analytical paradigm rather than, as the neoclassical synthesis had done, to make peace with it through the adoption of ad hoc assumptions about price and wage rigidity, thereby draining Keynes’s contribution of novelty and significance.

And then Lucas came along to dispense with the auctioneer, eliminate tâtonnement, while achieving the same result by way of a methodological stratagem in three parts: a) insisting that all agents be treated as equilibrium optimizers, and b) who therefore form identical rational expectations of all future prices using the same common knowledge, so that c) they all correctly anticipate the equilibrium price vector that earlier economists had assumed could be found only through the intervention of an imaginary auctioneer conducting a fantastical tâtonnement process.

This methodological imperatives laid down by Lucas were enforced with a rigorous discipline more befitting a religious order than an academic research community. The discipline of equilibrium reasoning, it was decreed by methodological fiat, imposed a question-begging research strategy on researchers in which correct knowledge of future prices became part of the endowment of all optimizing agents.

While microfoundations for Axel, Clower, Alchian, Phelps and their collaborators and followers had meant relaxing the informational assumptions of the standard neoclassical model, for Lucas and his followers microfoundations came to mean that each and every individual agent must be assumed to have all the knowledge that exists in the model. Otherwise the rational-expectations assumption required by the model could not be justified.

The early Lucasian models did assume a certain kind of informational imperfection or ambiguity about whether observed price changes were relative changes or absolute changes, which would be resolved only after a one-period time lag. However, the observed serial correlation in aggregate time series could not be rationalized by an informational ambiguity resolved after just one period. This deficiency in the original Lucasian model led to the development of real-business-cycle models that attribute business cycles to real-productivity shocks that dispense with Lucasian informational ambiguity in accounting for observed aggregate time-series fluctuations. So-called New Keynesian economists chimed in with ad hoc assumptions about wage and price stickiness to create a new neoclassical synthesis to replace the old synthesis but with little claim to any actual analytical insight.

The success of the Lucasian paradigm was disheartening to Axel, and his research agenda gradually shifted from macroeconomic theory to applied policy, especially inflation control in developing countries. Although my own interest in macroeconomics was largely inspired by Axel, my approach to macroeconomics and monetary theory eventually diverged from Axel’s, when, in my last couple of years of graduate work at UCLA, I became close to Earl Thompson whose courses I had not taken as an undergraduate or a graduate student. I had read some of Earl’s monetary theory papers when preparing for my preliminary exams; I found them interesting but quirky and difficult to understand. After I had already started writing my dissertation, under Harold Demsetz on an IO topic, I decided — I think at the urging of my friend and eventual co-author, Ron Batchelder — to sit in on Earl’s graduate macro sequence, which he would sometimes offer as an alternative to Axel’s more popular graduate macro sequence. It was a relatively small group — probably not more than 25 or so attended – that met one evening a week for three hours. Each session – and sometimes more than one session — was devoted to discussing one of Earl’s published or unpublished macroeconomic or monetary theory papers. Hearing Earl explain his papers and respond to questions and criticisms brought them alive to me in a way that just reading them had never done, and I gradually realized that his arguments, which I had previously dismissed or misunderstood, were actually profoundly insightful and theoretically compelling.

For me at least, Earl provided a more systematic way of thinking about macroeconomics and a more systematic critique of standard macro than I could piece together from Axel’s writings and lectures. But one of the lessons that I had learned from Axel was the seminal importance of two Hayek essays: “The Use of Knowledge in Society,” and, especially “Economics and Knowledge.” The former essay is the easier to understand, and I got the gist of it on my first reading; the latter essay is more subtle and harder to follow, and it took years and a number of readings before I could really follow it. I’m not sure when I began to really understand it, but it might have been when I heard Earl expound on the importance of Hicks’s temporary-equilibrium method first introduced in Value and Capital.

In working out the temporary equilibrium method, Hicks relied on the work of Myrdal, Lindahl and Hayek, and Earl’s explanation of the temporary-equilibrium method based on the assumption that markets for current delivery clear, but those market-clearing prices are different from the prices that agents had expected when formulating their optimal intertemporal plans, causing agents to revise their plans and their expectations of future prices. That seemed to be the proper way to think about the intertemporal-coordination failures that Axel was so concerned about, but somehow he never made the connection between Hayek’s work, which he greatly admired, and the Hicksian temporary-equilibrium method which I never heard him refer to, even though he also greatly admired Hicks.

It always seemed to me that a collaboration between Earl and Axel could have been really productive and might even have led to an alternative to the Lucasian reign over macroeconomics. But for some reason, no such collaboration ever took place, and macroeconomics was impoverished as a result. They are both gone, but we still benefit from having Duncan Foley still with us, still active, and still making important contributions to our understanding, And we should be grateful.

A Tale of Two Syntheses

Published May 8, 2020 Arrow-Debrew-McKenzie model , Axel Leijonfuvud , comparative statics , coordination failure , Don Patinkin , DSGE models , Franklin Fisher , general equilibrium , Hawtrey , Hayek , intertemporal equilibrium , Kenneth Arrow , macroeconomics , microfoundations , neoclassical synthesis , New Classical macroeconomics , New Keynesians , Oskar Morgensterm , Robert Lucas , Roy Radner , Samuelson , stability of general equilibrium , temporary equilibrium , Thomas Schelling , Walrasian equilibrium 13 Comments
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I recently finished reading a slender, but weighty, collection of essays, Microfoundtions Reconsidered: The Relationship of Micro and Macroeconomics in Historical Perspective, edited by Pedro Duarte and Gilberto Lima; it contains in addition to a brief introductory essay by the editors, and contributions by Kevin Hoover, Robert Leonard, Wade Hands, Phil Mirowski, Michel De Vroey, and Pedro Duarte. The volume is both informative and stimulating, helping me to crystalize ideas about which I have been ruminating and writing for a long time, but especially in some of my more recent posts (e.g., here, here, and here) and my recent paper “Hayek, Hicks, Radner and Four Equilibrium Concepts.”

Hoover’s essay provides a historical account of the microfoundations, making clear that the search for microfoundations long preceded the Lucasian microfoundations movement of the 1970s and 1980s that would revolutionize macroeconomics in the late 1980s and early 1990s. I have been writing about the differences between varieties of microfoundations for quite a while (here and here), and Hoover provides valuable detail about early discussions of microfoundations and about their relationship to the now regnant Lucasian microfoundations dogma. But for my purposes here, Hoover’s key contribution is his deconstruction of the concept of microfoundations, showing that the idea of microfoundations depends crucially on the notion that agents in a macroeconomic model be explicit optimizers, meaning that they maximize an explicit function subject to explicit constraints.

What Hoover clarifies is vacuity of the Lucasian optimization dogma. Until Lucas, optimization by agents had been merely a necessary condition for a model to be microfounded. But there was also another condition: that the optimizing choices of agents be mutually consistent. Establishing that the optimizing choices of agents are mutually consistent is not necessarily easy or even possible, so often the consistency of optimizing plans can only be suggested by some sort of heuristic argument. But Lucas and his cohorts, followed by their acolytes, unable to explain, even informally or heuristically, how the optimizing choices of individual agents are rendered mutually consistent, instead resorted to question-begging and question-dodging techniques to avoid addressing the consistency issue, of which one — the most egregious, but not the only — is the representative agent. In so doing, Lucas et al. transformed the optimization problem from the coordination of multiple independent choices into the optimal plan of a single decision maker. Heckuva job!

