This article attempts to bring a first round of closure to an entire series of articles on command control . This contribution is of significance for the Gibsonian program (e.g., Iberall, 1995). This article attempts to complete a primitive physical foundation for that control process, for the basis of attention, action, and so-called purposeful or intentional movement or change in all complex systems, particularly mammalian and human. It assumes and neglects the very high-speed reflex actions that are dealt with by the autonomic nervous system. A discussion is included on the general character of the dynamic problem of command control in all of nature.One of my previous articles in this journal (Iberall, 1995) sketched much of the homeokinetic (HK) framework but did not pursue the topics that are needed to complete the brain modeling that the HK approach makes possible. This article focuses on the role of pressure in running an animal (or plant) system and connecting that pressure, whether it be actual physical pressure or a transformed social pressure to the conduct of human activities, recognizing the entire range of possible value systems as studied, say, in cultural anthropology.A brief summary of some of the views of the development of ideas and contributions to the physics of fluid systems at various hierarchical levels is given in Appendix A.Throughout my career, while working out detailed accounts of processes at many levels of the physical, biological, and industrial world, I maintained commitment to strictly physical accounts and, in fact, to even achieving a thoroughgoing high hierarchical level of a social physics. The physics that has served best to span ECOLOGICAL PSYCHOLOGY, 12(2), 109-139 Copyright © 2000, Lawrence Erlbaum Associates, Inc.Requests for reprints should be sent to Arthur S. Iberall, 5070 Avenida del Sol, Laguna Woods, CA 92653. E-mail: aiberall@uci.edu the gamut of the interests of those complex systems in a unified way is irreversible thermodynamics, its persistent alliance with statistical (almost invariably fluid) mechanics, and its energetic and atomistic material foundations. These conceptual tools have been used to develop such a physically grounded approach to complex systems, which also can be mathematically quantified but not promiscuously so. Because of the fundamental position of thermodynamics and hydrodynamics (via the Navier-Stokes equation set), these will be reviewed in a caricatured fashion, both in the text and in the appendixes, to make certain that readers can get the flavor of where these tools fit and what they can do. It is also worth noting that this approach emphasizes processes that function by moving a system toward an equilibrium state of sorts. This tends to be in contrast to approaches that emphasize "far from equilibrium" states such as those popularized by Prigogine (1978).
A BASIC FLUID LEVEL: THE NAVIER-STOKES EQUATION SETThe basic bottom macroscopic level of a fluid system, for which the atomisms (atomistic-like units) are the individual molecules...