Complex system: Difference between revisions

:''“When a {{sex|man}} throws a ball high in the air and catches it again, he behaves as if he had solved a set of differential equations in predicting the trajectory of the ball. He may neither know nor care what a differential equation is, but this does not affect his skill with the ball. ''At some subconscious level, something functionally equivalent to the mathematical calculations is going on''.”''

::— {{author|Richard Dawkins}}

You ''cannot'' brute-force compute a [[wicked problem]], like catching a ball,<ref>Ohh, but catching a ball isn’t a wicked problem! I hear you cry. For hard-determinist, reductionist types maybe, but if you have ever pondered the odd lack of tenured physics professors in the national cricket team you may, like the [[JC]] beg to differ. The [[JC]]’s celebrated experiments with [[the proverbial crisp packet in St Mark’s Square]] may help explain.</ref> ''but you can still catch a ball'': don’t think, “punch all the variables into a machine and run round to the resulting co-ordinate and stick your hand out.”  You don’t have nearly enough information to even make the calculation. Instead, just run towards the damn thing, watching it, adjusting as you go.<ref>A study a while back found professional baseball players, while ''excellent'' at catching moving balls they were allowed to run towards, had a lot more trouble predicting where those balls would land when made to stand still.</ref>

Now, compare catching a ball with predicting any future event — be it the expected local weather in [[Lissingdown]],<ref>May the lord bless and watch over Ronnie Barker.</ref> or the level of the Eurostoxx, six months from now. The further in the future the event, the poorer your snapshot prediction will be, however sophisticated your apparatus. Ball-catching isn't ''that'' wicked, weather predicting is more wicked, and stock markets are properly wicked, but the principle remains the same.

Calculating the ball’s precise parabola from initial conditions — even if you have fairly close approximations to hand, which you won’t — will give you a general direction and rough distance, but the error range will be far too great to get near the ball. Likewise, the prediction of the rain in [[Lissingdown]] a month in advance is is highly speculative: we may have average rainfall data, but as to whether it will rain or not at a given moment, who can say?  

Where the [[gaze heuristic]] helps us is by constantly, and cheaply, refining that prediction as more information becomes available. The skill lies in the experience and judgment in making those on-the-fly adjustments. Likewise, with a weather forecast: my guess is as good as yours whether it will be raining 6 months from now; but I can be certain as I look out my window to a clear blue Lissingdown sky that it will not rain 5 ''minutes'' from now.