Scientists were probably the last people to find out about chaos. Everyone knows our lives are chaotic and unpredictable in the long run. Benjamin Franklin wrote the famous lines: 鈥淔or the want of a nail, the shoe was lost; for the want of a shoe the horse was lost; and for the want of a horse the rider was lost, being overtaken and slain by the enemy, all for the want of care about a horseshoe nail.鈥�
Others carried this story further so that losing the rider and his message lead to the loss of a battle, then a war, and finally a kingdom, all for the want of a horseshoe nail. Closer to home, the mother of a friend of mine married the driver of a taxi she had taken. If she had taken a different taxi, my friend would never have existed.
Our predictions must be flexible: I often say that the most successful people are those who are good at plan B. Chaos theory is an area of science and mathematics that deals with plans B to Z, describing unstable situations where small changes can cascade into larger and larger long-term effects.
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Of course, scientists have always known that the world is chaotic, but until the last 30 years few recognised that scientific environments can be quite unpredictable in the long run, even where change is governed by precise rules. It is instability rather than complexity that causes chaos: meteorologist Edward Lorenz, one of the founders of chaos theory, suggested in 1960 that the flap of a butterfly鈥檚 wing in Brazil might set off a tornado in Texas, for example. His point was that we can never know all the factors that determine our weather; at best we can only predict the details a few days ahead. Scientists have now found that many other situations are equally unstable. Computer models have greatly helped us to understand how pervasive chaos is throughout science. Our group at the University of Maryland, for instance, has aimed at telling scientists how to look for varieties of chaos, for specific phenomena common to many situations. But I continue to wonder, if nearly all scientists missed this pervasive phenomenon, what other obvious phenomenon might we all be missing now? Maybe chaos is trying to tell us something.
