In 1946, my grandfather, writing as “Murray Leinster”, published a science fiction story called “A Logic Named Joe”. In it, everyone has a computer (a “logic”) connected to a global network that does everything from banking to newspapers and video calls. One day, one of these logics, Joe, starts giving helpful answers to any request anywhere on the network: invent an undetectable poison, say, or suggest the best way to rob a bank. Panic ensues — “Check your censorship circuits!” — until they work out what to unplug.