Lance Taylor (1940-2022) and his legacy

With Lance in Beijing (2001)

I took Lance’s macro class in the Fall of 1995 at the New School for Social Research (NSSR), and then was his Teaching Assistant for two years. The book we formally used was Income Distribution, Inflation and Growth: Lectures on Structuralist Macroeconomic Theory, in which the terms (not the concepts) for wage-led and profit-led economies were first used (at least that's what I think; profit-led does not appear in the index, I must note). But classes were based on his notes, on what became his next book Reconstructing Macroeconomics (he thanked me for all the input in my copy; I had to learn how to read his handwriting, which was not easy). In many ways, my thinking was influenced more by the Sraffian professors at the NSSR, both John Eatwell (I was also his TA in the micro class) and Ed Nell (who really was the first to discuss functional finance in my classes), in part because the blend of Cambridge left-of-center Keynesianism and Latin American Structuralism, that Lance exposed, was more familiar to me coming from Brazil.

My plan was to work on inflation theory (and I did write a conflict model, that can be seen as being in Lance’s tradition later on; in my view his best book is the one that is less formal, and is on inflation, his Marshall Lecture at Cambridge, Varieties of Stabilization Experience; at the time I first read it I didn't know that the title was a quote from Henry James; the other candidate is his book with Eatwell Global Finance at Risk. Both are more books than manuals). But I started working with Wynne Godley on his stock-flow model for the joint Center for Economic and Policy Analysis (CEPA) and Levy Economic Institute project. A year into the project I told Lance that it would make sense if I worked on something related to the project, namely the sustainability of the US external account. Lance was very nice about it, and not only went along, but also provided funding, since I received CEPA’s dissertation grant.

I ended up writing something that was very close to Massimo Pivetti’s monetary theory of distribution. The theory at least. Lance provided comments and feedback, and, at some point, told me that I was obsessed with this monetary distribution thing (I was, indeed). But he also provided support, and his criticism was always constructive. Lance was the best supervisor one could have. He guided the work with frequent conversations, read and criticized what I gave him to read, and, after it passed certain standards, approved it, even if it wasn't exactly a Lance Taylor dissertation. He never tried to mold my thinking, or force me to work on own his terms. Sadly, that isn’t the norm in academia. I think he had been lucky with his supervisor too. He once spoke fondly of Hollis Chenery (his supervisor; not his mentor, which I think was Rosenstein-Rodan; I might be wrong), because he protected the radicals, which were under pressure in the late 1960s at Harvard. His intellectual generosity, among several other qualities, is something that will be deeply missed.

Lance was open to alternative methods, and approaches, what he called closures (certainly more than I am), and his comparative method was influenced by other disciplines, the qualitative "thick descriptions" a la Clifford Geertz that he liked. I actually ended up reading a bit of Geertz because of my conversations with Lance, particularly when I was the assistant director at CEPA (he was the director) and he organized a book on several comparative studies of liberalization in peripheral countries (the one on Brazil, which was supposed to appear in a previous volume, and should have been written by Edward Amadeo, was eventually written by me; photo above is from one of the conferences that led to that book). Geertz saw anthropology, as he famously put it, "not [as] an experimental science in search of law but an interpretive one in search of meaning." The thick description was essentially the interpretive work of the ethnographer. Lance took that view, in some sense, of economics, blending the description of the historical and institutional features of peripheral countries, with relatively simple models in what Paul Krugman (a co-author; Paul's first paper was the one on contractionary depreciations with Lance) called the MIT or Solow type models (my only other model in that sense, is the currency crisis one that puts Krugman's one upside down).

 

I tend to think that this methodological stance is Lance most enduring legacy, and the one that had the most influence on my own work. Most discussions of his work emphasize the gap models (which I think are problematic, the savings and fiscal gaps in particular), or the stagnationist model of growth, which builds on Bob Rowthorn's seminal Neo-Kaleckian growth model (and also on Amitava Dutt's model, which I think was part of his dissertation work under Lance). Some might even think that it was the reversal of his views on the role of exchange rates in development, his paper with Roberto Frenkel on stable and depreciated exchange rates as engines of growth (which can be seen in line with Luiz Carlos Bresser-Pereira and Jaime Ros views, and as being at the center of New Developmentalism). Others might think it's his work on Social Accounting Matrices that prefigured, and went hand in hand with his appreciation for Wynne Godley's stock-flow consistent models (on Wynne's methodological stance, see this old post).

