ABSTRACT
A locomoting animal is not a simple atomism in motion. Biological systems possess available on-board sources of potential energy. Their interiors are functionally rich. So how might the physical principles governing flow processes defined over simple atomisms be extended to complex biological atomisms? And if these principles are to be elaborated, then what direction must the elaboration take so that it does not impugn them? Answers are suggested, perhaps suprisingly, by the classical theory of collisions.
Interactions between simple Newtonian particles and their surroundings are dominated by descriptions that involve the mass dimension. Ordinary interactions are said to occur through forces (a force, dimensionally, is MLT-2). In contrast, interactions between complex biological particles and their surroundings are dominated by descriptions in which the mass term is absent. These descriptions are kinematic (space/time), and/or geometric (spatial), and/or spectral (temporal). Indeed, interactions that do not involve mass-based descriptions or observables might be taken as the hallmark of systemic behavior at the ecological scale. At the ecological scale interactions are largely informational, not forceful. The significance of this fact is that suppression or removal of the mass dimension from the state description eliminates the "interactive violence" associated with the shock waves and impulses that strain 65 the internal constraints and ultimately lead to internal fracture and "organizational death."
A historical challenge for the physically minded scientist has been the removal of vitalism from explanatory accounts of biological systems. A less heralded but no less important challenge is the removal of the interactive violence associated with mass-dominated interactions. A physical pursuit of this latter challenge brings to the forefront the centrality of the concept of information and puts a "non-Newtonian life" back into biology. This pursuit was anticipated by Gibson, and a paradigm for interactions or collisions that asserts the primacy of kinematic flow-field descriptions might be termed Gibsonian. An elaboration of Gibson's methodology focuses on the physical and functional significance of nonmass interactions in a manner that is continuous with the theory of collisions. The promise is of a natural transition from the physical theory of self-organization to a theory of self-organizing "information systems."
An example is given of a self-organizing information system—the periodic assembling of a nest by a population of social insects. A detailed analysis of this phenomenon focuses on the nature of various field couplings (macro/micro, flow/force) and the strategic role each assumes. More particularly, the analysis focuses on a coupling between the macroscopic locomotory processes of the insects and a microscopic, dissipative field of dispersing pheromones. The coupling is realized as a description that is not invariant over direction. The chemical diffusion field (i.e., the dispersing pheromones) interacts with the insects through a Newtonian force-field description. In comparison, the insects interact in locomotion with the diffusion field through a non-Newtonian flow-field description.
The significance of the embedded nest-building activities is that they exemplify a self-organizing system that is dominated macroscopically by "kinematic flow-field" properties and microscopically by "force-field" properties. This design may be very general. A presentation is given of Gibson's ecological optics and of the optical flow-field properties (kinematic, geometric, and spectral) that constrain locomotory activity. A case is made for a Gibsonian paradigm for interactions (asserting the primacy of flows) to supplement the Newtonian paradigm for interactions (asserting the primacy of forces) at the ecological scale of living things and their environments.
