In 2009, UC Berkeley Economics Professor and former Clinton adviser Brad DeLong took a potshot at David Harvey on his blog. Headlined “Department of ‘Huh?’,” and beginning “Why neoclassical economics is an absolutely wonderful thing,” the post quotes eleven straight paragraphs from a Harvey essay, which DeLong proceeds to ridicule.

For DeLong, the essay is contentless waffle. It strings together economic concepts without making an economic argument. He would call it “intellectual masturbation,” except it “does not feel good at all.” Only in the eleventh paragraph does he find “the suggestion of a shadow of an argument.” Here Harvey argues that the US stimulus package is bound to fail because the deficit needs to be financed by foreign powers, and the amount of Treasury bonds it will be able to sell to the likes of the Chinese central bank will not fund a big enough stimulus. DeLong responds that this is a question that requires a theory of the bond market and interest rates, which Harvey does not provide: “The question is thus not can government deficit spending be financed . . . the question is at what interest rate will financial markets finance that deficit spending.”

Harvey responded with some anger at “the arrogance of the neoclassical economists”:

I would have thought that in a profession dominated by neoclassical and increasingly neoliberal theory these last thirty years, that there might have appeared at least some sliver of humility. They have collectively provided us with no guidance on how to avoid the current mess and now, when faced with a crisis, they can only say, as Marx long ago presciently noted, that things would not be so if the economy only performed according to their textbooks. Maybe it is time to revise if not change the textbooks.

He goes on to bring up Sraffa and the “Cambridge capital controversies” of the 1960s, which, he argues, showed that “all of neoclassical theory is based on a tautology”. DeLong’s argument was “a bit of casual empiricism about the current low and seemingly stable rate of return on long-term treasuries”. “Why bother” with neoclassical economics at all, he asks.

Many will already be laughing and mocking along with Harvey. And perhaps DeLong deserves no better. Yet on the point at issue, he was right — it is a question of interest rates, not of the number of bonds that can be sold. When Harvey went on to clarify his argument, it was only with some casual empiricism of his own. He noted that he was hardly the only one to be making the argument that East Asian central banks could stop collecting US Treasuries, so that “the track of long-term treasury interest rates may go the way of the housing market data in just a couple of years (if not months).” This was an argument you could read in mainstream business pages; there was nothing particularly Marxist about it. Now that we are more than a couple of years down the track, DeLong still looks right: the yields on long-term Treasury bonds are, as I write in July 2011, about the same as they were in February 2009, when the exchange took place. The limits to stimulus have been political, not financial.

Many Marxists see mainstream economics as a degenerate mirror image of what they think Capital provides for them: a systematic model of capitalism built up from first principles. The main difference is that mainstream economics is ideological and apologetic, hopelessly inadequate for understanding the true nature of capitalism. So for Harvey the ultimate charge he can throw is that it is “based on a tautology”: a logical flaw was discovered in the 1960s that should have spelled its end; everything since is “casual empiricism.”

There really are neoclassical economists who insist on building a system from axioms, who believe, among other things, that no macroeconomics is worthwhile until it has been grounded in the “micro-foundations” of formally modeled rational individual action. But this is a minority, academic pursuit that has little to do with the pragmatic economics involved, for example, in analyzing the relationship between the US federal government’s deficit and long term interest rates. Criticism of the incoherence or unrealistic assumptions of neoclassical economics can be easily deflected — most economists will freely admit they are simply heuristics and would be quite happy to be considered pragmatic “casual empiricists.” Textbook epigraphs and departmental websites quote Keynes:

The Theory of Economics does not furnish a body of settled conclusions immediately applicable to policy. It is a method rather than a doctrine, an apparatus of the mind, a technique of thinking, which helps its possessor to draw correct conclusions.

There are generations of economists who would call themselves Marxists, or admit Marx as a major influence, who have taken a similar approach. They have engaged with other strands of economic thought and folded them into their worldview, have worried little about dropping from their analyses those aspects of Marx’s argument they believed to be wrong or unhelpful, and have felt no need to pepper their writing with appeals to authority in the form of biblical quotations.

But in each generation, there are others who have defended an “orthodox” Marxian economics as a separate and superior paradigm, which can only be contaminated by absorbing ideas from elsewhere. The pugnacious Andrew Kliman, for example, opens his Reclaiming Marx’s Capital with the line “The economists have changed Marx, in various ways; the point is to interpret him — correctly.” Accordingly, he unabashedly spends a chapter on hermeneutic method, and the book is devoted to proving the internal logical consistency of a method for transforming the values of Volume I into the production prices of Volume III. This, at least, is more sophisticated than what we might call Frankenstein Marx — the stitching together of an argument from authority by stringing together famous quotations torn out of context. Criticizing Frankenstein Marxism is like campaigning for motherhood and apple pie — no one will disagree.

What I call Zombie Marx is different — the reanimation of a corpse which still holds organically together in some way. This is the reconstruction of Marxist economics as a coherent body of thought, not a collection of quotations. That this work is dogmatic is not my complaint. As Thomas Kuhn suggested in The Structure of Scientific Revolutions , a little dogmatism is important to most science, maintaining the coherence of a community of researchers and organizing its research agenda. Mainstream academic economics is very dogmatic about its theoretical core — methodological individualism and the general equilibrium apparatus. It is unfair to single out Marxists. Rather, it is scholasticism that is the problem — the need to ground everything in a 140-year-old text. It would be wrong to say that the likes of Kliman are dogmatic in the sense that they demand unthinking acceptance of everything in Capital — it is obviously a lot of intellectual hard work to “interpret Marx correctly.” It cannot be taken for granted that Marx was right; it must be proven anew with each generation, against both rival interpretations and the revisions the previous generation had found necessary to make.

Reanimating Marx can be very fruitful at times, and who has shown this better than David Harvey? His Limits to Capital is a masterpiece of social theory drawing on nothing but Capital and the secondary literature around it. This groundbreaking work is original mainly in the way it reorganizes Marx’s work, but in his analysis of the geography of capitalism Harvey proved that Capital had still not finished giving. However, Limits is a book written at the high tide of Marxian intellectual confidence, in the wake of a flowering of radical political economy. It could admit frankly in its first chapter that the “critics of value theory have mounted a quite successful campaign against traditional interpretations” of the “labor theory of value”, and the rest of the book was a testament to how little that mattered.

Thirty years on, that intellectual confidence has receded. The fundamentalist “back to the text” movement is the downswing of a familiar cycle in the history of Marxian economics. It is a pattern, I think, that has more to do with the social conditions of its reproduction than anything inherent in its content. Modern neoclassical economics is the overwhelmingly dominant paradigm in a mature, prestigious academic discipline. Students are introduced into a system of thought as a physics student might, proceeding through textbooks, with exercises at the end of each chapter, with each section building on the ones before, and with each year’s textbooks adding complications and refinements to what was learned the previous year. The history of the received wisdom leaves traces only in the names attached to various concepts: “Pareto optimality,” “the Slutsky equation,” “Okun’s law.” In contrast, Marxian economics is united mainly through shared adherence to a political tradition — a very fractious political tradition. It is academically marginal, with few institutional supports — its theorists tend to lead isolated scholarly existences, in a pocket of like-minded thinkers at best. Instead, its history shows a succession of writers, occasionally coalescing for a time into schools, who have developed in one direction or another, only to be ignored or rejected by those who came after. There is a tendency for productive debates, which drive analysis forward, to peter out and be forgotten as the tradition repeatedly circles back to its founding text, its only common ground. Interpretation of a text has trumped interpretation of the world.