In a way, all these models, and others (I could have added the Minsky crisis one, that is often neglected), to some extent show the use of models for Lance. He was somewhat eclectic, and use them to illustrate some of the issues with developing countries. But for him that had to be complemented by the interpretive thick descriptions. In my view, the models per se were less relevant for Lance, who was an unorthodox lefty that remained so, as someone remembered recently, even as the whole world moved to the right in the 1980s, and 1990s (he told me that a director of research at the World Bank, that had become a neoliberal, told him in his last visit to that institution, if he wasn't ashamed for still defending those structuralist views). And he did leave MIT for the NSSR, which was a strong signal of his political views. The simple model allowed him to tell the stories.

I have a tendency to prefer greater consistency in the models, and I'm less keen on accepting some possibilities of neoclassical/monetarists closures for the real world. But his methodology, which in some sense contrasts with the large stock-flow models that my other mentor (Wynne) liked, is certainly something I think it is a more fruitful way of thinking about macroeconomic problems. But again the specific models per se are less relevant, and the thick description that they illustrate with simplicity matter more.

The New School for Social Research at 100: A view from the Econ. Dept.

From a late 1990s catalogue; Lance Taylor (center), and also in no particular order

and from what I can remember (Ellen Houston, Adalmir Marquetti, myself (with goaty

on the left side), Margaret Duncan, Josh Bivens and Carlos Bastos (Orozco Room)

The New School for Social Research was founded 100 years ago by a group of academics dissatisfied with the direction of American higher education. Economics was central to the early history of the New School, and my brief, very incomplete, and certainly idiosyncratic historical account emphasizes the Economics Department of what used to be called the Graduate Faculty.

Thorstein Veblen, one of the founders, had written his famous Higher Learning in America, which in a sense is the original critique of the corporate university. The idea was to put learning at the center, and avoid the conventional trappings of universities, with no degrees provided to students. The foundations of the critical perspectives provided at the New School came from institutionalists (like Veblen), pragmatists, represented by another prominent founder, namely John Dewey, and revisionism in history, with Charles Beard as its main voice at the new institution. Many came from Columbia University and were dissatisfied with both institutions of higher education and the direction the country had taken, in particular with World War I. These were mostly anti-war, progressive social scientists.

Perhaps the key person at the inception of the New School was Alvin Johnson, a somewhat difficult to classify economist (Gonçalo Fonseca at the HET website suggests that he might be seen as Austrian), that has been almost completely forgotten. Johnson was the editor of the massive Encyclopaedia of the Social Sciences, later substituted by the International Encyclopedia of the Social Sciences (last edition under Sandy Darity, and I have two entries on Export Promotion and James Mill), which put him in contact with several economists around the world, many in Germany.

A group of scholars that he met as the editor of the encyclopedia was the basis for the so-called University in Exile, which eventually was the basis for the Graduate Faculty, the division that now still is called the New School for Social Research (while the whole is just The New School, if I do understand the naming changes at my alma mater). The most important and cohesive group of economists that arrived at the New School in 1933, and the following years, escaping persecution in Nazi Germany, were the ones related to the Kiel School, including Gerhard Colm (on Colm I co-authored this paper with Luca Fiorito), Adolph Lowe, Jacob Marschak, and Hans Neisser. In that group, Lowe, the mentor to Robert Heilbroner, was to be the more consequential for the New School.

The New School was not orthodox in its economic teaching, but the 1930s were a period of flux in the profession. The Keynesian Revolution was in course, and Keynes was acquainted with Johnson and the New School, as it can be seen in the letter he gave to H. G. Bab (see below; click to amplify). In that sense, while it is true that the place was somewhat unorthodox, given its origins and the historical period in question, that should not be exaggerated. Note that Marschak went on to be the head of the Cowles Commission, and a leading mainstream economist. While at the New School he supervised Franco Modigliani's doctoral thesis, which was the basis for his famous neoclassical synthesis paper of an ISLM model with rigid wages and for his Sveriges Riksbank Prize in Economic Sciences in Memory of Alfred Nobel.

