I’m stunned by how good the new Jacobin piece by Seth Ackerman is: “Piketty’s Fair-Weather Friends.” It gives what I find to be the best understanding so far of the whole Piketty “think space.”
It’s so good that I can’t encapsulate it, so I’ll just share some of the passages I’m most taken with, with my highlights for your skimming pleasure. RTWT.
it’s increasingly doubtful whether (or how) [Capital‘s] arguments can be reconciled with the MIT-style economic paradigm to which Piketty’s most ardent American promoters — liberal economists like Joseph Stiglitz, Paul Krugman, Brad DeLong — swear allegiance.
For [Paul Krugman], the lesson of Capital in the Twenty-First Century is that mainstream theory has shown its worth: “You really don’t need to reject standard economics either to explain high inequality or to consider it a bad thing.”
At the heart of the neoclassical apparatus lie the twin concepts of marginal productivity and the aggregate production function (more on these below), and as Thomas Palley has written, when it comes to these totems, “you are either in or out.” Thus, as soon as an economist who aspires to theoretical originality wishes to investigate the dynamics of income distribution, she’s liable to find herself swiftly tangled in a conservative straightjacket.
Now that the book’s arguments are being digested, the same liberal, MIT-style economists who did so much to thrust Piketty’s book into the spotlight are expressing serious doubts — and the reason goes back to marginal productivity theory. That theory might end up resembling less a wall that Piketty could circumvent than a maze in which he will find himself trapped.
Marginal productivity theory … makes up something like neoclassical economics’ “operating system” — the language in which almost every proposition must be embedded in order to work.
Popular attempts to recount [the Cambridge Capital] debate tend to get needlessly bogged down in the abstract. They typically focus on the brain-teaser question of whether it’s possible to quantify the “amount” of capital in the economy, given that this capital stock is made up of a vast number of heterogeneous goods, from jackhammers to hard drives. And that was, in fact, the issue that first got the debate started.
But what the argument was fundamentally about was whether the marginal productivity theory of income distribution — marginalism — is a logically coherent theory.
In the Cambridge capital debate, this textbook theory was advanced by neither side. It’s a fairy tale told to undergraduates.
the leading mid-century neoclassicals, they had long disavowed any claim that this story could logically explain the income distribution, for a simple reason: whether or not such marginal products actually exist in the real world is an entirely empirical question, and the answer is that they generally don’t.
Today, empirical studies of manufacturing industries are unanimous in finding that per-worker productivity is constant, not diminishing, as more are put to work in a factory; while even in fast food joints (as this riveting online tutorial for McDonalds managers makes clear) the volume of sales per worker does not depend on how busy the store is, except maybe during the graveyard shift, due to a residuum of fixed labor costs.
…it would be irrational for a firm to lay off some workers just because, say, a strike or a minimum wage law hiked up their wage. The employer would get the worst of both worlds: a lower profit margin on every unit of output produced (because of the higher wage) and fewer units produced (because of the laid-off workers). Rather, her best option would be to keep producing as much as she can manage to sell while simply accepting the lower profit rate, assuming profits are still being made. Analyzed in this way, there’s no necessary reason why the platitude “when the price goes up, less is bought” ought to apply to human labor.
But the neoclassical economists on the MIT side of the Cambridge debate already knew all that. They were defending a more sophisticated version of marginal productivity theory that was subtler and, in a way, simpler.
It argued as follows: when the wage is hiked up …consumers switch their purchases from labor-intensive to capital-intensive goods, while firms and entrepreneurs building new lines of business choose more capital-intensive, rather than labor-intensive, techniques. … they are exerting demand for labor or capital through their purchases
And this was the argument that the Cambridge University side defeated
it becomes clear that a rise in the wage does not necessarily make labor-intensive goods relatively more costly to produce, as the neoclassicals had assumed. …it all depends on the complex pattern of input-output relations in the economy as a whole — how many units of good A it takes to produce good B, how many of good B to produce good C, etc., for all the millions of goods in the economy.
