The Terrain Theory of Social Disease/Contagion; or, The Whale Jon I take it for granted that most readers who have come across this stack are somewhat familiar with “terrain theory” in the health context. But for exposition sake, and to get my own cognitive wheels turning, allow me to refresh your memory with a condescending, simplified version of the germ vs. terrain theory debate. Here goes: Sometimes people get sick. Usually it is because they ate something rotten or drank too much booze or were poisoned by a jilted lover. But sometimes it isn’t. So, if no gas-station sushi, box wine, or conniving ex is involved, why do people get sick? Well, sometimes we notice that people get sick despite no obvious (such as the aforementioned) reasons, and then subsequently other people around them get sick too, with the same symptoms. Yet we don’t see any reason for the first person getting sick, and we certainly don’t see any behavioral factors (beyond proximity) for the subsequent people get