The New School, more enjoyable and compatible people than at Columbia, for sure (click to enlarge)

I say this because there is a tendency to think of the New School as being always heterodox, and taking that term to have more or less a contemporary meaning (for what I mean about that go here; for a great and more in depth discussion see this post by Ingrid Kvangraven and Carolina Alves). Many others taught at the New School in this period, perhaps, worth mentioning is the case of Abba Lerner, the main author of the functional finance school (something that is at the core of Modern Money Theory, but is more restrictive and specific than MMT).

The Kiel School was what one could term eclectic. They certainly had roots on elements of the German Historical School, and readings of marginalist and non-marginalist authors, including Marxists. Gonçalo puts Tugan-Baranovsky as one of the influences on the Kiel School. Tugan, a "semi-critic of Marx" according to Schumpeter, argued that a disproportion between the investment and consumption goods sectors would lead to recurrent industrial crises, and that notion of structural imbalances was central for Kiel authors. Leontief was also connected to the Kiel School.

While many in the Kiel School were open to and used marginalist concepts, as in the case of institutionalists, not all were neoclassical, and Lowe's views arguably were the most clearly connected to the works of the old classical political economists. Ed Nell, in the appendix to Lowe's book The Path of Economic Growth compares it with Leontief, Von Neumann, and Sraffa, as being classically inspired. One can think of Ed's Transformational Growth research program as building on that tradition.

But it would be a stretch to suggest that Bob Heilbroner, Lowe's main disciple at the New School, and the next key person in the history of the Economics Department at the Graduate Faculty, was a follower of classical political economy. A cursory reading of his classic, The Worldly Philosophers, shows that his reading of Smith is perfectly compatible modern mainstream readings, which imply that Smith was a precursor of supply and demand theories. The chapter on Smith discusses the law of markets, but the labor theory of value only makes an appearance in the chapter on Marx, and to suggest that it was a deviation from Smith and Ricardo. The degree to which Heilbroner conflates classical and marginalist or neoclassical theory is clear in that he argues that the Walrasian circular-flow in Schumpeter's theory resembles Ricardo's stationary state. And in the discussion of Schumpeter's notion of profit he suggests, regarding the labor theory of value, that "everyone knew to be wrong and therefore did not have to be reckoned with."*

Further, his views on economic growth, as evidenced in his book on the economics history of the Unites States, were essentially that growth was supply-side constrained and dependent on technological innovation, in ways that seem to be closer to his Harvard undergraduate teacher, Joseph Schumpeter, than classical political economy authors (Smith had, arguably, a demand driven view of growth, at least for some, while Ricardo most certainly didn't, and Marx is open to many different views; I'll keep that to another post). I emphasize this to show that even if he was unorthodox in many ways, Bob was not necessarily what we would term heterodox in the modern sense of the word (even if taken loosely as not being neoclassical).** In my view, no clear heterodox bias existed up to the 1960s, in a department that had basically been under the shadow of three economists, Johnson, Lowe and Heilbroner. Note that this somewhat eclectic persistence of different approaches was more or less common in many departments at that time.

But the Johnson-Lowe-Heilbroner nexus provided the basis for the changes that shaped the department with the arrival of Ed Nell in the late 1960s. Ed had worked with Hicks at Oxford, and he was from early on critical of methodological individualism, something that is clear from his critique of the concept of the rational economic man. More importantly he was concerned with growth, and that led to a discussion of the theories of value and distribution (perhaps influenced by Hicks' Capital and Growth, which remains an important book), and was influenced by Sraffa's revival of classical political economy. It was after Ed arrived that a series of new hires, among them Stephen Hymer, Anwar Shaikh, and David Gordon, changed the department. Note that the late 1960s and early 1970s too is the period in which the economics profession segregates the heterodox groups, makes it harder for radicals to get tenure in conventional and prestigious departments (e.g. Sam Bowles at Harvard), and publishing requires the foundation of new journals (e.g Journal of Post Keynesian Economics, and the Cambridge Journal of Economics).

