Here the decline in work-force participation is of a piece with the broader turn away from community in America — from family breakdown and declining churchgoing to the retreat into the virtual forms of sport and sex and friendship. Like many of these trends, it poses a much greater threat to social mobility than to absolute prosperity. (A nonworking working class may not be immiserated; neither will its members ever find a way to rise above their station.) And its costs will be felt in people’s private lives and inner worlds even when they don’t show up in the nation’s G.D.P.In a sense, the old utopians were prescient: we’ve gained a world where steady work is less necessary to human survival than ever before. But human flourishing is another matter. And it’s our fulfillment, rather than the satisfaction of our appetites, that’s threatened by the slow decline of work.