Chaos theory is the study of non-linear dynamic systems, that is, systems of activities (weather, turbulence in fluids, the stock market) that cannot be visualized in a graph with a straight line. Although dictionaries usually define "chaos" as "complete confusion," scientists who study chaos have discovered deep patterns that predict global stability in dynamic systems in spite of local instabilities.

Isaac Newton and the physicists of the 18th and 19th centuries who built upon his work showed that many natural phenomena could be accounted for in equations that would predict outcomes. If enough was known about the initial states of a dynamic system, then, all things being equal, the behavior of the system could be predicted with great accuracy for later periods, because small changes in initial states would result in small changes later on. For Newtonians, if a natural phenomenon seemed complex and chaotic, then...