Archive for the 'Samuelson' Category

Macroeconomic Science and Meaningful Theorems

Greg Hill has a terrific post on his blog, providing the coup de grace to Stephen Williamson’s attempt to show that the way to increase inflation is for the Fed to raise its Federal Funds rate target. Williamson’s problem, Hill points out is that he attempts to derive his results from relationships that exist in equilibrium. But equilibrium relationships in and of themselves are sterile. What we care about is how a system responds to some change that disturbs a pre-existing equilibrium.

Williamson acknowledged that “the stories about convergence to competitive equilibrium – the Walrasian auctioneer, learning – are indeed just stories . . . [they] come from outside the model” (here).  And, finally, this: “Telling stories outside of the model we have written down opens up the possibility for cheating. If everything is up front – written down in terms of explicit mathematics – then we have to be honest. We’re not doing critical theory here – we’re doing economics, and we want to be treated seriously by other scientists.”

This self-conscious scientism on Williamson’s part is not just annoyingly self-congratulatory. “Hey, look at me! I can write down mathematical models, so I’m a scientist, just like Richard Feynman.” It’s wildly inaccurate, because the mere statement of equilibrium conditions is theoretically vacuous. Back to Greg:

The most disconcerting thing about Professor Williamson’s justification of “scientific economics” isn’t its uncritical “scientism,” nor is it his defense of mathematical modeling. On the contrary, the most troubling thing is Williamson’s acknowledgement-cum-proclamation that his models, like many others, assume that markets are always in equilibrium.

Why is this assumption a problem?  Because, as Arrow, Debreu, and others demonstrated a half-century ago, the conditions required for general equilibrium are unimaginably stringent.  And no one who’s not already ensconced within Williamson’s camp is likely to characterize real-world economies as always being in equilibrium or quickly converging upon it.  Thus, when Williamson responds to a question about this point with, “Much of economics is competitive equilibrium, so if this is a problem for me, it’s a problem for most of the profession,” I’m inclined to reply, “Yes, Professor, that’s precisely the point!”

Greg proceeds to explain that the Walrasian general equilibrium model involves the critical assumption (implemented by the convenient fiction of an auctioneer who announces prices and computes supply and demand at that prices before allowing trade to take place) that no trading takes place except at the equilibrium price vector (where the number of elements in the vector equals the number of prices in the economy). Without an auctioneer there is no way to ensure that the equilibrium price vector, even if it exists, will ever be found.

Franklin Fisher has shown that decisions made out of equilibrium will only converge to equilibrium under highly restrictive conditions (in particular, “no favorable surprises,” i.e., all “sudden changes in expectations are disappointing”).  And since Fisher has, in fact, written down “the explicit mathematics” leading to this conclusion, mustn’t we conclude that the economists who assume that markets are always in equilibrium are really the ones who are “cheating”?

An alternative general equilibrium story is that learning takes place allowing the economy to converge on a general equilibrium time path over time, but Greg easily disposes of that story as well.

[T]he learning narrative also harbors massive problems, which come out clearly when viewed against the background of the Arrow-Debreu idealized general equilibrium construction, which includes a complete set of intertemporal markets in contingent claims.  In the world of Arrow-Debreu, every price in every possible state of nature is known at the moment when everyone’s once-and-for-all commitments are made.  Nature then unfolds – her succession of states is revealed – and resources are exchanged in accordance with the (contractual) commitments undertaken “at the beginning.”

In real-world economies, these intertemporal markets are woefully incomplete, so there’s trading at every date, and a “sequence economy” takes the place of Arrow and Debreu’s timeless general equilibrium.  In a sequence economy, buyers and sellers must act on their expectations of future events and the prices that will prevail in light of these outcomes.  In the limiting case of rational expectations, all agents correctly forecast the equilibrium prices associated with every possible state of nature, and no one’s expectations are disappointed. 

