Computers are near-omnipotent cauldrons of processing power, but they re also stupid. They are the undisputed chess champions of the world, but they can t understand a simple English conversation. IBM’s Watson supercomputer defeated two top Jeopardy! players last year, but for the clue “What grasshoppers eat,” Watson answered: “Kosher.” For all the data he could access within a fraction of a second—one of the greatest corpuses ever assembled—Watson looked awfully dumb.