butterfly effect

Meaning

Noun

• The technical notion of sensitive dependence on initial conditions in chaos theory.
• The notion that small changes in the past via time travel can cause disproportionately large and unforeseeable consequences in the present.

Origin

• in his book Chaos: Making a New Science, whose first chapter bears the title “The Butterfly Effect”, and in which he discusses “the paradox of the butterfly’s wings” potentially making the difference whether a hurricane will or will not arise somewhere else later. Meteorologist Edward Lorenz, the founder of modern chaos theory, had in 1972, at a scientific meeting, presented a paper entitled “Does the flap of a butterfly’s wings set off a tornado in Texas?” without using the specific term butterfly effect. Lorenz also notes that representations of the strange attractor now known as the “Lorenz attractor” resemble a butterfly, as well as that correspondents have drawn his attention to Ray Bradbury’s short science fiction story “A Sound of Thunder”, in which a time traveler’s crushing a butterfly in the Late Cretaceous changes the outcome of a present-day presidential election. But the metaphorical butterfly was actually introduced in the title of the 1972 presentation by meteorologist Philip Merilees, who was not familiar with Bradbury’s story.