The cluster illusion, like other post hoc fallacies in probability, is the source of many superstitions: that bad things happen in threes, people are born under a bad sign, or an annus horribilis means the world is falling apart. When a series of plagues is visited upon us, it does not mean there is a God who is punishing us for our sins or testing our faith. It means there is not a God who is spacing them apart.
