Part of being human is being able to defy the odds. Algorithmic prophecies undermine that. For every move you make online, dozens of hidden algorithms are analysing your behaviour to make inferences about your future: what you're going to buy, what you'll eat or even if you're likely to get sick. These predictions are supposed to help us. However, as Carissa Véliz discusses, the ways we're using them also raise ethical issues that lead back to one of the oldest debates in philosophy.