Once this neoclassical story — where the relative demands for labor and capital are dependent on their relative prices — is “debunked,” to use Paul Samuelson’s contrite term [he admitted that he lost the argument –SFR], the competitive market economy no longer contains any necessary mechanism pushing the various wage rates or the profit rate to any determinate level.
Rather, history and custom, as well as politics, laws and struggle, will determine who gets what. It’s a system of grab what you can.
Or in my words: the distribution of income, and supermanager compensation, is determined not by scarcity, but by rivalry. The prize goes not to those who put resources to best use, but to those who control who gets them.
it’s unsurprising we should find marginal productivity to be the point where Piketty’s sweeping vision of modern inequality would run into trouble with the economics mainstream.
marginal productivity theory sees a rise in the capital-output ratio as an increase in the “supply of capital,” which, in classic supply-and-demand logic, ought to bring about a reduction in its “price” — that is, a fall in r. According to the theory, this should neutralize the effect on the r–g gap.
[Piketty] contended that as growth slows and the capital-output ratio rises, r might decline (as theory predicts) but the magnitude of the decline might still be small enough to permit a net widening in the r – g gap.
The technical term for the quantitative relationship involved (that is, between the size of a change in the capital-output ratio and the size of the change in r that supposedly results, or vice versa) is the elasticity of substitution: the higher the elasticity, the smaller the “response” of r to a given change in the volume of capital.
Piketty’s estimate of the elasticity of substitution can’t really be compared with those in the literature. … his pertain to all private wealth, while the literature focuses narrowly on production capital. These are very different concepts.
To interject: this is exactly what I’ve been trying to say, folks. Returns on financial wealth (in the form of money/financial assets/dollars) have only the vaguest and most tenuous relationship to returns (in the form of real output) on real capital — even over very long periods. That’ the crucial lesson of the Cambridge Capital Controversy.
Money matters, and money doesn’t only appear due to the creation of real assets. It appears when real assets are indebted (particularly or generally).
Wealth is (financial assets, including deeds, are) claims on real capital — both particular claims on particular assets, and generalized claims on the stock of real assets. The relationship between wealth and capital remains almost entirely untheorized by economists.
Wealth is not an input to production. Capital is. The creation of wealth in the form of financial assets requires no inputs to production, or any real production at all. Capital does.
Even Piketty fails here; he uses “wealth” and “capital” synonymously, thereby walking right into the rhetorical mind-trap that is marginal productivity theory.
Ackerman says it perfectly:
the elasticity of substitution simply cannot be regarded as a meaningful measure of an economy’s technology (or anything else), or as providing any clue to its future.
What’s essential, rather, is Piketty’s empirical demonstration that the rate of return on wealth has been remarkably stable over centuries — and, contra Summers, with no visible tendency to vary in any consistent way against the “supply of capital.”
And that brings us to a lacuna in Piketty’s analysis that Paul Krugman and other reviewers of Capital have rightly pointed to. The skyrocketing of top-end income inequality we’ve actually witnessed so far in the English-speaking world has mainly come in the form of inflated “labor” earnings, rather than pure capital income.
Which brings us back to marginal productivity theory. Manacled to that concept as their “baseline” theory of income distribution, most liberal economists have done no better than Piketty in their efforts to account for the elephantine growth of these managerial incomes. They’ve had to depict that growth as the result of “rents,”
The problem with these arguments is that neither financiers nor public company executives have led the swelling of high-end incomes over the past several decades. Rather, the single largest contributor has been the income growth of managers in closely-held corporations outside the finance sector — that is, firms with only a few shareholders, where the controlling owners are almost always the managers themselves, usually family members.
the incomes of supermanagers are in fact an inseparable blend of “labor” and “capital” income.
resurgent capitalists in the 1970s and 1980s, emboldened by a weakened working class, drafted managers tightly into their ranks using the tools and personnel of Wall Street, and reshaped the economic landscape.
Capital has used extraordinary compensation schemes to conscript top management into their ultimate project: ensuring that all possible surplus from production goes to them.
Unskilled labor has been pushed to its reservation price, skilled labor is receiving its marginal product, and all the value creation [the surplus from production] is being split between top management and capital.
I’d say that pretty much nails it.
Cross-posted at Asymptosis.