Chaos Theory

A major breakthrough of the 20th century, which has been facilitated by computer science, has been the recognition that simple rules do not always lead to stable order but in many circumstances instead lead to an apparent disorder characterized by marked instability and unpredictable variation for reasons intrinsic to the rules themselves. The phenomenon of rules causing emerging disorder, counterintuitive to many people, is the environment currently being explored as self-organization, fractals (a fragmented geometric shape that can be split into parts, each of which is a reduced-size copy of the whole, a property called self-similarity), nonlinear dynamical systems, and chaos.

Chaos theory, also called nonlinear systems theory, provides new insights into processes previously thought to be unpredictable and random. It also provides a new set of tools that can be used to analyze physiological and clinical data such as the electric signals coming from the heart or from the brain.

Chaos theory was born originally as a branch of mathematical physics in the 20th century thanks to the work of Edward Lorenz in meteorology. Chaos theory is concerned with finding rational explanations for such phenomena as unexpected changes in weather and deals with events and processes that cannot be modeled or predicted using conventional mathematical laws and theorems, such as those of probability theory. The theory basically assumes that small, localized perturbations in one part of a complex system can have profound consequences throughout the system. Thus, for nonlinear systems, proportionality simply does not hold. Small changes can have dramatic and unanticipated consequences. The fascinating example often used to describe this concept, which is known as the butterfly effect, is that the beating of a butterfly's wings in China can lead to a hurricane in Brazil, given a critical combination of air pressure changes.

The key word is critical, and many of the efforts of scientists working on chaos theory are concerned with attempts to model circumstances based on specific conditional conjunction. Unpredictable events in medicine, such as ventricular arrhythmias and sudden cardiac death in athletes, the course of certain cancers, and the fluctuations in frequency of some diseases, may be attributable to chaos theory.