In my view, it is no coincidence that this is also when the change in the notion of equilibrium, as discussed by Garegnani, takes place (some discussion of that here). The point is that the capital debates had shown the limits of marginalist (neoclassical) economics, and the profession embraced what I have referred to as vulgar economics after that. The hiring of heterodox economists, critical of the mainstream in this period, and the sociology of academia, locked in heterodox hegemony at the Econ. Dept. of the Graduate Faculty.

Many other heterodox economists taught at the New School's Econ. Dept. from that point onwards. I might note Paul Sweezy, which if I'm not wrong was instrumental in making Bob Pollin choose the New School for his PhD, was among the teachers in the 1970s. And also many Sraffians like Piero Garegnani, John Eatwell, taught on a recurring basis, while many were visitors for shorter periods. Again, somewhat idiosyncratically, in my view it is the arrival of Lance Taylor in 1993 and a few years later of Duncan Foley that consolidated the persistence of the heterodoxy, and the type of heterodox department (with a mix of structural Keynesianism and Marxism), that the New School has today.

Perhaps, it is important to emphasize how limited this story is. There is a missing story about the role of David Gordon, who was also a key player in the department for many decades, and of Anwar Shaikh, that I always saw as somewhat of an influential outsider (maybe I'm wrong), even by the New School standards. And also the many other wonderful and creative heterodox economists that passed through the New School over the years. There is a question about the gender imbalances at the New School, and within heterodoxy itself, that I do not address. I'll explicitly avoid saying any additional names, since in this way I cannot be accused of forgetting someone (I'm leaving out a ton, including the many alumni that went on to remarkable careers). Hopefully this provides a window on how the New School became heterodox and why it remains so.

* It should be noted that Bob's book was published in 1953, a few years before the labor theory of value was rehabilitated by Sraffa's Production of Commodities.

** On a personal note, I remember talking to Bob on an interval of a conference organized by Ed Nell on functional finance, in 1997, I think, in which he argued that the Maastricht limits (3 per cent for deficits, and 60 per cent for debt) were reasonable measures to constrain the size of government. He was a liberal in an older sense of the word, perhaps.

Brexit and Euroskepticism

British exit from the European Union (EU) is more radical than Grexit, which basically was exit from the eurozone (EZ), the currency area, but not the union. Wynne Godley, for example, was against the euro (see this), but he was not against the EU. Quite the opposite, he was pro-Europe, as were many progressive economists, several connected to Labor (Lord Eatwell being an example). The whole isue now became relevant, since David Cameron, the prime minister, set the date for a referendum on Brexit for June 23rd. Map below shows the degrees of euroskepticism (as in EU membership, not EZ) around Europe.

Note that in the UK there is a significant amount of euroskeptics, more than in the parts of Europe that have suffered from the problems with the monetary union (source here). The UK and the countries with more developed welfare systems in Northern Europe (Denmark, Sweden, Finland) tend to have a less favorable view of the European Union.

I'll discuss the pros and cons, from an economic perspective, of EU membership in another post. I do feel like Wynne that, while EZ membership is not necessarily good (at least with the current fiscal rules), EU membership is better than the alternative.

Lord Eatwell in the Financial Times

A short Letter to the Editor, but worth reading. He clearly explains the policy failure since the global crisis and the reasons for the current problems in financial markets in developed and developing countries. He says:

The adage that, in the absence of the prospect of growing demand, cheap money amounts to “pushing on a string” has been once again confirmed in advanced economies by the slowest recovery from any modern recession. Instead of funding real investment, monetary expansion has resulted in a boom in asset prices — not just in real estate and equity markets, but in the flow of funds into emerging market corporate bonds in the search for higher return. All these asset markets are extremely unstable, as is now all too evident. And, as has been once again demonstrated in the last 7 years, financial instability leads to substantial real economic loss.

