You don’t see it coming. You probably couldn’t if you tried. The effects of large changes in scale are frequently beyond our powers of perception, even our imagination. They seem to emerge out of nowhere: the cumulative effects of climate change, the creation of a black hole, the spookiness of quantum mechanics, the societal tipping points reached when the rich have billions rather than millions—even the sudden boiling of water in a slowly heating pot. More or less of almost anything can change nearly everything.