Unfortunately, the notion that rational expectations about future prices can replace the complete menu of Arrow-Debreu prices is hard to swallow.  Frank Hahn, who co-authored “General Competitive Analysis” with Kenneth Arrow (1972), could not begin to swallow it, and, in his disgorgement, proceeded to describe in excruciating detail why the assumption of rational expectations isn’t up to the job (here).  And incomplete markets are, of course, but one departure from Arrow-Debreu.  In fact, there are so many more that Hahn came to ridicule the approach of sweeping them all aside, and “simply supposing the economy to be in equilibrium at every moment of time.”

Just to pile on, I would also point out that any general equilibrium model assumes that there is a given state of knowledge that is available to all traders collectively, but not necessarily to each trader. In this context, learning means that traders gradually learn what the pre-existing facts are. But in the real world, knowledge increases and evolves through time. As knowledge changes, capital — both human and physical — embodying that knowledge becomes obsolete and has to be replaced or upgraded, at unpredictable moments of time, because it is the nature of new knowledge that it cannot be predicted. The concept of learning incorporated in these sorts of general equilibrium constructs is a travesty of the kind of learning that characterizes the growth of knowledge in the real world. The implications for the existence of a general equilibrium model in a world in which knowledge grows in an unpredictable way are devastating.

Greg aptly sums up the absurdity of using general equilibrium theory (the description of a decentralized economy in which the component parts are in a state of perfect coordination) as the microfoundation for macroeconomics (the study of decentralized economies that are less than perfectly coordinated) as follows:

What’s the use of “general competitive equilibrium” if it can’t furnish a sturdy, albeit “external,” foundation for the kind of modeling done by Professor Williamson, et al?  Well, there are lots of other uses, but in the context of this discussion, perhaps the most important insight to be gleaned is this: Every aspect of a real economy that Keynes thought important is missing from Arrow and Debreu’s marvelous construction.  Perhaps this is why Axel Leijonhufvud, in reviewing a state-of-the-art New Keynesian DSGE model here, wrote, “It makes me feel transported into a Wonderland of long ago – to a time before macroeconomics was invented.”

To which I would just add that nearly 70 years ago, Paul Samuelson published his magnificent Foundations of Economic Analysis, a work undoubtedly read and mastered by Williamson. But the central contribution of the Foundations was the distinction between equilibrium conditions and what Samuelson (owing to the influence of the still fashionable philosophical school called logical positivism) mislabeled meaningful theorems. A mere equilibrium condition is not the same as a meaningful theorem, but Samuelson showed how a meaningful theorem can be mathematically derived from an equilibrium condition. The link between equilibrium conditions and meaningful theorems was the foundation of economic analysis. Without a mathematical connection between equilibrium conditions and meaningful theorems analogous to the one provided by Samuelson in the Foundations, claims to have provided microfoundations for macroeconomics are, at best, premature.

The Road to Serfdom: Good Hayek or Bad Hayek?

A new book by Angus Burgin about the role of F. A. Hayek and Milton Friedman and the Mont Pelerin Society (an organization of free-market economists plus some scholars in other disciplines founded by Hayek and later headed by Friedman) in resuscitating free-market capitalism as a political ideal after its nineteenth-century version had been discredited by the twin catastrophes of the Great War and the Great Depression was the subject of an interesting and in many ways insightful review by Robert Solow in the latest New Republic. Despite some unfortunate memory lapses and apologetics concerning his own errors and those of his good friend and colleague Paul Samuelson in their assessments of the of efficiency of central planning, thereby minimizing the analytical contributions of Hayek and Friedman, Solow does a good job of highlighting the complexity and nuances of Hayek’s thought — a complexity often ignored not only by Hayek’s critics but by many of his most vocal admirers — and of contrasting Hayek’s complexity and nuance with Friedman’s rhetorically and strategically compelling, but intellectually dubious, penchant for simplification.

First, let’s get the apologetics out of the way. Tyler Cowen pounced on this comment by Solow:

The MPS [Mont Pelerin Society] was no more influential inside the economics profession. There were no publications to be discussed. The American membership was apparently limited to economists of the Chicago School and its scattered university outposts, plus a few transplanted Europeans. “Some of my best friends” belonged. There was, of course, continuing research and debate among economists on the good and bad properties of competitive and noncompetitive markets, and the capacities and limitations of corrective regulation. But these would have gone on in the same way had the MPS not existed. It has to be remembered that academic economists were never optimistic about central planning. Even discussion about the economics of some conceivable socialism usually took the form of devising institutions and rules of behavior that would make a socialist economy function like a competitive market economy (perhaps more like one than any real-world market economy does). Maybe the main function of the MPS was to maintain the morale of the free-market fellowship.