Yet in the face of evident policy failure, and of severe asset market distortions that can only lead to further financial instability, the response seems to be “more of the same”, or even, in the case of negative interest rates, “very much more of the same”. There was a significant fiscal expansion in the US in 2009 that had a clear positive impact. But the federal government lost its nerve and reined back on the expansion just as it was gathering pace. The quiet abandonment of severe austerity by the UK government in 2012 at least enabled something of a recovery, albeit fuelled by growing household debt. Fiscal policy works. 

Given that the cost of funds to most governments is today negative in real terms (and sometimes in money terms too) it is difficult to understand the failure to initiate a major expansion of investment in infrastructure and the other major components of “supply-side” strength. This failure is resulting not just in a loss of output today, but a long-term loss of competitive productive capacity (a particularly severe problem for the UK). Fiscal policy can provide the pull on the string required to validate the monetary push.

Read the full letter here (subscription required). Pushing on a string as an explanation for the inefficiency of monetary policy in a crisis was a term popularized by Marriner Eccles, by the way.

Eatwell on the relevance of pure theory

Eatwell on the relevance of theory for policy debates, introduced by Arestis. John used to say in class that no debate was ever solved by empirical analysis.

Hat tip to Alejandro Fiorito and Franklin Serrano.

John Eatwell on the theoretical lessons from the crisis

It's from 2012, but still very much relevant. Short and to the point about the limitations of the mainstream to understand the crisis. I would put less emphasis on the Sonnenschein–Mantel–Debreu theorem, and more on the Sraffa-Garegnani critique of General Equilibrium, but that's a detail. He is correct in pointing out to Keynes' Principle of Effective Demand (PED), and to the insidious role of finance.

The Economist thinks bubbles are rational

Or at least is what they suggest in the popular blog Free Exchange. They bring back Peter Garber's research on the Tulipmania, and more recent research by Earl Thompson, which suggests that "the market for tulips was an efficient response to changing financial regulation." They conclude by arguing that:

"It is easy to claim that bubbles are irrational. They seem to represent a deviation of prices from fundamental values—and they contradict basic economic theory. But there has been little attempt to understand how speculation actually works. The example of tulipmania shows the importance of doing that—rather than relying on lazy quips about 'animal spirits' or irrationality."

The notion is related to the idea of the Arrow-Debreu models in which short term prices (they don't have long term prices associated with a uniform rate of profit) do reflect the fundamental values associated to the preferences of agents and the given technology and factor endowments. In this context, the efficient market hypothesis (EMH) suggests that the prices of financial assets reflect all market information, and as a result those prices would not deviate from their fundamentals. In other words, according to the EMH, bubbles do not exist.

Rational bubbles assume that rational behavior may still be associated with deviations of asset prices away from their fundamental values. In general, a self-confirming belief that asset prices depend on a variable that is intrinsically irrelevant, that is, not part of market fundamentals, is assumed. Much discussion goes into the behavioral assumptions that would make rational bubbles possible. Justin Fox's The Myth of the Rational Market, which I reviewed here (subscription required) provides an accessible introduction.

John Eatwell (here; subscription required) noted that a more relevant question than the rationality or not of bubbles is whether they are useful or not. Railroads were built on bubbles, and the dot.com bubble even left some infrastructure in terms of telecommunications that has been useful. Other bubbles, like the one associated with the subprime, are less obviously useful.

Finally, note that the old capital debates are still important to understand the limitations of much of this literature. Garegnani and Petri have noted that even the short run Arrow-Debreu models must bring investment to equality to full employment savings, and as a result some notion of a natural rate of interest is implicitly needed. And then all the problems of the aggregative model apply. So it is not possible to show that long term prices do reflect fundamentals associated with preferences, technology and endowments.

PS: On the related topic of whether the Bubble Act (financial regulation), that followed the South Sea Bubble, led to lower rates of growth see here. For the capital debates go here.

Eatwell on Garegnani again

I linked to Eatwell's lecture in honor to Garegnani at the University of Rome. The text has been published in Contributions to Political Economy (full text here, subscription required). It is important to note how central Garegnani's PhD dissertation was for his following work.

