David Peat

142 From Certainty to UncertaintyAnd while it is looking outward it must also preserve its internal environment.From day to night, winter to summer, the body must maintaina stable core temperature. It must monitor and control levels ofsodium, potassium, oxygen, and carbon dioxide in the blood. In thisway a complex web of interactions maintains the activities of the brain,circulatory systems, waste elimination, and so on. Clearly with this levelof organizational complexity, the human body and its functioning area far cry from patterns in a pan of heated water.Through the long processes of evolution, the human body developedhighly sophisticated control mechanisms to maintain a high degreeof internal stability (homeostasis) within a contingent world. Shiftcore temperature by a few degrees and the result is coma or death byhypothermia. While the message of chaos theory is that natural andsocial systems can self-organize out of underlying chaos, the more sophisticatedthe resulting system, the more a balance must be maintainedbetween chaos and order and the more complex (and robust)must be its internal structures and control mechanisms. At one levelthe body appears to function in a hierarchical fashion, with its particularfunctions designated to semiautonomous players such as the immunesystem, brain, and circulatory system. At the same time, all theseplayers are richly interconnected through a wide variety of feedbackloops.Yet despite, or indeed because of, its stability, chaos also plays arole within the body’s structures and processes. Take the human heartbeat,for example. When it is totally regular this indicates disease oreven the onset of a heart attack. If it demonstrates too much chaosthen it has entered a state of fibrillation, and death may ensue. Insteadthe healthy heart maintains small (“chaotic”) fluctuations around itssteady beat. Good health therefore depends on allowing a smallamount of chaos into the system. Something similar applies to brainpatterns. When they are totally regular and free from fluctuations thisindicates that a person is in coma or under a deep anesthetic. A beatingheart and a functioning brain are complex systems resulting from thecooperative behavior of many smaller subsystems. In this sense, thebrain and heart are self-organized systems that, for their continuedhealth, must combine an overall goal (a regular beating heart, for ex-