The second essay by Robert Leonard, though not directly addressing the question of microfoundations, helps clarify and underscore the misrepresentation perpetrated by the Lucasian microfoundational dogma in disregarding and evading the need to describe a mechanism whereby the optimal choices of individual agents are, or could be, reconciled. Leonard focuses on a particular economist, Oskar Morgenstern, who began his career in Vienna as a not untypical adherent of the Austrian school of economics, a member of the Mises seminar and successor of F. A. Hayek as director of the Austrian Institute for Business Cycle Research upon Hayek’s 1931 departure to take a position at the London School of Economics. However, Morgenstern soon began to question the economic orthodoxy of neoclassical economic theory and its emphasis on the tendency of economic forces to reach a state of equilibrium.

In his famous early critique of the foundations of equilibrium theory, Morgenstern tried to show that the concept of perfect foresight, upon which, he alleged, the concept of equilibrium rests, is incoherent. To do so, Morgenstern used the example of the Holmes-Moriarity interaction in which Holmes and Moriarty are caught in a dilemma in which neither can predict whether the other will get off or stay on the train on which they are both passengers, because the optimal choice of each depends on the choice of the other. The unresolvable conflict between Holmes and Moriarty, in Morgenstern’s view, showed that the incoherence of the idea of perfect foresight.

As his disillusionment with orthodox economic theory deepened, Morgenstern became increasingly interested in the potential of mathematics to serve as a tool of economic analysis. Through his acquaintance with the mathematician Karl Menger, the son of Carl Menger, founder of the Austrian School of economics. Morgenstern became close to Menger’s student, Abraham Wald, a pure mathematician of exceptional ability, who, to support himself, was working on statistical and mathematical problems for the Austrian Institute for Business Cycle Resarch, and tutoring Morgenstern in mathematics and its applications to economic theory. Wald, himself, went on to make seminal contributions to mathematical economics and statistical analysis.

Moregenstern also became acquainted with another student of Menger, John von Neumnn, with an interest in applying advanced mathematics to economic theory. Von Neumann and Morgenstern would later collaborate in writing The Theory of Games and Economic Behavior, as a result of which Morgenstern came to reconsider his early view of the Holmes-Moriarty paradox inasmuch as it could be shown that an equilibrium solution of their interaction could be found if payoffs to their joint choices were specified, thereby enabling Holmes and Moriarty to choose optimal probablistic strategies.

I don’t think that the game-theoretic solution to the Holmes Moriarty game is as straightforward as Morgenstern eventually agreed, but the critical point in the microfoundations discussion is that the mathematical solution to the Holmes-Moriarty paradox acknowledges the necessity for the choices made by two or more agents in an economic or game-theoretic equilibrium to be reconciled – i.e., rendered mutually consistent — in equilibrium. Under Lucasian microfoundations dogma, the problem is either annihilated by positing an optimizing representative agent having no need to coordinate his decision with other agents (I leave the question who, in the Holmes-Moriarty interaction, is the representative agent as an exercise for the reader) or it is assumed away by positing the existence of a magical equilibrium with no explanation of how the mutually consistent choices are arrived at.

The third essay (“The Rise and Fall of Walrasian Economics: The Keynes Effect”) by Wade Hands considers the first of the two syntheses – the neoclassical synthesis — that are alluded to in the title of this post. Hands gives a learned account of the mutually reinforcing co-development of Walrasian general equilibrium theory and Keynesian economics in the 25 years or so following World War II. Although Hands agrees that there is no necessary connection between Walrasian GE theory and Keynesian theory, he argues that there was enough common ground between Keynesians and Walrasians, as famously explained by Hicks in summarizing Keynesian theory by way of his IS-LM model, to allow the two disparate research programs to nourish each other in a kind of symbiotic relationship as the two research programs came to dominate postwar economics.

The task for Keynesian macroeconomists following the lead of Samuelson, Solow and Modigliani at MIT, Alvin Hansen at Harvard and James Tobin at Yale was to elaborate the Hicksian IS-LM approach by embedding it in a more general Walrasian framework. In so doing, they helped to shape a research agenda for Walrasian general-equilibrium theorists working out the details of the newly developed Arrow-Debreu model, deriving conditions for the uniqueness and stability of the equilibrium of that model. The neoclassical synthesis followed from those efforts, achieving an uneasy reconciliation between Walrasian general equilibrium theory and Keynesian theory. It received its most complete articulation in the impressive treatise of Don Patinkin which attempted to derive or at least evaluate key Keyensian propositions in the context of a full general equilibrium model. At an even higher level of theoretical sophistication, the 1971 summation of general equilibrium theory by Arrow and Hahn, gave disproportionate attention to Keynesian ideas which were presented and analyzed using the tools of state-of-the art Walrasian analysis.

Hands sums up the coexistence of Walrasian and Keynesian ideas in the Arrow-Hahn volume as follows:

Arrow and Hahn’s General Competitive Analysis – the canonical summary of the literature – dedicated far more pages to stability than to any other topic. The book had fourteen chapters (and a number of mathematical appendices); there was one chapter on consumer choice, one chapter on production theory, and one chapter on existence [of equilibrium], but there were three chapters on stability analysis, (two on the traditional tatonnement and one on alternative ways of modeling general equilibrium dynamics). Add to this the fact that there was an important chapter on “The Keynesian Model’; and it becomes clear how important stability analysis and its connection to Keynesian economics was for Walrasian microeconomics during this period. The purpose of this section has been to show that that would not have been the case if the Walrasian economics of the day had not been a product of co-evolution with Keynesian economic theory. (p. 108)

What seems most unfortunate about the neoclassical synthesis is that it elevated and reinforced the least relevant and least fruitful features of both the Walrasian and the Keynesian research programs. The Hicksian IS-LM setup abstracted from the dynamic and forward-looking aspects of Keynesian theory, modeling a static one-period model, not easily deployed as a tool of dynamic analysis. Walrasian GE analysis, which, following the pathbreaking GE existence proofs of Arrow and Debreu, then proceeded to a disappointing search for the conditions for a unique and stable general equilibrium.

It was Paul Samuelson who, building on Hicks’s pioneering foray into stability analysis, argued that the stability question could be answered by investigating whether a system of Lyapounov differential equations could describe market price adjustments as functions of market excess demands that would converge on an equilibrium price vector. But Samuelson’s approach to establishing stability required the mechanism of a fictional tatonnement process. Even with that unsatisfactory assumption, the stability results were disappointing.

Although for Walrasian theorists the results hardly repaid the effort expended, for those Keynesians who interpreted Keynes as an instability theorist, the weak Walrasian stability results might have been viewed as encouraging. But that was not any easy route to take either, because Keynes had also argued that a persistent unemployment equilibrium might be the norm.

It’s also hard to understand how the stability of equilibrium in an imaginary tatonnement process could ever have been considered relevant to the operation of an actual economy in real time – a leap of faith almost as extraordinary as imagining an economy represented by a single agent. Any conventional comparative-statics exercise – the bread and butter of microeconomic analysis – involves comparing two equilibria, corresponding to a specified parametric change in the conditions of the economy. The comparison presumes that, starting from an equilibrium position, the parametric change leads from an initial to a new equilibrium. If the economy isn’t stable, a disturbance causing an economy to depart from an initial equilibrium need not result in an adjustment to a new equilibrium comparable to the old one.

