THE TORNADO HAS NO AUTHOR: WHAT BUTTERFLY EFFECT IS NOT

A butterfly flaps its wings in Brazil and a tornado tears through Texas. It is the most quoted sentence in modern science, and nearly everything the world has taken from it is wrong. Edward Lorenz did not write that sentence. A conference organizer did, on a deadline, because he wanted a title that would pull people away from the rival session down the hall. Lorenz himself said something almost nobody repeats: that the same flap could just as easily prevent a tornado as cause one. The discovery he made in the winter of 1961, after dropping three digits from a printout and going down the hall for coffee, was not that small things matter enormously. It was that past a certain horizon, causes cannot be named at all. This book separates the science from the folklore, and then asks the question the folklore makes impossible. If you cannot predict the event, and you cannot name its cause, what exactly can you do? The answer turns out to be a great deal. You cannot forecast which spark will catch, but you can count the deadwood. You cannot identify the butterfly, but you can measure the connectivity that lets a small disturbance grow into a large one, and you can change it. From a cluttered office at the Massachusetts Institute of Technology to the quay at Sarajevo where six assassins waited for one car, from forest fires and flood plains to the critical density of cities, Boris Kriger takes apart the twentieth century's favorite metaphor and puts something more useful in its place: a working distinction between what cannot be known and what cannot be done. Keywords: chaos theory, butterfly effect, Edward Lorenz, prediction, complex systems, risk, causation