And one of Tyler’s commenters unearthed this gem from Samuelson’s legendary textbook:

The Soviet economy is proof that, contrary to what many skeptics had earlier believed, a socialist command economy can function and even thrive.

Tyler also dug up this nugget from the classic paper by Sameulson and Solow on the Phillips Curve (but see this paper by James Forder for some revisionist history about the Samuelson-Solow paper):

We have not here entered upon the important question of what feasible institutional reforms might be introduced to lessen the degree of disharmony between full employment and price stability. These could of course involve such wide-ranging issues as direct price and wage controls, antiunion and antitrust legislation, and a host of other measures hopefully designed to move the American Phillips’ curves downward and to the left.

But actually, Solow was undoubtedly right that the main function of the MPS was morale-building! Plus networking. Nothing to be sneered at, and nothing to apologize for. The real heavy lifting was done in the 51 weeks of the year when the MPS was not in session.

Anyway, enough score settling, because Solow does show a qualified, but respectful, appreciation for Hayek’s virtues as an economist, scholar, and social philosopher, suggesting that there was a Good Hayek, who struggled to reformulate a version of liberalism that transcended the inadequacies (practical and theoretical) that doomed the laissez-faire liberalism of the nineteenth century, and a Bad Hayek, who engaged in a black versus white polemical struggle with “socialists of all parties.” The trope strikes me as a bit unfair, but Hayek could sometimes be injudicious in his policy pronouncements, or in his off-the-cuff observations and remarks. Despite his natural reserve, Hayek sometimes indulged in polemical exaggeration. The appetite for rhetorical overkill was especially hard for Hayek to resist when the topic of discussion was J. M. Keynes, the object of both Hayek’s admiration and his disdain. Hayek seemingly could not help but caricature Keynes in a way calculated to make him seem both ridiculous and irresistible.  Have a look.

So I would not dispute that Hayek occasionally committed rhetorical excesses when wearing his policy-advocate hat. And there were some other egregious lapses on Hayek’s part like his unqualified support for General Pinochet, reflecting perhaps a Quixotic hope that somewhere there was a benevolent despot waiting to be persuaded to implement Hayek’s ideas for a new liberal political constitution in which the principle of the separation of powers would be extended to separate the law-making powers of the legislative body from the governing powers of the representative assembly.

But Solow exaggerates by characterizing the Road to Serfdom as an example of the Bad Hayek, despite acknowledging that the Road to Serfdom was very far from advocating a return to nineteenth-century laissez-faire. What Solow finds troubling is thesis that

the standard regulatory interventions in the economy have any inherent tendency to snowball into “serfdom.” The correlations often run the other way. Sixty-five years later, Hayek’s implicit prediction is a failure, rather like Marx’s forecast of the coming “immiserization of the working class.”

This is a common interpretation of Hayek’s thesis in the Road to Serfdom.   And it is true that Hayek did intimate that piecemeal social engineering (to borrow a phrase coined by Hayek’s friend Karl Popper) created tendencies, which, if not held in check by strict adherence to liberal principles, could lead to comprehensive central planning. But that argument is a different one from the main argument of the Road to Serfdom that comprehensive central planning could be carried out effectively only by a government exercising unlimited power over individuals. And there is no empirical evidence that refutes Hayek’s main thesis.

