A generation of mathematically inclined economists neglected many of Keynes’s insights about the Depression because he put them into words. For decades economists sweated over fiendish mathematical equations, only to be brought down to earth by the credit crunch: Keynes’s well-turned phrases had come back to life.
I recently attended a talk, titled Street Hacks, by Jan Chipchase with Eric Von Hippel’s group at MIT Sloan, in which he showcased a number of interesting innovations that his team has uncovered in urban slums throughout the developing world. He included one particularly fascinating example of markets where you can buy a dual sim card in which someone has removed the chips from two existing carrier sims and soldered them onto a single sim. This allows mobile phone users to switch back and forth between carriers on the fly, depending on rates and how much they have in each account. We are years away from enjoying an innovation like that in the U.S.
