Have you bought my book yet? Photo: Justin Sullivan/Getty Images

Thomas Piketty’s Capital in the Twenty-First Century has thoroughly dominated the elite intellectual conversation during the four weeks since it was published. But it’s now also become a middlebrow phenomenon, the fourth-most popular nonfiction book in the country, according to the New York Times best-seller list and third-best seller (as I write) on Amazon, fiction or non-. That is an astonishing number of books sold to people who are mostly not social scientists. Its sales put it in the same blockbuster category as volumes in which a physician encounters God or Robin Roberts encounters cancer. Its popularity has helped turn inequality into a constant theme not just on MSNBC, but on Fox News. Given the density of the Frenchman’s subject matter, spooling out over 700 pages, all of this is a pretty incredible feat, and a testament to the power and lucidity of Piketty’s central idea. But it also makes you notice something else: how completely our intellectual conversation is now a conversation about economics. It isn’t just that economics is the topic we are most interested in; economics, increasingly, is the only language that we’re speaking.

During the first five or six years of the century — the Bush years, before the financial crisis — the big books and the op-ed columns were about something else entirely: American identity (red states, blue states) and whether it was an honest expression of that identity to routinely invade other countries in order to overthrow their governments, then erect fortified Taco Bells on the Euphrates. It’s no accident that the final rebuke to Bush was delivered by Barack Obama, arguing very explicitly that the Texan had misunderstood what being American was all about. Before that, in the late 1990s, the propulsive ideas were about the culture of the meritocracy, about what kinds of people got ahead in American life. That these questions have become obsolete is one reason that David Brooks and Thomas Friedman (even when they have something insightful to say) never really seem urgent anymore. But Paul Krugman always does.

But ever since the financial crash, and especially since Obama’s election, the matter of how economic gains are divided — of who gets the money — have seemed to sweep aside virtually everything else. The galvanizing movement on the left (Warrenism) is an argument that the government has done a very bad job of managing the division of these gains. The energy on the right (around the tea party) has all been behind the conviction that the government should not get to do the dividing at all. The subjects of cultural obsession have been the engines of economic growth: First Wall Street, and now increasingly Silicon Valley. Even our declinists are economists now. As media outlets have tried to reorganize themselves, to find new and more meaningful explanatory modes, a single model keeps coming up: FiveThirtyEight, Vox, the Upshot — projects that often use economics and statistical analysis as lenses through which to perceive the world. It is hard to even define what the theoretical arguments are right now about globalization, or America’s place in the world, or about gender relations, or psychological pathology and therapy. They exist, they are urgent, but they are (sometimes) expressed in economic terms and (more often) confined to little academic lagoons. Meanwhile the work of one department, economics, is always on the front pages. When your dreamy young novelists start giving up fiction to write argued tracts about Wall Street and Marx, something is up.

What is up isn’t a mystery. It makes perfect sense to be seeking economic explanations in the years just after the economy has imploded, and while the presidency is preoccupied with trying to fix it. I suspect there’s something else contributing, too — a desire for an objective, numerate authority when elites and their subjective authority are so broadly distrusted.

But its not just that the economy has taken center stage. Economists and the number-crunchers (like Nate Silver) who use some of the same statistical tools have steadily expanded their topical reach, so that its hard to find an intellectual debate in which data doesn’t play the decisive role. You might have some ideas about how happy women are on the whole and how that has changed over time, but economists Betsey Stevenson and Justin Wolfers have the data. Why do people make weird choices in everyday life? Richard Thaler has that covered, as well as the NFL draft. During the 2012 election, you probably had some instincts about who was likely to win, and whether the suggestions of a Romney boom or a looming Obama headwind were real or not. But you were also probably checking Nate Silver’s tallies, just to be sure. All of this is good, or at least much more good than bad: It is better to have data, and the greater certainty it brings, than to have anecdotes and instincts. But it has also imposed a curious kind of hesitancy and conditionality on the rest of intellectual culture: There is always the possibility that a data set will drop, and all of your assumptions will turn out to have been wrong all along.

It also means that many of the intellectual debates that matter the most take place among a strikingly small group of people. The New Republic’s correspondent, reporting on Piketty’s big public talk at NYU, reported that the technical debate over weaknesses in the economist’s theory was “frankly above my head.” And if even the technocratic New Republic cannot make independent sense of Piketty, what hope is there for the tens of thousands of readers diligently buying his book? It feels a little like an intellectual culture crouched around a tiny seminar, intently listening to that seminar being conducted, sometimes literally, in French.

“Krugman — pfft,” Piketty told my colleague Boris Kachka. “You know he liked the book a lot.”

Krugman liked Piketty’s work. Not too long ago, this would have mattered in the cloistered universe of a tenure committee, a job talk, a visiting lecture. Now it seems to contain something much more vast: Real publicity, politics, a view of the world.