Thomas Piketty Is Right About the Past and Wrong About the Future

Capital in the 21st Century deserves all of its praise, but it should not serve as gospel on inequality.
Thomas Piketty (AP)

Once in a great while, a heavy academic tome dominates for a time the policy debate and, despite bristling with footnotes, shows up on the best-seller list. Thomas Piketty’s Capital in the Twenty-First Century is such a volume. As with Paul Kennedy’s The Rise and Fall of the Great Powers, which came out at the end of the Reagan Administration and hit a nerve by arguing the case against imperial overreach through an extensive examination of European history, Piketty’s treatment of inequality is perfectly matched to its moment.

Like Kennedy a generation ago, Piketty has emerged as a rock star of the policy-intellectual world. His book was for a time Amazon’s bestseller. Every pundit has expressed a view on his argument, almost always wildly favorable if the pundit is progressive and harshly critical if the pundit is conservative. Piketty’s tome seems to be drawn on a dozen times for every time it is read.

This should not be surprising. At a moment when our politics seem to be defined by a surly middle class and the President has made inequality his central economic issue, how could a book documenting the pervasive and increasing concentration of wealth and income among the top 1, .1, and .01 percent of households not attract great attention? Especially when it exudes erudition from each of its nearly 700 pages, drips with literary references, and goes on to propose easily understood laws of capitalism that suggest that the trend toward greater concentration is inherent in the market system and will persist absent the adoption of radical new tax policies.

Piketty’s timing may be impeccable, and his easily understandable but slightly exotic accent perfectly suited to today’s media; but make no mistake, his work richly deserves all the attention it is receiving. This is not to say, however, that all of its conclusions will stand up to scholarly criticism from his fellow economists in the short run or to the test of history in the long run. Nor is it to suggest that his policy recommendations are either realistic or close to complete as a menu for addressing inequality.

Start with its strengths. In many respects, Capital in the Twenty-First Century embodies the virtues that we all would like to see but find too infrequently in the work of academic economists. It is deeply grounded in painstaking empirical research. Piketty, in collaboration with others, has spent more than a decade mining huge quantities of data spanning centuries and many countries to document, absolutely conclusively, that the share of income and wealth going to those at the very top—the top 1 percent, .1 percent, and .01 percent of the population—has risen sharply over the last generation, marking a return to a pattern that prevailed before World War I. There can now be no doubt that the phenomenon of inequality is not dominantly about the inadequacy of the skills of lagging workers. Even in terms of income ratios, the gaps that have opened up between, say, the top .1 percent and the remainder of the top 10 percent are far larger than those that have opened up between the top 10 percent and average income earners. Even if none of Piketty’s theories stands up, the establishment of this fact has transformed political discourse and is a Nobel Prize-worthy contribution.

Piketty provides an elegant framework for making sense of a complex reality. His theorizing is bold and simple and hugely important if correct. In every area of thought, progress comes from simple abstract paradigms that guide later thinking, such as Darwin’s idea of evolution, Ricardo’s notion of comparative advantage, or Keynes’s conception of aggregate demand. Whether or not his idea ultimately proves out, Piketty makes a major contribution by putting forth a theory of natural economic evolution under capitalism. His argument is that capital or wealth grows at the rate of return to capital, a rate that normally exceeds the economic growth rate. Thus, economies will tend to have ever-increasing ratios of wealth to income, barring huge disturbances like wars and depressions. Since wealth is highly concentrated, it follows that inequality will tend to increase without bound until a policy change is introduced or some kind of catastrophe interferes with wealth accumulation.

Piketty writes in the epic philosophical mode of Keynes, Marx, or Adam Smith rather than in the dry, technocratic prose of most contemporary academic economists. His pages are littered with asides referencing Jane Austen, the works of Balzac, and many other literary figures. For those who don’t like or trust economics and economists, Piketty’s humane and urbane learning makes his analysis that much more compelling. As well it should: The issues of fairness of market outcomes that he deals with are best thought of as part of a broad contemplation of our society rather than in narrow numerical terms.

All of this is more than enough to justify the rapturous reception accorded Piketty in many quarters. But recall that Kennedy seemed to hit the zeitgeist perfectly but turned out later to have missed his mark as the Berlin Wall fell and the United States enjoyed an economic renaissance in the decade after he wrote; similarly, I have serious reservations about Piketty’s theorizing as a guide to understanding the evolution of American inequality. And, as even Piketty himself recognizes, his policy recommendations are unworldly—which could stand in the way of more feasible steps that could make a material difference for the middle class.

Piketty’s argument is straightforward, relying, as he says in his conclusion, on a simple inequality: r>g, in which the rate of return on capital exceeds the growth rate. Its essence is most easily grasped by thinking about population growth. Think first of a world where couples have four children. In that case, an accumulated fortune will dissipate, as the third generation of descendants has 64 members and the fourth has 256 members. On the other hand, if couples have only two children, a fortune has to be split only 16 ways even after four generations. So slow growth is especially conducive to rising levels of wealth inequality, as is a high rate of return on capital that accelerates wealth accumulation. Piketty argues that as long as the return to wealth exceeds an economy’s growth rate, wealth-to-income ratios will tend to rise, leading to increased inequality. According to Piketty, this is the normal state of capitalism. The middle of the twentieth century, a period of unprecedented equality, was also marked by wrenching changes associated with the Great Depression, World War II, and the rise of government, making the period from 1914 to 1970 highly atypical.

This rather fatalistic and certainly dismal view of capitalism can be challenged on two levels. It presumes, first, that the return to capital diminishes slowly, if at all, as wealth is accumulated and, second, that the returns to wealth are all reinvested. Whatever may have been the case historically, neither of these premises is likely correct as a guide to thinking about the American economy today.

Economists universally believe in the law of diminishing returns. As capital accumulates, the incremental return on an additional unit of capital declines. The crucial question goes to what is technically referred to as the elasticity of substitution. With 1 percent more capital and the same amount of everything else, does the return to a unit of capital relative to a unit of labor decline by more or less than 1 percent? If, as Piketty assumes, it declines by less than 1 percent, the share of income going to capital rises. If, on the other hand, it declines by more than 1 percent, the share of capital falls.

Jump to comments
Presented by

Lawrence Summers is an economist. He is a former U.S. treasury secretary and a former president of Harvard University.

Get Today's Top Stories in Your Inbox (preview)

A Delightful, Pixar-Inspired Cartoon About the Toys in Your Cereal Box

The story of an action figure and his reluctant sidekick, who trek across a kitchen in search of treasure.

Elsewhere on the web

Join the Discussion

After you comment, click Post. If you’re not already logged in you will be asked to log in or register. blog comments powered by Disqus


Juice Cleanses: The Worst Diet

A doctor tries the ever-popular Master Cleanse. Sort of.


Why Did I Study Physics?

Using hand-drawn cartoons to explain an academic passion


What If Emoji Lived Among Us?

A whimsical ad imagines what life would be like if emoji were real.


Living Alone on a Sailboat

"If you think I'm a dirtbag, then you don't understand the lifestyle."


The Future of Iced Coffee

Are artisan businesses like Blue Bottle doomed to fail when they go mainstream?



More in Business

Just In