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". In artificial selection, specific features are retained or eliminated depending on a goal or intention of an actor (e.g. the objective of a cattle breeder who would like to have cows that produce more milk). The goal of natural selection is survival, i.e. reproduction of a configuration. The selection is deemed natural because there is no known actor or purpose leading to the selection. Natural selection is purely automatic or spontaneous, without evidence of any plan or design.
Evolution typically leads to greater complexity, although one must be careful how one defines complexity.
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trial-and-error;
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evolution to greater complexity;
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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:
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.
Mis à jour le 01/04/2016 pratclif.com