A few years ago, in perhaps his last published article, Paul Samuelson wrote a brief historical assessment of Hayek, including personal recollections of their mostly friendly interactions and of one not so pleasant exchange they had in Hayek’s old age, when Hayek wrote to Samuelson demanding that Samuelson retract the statement in his textbook (essentially the same as the one made by Solow) that the empirical evidence, showing little or no correlation between economic and political freedom, refutes the thesis of the Road to Serfdom that intervention leads to totalitarianism. Hayek complained that this charge misrepresented what he had argued in the Road to Serfdom. Observing that Hayek, with whom he had long been acquainted, never previously complained about the passage, Samuelson explained that he tried to placate Hayek with an empty promise to revise the passage, attributing Hayek’s belated objection to the irritability of old age and a bad heart. Whether Samuelson’s evasive response to Hayek was an appropriate one is left as an exercise for the reader.

Defenders of Hayek expressed varying degrees of outrage at the condescending tone taken by Samuelson in his assessment of Hayek. I think that they were overreacting. Samuelson, an academic enfant terrible if there ever was one, may have treated his elders and peers with condescension, but, speaking from experience, I can testify that he treated his inferiors with the utmost courtesy. Samuelson was not dismissing Hayek, he was just being who he was.

The question remains: what was Hayek trying to say in the Road to Serfdom, and in subsequent works? Well, believe it or not, he was trying to say many things, but the main thesis of the Road to Serfdom was clearly what he always said it was: comprehensive central planning is, and always will be, incompatible with individual and political liberty. Samuelson and Solow were not testing Hayek’s main thesis. None of the examples of interventionist governments that they cite, mostly European social democracies, adopted comprehensive central planning, so Hayek’s thesis was not refuted by those counterexamples. Samuelson once acknowledged “considerable validity . . . for the nonnovel part [my emphasis] of Hayek’s warning” in the Road to Serfdom: “controlled socialist societies are rarely efficient and virtually never freely democratic.” Presumably Samuelson assumed that Hayek must have been saying something more than what had previously been said by other liberal economists. After all, if Hayek were saying no more than that liberty and democracy are incompatible with comprehensive central planning, what claim to originality could Hayek have been making? None.

Yep, that’s exactly right; Hayek was not making any claim to originality in the Road to Serfdom. But sometimes old truths have to be restated in a new and more persuasive form than that in which they were originally stated. That was especially the case in the early 1940s when collectivism and planning were widely viewed as the wave of the future, and even so thoroughly conservative and so eminent an economic theorist as Joseph Schumpeter could argue without embarrassment that there was no practical or theoretical reason why socialist central planning could not be implemented. And besides, the argument that every intervention leads to another one until the market system becomes paralyzed was not invented by Hayek either, having been made by Ludwig von Mises some twenty years earlier, and quite possibly by other writers before that.  So even the argument that Samuelson tried to pin on Hayek was not really novel either.

To be sure, Hayek’s warning that central planning would inevitably lead to totalitarianism was not the only warning he made in the Road to Serfdom, but conceptually distinct arguments should not be conflated. Hayek clearly wanted to make the argument that an unprincipled policy of economic interventions was dangerous, because interventions introduce distortions that beget further interventions, producing a cumulative process of ever-more intrusive interventions, thereby smothering market forces and eventually sapping the productive capacity of the free enterprise system. That is an argument about how it is possible to stumble into central planning without really intending to do so.  Hayek clearly believed in that argument, often invoking it in tandem with, or as a supplement to, his main argument about the incompatibility of central planning with liberty and democracy. Despite the undeniable tendency for interventions to create pressure (for both political and economic reasons) to adopt additional interventions, Hayek clearly overestimated the power of that tendency, failing to understand, or at least to take sufficient account of, the countervailing political forces resisting further interventions. So although Hayek was right that no intellectual principle enables one to say “so much intervention and not a drop more,” there could still be a kind of (messy) democratic political equilibrium that effectively limits the extent to which new interventions can be piled on top of old ones. That surely was a significant gap in Hayek’s too narrow, and overly critical, view of how the democratic political process operates.

That said, I think that Solow came close to getting it right in this paragraph:

THE GOOD HAYEK was not happy with the reception of The Road to Serfdom. He had not meant to provide a manifesto for the far right. Careless readers ignored his rejection of unqualified laissez-faire, and the fact that he reserved a useful, limited economic role for government. He had not actually claimed that the descent into serfdom was inevitable. There is no reason to doubt Hayek’s sincerity in this (although the Bad Hayek occasionally made other appearances). Perhaps he would be appalled at the thought of a Congress full of Tea Party Hayekians. But it was his book, after all. The fact that natural allies such as Knight and moderates such as Viner thought that he had overreached suggests that the Bad Hayek really was there in the text.

