Everybody else seems to have an opinion about Thomas PIketty, so why not me? As if the last two months of Piketty-mania (reminiscent, to those of a certain age, of an earlier invasion of American shores, exactly 50 years ago, by four European rock-stars) were not enough, there has been a renewed flurry of interest this week about Piketty’s blockbuster book triggered by Chris Giles’s recent criticism in the Financial Times of Piketty’s use of income data, which mainly goes to show that, love him or hate him, people cannot get enough of Professor Piketty. Now I will admit upfront that I have not read Piketty’s book, and from my superficial perusal of the recent criticisms, they seem less problematic than the missteps of Reinhart and Rogoff in claiming that, beyond a critical 90% ratio of national debt to national income, the burden of national debt begins to significantly depress economic growth. But in any event, my comments in this post are directed at Piketty’s conceptual approach, not on his use of the data in his empirical work. In fact, I think that Larry Summers in his superficially laudatory, but substantively critical, review has already made most of the essential points about Piketty’s book. But I think that Summers left out a couple of important issues – issues touched upon usefully by George Cooper in a recent blog post about Piketty — which bear further emphasis, .
Just to set the stage for my comments, here is my understanding of the main conceptual point of Piketty’s book. Piketty believes that the essence of capitalism is that capital generates a return to the owners of capital that, on average over time, is equal to the rate of interest. Capital grows; it accumulates. And the rate of accumulation is equal to the rate of interest. However, the rate of interest is generally somewhat higher than the rate of growth of the economy. So if capital is accumulating at a rate of growth equal to, say, 5%, and the economy is growing at a rate of growth equal to only 3%, the share of income accruing to the owners of capital will grow over time. It is in this simple theoretical framework — the relationship between the rate of economic growth to the rate of interest — that Piketty believes he has found the explanation not only for the increase in inequality over the past few centuries of capitalist development, but for the especially rapid increase in inequality over the past 30 years.
While praising Piketty’s scholarship, empirical research and rhetorical prowess, Summers does not handle Piketty’s main thesis gently. Summers points out that, as accumulation proceeds, the incentive to engage in further accumulation tends to weaken, so the iron law of increasing inequality posited by Piketty is not nearly as inflexible as Piketty suggests. Now one could respond that, once accumulation reaches a certain threshold, the capacity to consume weakens as well, if only, as Gary Becker liked to remind us, because of the constraint that time imposes on consumption.
Perhaps so, but the return to capital is not the only, or even the most important, source of inequality. I would interpret Summers’ point to be the following: pure accumulation is unlikely to generate enough growth in wealth to outstrip the capacity to increase consumption. To generate an increase in wealth so large that consumption can’t keep up, there must be not just a return to the ownership of capital, there must be profit in the Knightian or Schumpeterian sense of a profit over and above the return on capital. Alternatively, there must be some extraordinary rent on a unique, irreproducible factor of production. Accumulation by itself, without the stimulus of entrepreneurial profit, reflecting the the application of new knowledge in the broadest sense of the term, cannot go on for very long. It is entrepreneurial profits and rents to unique factors of production (or awards of government monopolies or other privileges) not plain vanilla accumulation that account for the accumulation of extraordinary amounts of wealth. Moreover, it seems that philanthropy (especially conspicuous philanthropy) provides an excellent outlet for the dissipation of accumulated wealth and can easily be combined with quasi-consumption activities, like art patronage or political activism, as more conventional consumption outlets become exhausted.
Summers backs up his conceptual criticism with a powerful factual argument. Comparing the Forbes list of the 400 richest individuals in 1982 with the Forbes list for 2012 Summers observes:
When Forbes compared its list of the wealthiest Americans in 1982 and 2012, it found that less than one tenth of the 1982 list was still on the list in 2012, despite the fact that a significant majority of members of the 1982 list would have qualified for the 2012 list if they had accumulated wealth at a real rate of even 4 percent a year. They did not, given pressures to spend, donate, or misinvest their wealth. In a similar vein, the data also indicate, contra Piketty, that the share of the Forbes 400 who inherited their wealth is in sharp decline.
But something else is also going on here, a misunderstanding, derived from a fundamental ambiguity, about what capital actually means. Capital can refer either to a durable physical asset or to a sum of money. When economists refer to capital as a factor of production, they are thinking of capital as a physical asset. But in most models, economists try to simplify the analysis by collapsing the diversity of the entire stock of heterogeneous capital assets into single homogeneous substance called “capital” and then measure it not in terms of its physical units (which, given heterogeneity, is strictly impossible) but in terms of its value. This creates all kinds of problems, leading to some mighty arguments among economists ever since the latter part of the nineteenth century when Carl Menger (the first Austrian economist) turned on his prize pupil Eugen von Bohm-Bawerk who wrote three dense volumes discussing the theory of capital and interest, and pronounced Bohm-Bawerk’s theory of capital “the greatest blunder in the history of economics.” I remember wanting to ask F. A. Hayek, who, trying to restate Bohm-Bawerk’s theory in a coherent form, wrote a volume about 75 years ago called The Pure Theory of Capital, which probably has been read from cover to cover by fewer than 100 living souls, and probably understood by fewer than 20 of those, what he made of Menger’s remark, but, to my eternal sorrow, I forgot to ask him that question the last time that I saw him.
