
What Is the Butterfly Effect: Chaos Theory Explained
The butterfly effect describes how small changes in initial conditions can produce vastly different outcomes in complex systems.
Page Summary
An explainer of the butterfly effect and chaos theory, opening with Edward Lorenz's 1961 discovery that rounding a weather-model input by less than a part in a thousand produced a completely different forecast. It covers sensitive dependence on initial conditions, why small errors grow exponentially, the mathematics of chaos, strange attractors and the order within chaos, fractal geometry and Mandelbrot, where chaos theory applies (weather, ecology, finance, physiology, epidemiology), what the butterfly effect is not, and its legacy in complexity science.
Contributions
Every accepted correction to this page is recorded with the exact change, so readers can see how the page improved over time.
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Anderson & May's foundational work was published in 1991, not 1992
BeforeRoy Anderson (1992) showed decades before COVID
AfterRoy Anderson (1991) showed decades before COVID
Why: Corrected the publication year; Anderson and May's foundational epidemic-chaos work was published in 1991, not 1992. Verified already live on the article; also confirmed no leftover instances in faq, excerpt, meta_description, or seo_keywords.
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