butterfly effect

Syllable breakdown

Dictionary meaning

The idea that in a chaotic system, a small initial change (metaphorically, the flapping of a butterfly's wings in Brazil) can lead to large-scale, unpredictable consequences far from the original event (a tornado in Texas); illustrates sensitive dependence on initial conditions in nonlinear dynamical systems

History and origin

Coined by Edward Lorenz, who used the image in a 1972 talk 'Does the flap of a butterfly's wings in Brazil set off a tornado in Texas?'; the mathematical concept of sensitive dependence predates this image

Examples

• The butterfly effect explains why weather forecasts become unreliable beyond about ten days.
• In social systems, butterfly effects can be seen when a single viral post triggers a cascade of unforeseen political consequences.

Synonyms: sensitive dependence on initial conditions, Lorenz effect