How to know if artificial intelligence is about to destroy civilization

Some theorists, like Bostrom, argue that we must nonetheless plan for very low-probability but high-consequence events as though they were inevitable. The consequences, they say, are so profound that our estimates of their likelihood aren't important. This is a silly argument: it can be used to justify just about anything. It is a modern-day version of the argument by the 17th-century philosopher Blaise Pascal that it is worth acting as if a Christian God exists because otherwise you are at risk of an everlasting hell. He used the infinite cost of an error to argue that a particular course of action is "rational" even if it is based on a highly improbable premise.