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Evolution and Optimum Seeking

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R<strong>and</strong>om Strategies 103<br />

out, a limited life span of all individuals is an important ingredient in such cases (principle<br />

of forgetting).<br />

Two others who have tried to explain brain processes on an evolutionary, at least<br />

selectionist, basis are Edelman (1987) <strong>and</strong> Conrad (1988). Though their approach has<br />

not yet been embraced by the main stream of neural network research, this mighthappen<br />

in the near future (e.g., Banzhaf <strong>and</strong> Schmutz, 1992).<br />

An even more general paradigm shift in the eld of arti cial intelligence (AI) has<br />

emerged under the label arti cial life (AL see Langton, 1989, 1994a,b Langton et al.,<br />

1992 Varela <strong>and</strong> Bourgine, 1992). Whereas Lindenmayer (see Prusinkiewicz <strong>and</strong> Lindenmayer,<br />

1990) demonstrates the possibility of (re-)creating plant forms by means of<br />

rather simple computer algorithms, the AL community tries to imitate animal behavior<br />

computationally. In most cases the goal is to design \intelligent" robots, sometimes called<br />

knowbots or animats (Meyer <strong>and</strong> Wilson, 1991 Meyer, 1992 Meyer, Roitblat, <strong>and</strong> Wilson,<br />

1993).<br />

The attraction of even simple evolutionary models (re-)producing fairly complex behavior<br />

of multi-individual systems simulated on computers is already spreading across<br />

the narrow bounds of computer science as such. New ideas are emerging from evolutionary<br />

computation, not only towards the organization of software development (Huberman,<br />

1988), but also into the eld of economics (e.g., Witt, 1992 Nissen, 1993, 1994) <strong>and</strong> even<br />

beyond (Schwefel, 1988 Haefner, 1992). It may be questionable whether worthwhile conclusions<br />

from the new ndings can reach as far as that, but ecology at least should be a<br />

eld that could bene t from a consequent use of evolutionary thinking (see Wol , Soeder,<br />

<strong>and</strong> Drepper, 1988).<br />

Computers have opened a third way of systems analysis aside from the classical mathematical/analytical<br />

<strong>and</strong> experimental/empirical main roads: i.e., numerical <strong>and</strong>/or symbolical<br />

simulation experiments. There is some hope that we may learn this way quickly<br />

enough so that we can maintain life on earth before we more or less unconsciously destroy<br />

it. Real evolution always had to deal with unpredictable environmental changes, not only<br />

those resulting from exogenous in uences, but also self-induced endogenous ones. The<br />

l<strong>and</strong>scape is some kind of n-dimensional trampoline, <strong>and</strong> every good imitation of organic<br />

evolution, whether it be called adaptive or meliorizing, must be able to work properly under<br />

such hard conditions. The multimembered evolution strategy (see Chap. 5, Sect. 5.2)<br />

with limited life span of the individuals ful lls that requirement to some extent.

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