ABSTRACT
The notion of system we are interested in may be described generally as a complex of elements or components directly or indirectly related in a network of interrelationships of various kinds, such that it constitutes a dynamic whole with emergent properties. l The components may be relatively simple and stable, or complex and varying; they may vary in only one or two properties or take on many different states. The interrelations between them may be mutual or unidirectional, linear, nonlinear or intermittent, and varying in degrees of causal efficacy or probability. The particular kinds of more or less stable interrelationships of components that become established at any time constitute the particular structure of the system at that time, thus achieving a kind of "whole" with some degree of continuity and boundary. Also, we are mainly interested in systems within which some process is going on, including an inter-
change of material, energy, and/or information, with an environment. It is generally agreed that when we deal with the more open system with a flexible structure, the distinction between the boundaries and the environment becomes a more and more arbitrary matter, dependent on the purpose of the observer.
