Opinions about artificial intelligence tend to fall on a wide spectrum. At one extreme is the utopian view that AI will cause runaway economic growth, accelerate scientific research and perhaps make humans immortal. At the other extreme is the dystopian view that AI will cause abrupt, widespread job losses and economic disruption, and perhaps go rogue and wipe out humanity. So a paper published earlier this year by Arvind Narayanan and Sayash Kapoor, two computer scientists at Princeton University, is notable for the unfashionably sober manner in which it treats AI: as “normal technology”. The work has prompted much debate among AI researchers and economists.