Around April Fool’s Day in 1708, Jonathan Swift, ever mischievous, set out to humiliate one, John Partridge, a noted English astrologer and almanac-maker.
Under the pseudonym Isaac Bickerstaff, Esq., Swift published “Predictions for the Year 1708,” which foretold Partridge would die of a “raging fever” on March 29 that year. To deepen the prank, Swift then fabricated a letter from a purported acquaintance confirming Partridge had died as predicted.
Swift’s prank was wildly successful. People in the community even began undertaking funeral preparations when they heard the alleged news. But Swift’s hoax is fascinating for another reason—at least for word lovers.
Describing Partridge’s final days, the ‘acquaintance’ notes:
The people about him said, he had been for some time delirious; but when I saw him, he had his understanding as well as ever I knew, and spake strong and hearty, without any seeming uneasiness or constraint.
According to the Oxford English Dictionary, this passage contains notable early use of delirious in the English language. (As writer Ammon Shea since alerted me on Twitter since publishing, delirious has been used as an adjective since the late 16th century and enjoyed a fair amount of currency in the 17th.) Here, Swift used delirious to describe the incoherence, restlessness, and frenzy specifically caused by fever—or, as Swift’s mockery suggests, the ridiculous pseudoscience of astrology Partridge was peddling.
Delirious was formed in English from delirium, imported some time in the late 16th century directly from the Latin dēlīrium, meaning “derangement” or “frenzy.” The record suggests the English delirium was a scholarly borrowing, soon after taken up in both medical and figurative contexts.
Latin’s dēlīrium issues from dēlīrāre, “to be mad” or “rave.” The verb, in turn, joins de- (“off”) and līrā (“furrow”). Delirium, then, originates as a farming metaphor: If you’re delirious, you have literally gone “off the furrow” when you are ploughing the fields. English has something of an analogous expression in “go off the rails.”
The līrā behind delirious, according to etymologists, is related to a yet more familiar word: learn. From the Old English leornian, the Germanic-based learn shares an Indo-European root with Latin’s līrā: *leis, or “track, furrow.” To learn, apparently, emerged as a metaphor over the millennia, developing from “following a track” to “following a course of study.”
Partridge did seem to learn a lesson from Swift’s delirious. With the prank dealing a serious blow to his reputation and business, he stopped publishing his ‘clairvoyant’ almanacs after the hoax was cleared up—for six years at least, until he actually died shortly thereafter.