As Eatwell notes:

"Key elements in the life's work of Pierangelo Garegnani (9th August 1930–14th October 2011) derive from the analytical results first developed in his 1958 PhD dissertation at Cambridge University. The critique of Walras's theory of capital articulated in the dissertation was extended in later years to the identification of the implications of the change in the concept of equilibrium in the works of Hicks and Debreu."

Further, the essential element in the dissertation was the clear anlytical stance, which, in Eatwell's words, shows how economics should be done. Again in his words:

"First, he specified the problem clearly: the determination of natural/normal prices, i.e. the solution to the problem of value and distribution.

Secondly, he clarified the structure of the competing theories, classical and neoclassical, by defining the data of the theory, i.e. the propositions taken as given. In the case of classical theory these were the social product (its size and composition) the technique or techniques of reproduction and (sometimes) the real wage. In the case of neoclassical theory the data were preferences, endowments, and the technology (constrained to constant returns to scale by the requirements of perfect competition).

Thirdly, he defined the analytical problems faced within each theoretical construct in terms of measurement: in classical theory measurement of the social product independently of its distribution; in neoclassical theory the measurement of the endowment of reproducible means of production in a manner compatible with the determination of normal prices, i.e. with a uniform rate of profit on all capital goods."

The limits of the mainstream approach, and the open possibilities of the alternative classical-Keynesian approach can still be derived from his seminal work.

Sraffa and the Marshallian system

(Sraffa circa 1976)

G. L. S. Shackle argues in The Years of High Theory that ‘there began in the mid-1920s an immense creative spasm, lasting for fourteen years until the Second World War, and yielding six or seven major innovations of theory, which together have completely altered the orientation and character of economics’ (Shackle, 1967, p. 5). However, by 1967, the two most important developments of this period—Keynes’s principle of effective demand and Sraffa’s criticism of the marginalist theory of value—were rapidly fading from the main corpus of mainstream theory.

The relative ease with which neoclassical economics reasserted its main conclusions is, in fact, explained by Shackle’s account of those years. First, Sraffa’s critique of the Marshallian theory of value is seen only as a step in the development of the theories of imperfect competition by Joan Robinson and Edward Chamberlin. Second, Keynes’s General Theory is seen as stating that unemployment results from the existence of uncertainty and irrational expectations (Shackle, 1967, p. 129). Both developments can be interpreted as asserting that market imperfections render neoclassical theory, although internally coherent, irrelevant for the analysis of the real world.

Also Shackle’s failure in 1967 — well after the publication of Production of Commodities — to acknowledge the importance of the revival of classical political economy to the debates of the 1930s represents a serious inadequacy of his interpretation of ‘the years of high theory’.

Before getting into Sraffa's critique of Marshall, it is worth noticing that Sraffa came to economics via monetary economics, like Ricardo and Keynes. His dissertation for the Law Degree, L’Inflazione Monetaria in Italia Durante e Dopo la Guerra (subscription required), dealt with postwar inflation and the return to the Gold Standard, the same topic of Keynes’s Tract on Monetary Reform. According to Eatwell and Panico (subscription required), in the analysis of the asymmetric effects of inflation and deflation Sraffa reveals the heterodox character of his position, more akin with the works of the classical authors and Marx than the conventional marginalist analysis. The notion that social conflicts and monetary factors determine the normal real wage was part of Sraffa’s analysis, although several elements of his analysis were still conventional, e.g. the acceptance of the Quantity Theory and of the Purchasing Power Parity theory.

Sraffa’s criticism of the Marshallian theory of supply represents an analogous situation, in the sense that some elements of the conventional marginalist views were still present. Marshall’s or Sraffa’s dilemma (which appears in Sraffa's 1926 paper) refers to the incompatibility between increasing returns and perfect competition. It is a long period problem. Sraffa’s critique can be summarized in the following way. First, rising costs derive from diminishing returns to substitution, and, therefore, in the general case where there are no fixed factors, increasing costs do not seem to exist. Secondly, increasing returns are incompatible with perfect competition. In the long period, when the firm cannot experience marginal costs arising from the existence of some fixed input, there can be no diminishing returns. Replication is always possible, except for the case of indivisibilities. In addition, Sraffa showed that increasing returns to scale are inconsistent with the notion of perfect competition.

