Pharyngula

What properties should we expect from an evolved system rather than a designed one? Complexity is one, another is surprises. We should see features that baffle us and that don’t make sense from a simply functional and logical standpoint.

That’s also exactly what we see in systems designed by processes of artificial evolution. Adrian Thompson used randomized binary data on Field-Programmable Gate Arrays, followed by selection for FPGAs that could recognize tones input into them. After several thousand generations, he had FPGAs that would discriminate between two tones, or respond to the words “stop” and “go”, by producing 0 or 5 volts. Then came the fun part: trying to figure out how the best performing chip worked:

Dr. Thompson peered inside his perfect offspring to gain insight into its methods, but what he found inside was baffling. The plucky chip was utilizing only thirty-seven of its one hundred logic gates, and most of them were arranged in a curious collection of feedback loops. Five individual logic cells were functionally disconnected from the rest — with no pathways that would allow them to influence the output — yet when the researcher disabled any one of them the chip lost its ability to discriminate the tones. Furthermore, the final program did not work reliably when it was loaded onto other FPGAs of the same type.

That looks a lot like what we see in developmental networks in living organisms — unpredictable results when pieces are “disconnected”, or mutated, lots and lots of odd feedback loops everywhere, and sensitivity to specific conditions (although we also see selection for fidelity from generation to generation, more so than occurred in this exercise, I think). This is exactly what evolution does, producing a functional complexity from random input.

I suppose it’s possible, though, that Michael Behe’s God also tinkers with electronics as a hobby, and applied his ineffably l33t hacks to the chips when Thompson wasn’t looking.

Comments

  1. #1 Torbjörn Larsson, OM
    June 30, 2007

    Interesting how the single chip experiment directly showed that evolution over a population is needed to not get stuck in too constrained solutions. There is no secret that digital IC’s are individuals as analogue chips (which is one reason digital techniques are preferred), but that the sometimes small differences would affect the result is still cool IMO.

    One really can’t illustrate the errors of ID with any experiment, since experiments (at least deliberate ones) must have Designers.

    That is the illustration right there, ‘design’ is not a scientific theory because it can’t be falsified. Their idea is…, um, “designed” to not make predictions.

    On another note, one can make it pretty hard on creationists by letting the experiment choose random targets and constraints as well. (Rather like biological evolution btw, where increased fitness ‘targets’ may be shortterm and contingent.) Their last resort then is to make the handwaving you noted above.

    But no amount of handwaving will get that idea to fly.

  2. #2 David Marjanovi?
    July 1, 2007

    Somebody like Behe could very well argue that the goal of a god-driven evolution is the production of a conscient humanoid mirroring its creator…

    Then why are there so many byproducts? Like, the whole rest of the world?

    “Inordinate fondness of beetles”?

    mutations just grind to a halt when there are no more easy ones with obvious survival advantages in the existing environment.

    Mutations never grind to a halt. You’re talking about directional selection becoming stabilizing selection (and even this doesn’t work on neutral mutations — there’s still drift).

  3. #3 David Marjanovi?
    July 1, 2007

    Somebody like Behe could very well argue that the goal of a god-driven evolution is the production of a conscient humanoid mirroring its creator…

    Then why are there so many byproducts? Like, the whole rest of the world?

    “Inordinate fondness of beetles”?

    mutations just grind to a halt when there are no more easy ones with obvious survival advantages in the existing environment.

    Mutations never grind to a halt. You’re talking about directional selection becoming stabilizing selection (and even this doesn’t work on neutral mutations — there’s still drift).

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