Date : May 10, 1994 (modified); Aug 1993 (created)
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Evolutionary Theory
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We see evolution as based on the trial-and-error process of variation and natural selection of systems at all levels of complexity. The name of 'natural selection' comes from the Darwinian theory of biological evolution, which distinguishes "natural" selection from "artificial" selection, where specific features are retained or eliminated depending on a goal or intention (e.g. the objective of a cattle breeder who would like to have cows that produce more milk). The "implicit goal" of natural selection is maintenance or reproduction of a configuration at some level of abstraction. The selection is natural in the sense that there is no actor or purposive system making the selection. The selection we are discussing is purely automatic or spontaneous, without plan or design involved.
Many criticisms have been and are being raised against the Darwinian view of evolution. We will discuss the criticisms stating that there are designs or plans guiding evolution in a different section. Here we will focus on a more recent upsurge of people, many of whom are associated with the systems movement, who state that natural selection must be complemented by self-organization in order to explain evolution. (see e.g. Jantsch, 19; Kauffman, 1991; Swenson, 19). However, we must not confuse the specific theory of Darwinian evolution with the general principle of natural selection.
The narrow or specific interpretation of Darwinism sees evolution as the result of selection by the environment acting on a population of organisms competing for resources. The winners of the competition, those who are most fit to gain the resources necessary for survival and reproduction, will be selected, the others are eliminated. Even when abstracting from the fact that we are speaking about "organisms", this view of evolution entails two strong restriction: 1) it assumes that there is a multitude ("population") of configurations undergoing selection; 2) it assumes that selection is carried out by their common environment.
Like Swenson (19) notes, it cannot explain the evolution of a "population of one". In our present, more general interpretation, there is no need for competition between simultaneously present configurations. A configuration can be selected or eliminated independently of the presence of other configurations: a single system can pass through a sequence of configurations, some of which are retained while others are eliminated (see the Principle of Selective Retention). The only "competition" involved is one between subsequent states of the same system. Such selection can still be "natural".
Self-organization
More importantly this selection does not in any way presuppose the existence of an environment external to the configuration undergoing selection. It is easy enough to imagine configurations that are intrinsically stable or unstable. A cloud of gas molecules in a vacuum (i.e. an "empty" environment) will diffuse, independently of any outside forces. A crystal in the same vacuum will retain its rigid crystalline structure. The first configuration (the cloud) is eliminated, the second one maintains. The stability of the structure, functioning as a selection criterion, is purely internal to the configuration: no outsides forces or pressures are necessary to explain them.
In cases like these, the selection is inherent in the configuration itself, and an asymmetric transition from varying to stable may be called "self-organization". In the present view, "natural selection" encompasses both external, Darwinian selection, and internal, "self-organizing" selection.
Self-organization is usually associated with more complex, non-linear phenomena, rather than with the relatively simple processes of structure maintenance of diffusion. All the intricacies (limit cycles, chaos, sensitivity to initial conditions, dissipative structuration, ...) associated with non-linearity can simply be understood through the interplay of positive and negative feedback cycles: some variations tend to reinforce themselves (see Autocatalytic Growth), others tend to reduce themselves. Both types of feedback fuel natural selection: positive feedback because it increases the number of configurations (up to the point where resources become insufficient), negative feedback because it stabilizes configurations. Either of them provides the configuration with a selective advantage over competing configurations. The interaction between them (variations can be reinforced in some directions while being reduced in others) may create intricate and unpredictable patterns, which can develop very quickly until they reach a stable configuration (attractor). The process as a whole is characterized by a decrease of statistical entropy (see the Principle of Asymmetric Transitions).
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http://pespmc1.vub.ac.be/EVOLUT.html (PC Press Internet CD, 03/1996)