A butterfly has the potential to create tiny changes which, while not creating a typhoon, could alter its trajectory. A flapping wing represents the minuscule changes in atmospheric pressure, and these changes compound as a model progresses. Given that small, nearly imperceptible changes can have massive implications in complex systems, Lorenz concluded that attempts to predict the weather were impossible.

A butterfly has the potential to create tiny changes 

"Some systems … are very sensitive to their starting conditions, so that a tiny difference in the initial ‘push’ you give them causes a big difference in where they end up, and there is feedback, so that what a system does affects its own behavior.”

Imagine you bumped into someone at a coffee shop that happens to work at your dream company and eventually got you an interview there. What if you had chosen a different coffee shop, or been there five minutes later? You may not have met the person that got you into your dream job. The idea that something small, like getting coffee, can have much larger effects, such as altering your career is called the butterfly effect.

Example

“You could not remove a single grain of sand from its place without thereby … changing something throughout all parts of the immeasurable whole.”

Of course, a single act like the butterfly flapping its wings cannot cause a typhoon. Small events can, however, serve as catalysts that act on starting conditions.

However 

In an experiment to model a weather prediction, Edward Lorenz ( a meteorologist and a mathematician) entered the initial condition as 0.506, instead of 0.506127. The result was surprising: a somewhat different prediction. From this, he deduced that the weather must turn on a dime. A tiny change in the initial conditions had enormous long-term implications.

Edward Lorenz and the Discovery of the Butterfly Effect  

The butterfly effect rests on the notion that the world is deeply interconnected, such that one small occurrence can influence a much larger complex system. The effect is named after an allegory for chaos theory; it evokes the idea that a small butterfly flapping its wings could, hypothetically, cause a typhoon.

What Is Exactly The Butterfly Effect 

He theorized that weather prediction models are inaccurate because knowing the precise starting conditions is impossible, and a tiny change can throw off the result. To make the concept understandable to non-scientific audiences, Lorenz began to use the butterfly analogy.

Tiny Changes Can Throw Off Results 

he butterfly effect is somewhat humbling—a model that exposes the flaws in other models. It shows science to be less accurate than we assume, as we have no means of making accurate predictions due to the exponential growth of errors.

It is symbolic representation of an unknowable quantity

The butterfly effect is an often misunderstood phenomenon wherein a small change in starting conditions can lead to vastly different outcomes. Understanding the butterfly effect can give us a new lens through which to view business, markets, and more.

The butterfly effect rests on the notion that the world is deeply interconnected, such that one small occurrence can influence a much larger complex system.