If conventional comparative statics hinges on an implicit stability assumption, it’s hard to see how a stability analysis of tatonnement has any bearing on the comparative-statics routinely relied upon by economists. No actual economy ever adjusts to a parametric change by way of tatonnement. Whether a parametric change displacing an economy from its equilibrium time path would lead the economy toward another equilibrium time path is another interesting and relevant question, but it’s difficult to see what insight would be gained by proving the stability of equilibrium under a tatonnement process.

Moreover, there is a distinct question about the endogenous stability of an economy: are there endogenous tendencies within an economy that lead it away from its equilibrium time path. But questions of endogenous stability can only be posed in a dynamic, rather than a static, model. While extending the Walrasian model to include an infinity of time periods, Arrow and Debreu telescoped determination of the intertemporal-equilibrium price vector into a preliminary time period before time, production, exchange and consumption begin. So, even in the formally intertemporal Arrow-Debreu model, the equilibrium price vector, once determined, is fixed and not subject to revision. Standard stability analysis was concerned with the response over time to changing circumstances only insofar as changes are foreseen at time zero, before time begins, so that they can be and are taken fully into account when the equilibrium price vector is determined.

Though not entirely uninteresting, the intertemporal analysis had little relevance to the stability of an actual economy operating in real time. Thus, neither the standard Keyensian (IS-LM) model nor the standard Walrasian Arrow-Debreu model provided an intertemporal framework within which to address the dynamic stability that Keynes (and contemporaries like Hayek, Myrdal, Lindahl and Hicks) had developed in the 1930s. In particular, Hicks’s analytical device of temporary equilibrium might have facilitated such an analysis. But, having introduced his IS-LM model two years before publishing his temporary equilibrium analysis in Value and Capital, Hicks concentrated his attention primarily on Keynesian analysis and did not return to the temporary equilibrium model until 1965 in Capital and Growth. And it was IS-LM that became, for a generation or two, the preferred analytical framework for macroeconomic analysis, while temproary equilibrium remained overlooked until the 1970s just as the neoclassical synthesis started coming apart.

The fourth essay by Phil Mirowski investigates the role of the Cowles Commission, based at the University of Chicago from 1939 to 1955, in undermining Keynesian macroeconomics. While Hands argues that Walrasians and Keynesians came together in a non-hostile spirit of tacit cooperation, Mirowski believes that owing to their Walrasian sympathies, the Cowles Committee had an implicit anti-Keynesian orientation and was therefore at best unsympathetic if not overtly hostile to Keynesian theorizing, which was incompatible the Walrasian optimization paradigm endorsed by the Cowles economists. (Another layer of unexplored complexity is the tension between the Walrasianism of the Cowles economists and the Marshallianism of the Chicago School economists, especially Knight and Friedman, which made Chicago an inhospitable home for the Cowles Commission and led to its eventual departure to Yale.)

Whatever differences, both the Mirowski and the Hands essays support the conclusion that the uneasy relationship between Walrasianism and Keynesianism was inherently problematic and unltimately unsustainable. But to me the tragedy is that before the fall, in the 1950s and 1960s, when the neoclassical synthesis bestrode economics like a colossus, the static orientation of both the Walrasian and the Keynesian research programs combined to distract economists from a more promising research program. Such a program, instead of treating expectations either as parametric constants or as merely adaptive, based on an assumed distributed lag function, might have considered whether expectations could perform a potentially equilibrating role in a general equilibrium model.

The equilibrating role of expectations, though implicit in various contributions by Hayek, Myrdal, Lindahl, Irving Fisher, and even Keynes, is contingent so that equilibrium is not inevitable, only a possibility. Instead, the introduction of expectations as an equilibrating variable did not occur until the mid-1970s when Robert Lucas, Tom Sargent and Neil Wallace, borrowing from John Muth’s work in applied microeconomics, introduced the idea of rational expectations into macroeconomics. But in introducing rational expectations, Lucas et al. made rational expectations not the condition of a contingent equilibrium but an indisputable postulate guaranteeing the realization of equilibrium without offering any theoretical account of a mechanism whereby the rationality of expectations is achieved.

The fifth essay by Michel DeVroey (“Microfoundations: a decisive dividing line between Keynesian and new classical macroeconomics?”) is a philosophically sophisticated analysis of Lucasian microfoundations methodological principles. DeVroey begins by crediting Lucas with the revolution in macroeconomics that displaced a Keynesian orthodoxy already discredited in the eyes of many economists after its failure to account for simultaneously rising inflation and unemployment.

The apparent theoretical disorder characterizing the Keynesian orthodoxy and its Monetarist opposition left a void for Lucas to fill by providing a seemingly rigorous microfounded alternative to the confused state of macroeconomics. And microfoundations became the methodological weapon by which Lucas and his associates and followers imposed an iron discipline on the unruly community of macroeconomists. “In Lucas’s eyes,” DeVroey aptly writes,“ the mere intention to produce a theory of involuntary unemployment constitutes an infringement of the equilibrium discipline.” Showing that his description of Lucas is hardly overstated, DeVroey quotes from the famous 1978 joint declaration of war issued by Lucas and Sargent against Keynesian macroeconomics:

After freeing himself of the straightjacket (or discipline) imposed by the classical postulates, Keynes described a model in which rules of thumb, such as the consumption function and liquidity preference schedule, took the place of decision functions that a classical economist would insist be derived from the theory of choice. And rather than require that wages and prices be determined by the postulate that markets clear – which for the labor market seemed patently contradicted by the severity of business depressions – Keynes took as an unexamined postulate that money wages are sticky, meaning that they are set at a level or by a process that could be taken as uninfluenced by the macroeconomic forces he proposed to analyze.

Echoing Keynes’s famous description of the sway of Ricardian doctrines over England in the nineteenth century, DeVroey remarks that the microfoundations requirement “conquered macroeconomics as quickly and thoroughly as the Holy Inquisition conquered Spain,” noting, even more tellingly, that the conquest was achieved without providing any justification. Ricardo had, at least, provided a substantive analysis that could be debated; Lucas offered only an undisputable methodological imperative about the sole acceptable mode of macroeconomic reasoning. Just as optimization is a necessary component of the equilibrium discipline that had to be ruthlessly imposed on pain of excommunication from the macroeconomic community, so, too, did the correlate principle of market-clearing. To deviate from the market-clearing postulate was ipso facto evidence of an impure and heretical state of mind. DeVroey further quotes from the war declaration of Lucas and Sargent.

Cleared markets is simply a principle, not verifiable by direct observation, which may or may not be useful in constructing successful hypotheses about the behavior of these [time] series.

What was only implicit in the war declaration became evident later after right-thinking was enforced, and woe unto him that dared deviate from the right way of thinking.

