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What Is the Butterfly Effect?

How can the wing movements of a butterfly affect the weather system of a country on the other side of the world? It doesn’t seem possible, but proponents of the Chaos Theory use this—the “Butterfly Effect”—to illustrate how small variations can have monumental impact on large, complex systems.

In this light, The Butterfly Effect explains why it is almost impossible to accurately predict the way a system will behave, or even the final outcome of a series of events. There are too many small variables that can tip the results in one direction or another.

This theory was first put forth by mathematician and meteorologist Edward Norton Lorenz, who worked on the Chaos theory for several years. While his first example was the wing patterns of seagulls (which he studied for around a decade) but when he first delivered his landmark speech on the topic, scientist Philip Merilees provided a more poetic title: “Does the Flap of a Butterfly’s Wings in Brazil Set off a Tornado in Texas.”

While the Chaos Theory is relatively new—at least in “formal” science—fiction writers have played with the idea for a long, long time. For example, any story on time travel dwells with the question of how history could be changed by one seemingly irrelevant act. Psychologists have also talked about how the unconscious can be affected by very subtle actions or comments, or even half-forgotten experiences. People who observe someone’s “irrational” decision would never have access to the thought processes that led to it. Clearly human behavior, like weather systems, can never completely be deciphered.

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