Nonlinearity in Biological Systems: How Can Physics Help?

Abstract

Physical theory can explain all events known to occur in the inanimate world. In stark contrast, theory cannot explain or predict any behavior in even the simplest living organisms. The reason living systems are essentially unpredictable is that their interactions with factors in the environment are governed by nonlinear dynamical laws. When appropriate analytical methods are employed, it is possible to routinely observe the nonlinear determinism manifested by biological systems. The present fashion in biology, which is to pursue the study of mechanisms but ignore the dynamical laws that drive them, is inadequate for approaching many significant scientific problems. To solve them it will be necessary to think like a physicist, that is to think in terms of mathematical laws that govern the system under consideration. But it is not a physicist rooted in the traditions of the past that is needed, where essentially all the objects of study and analysis were linear systems governed by equations directly traceable to the deep laws of physics. Physics in the context of biology must be reconceptualized so that probabilistic explanations and short-term predictions based on heuristic laws are seen as the ultimate obtainable goal.