But, as DeVroey skillfully shows, what is most remarkable is that, having declared market clearing an indisputable methodological principle, Lucas, contrary to his own demand for theoretical discipline, used the market-clearing postulate to free himself from the very equilibrium discipline he claimed to be imposing. How did the market-clearing postulate liberate Lucas from equilibrium discipline? To show how the sleight-of-hand was accomplished, DeVroey, in an argument parallel to that of Hoover in chapter one and that suggested by Leonard in chapter two, contrasts Lucas’s conception of microfoundations with a different microfoundations conception espoused by Hayek and Patinkin. Unlike Lucas, Hayek and Patinkin recognized that the optimization of individual economic agents is conditional on the optimization of other agents. Lucas assumes that if all agents optimize, then their individual optimization ensures that a social optimum is achieved, the whole being the sum of its parts. But that assumption ignores that the choices made interacting agents are themelves interdependent.

To capture the distinction between independent and interdependent optimization, DeVroey distinguishes between optimal plans and optimal behavior. Behavior is optimal only if an optimal plan can be executed. All agents can optimize individually in making their plans, but the optimality of their behavior depends on their capacity to carry those plans out. And the capacity of each to carry out his plan is contingent on the optimal choices of all other agents.

Optimizing plans refers to agents’ intentions before the opening of trading, the solution to the choice-theoretical problem with which they are faced. Optimizing behavior refers to what is observable after trading has started. Thus optimal behavior implies that the optimal plan has been realized. . . . [O]ptmizing plans and optimizing behavior need to be logically separated – there is a difference between finding a solution to a choice problem and implementing the solution. In contrast, whenever optimizing behavior is the sole concept used, the possibility of there being a difference between them is discarded by definition. This is the standpoint takenby Lucas and Sargent. Once it is adopted, it becomes misleading to claim . . .that the microfoundations requirement is based on two criteria, optimizing behavior and market clearing. A single criterion is needed, and it is irrelevant whether this is called generalized optimizing behavior or market clearing. (De Vroey, p. 176)

Each agent is free to optimize his plan, but no agent can execute his optimal plan unless the plan coincides with the complementary plans of other agents. So, the execution of an optimal plan is not within the unilateral control of an agent formulating his own plan. One can readily assume that agents optimize their plans, but one cannot just assume that those plans can be executed as planned. The optimality of interdependent plans is not self-evident; it is a proposition that must be demonstrated. Assuming that agents optimize, Lucas simply asserts that, because agents optimize, markets must clear.

That is a remarkable non-sequitur. And from that non-sequitur, Lucas jumps to a further non-sequitur: that an optimizing representative agent is all that’s required for a macroeconomic model. The logical straightjacket (or discipline) of demonstrating that interdependent optimal plans are consistent is thus discarded (or trampled upon). Lucas’s insistence on a market-clearing principle turns out to be subterfuge by which the pretense of its upholding conceals its violation in practice.

My own view is that the assumption that agents formulate optimizing plans cannot be maintained without further analysis unless the agents are operating in isolation. If the agents interacting with each other, the assumption that they optimize requires a theory of their interaction. If the focus is on equilibrium interactions, then one can have a theory of equilibrium, but then the possibility of non-equilibrium states must also be acknowledged.

That is what John Nash did in developing his equilibrium theory of positive-sum games. He defined conditions for the existence of equilibrium, but he offered no theory of how equilibrium is achieved. Lacking such a theory, he acknowledged that non-equilibrium solutions might occur, e.g., in some variant of the Holmes-Moriarty game. To simply assert that because interdependent agents try to optimize, they must, as a matter of principle, succeed in optimizing is to engage in question-begging on a truly grand scale. To insist, as a matter of methodological principle, that everyone else must also engage in question-begging on equally grand scale is what I have previously called methodological arrogance, though an even harsher description might be appropriate.

In the sixth essay (“Not Going Away: Microfoundations in the making of a new consensus in macroeconomics”), Pedro Duarte considers the current state of apparent macroeconomic consensus in the wake of the sweeping triumph of the Lucasian micorfoundtions methodological imperative. In its current state, mainstream macroeconomists from a variety of backgrounds have reconciled themselves and adjusted to the methodological absolutism Lucas and his associates and followers have imposed on macroeconomic theorizing. Leading proponents of the current consensus are pleased to announce, in unseemly self-satisfaction, that macroeconomics is now – but presumably not previously – “firmly grounded in the principles of economic [presumably neoclassical] theory.” But the underlying conception of neoclassical economic theory motivating such a statement is almost laughably narrow, and, as I have just shown, strictly false even if, for argument’s sake, that narrow conception is accepted.

Duarte provides an informative historical account of the process whereby most mainstream Keynesians and former old-line Monetarists, who had, in fact, adopted much of the underlying Keynesian theoretical framework themselves, became reconciled to the non-negotiable methodological microfoundational demands upon which Lucas and his New Classical followers and Real-Business-Cycle fellow-travelers insisted. While Lucas was willing to tolerate differences of opinion about the importance of monetary factors in accounting for business-cycle fluctuations in real output and employment, and even willing to countenance a role for countercyclical monetary policy, such differences of opinion could be tolerated only if they could be derived from an acceptable microfounded model in which the agent(s) form rational expectations. If New Keynesians were able to produce results rationalizing countercyclical policies in such microfounded models with rational expectations, Lucas was satisfied. Presumably, Lucas felt the price of conceding the theoretical legitimacy of countercyclical policy was worth paying in order to achieve methodological hegemony over macroeconomic theory.

And no doubt, for Lucas, the price was worth paying, because it led to what Marvin Goodfriend and Robert King called the New Neoclassical Synthesis in their 1997 article ushering in the new era of good feelings, a synthesis based on “the systematic application of intertemporal optimization and rational expectations” while embodying “the insights of monetarists . . . regarding the theory and practice of monetary policy.”

While the first synthesis brought about a convergence of sorts between the disparate Walrasian and Keynesian theoretical frameworks, the convergence proved unstable because the inherent theoretical weaknesses of both paradigms were unable to withstand criticisms of the theoretical apparatus and of the policy recommendations emerging from that synthesis, particularly an inability to provide a straightforward analysis of inflation when it became a serious policy problem in the late 1960s and 1970s. But neither the Keynesian nor the Walrasian paradigms were developing in a way that addressed the points of most serious weakness.

On the Keynesian side, the defects included the static nature of the workhorse IS-LM model, the absence of a market for real capital and of a market for endogenous money. On the Walrasian side, the defects were the lack of any theory of actual price determination or of dynamic adjustment. The Hicksian temporary equilibrium paradigm might have provided a viable way forward, and for a very different kind of synthesis, but not even Hicks himself realized the potential of his own creation.

While the first synthesis was a product of convenience and misplaced optimism, the second synthesis is a product of methodological hubris and misplaced complacency derived from an elementary misunderstanding of the distinction between optimization by a single agent and the simultaneous optimization of two or more independent, yet interdependent, agents. The equilibrium of each is the result of the equilibrium of all, and a theory of optimization involving two or more agents requires a theory of how two or more interdependent agents can optimize simultaneously. The New neoclassical synthesis rests on the demand for a macroeconomic theory of individual optimization that refuses even to ask, let along provide an answer to, the question whether the optimization that it demands is actually achieved in practice or what happens if it is not. This is not a synthesis that will last, or that deserves to. And the sooner it collapses, the better off macroeconomics will be.