In the case of increasing returns, the average cost is decreasing, implying that the marginal cost is below average variable cost, and, hence, there is no infinite, non-zero solution for the profit maximization problem. In other words, there is a tendency for the firm to expand to infinite size. Sraffa’s argument proves the failure of perfectly competitive assumptions to determine any equilibrium of the individual firm. Two alternatives are opened by Sraffa’s critique of Marshallian theory. If it is not legitimate to treat average cost as either increasing or decreasing within the framework of perfect competition, we are left with the result that the only satisfactory assumption is that of constant returns. On the other hand, ‘everyday experience shows that a very large number of undertakings work under conditions of individual diminishing costs’ (Sraffa, 1926, p. 543), which suggests that we should instead abandon the notion of perfect competition.

Sraffa considered the imperfect competition approach to be the only logical way to develop the theory of value along Marshallian lines. However, he showed no inclination to pursue this solution, and he appears to have already been working toward the revival of the classical approach. The origins of this project can be traced back to his early draft of the opening propositions of the Production of Commodities, which he asked Keynes to read in 1928 (Sraffa, 1960, p. vi). The reasons for not pursuing imperfect competition were never quite explained by Sraffa, but are fairly reasonable to infer (note that in Cambridge it was two of his students, Richard Kahn and Joan Robinson, that developed the imperfect competition theory).

Note that in order to obtain partial equilibrium, which is what the Marshallian model presumes, one must assume that prices in a particular industry are not affected by and do not affect the prices in other industries. Hence, externalities have to be internal to the industry, since otherwise production in one sector would affect the prices in other industries [perfect competition in partial equilibrium, the U-shaped cost curves and the equilibrium at the minimum with marginal cost equal marginal revenue, require also that externalities are external to the firm, since if they weren't the firm would became a monopolist; of course externalities that are internal to an industry and external to firms are an empty set]. That seems to be a dead end. Sraffa was already interested in the determination of long term prices. By this time, the summer of 1927 when he was preparing his ‘Lectures on Advanced Value Theory’ that he gave from 1928 until 1930, it was already clear to him that he needed to start from classical preocupation of determining relative prices and one of the distributive variables (the rate of profits or wages) strictly in material terms, that is, the quantities of labor and commodities needed to produce commodities.

For further on Sraffa's critique of Marshall see Gary Mongiovi's paper here (subscription required). For a general critique of Shackle's stance in the history of 'the years of high theory' read this one. For the implications of Sraffa's 1960 book for economics go to this old post (yes on the capital debates!).

More on the capital debates: Eatwell on Garegnani

Follow up on my previous post. Here is the link to the lecture given by John Eatwell in honor of Piero Garegnani (hat tip Revista Circus). It goes beyond the question of showing why and how mainstream (aggregative or intertemporal models) are flawed. It shows that the classical-Keynesian approach is rooted in a historical-institutional which makes it directly relevant for policy analysis. As he says:

"Economics is meant to be useful. Not only is it supposed to give a greater understanding of how a market economy works, but also it should be a guide to economic policy.

... classical value theory and Keynesian theory share a common structure that both are dependent upon empirical data from outside the theoretical core. Classical theory is dependent upon market structure, the composition of output and the distribution of income (or, to be more accurate, one of the distributive variables, the wage or the rate of profit). These data can be derived from the historical position of the economy, the stage of evolution in the history of technical progress, the structure of international trade, the structure of corporate enterprise, the financial and monetary system, the policies of the state, and so on, all of which are arrayed outside the core, but are vital to its specification. Similarly Keynesian theory is inconceivable without a clear specification of the structure of finance. The principle of effective demand is dependent upon the existence of a relatively sophisticated financial sector, and developments in the financial sector will in turn have an impact upon the determination of investment and the process of accumulation. It is one of the obvious failures of neoclassical theory that financial variables play no role in the determination of prices and outputs. It is an abiding strength of classical and Keynesian analysis that not only can financial variables be readily accommodated, some of the analysis will not work without them."

Read the rest here.