LORENZ SHOWED THAT small changes in the atmosphere could have a dramatic effect on the weather. When he announced his breakthrough to colleagues, one of them pointed out that if his theory were true, a single flap of a seagull’s wings could alter weather patterns forever.
The seagull analogy gradually changed into a more poetic butterfly and a few years later Lorenz gave a talk at a conference, asking, ‘Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?’
The ‘butterfly effect’ has since become a byword for anything that is highly dependent on initial conditions. Of course, the effect could take many forms: the butterfly may cause a tornado, or prevent one. All we know is that a world in which the butterfly flapped its wings could end up very different from one in which it didn’t.
Chaos Theory assumes that the world is ‘deterministic’: if we were to wind back time and start it running again with the exact same initial conditions, we would see the same result. However, if we don’t know the precise starting conditions, the butterfly effect will eventually ruin any predictions we make about the future.
Gathering more information will rarely fix the problem. Take a snooker ball: although it’s fairly easy to estimate where it will go after hitting one cushion, with each extra cushion it hits we need to know far more about the original shot (not to mention the ball and the table) to predict what will happen next.