A skeleton of physical ideas for the dynamics of complex systems

We define complex systems, from molecular ensembles and networks to galactic clusters, as fluid-plastic-elastic systems in which bulk/shear viscosity ratios are large, with the consequence that interactions among parts at any level lead to internalization of action (energy × time) and to variable process delays between external inputs and outputs. Living systems are notably complex by this measure. Complex systems can be comprehended dynamically through an extended statistical mechanics, irreversible thermodynamics, and nonlinear mechanics, in the form of an electrohydrodynamic field physics. Chemical reactivity (making, breaking, or exchanging bonds) is subsumed in the generalized mechanics as a diffusive process. In this paper we apply this physical construct to the problems of dynamic regulation and coordination among parts in the forms of life found in the more than 300 families of flowering plants. We choose to use these particular plants rather than vertebrates, mammals, or man, as exemplars of our theory to show how effective “chemical languages” can be, without the obfuscating arrangements of nervous systems and muscles designed to support locomotion.