What the answer is I don’t know, but if I had to offer a suggestion, the one offered by my teacher Axel Leijonhufvud towards the end of his great book, written more than half a century ago, strikes me as not bad at all:

One cannot assume that what went wrong was simply that Keynes slipped up here and there in his adaptation of standard tool, and that consequently, if we go back and tinker a little more with the Marshallian toolbox his purposes will be realized. What is required, I believe, is a systematic investigation, form the standpoint of the information problems stressed in this study, of what elements of the static theory of resource allocation can without further ado be utilized in the analysis of dynamic and historical systems. This, of course, would be merely a first-step: the gap yawns very wide between the systematic and rigorous modern analysis of the stability of “featureless,” pure exchange systems and Keynes’ inspired sketch of the income-constrained process in a monetary-exchange-cum-production system. But even for such a first step, the prescription cannot be to “go back to Keynes.” If one must retrace some steps of past developments in order to get on the right track—and that is probably advisable—my own preference is to go back to Hayek. Hayek’s Gestalt-conception of what happens during business cycles, it has been generally agreed, was much less sound than Keynes’. As an unhappy consequence, his far superior work on the fundamentals of the problem has not received the attention it deserves. (p. 401)

I agree with all that, but would also recommend Roy Radner’s development of an alternative to the Arrow-Debreu version of Walrasian general equilibrium theory that can accommodate Hicksian temporary equilibrium, and Hawtrey’s important contributions to our understanding of monetary theory and the role and potential instability of endogenous bank money. On top of that, Franklin Fisher in his important work, The Disequilibrium Foundations of Equilibrium Economics, has given us further valuable guidance in how to improve the current sorry state of macroeconomics.

 

Traffic Jams and Multipliers

Published December 12, 2014 Brian Arthur , complexity economics , coordination failure , general equilibrium , macroeconomics , microfoundations , multiplier 15 Comments
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Since my previous post which I closed by quoting the abstract of Brian Arthur’s paper “Complexity Economics: A Different Framework for Economic Thought,” I have been reading his paper and some of the papers he cites, especially Magda Fontana’s paper “The Santa Fe Perspective on Economics: Emerging Patterns in the Science of Complexity,” and Mark Blaug’s paper “The Formalist Revolution of the 1950s.” The papers bring together a number of themes that I have been emphasizing in previous posts on what I consider the misguided focus of modern macroeconomics on rational-expectations equilibrium as the organizing principle of macroeconomic theory. Among these themes are the importance of coordination failures in explaining macroeconomic fluctuations, the inappropriateness of the full general-equilibrium paradigm in macroeconomics, the mistaken transformation of microfoundations from a theoretical problem to be solved into an absolute methodological requirement to be insisted upon (almost exactly analogous to the absurd transformation of the mind-body problem into a dogmatic insistence that the mind is merely a figment of our own imagination), or, stated another way, a recognition that macrofoundations are just as necessary for economics as microfoundations.

Let me quote again from Arthur’s essay; this time a beautiful passage which captures the interdependence between the micro and macro perspectives

To look at the economy, or areas within the economy, from a complexity viewpoint then would mean asking how it evolves, and this means examining in detail how individual agents’ behaviors together form some outcome and how this might in turn alter their behavior as a result. Complexity in other words asks how individual behaviors might react to the pattern they together create, and how that pattern would alter itself as a result. This is often a difficult question; we are asking how a process is created from the purposed actions of multiple agents. And so economics early in its history took a simpler approach, one more amenable to mathematical analysis. It asked not how agents’ behaviors would react to the aggregate patterns these created, but what behaviors (actions, strategies, expectations) would be upheld by — would be consistent with — the aggregate patterns these caused. It asked in other words what patterns would call for no changes in microbehavior, and would therefore be in stasis, or equilibrium. (General equilibrium theory thus asked what prices and quantities of goods produced and consumed would be consistent with — would pose no incentives for change to — the overall pattern of prices and quantities in the economy’s markets. Classical game theory asked what strategies, moves, or allocations would be consistent with — would be the best course of action for an agent (under some criterion) — given the strategies, moves, allocations his rivals might choose. And rational expectations economics asked what expectations would be consistent with — would on average be validated by — the outcomes these expectations together created.)

This equilibrium shortcut was a natural way to examine patterns in the economy and render them open to mathematical analysis. It was an understandable — even proper — way to push economics forward. And it achieved a great deal. Its central construct, general equilibrium theory, is not just mathematically elegant; in modeling the economy it re-composes it in our minds, gives us a way to picture it, a way to comprehend the economy in its wholeness. This is extremely valuable, and the same can be said for other equilibrium modelings: of the theory of the firm, of international trade, of financial markets.

But there has been a price for this equilibrium finesse. Economists have objected to it — to the neoclassical construction it has brought about — on the grounds that it posits an idealized, rationalized world that distorts reality, one whose underlying assumptions are often chosen for analytical convenience. I share these objections. Like many economists, I admire the beauty of the neoclassical economy; but for me the construct is too pure, too brittle — too bled of reality. It lives in a Platonic world of order, stasis, knowableness, and perfection. Absent from it is the ambiguous, the messy, the real. (pp. 2-3)

Later in the essay, Arthur provides a simple example of a non-equilibrium complex process: traffic flow.

A typical model would acknowledge that at close separation from cars in front, cars lower their speed, and at wide separation they raise it. A given high density of traffic of N cars per mile would imply a certain average separation, and cars would slow or accelerate to a speed that corresponds. Trivially, an equilibrium speed emerges, and if we were restricting solutions to equilibrium that is all we would see. But in practice at high density, a nonequilibrium phenomenon occurs. Some car may slow down — its driver may lose concentration or get distracted — and this might cause cars behind to slow down. This immediately compresses the flow, which causes further slowing of the cars behind. The compression propagates backwards, traffic backs up, and a jam emerges. In due course the jam clears. But notice three things. The phenomenon’s onset is spontaneous; each instance of it is unique in time of appearance, length of propagation, and time of clearing. It is therefore not easily captured by closed-form solutions, but best studied by probabilistic or statistical methods. Second, the phenomenon is temporal, it emerges or happens within time, and cannot appear if we insist on equilibrium. And third, the phenomenon occurs neither at the micro-level (individual car level) nor at the macro-level (overall flow on the road) but at a level in between — the meso-level. (p. 9)

This simple example provides an excellent insight into why macroeconomic reasoning can be led badly astray by focusing on the purely equilibrium relationships characterizing what we now think of as microfounded models. In arguing against the Keynesian multiplier analysis supposedly justifying increased government spending as a countercyclical tool, Robert Barro wrote the following in an unfortunate Wall Street Journal op-ed piece, which I have previously commented on here and here.

Keynesian economics argues that incentives and other forces in regular economics are overwhelmed, at least in recessions, by effects involving “aggregate demand.” Recipients of food stamps use their transfers to consume more. Compared to this urge, the negative effects on consumption and investment by taxpayers are viewed as weaker in magnitude, particularly when the transfers are deficit-financed.

Thus, the aggregate demand for goods rises, and businesses respond by selling more goods and then by raising production and employment. The additional wage and profit income leads to further expansions of demand and, hence, to more production and employment. As per Mr. Vilsack, the administration believes that the cumulative effect is a multiplier around two.

If valid, this result would be truly miraculous. The recipients of food stamps get, say, $1 billion but they are not the only ones who benefit. Another $1 billion appears that can make the rest of society better off. Unlike the trade-off in regular economics, that extra $1 billion is the ultimate free lunch.

