The writer for Harper’s Magazine had a problem. Books he read and people he knew had been warning him that the nation and maybe mankind itself had wandered into a sort of creativity doldrums. Economic growth was slackening. The Internet revolution was less awesome than we had anticipated, and the forward march of innovation, once a cultural constant, had slowed to a crawl. One of the few fields in which we generated lots of novelties — financial engineering — had come back to bite us. And in other departments, we actually seemed to be going backward. You could no longer take…