IC from Evolvability

From: pruest@pop.dplanet.ch
Date: Mon Nov 13 2000 - 15:17:40 EST

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    David wrote:

    >I think we are basically agreeing that absolute lack of viable intermediates would be a good criterion for irreducible complexity. My point is that the criteria actually used to purportedly recognize intelligent design do not come close to eliminating the possibility of viable intermediates.
    >We cannot specify the complexity of an existing biological system ahead of time, because they already exist. (Some time ago, Dembski put in an appearance on this list. I raised this question and he replied that his next book would answer it. I have not tried to watch everything he published since, but cannot think on my own of a way to specify in advance something that already exists.) A valid argument for specified complexity also requires a priori statistical planning. You cannot just keep looking for something that matches your specifications until you find it and then consider that significant. For example, suppose I am trying to build a stone wall without mortar. As I come close to finishing it, I will need rocks of particular sizes and shapes to fill in gaps. Assuming that I had enough sense to build my wall somewhere where rocks are abundant, I can hunt around and find rocks that meet my established specifications. I may look at hundreds of rocks before find!
    g the right one, and thus I have no reason to consider the rock specially designed for the space in my wall. I will consider the match providential, but not intelligently designed in the sense of design advocates.
    >Likewise, I do not remember any of Behe's examples as being something required by every living organism. Half of a flagellum may be useless (or it may not-who knows?), but it is not deadly.
    > Dr. David Campbell

    If you just cut off half of a flagellum, you still have ALL the proteins
    required. But if you eliminate a gene specifying a given type of protein
    either of the rotor, or of the stator, or of the drive shaft, or of the
    flagellum, or of the hook linking them, or maybe any one of a few
    others, you won't have anything moving AT ALL. This may not be deadly to
    the bacterium (if it is in a nutrient broth), but it COMPLETELY
    eliminates the flagellum function. If, e.g., a crucial rotor protein is
    missing, a new "prospective" rotor protein certainly cannot be selected
    for (by some flagellar motion!) as long as it doesn't provide the
    missing function AT LEAST MINIMALLY. How did this minimal activity
    arise? To believe that it evolved from some other, similar sequence is a
    useless "just-so story". Do we have to prove that this evolution could
    NOT happen? Or do we have to show that it COULD? I don't know whether
    Behe would argue like this, nor how Dembski would estimate a probability
    for the flagellum case. But wouldn't the inference of irreducible
    complexity be the most reasonable one, given what we know at present?

    I agree with you that we cannot prove it. But at least we should admit
    that we cannot (yet?) conceive of any possible darwinian evolutionary
    path for the flagellum - and for 1001 other functions.

    For THEOLOGICAL reasons, on the other hand, I believe that we will never
    be able to scientifically prove intelligent design - which would
    necessarily imply the existence of a personal, intelligent, transcendent
    Designer - and lack of freedom for a faith decision on our part.

    Peter Ruest

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