It must be hard for Joseph Stiglitz to remain an optimist in the face of the grim future he fears may be coming. The Nobel laureate and former chief economist at the World Bank has thought carefully about how artificial intelligence will affect our lives. On the back of the technology, we could build ourselves a richer society and perhaps enjoy a shorter working week, he says. But there are countless pitfalls to avoid on the way. The ones Stiglitz has in mind are hardly trivial. He worries about hamfisted moves that lead to routine exploitation in our daily lives, that leave society more divided than ever and threaten the fundamentals of democracy.