The authors state that one of the reasons medical students favor specialist medicine over generalist medicine (i.e., primary care) is that they see generalist medicine as existing in a nebulous world of non-science. Students often feel that the scope of knowledge in generalist disciplines is so broad and unbounded that these fields cannot be approached with sufficient scientific rigor. Students hold this view in part because they are unable to see the shortcomings of the reductionist thinking that dominates medical education and specialty medical care. But now a new field, chaos science, reveals the intellectual basis for generalist medicine, because it finds patterns and order in the behavior of whole, complex systems (such as human beings) and explains the necessity for the experiential, holistic, and intuitive processes that are essential in generalist care. This intellectual basis is neither greater nor lesser than that of specialist medicine--just different. To explain these contentions, the history, strengths, and limits of reductionist thinking are discussed, and aspects of chaos science, such as the butterfly effect and strange attractors, are described. The authors close by emphasizing the importance of striking a balance between reductionist and whole-systems thinking, and challenge students who "have an eye for pattern and a taste for complexity, jagged edges, and sudden leaps" to consider a career in primary care medicine, where they will be, in effect, the chaos scientists of human beings.