The danger of continued expansive growth, both to individuals and to society generally, lies in its progression to a point at which further expansion and even renewal becomes impossible. The concept of societal homeostasis, although developed in part by scientists, is not in any rigorous sense a scientific theory. The following definition was adopted in 1964 by the Eighteenth Symposium of the Society for Experimental Biology: Homeostasis in its widest context includes the coordinated physiological processes which maintain most of the steady states in organisms. The principal intellectual problem in the recent history of thought on societal homeostasis has been to ascertain the validity of extrapolating a physiological theory to a social hypothesis. The historical development of the concept of societal homeostasis was largely an extension of physiological and natural-order propositions to theories of society. Health and homeostasis are social concepts fundamental in any assessment of the future prospects of modern society.