Most of us tend to assume that results change proportionally with inputs—that if we leave a little later we will get where we are going a little later, or if we study a little harder we will do a little better on the test. While that is often true, there are many situations in which it is not—situations in which a small difference at the beginning can result in a huge difference at the end. The study of such situations has developed into a new branch of science and mathematics over the past fifty years and is called Chaos Theory—aptly named for the havoc such “sensitive dependence on initial conditions” can create in your life. There is an amazing book that explains the development and uses of Chaos Theory, which I highly recommend: Chaos: The Making of a New Science, by James Gleick.
Some examples might help. I leave for work at five o’clock
in the morning. I do this not because I am naturally an early riser, but
because I know that if I leave then I will beat the traffic in which I will get
caught if I wait and leave at six o’clock—if I leave at five o’clock I reliably
get there by six thirty (one-and-a-half hours of travel), but if I leave at six
o’clock I will not get there until eight o’clock (two hours of travel) and
maybe not until nine o’clock (three hours of travel) if there is an accident,
which is more likely with more traffic. If, on the other hand, I could wait
until ten a.m. to leave, traffic would likely have dropped back off, and the
trip would likely be back to an hour and a half.
Sometimes the impact of small changes is even more extreme, with small quantitative changes (a few more or less of something) resulting in important qualitative changes (whether something happens at all or not). Think of what happens if you miss a train or bus or plane by just a few minutes or even seconds. That small difference in your arrival time at the depot or gate will result in a large, and probably inconvenient, difference in how your day develops—you may end up not making the trip at all! The last five minutes of studying may lock the information in your brain in ways the first ten hours did not (you may finally “get it”), ensuring success on the test. This idea that small changes can beget disproportionally large changes is sometimes called the “butterfly effect,” and is captured in an old nursery rhyme:
For want of a nail, the shoe was lost,
For want of the shoe, the horse was lost,
For want of the horse, the rider was lost,
For want of the rider, the message was lost.
For want of the message, the battle was
lost,
For want of the battle, the kingdom was
lost,
And all for the want of a horseshoe nail!
Once you understand the idea, you will come to realize that
we all experience the butterfly effect many times every day.
But there’s more. It turns out that situations or systems
that are sensitive to initial conditions can display very complex behavior—and
there are many, many natural systems that display that sensitivity. Consider,
for instance, weather, which was one of the first things to which Chaos theory
was understood to apply. A very small change in temperature or pressure (even
the beating of a butterfly’s wings—thus the name, butterfly effect) can cause
not just a large change in temperature or pressure, but a thunderstorm
experienced a few weeks later: change in a chaotic system often happens not
through a gradual, smooth process, but through turbulence. Thus it is expected
that the most important short term manifestation of global warming (whatever
its cause) is not the very slight increase in average temperatures around the
world, but a very significant increase in the number of storms, hurricanes, and
weather-related disasters—an increase in turbulence. This will likely have huge
economic impact as property along coasts is repeatedly damaged, fruit crops are
destroyed by late-winter temperature swings, and other consequences develop. We
are already seeing that and should expect to see more.
Comments
Post a Comment