How can it be right? Where was the market failure that allowed the government to improve things just by borrowing money and giving it to people? Keynes, in his “General Theory” (1936), was not so good at explaining why this worked, and subsequent generations of Keynesian economists (including my own youthful efforts) have not been more successful.

In the disequilibrium environment of a recession, it is at least possible that injecting additional spending into the economy could produce effects that a similar injection of spending, under “normal” macro conditions, would not produce, just as somehow withdrawing a few cars from a congested road could increase the average speed of all the remaining cars on the road, by a much greater amount than would withdrawing a few cars from an uncongested road. In other words, microresponses may be sensitive to macroconditions.

Aggregate Demand and Coordination Failures

Published October 8, 2014 Axel Leijonfuvud , coordination failure , credit deadlock , Earl Thompson , Hawtrey , Hayek , Keynes , liquidity trap 14 Comments
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Regular readers of this blog may have noticed that I have been writing less about monetary policy and more about theory and methodology than when I started blogging a little over three years ago. Now one reason for that is that I’ve already said what I want to say about policy, and, since I get bored easily, I look for new things to write about. Another reason is that, at least in the US, the economy seems to have reached a sustainable growth path that seems likely to continue for the near to intermediate term. I think that monetary policy could be doing more to promote recovery, and I wish that it would, but unfortunately, the policy is what it is, and it will continue more or less in the way that Janet Yellen has been saying it will. Falling oil prices, because of increasing US oil output, suggest that growth may speed up slightly even as inflation stays low, possibly even falling to one percent or less. At least in the short-term, the fall in inflation does not seem like a cause for concern. A third reason for writing less about monetary policy is that I have been giving a lot of thought to what it is that I dislike about the current state of macroeconomics, and as I have been thinking about it, I have been writing about it.

In thinking about what I think is wrong with modern macroeconomics, I have been coming back again and again, though usually without explicit attribution, to an idea that was impressed upon me as an undergrad and grad student by Axel Leijonhufvud: that the main concern of macroeconomics ought to be with failures of coordination. A Swede, trained in the tradition of the Wicksellian Stockholm School, Leijonhufvud immersed himself in the study of the economics of Keynes and Keynesian economics, while also mastering the Austrian literature, and becoming an admirer of Hayek, especially Hayek’s seminal 1937 paper, “Economics and Knowledge.”

In discussing Keynes, Leijonhufvud focused on two kinds of coordination failures.

First, there is a problem in the labor market. If there is unemployment because the real wage is too high, an individual worker can’t solve the problem by offering to accept a reduced nominal wage. Suppose the price of output is $1 a unit and the wage is $10 a day, but the real wage consistent with full employment is $9 a day, meaning that producers choose to produce less output than they would produce if the real wage were lower, thus hiring fewer workers than they would if the real wage were lower than it is. If an individual worker offers to accept a wage of $9 a day, but other workers continue to hold out for $10 a day, it’s not clear that an employer would want to hire the worker who offers to work for $9 a day. If employers are not hiring additional workers because they can’t cover the cost of the additional output produced with the incremental revenue generated by the added output, the willingness of one worker to work for $9 a day is not likely to make a difference to the employer’s output and hiring decisions. It is not obvious what sequence of transactions would result in an increase in output and employment when the real wage is above the equilibrium level. There are complex feedback effects from a change, so that the net effect of making those changes in a piecemeal fashion is unpredictable, even though there is a possible full-employment equilibrium with a real wage of $9 a day. If the problem is that real wages in general are too high for full employment, the willingness of an individual worker to accept a reduced wage from a single employer does not fix the problem.

In the standard competitive model, there is a perfect market for every commodity in which every transactor is assumed to be able to buy and sell as much as he wants. But the standard competitive model has very little to say about the process by which those equilibrium prices are arrived at. And a typical worker is never faced with that kind of choice posited in the competitive model: an impersonal uniform wage at which he can decide how many hours a day or week or year he wants to work at that uniform wage. Under those circumstances, Keynes argued that the willingness of some workers to accept wage cuts in order to gain employment would not significantly increase employment, and might actually have destabilizing side-effects. Keynes tried to make this argument in the framework of an equilibrium model, though the nature of the argument, as Don Patinkin among others observed, was really better suited to a disequilibrium framework. Unfortunately, Keynes’s argument was subsequently dumbed down to a simple assertion that wages and prices are sticky (especially downward).

Second, there is an intertemporal problem, because the interest rate may be stuck at a rate too high to allow enough current investment to generate the full-employment level of spending given the current level of the money wage. In this scenario, unemployment isn’t caused by a real wage that is too high, so trying to fix it by wage adjustment would be a mistake. Since the source of the problem is the rate of interest, the way to fix the problem would be to reduce the rate of interest. But depending on the circumstances, there may be a coordination failure: bear speculators, expecting the rate of interest to rise when it falls to abnormally low levels, prevent the rate of interest from falling enough to induce enough investment to support full employment. Keynes put too much weight on bear speculators as the source of the intertemporal problem; Hawtrey’s notion of a credit deadlock would actually have been a better way to go, and nowadays, when people speak about a Keynesian liquidity trap, what they really have in mind is something closer to Hawtreyan credit deadlock than to the Keynesian liquidity trap.

Keynes surely deserves credit for identifying and explaining two possible sources of coordination failures, failures affecting the macroeconomy, because interest rates and wages, though they actually come in many different shapes and sizes, affect all markets and are true macroeconomic variables. But Keynes’s analysis of those coordination failures was far from being fully satisfactory, which is not surprising; a theoretical pioneer rarely provides a fully satisfactory analysis, leaving lots of work for successors.

But I think that Keynes’s theoretical paradigm actually did lead macroeconomics in the wrong direction, in the direction of a highly aggregated model with a single output, a bond, a medium of exchange, and a labor market, with no explicit characterization of the production technology. (I.e., is there one factor or two, and if two how is the price of the second factor determined? See, here, here, here, and here my discussion of Earl Thompson’s “A Reformulation of Macroeconomic Theory,” which I hope at some point to revisit and continue.)

Why was it the wrong direction? Because, the Keynesian model (both Keynes’s own version and the Hicksian IS-LM version of his model) ruled out the sort of coordination problems that might arise in a multi-product, multi-factor, intertemporal model in which total output depends in a meaningful way on the meshing of the interdependent plans, independently formulated by decentralized decision-makers, contingent on possibly inconsistent expectations of the future. In the over-simplified and over-aggregated Keynesian model, the essence of the coordination problem has been assumed away, leaving only a residue of the actual problem to be addressed by the model. The focus of the model is on aggregate expenditure, income, and output flows, with no attention paid to the truly daunting task of achieving sufficient coordination among the independent decision makers to allow total output and income to closely approximate the maximum sustainable output and income that the system could generate in a perfectly coordinated state, aka full intertemporal equilibrium.

This way of thinking about macroeconomics led to the merging of macroeconomics with neoclassical growth theory and to the routine and unthinking incorporation of aggregate production functions in macroeconomic models, a practice that is strictly justified only in a single-output, two-factor model in which the value of capital is independent of the rate of interest, so that the havoc-producing effects of reswitching and capital-reversal can be avoided. Eventually, these models were taken over by modern real-business-cycle theorists, who dogmatically rule out any consideration of coordination problems, while attributing all observed output and employment fluctuations to random productivity shocks. If one thinks of macroeconomics as an attempt to understand coordination failures, the RBC explanation of output and employment fluctuations is totally backwards; productivity fluctuations, like fluctuations in output and employment, are the not the results of unexplained random disturbances, they are the symptoms of coordination failures. That’s it, eureka! Solve the problem by assuming that it does not exist.

