The purpose of this paper is to foster a dialogue among those interested in the genetic analysis of common chronic diseases. The need for an alternative to the Cartesian-Mendelian research strategy is discussed. A biological model that considers an individual's health to be an emergent property of a complex adaptive system is presented. A review of the contribution of the gene coding for apolipoprotein E to the genetic architecture of measures of lipid metabolism documents that an individual's coronary artery health has all the features expected of a complex adaptive system. Suggestions for enhancing our ability to use genetic information to predict onset, progression and severity of disease are offered.