But not exactly right. Hayek was not totally good. Who is? Hayek made mistakes. Let he who is without sin cast the first stone. Frank Knight didn’t like the Road to Serfdom. But as Solow, himself, observed earlier in his review, Knight was a curmudgeon, and had previously crossed swords with Hayek over arcane issues of capital theory.  So any inference from Knight’s reaction to the Road to Serfdom must be taken with a large grain of salt. And one might also want to consider what Schumpeter said about Hayek in his review of the Road to Serfdom, criticizing Hayek for “politeness to a fault,” because Hayek would “hardly ever attribute to opponents anything beyond intellectual error.”  Was the Bad Hayek really there in the text? Was it really “not a good book?” The verdict has to be: unproven.

PS  In his review, Solow expressed a wish for a full list of the original attendees at the founding meeting of the Mont Pelerin Society.  Hayek included the list as a footnote to his “Opening Address to a  Conference at Mont Pelerin” published in his Studies in Philosophy, Politics and Economics.  There is a slightly different list of original members in Wikipedia.

Maurice Allais, Paris

Carlo Antoni, Rome

Hans Barth, Zurich

Karl Brandt, Stanford, Calif.

John Davenport, New York

Stanley R. Dennison, Cambridge

Walter Eucken, Freiburg i. B.

Erich Eyck, Oxford

Milton Friedman, Chicago

H. D. Gideonse, Brooklyn

F. D. Graham, Princeton

F. A. Harper, Irvington-on-Hudson, NY

Henry Hazlitt, New York

T. J. B. Hoff, Oslo

Albert Hunold, Zurich

Bertrand de Jouvenal, Chexbres, Vaud

Carl Iversen, Copenhagen

John Jewkes, Manchester

F. H. Knight, Chicgao

Fritz Machlup, Buffalo

L. B. Miller, Detroit

Ludwig von Mises, New York

Felix Morely, Washington, DC

Michael Polanyi, Manchester

Karl R. Popper, London

William E. Rappard, Geneva

L. E. Read, Irvington-on-Hudson, NY

Lionel Robbins, London

Wilhelm Roepke, Geneva

George J. Stigler, Providence, RI

Herbert Tingsten, Stockholm

Fracois Trevoux, Lyon

V. O. Watts, Irvington-on-Hudson, NY

C. V. Wedgewood, London

In addition, Hayek included the names of others invited but unable to attend who joined MPS as original members

Constatino Bresciani-Turroni, Rome

William H. Chamberlin, New York

Rene Courtin, Paris

Max Eastman, New York

Luigi Einaudi, Rome

Howard Ellis, Berkeley, Calif.

A. G. B. Fisher, London

Eli Heckscher, Stockholm

Hans Kohn, Northampton, Mass

Walter Lippmann, New York

Friedrich Lutz, Princeton

Salvador de Madriaga, Oxford

Charles Morgan, London

W. A. Orten, Northampton, Mass.

Arnold Plant, London

Charles Rist, Paris

Michael Roberts, London

Jacques Rueff, Paris

Alexander Rustow, Istanbul

F. Schnabel, Heidelberg

W. J. H. Sprott, Nottingham

Roger Truptil, Paris

D. Villey, Poitiers

E. L. Woodward, Oxford

H. M. Wriston, Providence, RI

G. M. Young, London

About Me

David Glasner
Washington, DC

I am an economist at the Federal Trade Commission. Nothing that you read on this blog necessarily reflects the views of the FTC or the individual commissioners. Although I work at the FTC as an antitrust economist, most of my research and writing has been on monetary economics and policy and the history of monetary theory. 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.

Enter your email address to follow this blog and receive notifications of new posts by email.

Join 245 other followers


Get every new post delivered to your Inbox.

Join 245 other followers