If you are thinking that this seems like an Austrian critique of the Keynesian model or the Keynesian approach, you are right; it is an Austrian critique. But it has nothing to do with stereotypical Austrian policy negativism; it is a critique of the oversimplified structure of the Keynesian model, which foreshadowed the reduction ad absurdum or modern real-business-cycle theory, which has nearly banished the idea of coordination failures from modern macroeconomics. The critique is not about the lack of a roundabout capital structure; it is about the narrow scope for inconsistencies in production and consumption plans.

I think that Leijonhufvud almost 40 years ago was getting at this point when he wrote the following paragraph near toward end of his book on Keynes.

The unclear mix of statics and dynamics [in the General Theory] would seem to be main reason for later muddles. One cannot assume that what went wrong was simply that Keynes slipped up here and there in his adaptation of standard tools, and that consequently, if we go back and tinker a little more with the Marshallian toolbox his purposes will be realized. What is required, I believe, is a systematic investigation from the standpoint of the information problems stressed in this study, of what elements of the static theory of resource allocation can without further ado be utilized in the analysis of dynamic and historical systems. This, of course, would be merely a first step: the gap yawns very wide between the systematic and rigorous modern analysis of the stability of simple, “featureless,” pure exchange systems and Keynes’ inspired sketch of the income-constrained process in a monetary exchange-cum production system. But even for such a first step, the prescription cannot be to “go back to Keynes.” If one must retrace some step of past developments in order to get on the right track – and that is probably advisable – my own preference is to go back to Hayek. Hayek’s Gestalt-conception of what happens during business cycles, it has been generally agreed, was much less sound that Keynes’. As an unhappy consequence, his far superior work on the fundamentals of the problem has not received the attention it deserves. (pp. 401-02)

I don’t think that we actually need to go back to Hayek, though “Economics and Knowledge” should certainly be read by every macroeconomist, but we do need to get a clearer understanding of the potential for breakdowns in economic activity to be caused by inconsistent expectations, especially when expectations are themselves mutually dependent and reinforcing. Because expectations are mutually interdependent, they are highly susceptible to network effects. Network effects produce tipping points, tipping points can lead to catastrophic outcomes. Just wanted to share that with you. Have a nice day.

Nick Rowe Teaches Us a Lot about Apples and Bananas

Published September 17, 2014 coordination failure , expectations , networks , Nick Rowe 13 Comments
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Last week I wrote a post responding to a post by Nick Rowe about money and coordination failures. Over the weekend, Nick posted a response to my post (and to one by Brad Delong). Nick’s latest post was all about apples and bananas. It was an interesting post, though for some reason – no doubt unrelated to its form or substance – I found the post difficult to read and think about. But having now read, and I think, understood (more or less), what Nick wrote, I confess to being somewhat underwhelmed. Let me try to explain why I don’t think that Nick has adequately addressed the point that I was raising.

That point being that while coordination failures can indeed be, and frequently are, the result of a monetary disturbance, one that creates an excess demand for money, thereby leading to a contraction of spending, and thus to a reduction of output and employment, it is also possible that a coordination failure can occur independently of a monetary disturbance, at least a disturbance that could be characterized as an excess demand for money that triggers a reduction in spending, income, output, and employment.

Without evaluating his reasoning, I will just restate key elements of Nick’s model – actually two parallel models. There are apple trees and banana trees, and people like to consume both apples and bananas. Some people own apple trees, and some people own banana trees. Owners of apple trees and owners of banana trees trade apples for bananas, so that they can consume a well-balanced diet of both apples and bananas. Oh, and there’s also some gold around. People like gold, but it’s not clear why. In one version of the model, people use it as a medium of exchange, selling bananas for gold and using gold to buy apples or selling apples for gold and using gold to buy bananas. In the other version of the model, people just barter apples for bananas. Nick then proceeds to show that if trade is conducted by barter, an increase in the demand for gold, does not affect the allocation of resources, because agents continue to trade apples for bananas to achieve the desired allocation, even if the value of gold is held fixed. However, if trade is mediated by gold, the increased demand for gold, with prices held fixed, implies corresponding excess supplies of both apples and bananas, preventing the optimal reallocation of apples and bananas through trade, which Nick characterizes as a recession. However, if there is a shift in demand from bananas to apples or vice versa, with prices fixed in either model, there will be an excess demand for bananas and an excess supply of apples (or vice versa). The outcome is suboptimal because Pareto-improving trade is prevented, but there is no recession in Nick’s view because the excess supply of one real good is exactly offset by an excess demand for the other real good. Finally, Nick considers a case in which there is trade in apple trees and banana trees. An increase in the demand for fruit trees, owing to a reduced rate of time preference, causes no problems in the barter model, because there is no impediment to trading apples for bananas. However, in the money model, the reduced rate of time preference causes an increase in the amount of gold people want to hold, the foregone interest from holding more having been reduced, which prevents optimal trade with prices held fixed.

Here are the conclusions that Nick draws from his two models.

Bottom line. My conclusions.

For the second shock (a change in preferences away from apples towards bananas), we get the same reduction in the volume of trade whether we are in a barter or a monetary economy. Monetary coordination failures play no role in this sort of “recession”. But would we call that a “recession”? Well, it doesn’t look like a normal recession, because there is an excess demand for bananas.

For both the first and third shocks, we get a reduction in the volume of trade in a monetary economy, and none in the barter economy. Monetary coordination failures play a decisive role in these sorts of recessions, even though the third shock that caused the recession was not a monetary shock. It was simply an increased demand for fruit trees, because agents became more patient. And these sorts of recessions do look like recessions, because there is an excess supply of both apples and bananas.

Or, to say the same thing another way: if we want to understand a decrease in output and employment caused by structural unemployment, monetary coordination failures don’t matter, and we can ignore money. Everything else is a monetary coordination failure. Even if the original shock was not a monetary shock, that non-monetary shock can cause a recession because it causes a monetary coordination failure.

Why am I underwhelmed by Nick’s conclusions? Well, it just seems that, WADR, he is making a really trivial point. I mean in a two-good world with essentially two representative agents, there is not really that much that can go wrong. To put this model through its limited endowment of possible disturbances, and to show that only an excess demand for money implies a “recession,” doesn’t seem to me to prove a great deal. And I was tempted to say that the main thing that it proves is how minimal is the contribution to macroeconomic understanding that can be derived from a two-good, two-agent model.

But, in fact, even within a two-good, two-agent model, it turns out there is room for a coordination problem, not considered by Nick, to occur. In his very astute comment on Nick’s post, Kevin Donoghue correctly pointed out that even trade between an apple grower and a banana grower depends on the expectations of each that the other will actually have what to sell in the next period. How much each one plants depends on his expectations of how much the other will plant. If neither expects the other to plant, the output of both will fall.

