We will soon, TED talks promise, travel to the beach in driverless cars, where our artificial blood cells will enable us to stay underwater for hours. But we may prefer the virtual reality we will be able to inhabit thanks to direct brain implants, which will have replaced unfashionable headsets. As change proceeds exponentially, our biggest problem may be adjusting to all the dynamism.

That’s one story. But Tyler Cowen, professor of economics at George Mason University and coauthor of the wonderful blog Marginal Revolution, has another. America is much less dynamic and progressive than most of us imagine. We think we are a start-up nation but new firms have been “declining since the 1980s.” We think we are a mobile nation, but the “interstate migration rate has fallen 51 percent below its 1948 to 1971 average.” We think that we are moving, however slowly, toward racial integration, but the “average black student attends a school that is about 8.3 percent white.” We have been stalled, in many respects, for some time.