At any rate, treating capital as a homogeneous substance that can be measured in terms of its value rather than in terms of physical units involves serious, perhaps intractable, problems. For certain purposes, it may be worthwhile to ignore those problems and work with a simplified model (a single output which can be consumed or used as a factor of production), but the magnitude of the simplification is rarely acknowledged. In his discussion, Piketty seems, as best as I could determine using obvious search terms on Amazon, unaware of the conceptual problems involved in speaking about capital as a homogeneous substance measured in terms of its value.
In the real world, capital is anything but homogeneous. It consists of an array of very specialized, often unique, physical embodiments. Once installed, physical capital is usually sunk, and its value is highly uncertain. In contrast to the imaginary model of a homogenous substance that just seems to grow at fixed natural rate, the real physical capital that is deployed in the process of producing goods and services is complex and ever-changing in its physical and economic characteristics, and the economic valuations associated with its various individual components are in perpetual flux. While the total value of all capital may be growing at a fairly steady rate over time, the values of the individual assets that constitute the total stock of capital fluctuate wildly, and few owners of physical capital have any guarantee that the value of their assets will appreciate at a steady rate over time.
Now one would have thought that an eminent scholar like Professor Piketty would, in the course of a 700-page book about capital, have had occasion to comment on enormous diversity and ever-changing composition of the stock of physical capital. These changes are driven by a competitive process in which entrepreneurs constantly introduce new products and new methods of producing products, a competitive process that enriches some owners of new capital, and, it turns out, impoverishes others — owners of old, suddenly obsolete, capital. It is a process that Joseph Schumpeter in his first great book, The Theory of Economic Development, memorably called “creative destruction.” But the term “creative destruction” or the title of Schumpeter’s book does not appear at all in Piketty’s book, and Schumpeter’s name appears only once, in connection not with the notion of creative destruction, but with his, possibly ironic, prediction in a later book Capitalism, Socialism and Democracy that socialism would eventually replace capitalism.
Thus, Piketty’s version of capitalist accumulation seems much too abstract and too far removed from the way in which great fortunes are amassed to provide real insight into the sources of increasing inequality. Insofar as such fortunes are associated with accumulation of capital, they are likely to be the result of the creation of new forms of capital associated with new products, or new production processes. The creation of new capital simultaneously destroys old forms of capital. New fortunes are amassed, and old ones dissipated. The model of steady accumulation that is at the heart of Piketty’s account of inexorably increasing inequality misses this essential feature of capitalism.
I don’t say that Schumpeter’s account of creative destruction means that increasing inequality is a trend that should be welcomed. There may well be arguments that capitalist development and creative destruction are socially inefficient. I have explained in previous posts (e.g., here, here, and here) why I think that a lot of financial-market activity is likely to be socially wasteful. Similar arguments might be made about other kinds of activities in non-financial markets where the private gain exceeds the social gain. Winner-take-all markets seem to be characterized by this divergence between private and social benefits and costs, apparently accounting for a growing share of economic activity, are an obvious source of inequality. But what I find most disturbing about the growth in inequality over the past 30 years is that great wealth has gained increased social status. That seems to me to be a very unfortunate change in public attitudes. I have no problem with people getting rich, even filthy rich. But don’t expect me to admire them because they are rich.
Finally, you may be wondering what all of this has to do with Gerard Debreu. Well, nothing really, but I couldn’t help noticing that Piketty refers in an endnote (p. 654) to “the work of Adam Smith, Friedrich Hayek, and Kenneth Arrow and Claude Debreu” apparently forgetting that the name of his famous countryman, winner of the Nobel Memorial Prize for Economics in 1983, is not Claude, but Gerard, Debreu. Perhaps Piketty confused Debreu with another eminent Frenchman Claude Debussy, but I hope that in the next printing of his book, Piketty will correct this unfortunate error.
UPDATE (5/29 at 9:46 EDST): Thanks to Kevin Donoghue for checking with Arthur Goldhammer, who translated Piketty’s book from the original French. Goldhammer took responsibility for getting Debreu’s first name wrong in the English edition. In the French edition, only Debreu’s last name was mentioned.