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  Topic: Evolutionary Computation, Stuff that drives AEs nuts< Next Oldest | Next Newest >  

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Joined: Mar. 2008

(Permalink) Posted: July 06 2009,22:40   

The aspect of my simple weasel program that I find most interesting is the period after selection creates a population having high fitness. It then dithers around -- sometimes for fifty or a hundred generations -- without increasing fitness. Then, suddenly a long word will pop out, as if the program were waiting patiently for some hopeful monster.

My reading is that the plateau of high fitness is where any living population resides, and that so called neutral mutations are not really neutral, except that they have a fitness level as high as the existing average. Or perhaps they balance -- one up, one down.

It isn't really necessary to invoke any miracles of improbability. The dithering at high levels of fitness allows all kinds of things to emerge which could not emerge in one step from a low level of fitness.

I record the fitness scores of the mothers in my demo. When I see a 10 letter word emerge out of nowhere, I can trace the mothers and their fitness scores. Doing this, I see that for the most part, the history exhibits the same kind stepwise shift toward the 10 letter word that Dawkins' Weasel shows, as if that particular word were the goal.

Because I kill off the fittest every now and then, the scores sometimes go backwards. Sometimes the total count of "correct" letters will go backwards. All the more astonishing in retrospect. Dawkins' program can't do that.

But of course I wrote the program and I know the stepwise movement toward a target is an illusion. The program merely insures that given an adequate level of fecundity, fitness will always be high. After the first twenty or thirty generations, the population is never more than a few steps away from a "breakthrough."

I think what the cdesign proponentsists are missing is the fact that stasis in level of fitness does not imply genetic stasis. There are many variations that are equivalent in fitness. The path to a breakthrough structure doesn't have to  involve a continuous increase in overall fitness.

As an author, I'm biased, but I think my little program allows a person to see genetic drift. You see every mutation and every child. Of course I could be completely wacked. :p

Any version of ID consistent with all the evidence is indistinguishable from evolution.

  419 replies since Mar. 17 2009,11:00 < Next Oldest | Next Newest >  

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