When Pigs Fly

A classic "adynaton," a deliberately absurd figure of speech used to describe an impossibility, with roots that spread across several centuries and countries rather than one clean origin. An early English version appears in John Withals's 1616 dictionary as "pigs fly with their tails forward," and the 16th-century French writer Rabelais includes a vivid flying pig in Gargantua and Pantagruel. Similar sayings are recorded in both German and Scottish folk tradition. Nobody has pinned down which version came first, or whether they developed independently.