Wednesday, July 22, 2009

Evolution of the Seagull/Butterfly Effect

I first heard about the 'Butterfly Effect' reading Douglas Hofstaedter's amazing book 'Metamagical Themas', and subsequently James Gleick's book on Chaos when they came out decades ago.

Essentially, systems (like the weather) where the output is fed back into the input (i.e. 'iterated') demonstrate 'sensitive dependence on initial conditions'. In other words, a teeny tiny difference in the beginning setup may cause dramatic, and upredictable changes in future states. This is why long term weather forecasts are always unreliable. 'Chaos' theory demonstrates that, just because something is deterministic- it does not follow that it must be predictable.

What's got me fascinated recently, however, is how the original presentation of the theory has been modified- even by the original author himself!

Edward Lorenz, in a 1963 paper given to the New York Academy of Sciences stated: "one flap of a seagull's wings would be enough to alter the course of the weather forever.". Later, he gave a 1972 paper entitled: "Predictability: Does the Flap of a Butterfly's Wings in Brazil Set Off a Tornado in Texas?".

Perhaps this was based on a 1952 short story by Ray Bradbury titled "A Sound of Thunder" where a time-traveller inadvertently squishes a butterfly- with unintended consequences. It is unclear, however, if Lorenz ever read Bradbury- and in any case the butterfly in question should have been flapping it's wings and causing some distant, massive weather disturbance- not being squashed underfoot by a time traveller and altering world history.

It seems that no lazy journalist now bothers to look up Lorenz- they just substitute whatever they want into the equation:

"The Flap of a Butterfly's Wings in X can set off a Y in Z".

for example:

I suggest making it even more generic: i.e.

The 'W Effect' is when the V of a W in X can set off a Y in Z"
  • W is some sort of thing
  • V is something the thing does
  • X is the location of the journalist
  • Y is something big and/or frightening to the journalist
  • Z is somewhere exotic where the journalist might like to go on a holiday

1 comment:

  1. From Philip Merilees concocted Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas as a title.
    I guess it should be 'W Effect' is when the V of a W in Z can set off a Y in X",
    A journalist can sell more N's if there is a Y in X than if there is a Y in Z


Whaddaya think?