Commenting on an excellent paper by Backhouse and Laidler about the promising developments in macroeconomics that were cut short because of the IS-LM revolution, I made reference to a passage quoted by Backhouse and Laidler from Bjorn Hansson about the Stockholm School. It was the Stockholm School along with Hayek who really began to think deeply about the relationship between expectations and coordination failures. Keynes also thought about that, but didn’t grasp the point as deeply as did the Swedes and the Austrians. Sorry to quote myself, but it’s already late and I’m getting tired. I think the quote explains what I think is so lacking in a lot of modern macroeconomics, and, I am sorry to say, in Nick’s discussion of apples and bananas.

Backhouse and Laidler go on to cite the Stockholm School (of which Ohlin was a leading figure) as an example of explicitly dynamic analysis.

As Bjorn Hansson (1982) has shown, this group developed an explicit method, using the idea of a succession of “unit periods,” in which each period began with agents having plans based on newly formed expectations about the outcome of executing them, and ended with the economy in some new situation that was the outcome of executing them, and ended with the economy in some new situation that was the outcome of market processes set in motion by the incompatibility of those plans, and in which expectations had been reformulated, too, in the light of experience. They applied this method to the construction of a wide variety of what they called “model sequences,” many of which involved downward spirals in economic activity at whose very heart lay rising unemployment. This is not the place to discuss the vexed question of the extent to which some of this work anticipated the Keynesian multiplier process, but it should be noted that, in IS-LM, it is the limit to which such processes move, rather than the time path they follow to get there, that is emphasized.

The Stockholm method seems to me exactly the right way to explain business-cycle downturns. In normal times, there is a rough – certainly not perfect, but good enough — correspondence of expectations among agents. That correspondence of expectations implies that the individual plans contingent on those expectations will be more or less compatible with one another. Surprises happen; here and there people are disappointed and regret past decisions, but, on the whole, they are able to adjust as needed to muddle through. There is usually enough flexibility in a system to allow most people to adjust their plans in response to unforeseen circumstances, so that the disappointment of some expectations doesn’t become contagious, causing a systemic crisis.

But when there is some sort of major shock – and it can only be a shock if it is unforeseen – the system may not be able to adjust. Instead, the disappointment of expectations becomes contagious. If my customers aren’t able to sell their products, I may not be able to sell mine. Expectations are like networks. If there is a breakdown at some point in the network, the whole network may collapse or malfunction. Because expectations and plans fit together in interlocking networks, it is possible that even a disturbance at one point in the network can cascade over an increasingly wide group of agents, leading to something like a system-wide breakdown, a financial crisis or a depression.

But the “problem” with the Stockholm method was that it was open-ended. It could offer only “a wide variety” of “model sequences,” without specifying a determinate solution. It was just this gap in the Stockholm approach that Keynes was able to fill. He provided a determinate equilibrium, “the limit to which the Stockholm model sequences would move, rather than the time path they follow to get there.” A messy, but insightful, approach to explaining the phenomenon of downward spirals in economic activity coupled with rising unemployment was cast aside in favor of the neater, simpler approach of Keynes. No wonder Ohlin sounds annoyed in his comment, quoted by Backhouse and Laidler, about Keynes. Tractability trumped insight.

Unfortunately, that is still the case today. Open-ended models of the sort that the Stockholm School tried to develop still cannot compete with the RBC and DSGE models that have displaced IS-LM and now dominate modern macroeconomics. The basic idea that modern economies form networks, and that networks have properties that are not reducible to just the nodes forming them has yet to penetrate the trained intuition of modern macroeconomists. Otherwise, how would it have been possible to imagine that a macroeconomic model could consist of a single representative agent? And just because modern macroeconomists have expanded their models to include more than a single representative agent doesn’t mean that the intellectual gap evidenced by the introduction of representative-agent models into macroeconomic discourse has been closed.

Responding to Scott Sumner

Published September 14, 2014 coordination failure , Nick Rowe , Scott Sumner 12 Comments
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Scott Sumner cites this passage from my previous post about coordination failures.

I can envision a pure barter economy with incorrect price expectations in which individual plans are in a state of discoordination. Or consider a Fisherian debt-deflation economy in which debts are denominated in terms of gold and gold is appreciating. Debtors restrict consumption not because they are trying to accumulate more cash but because their debt burden is so great, any income they earn is being transferred to their creditors. In a monetary economy suffering from debt deflation, one would certainly want to use monetary policy to alleviate the debt burden, but using monetary policy to alleviate the debt burden is different from using monetary policy to eliminate an excess demand for money. Where is the excess demand for money?

Evidently, Scott doesn’t quite find my argument that coordination failures are possible, even without an excess demand for money, persuasive. So he puts the following question to me.

Why is it different from alleviating an excess demand for money?

I suppose that my response is this is: I am not sure what the question means. Does Scott mean to say that he does not accept that in my examples there really is no excess demand for money? Or does he mean that the effects of the coordination failure are no different from what they would be if there were an excess demand for money, any deflationary problem being treatable by increasing the quantity of money, thereby creating an excess supply of money. If Scott’s question is the latter, then he might be saying that the two cases are observationally equivalent, so that my distinction between a coordination failure with an excess demand for money and a coordination failure without an excess demand for money is really not a difference worth making a fuss about. The first question raises an analytical issue; the second a pragmatic issue.

Scott continues:

As far as I know the demand for money is usually defined as either M/P or the Cambridge K.  In either case, a debt crisis might raise the demand for money, and cause a recession if the supply of money is fixed.  Or the Fed could adjust the supply of money to offset the change in the demand for money, and this would prevent any change in AD, P, and NGDP.

I don’t know what Scott means when he says that the demand for money is usually defined as M/P. M/P is a number of units of currency. The demand for money is some functional relationship between desired holdings of money and a list of variables that influence those desired holdings. To say that the demand for money is defined as M/P is to assert an identity between the amount of money demanded and the amount in existence which rules out an excess demand for money by definition, so now I am really confused. The Cambridge k expresses the demand for money in terms of a desired relationship between the amount of money held and nominal income. But again, I can’t tell whether Scott is thinking of k as a functional relationship that depends on a list of variables or as a definition in which case the existence of an excess demand for money is ruled out by definition. So I am still confused.

I agree that a debt crisis could raise the demand for money, but in my example, it is entirely plausible that, on balance, the demand for money to hold went down because debtors would have to use all their resources to pay the interest owed on their debts.

I don’t disagree that the Fed could engage in a monetary policy that would alleviate the debt burden, but the problem they would be addressing would not be an excess demand for money; the problem being addressed would be the debt burden. but under a gold clause inflation wouldn’t help because creditors would be protected from inflation by the requirement that they be repaid in terms of a constant gold value.

Scott concludes:

Perhaps David sees the debt crisis working through supply-side channels—causing a recession despite no change in NGDP.  That’s possible, but it’s not at all clear to me that this is what David has in mind.

The case I had in mind may or may not be associated with a change in NGDP, but any change in NGDP was not induced by an excess demand for money; it was induced by an increase in the value of gold when debts were denominated, as they were under the gold clause, in terms of gold.

I hope that this helps.

PS I see that Nick Rowe has a new post responding to my previous post. I have not yet read it. But it is near the top of my required reading list, so I hope to have a response for him in the next day or two.

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.

My new book Studies in the History of Monetary Theory: Controversies and Clarifications has been published by Palgrave Macmillan

Follow me on Twitter @david_glasner

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