Dynamic system: a general definition

The phrase dynamic system contains the words dynamic – referring to the Greek “dynamikos,” which means “powerful” – and system – a word that stems from a Greek verb that means “to combine.” Thus, a dynamic system is a combination of things to which certain powers or forces apply. If a force is applied to something, it moves or changes (unless the force is counteracted). Defined in this way, the term dynamic system has an extremely broad meaning. For instance, a bunch of dry leaves blown by the autumn wind can already be considered a dynamic system. It consists of a collection of leaves all subject to the same external force, the wind.

In order to avoid such trivial applications, we should confine the term to something that is more conceptually appealing. Let us begin by confining the notion of system to collections of things that are related to one another in a way that corresponds with the notion of dynamic, that is force- or power-related. We shall call something a dynamic system if it consists of elements that exert specific influences or forces upon one another and, by doing so, change each other's and their own properties (for general, technical introductions to dynamic systems, see, among others, Beltrami, 1987; Jackson, 1991a, b).

In this chapter I shall adopt examples from different fields: physics, biology, and, of course, psychology. My point is to show that dynamic principles apply to systems, irrespective of those systems' actual form or nature. What matters are the relationships, not the content matter. Dynamic systems' thinking is basically a way of thinking about systems, not about psychology per se.