Saturday, March 20, 2004

Evo (part 1)...

I’ve been hitting evolution a lot lately so I wanted to stay away from it in order to touch on some other topics, but a recent set of articles caught my attention. Evidently there was quite a flap over a book review done by a Harvard Law Review student on Francis Beckwith’s book, Law, Darwinism & Public Education: The Establishment Clause and the Challenge of Intelligent Design. Brian Leiter, a philosopher of law, wrote a scathing review of Van Dyke’s review., to which Beckwith contributes, posted a blog on Leiter’s review titled, Letter and Harvard Law Review. National Review Online has also joined in the fracas, as well as Ed over at Dispatches. My intent here is not to get into that food-fight but to address a link that I saw on one of Ed’s posts related to this topic. He linked to a review of William Dembski’s book, No Free Lunch: Why Specified Complexity Cannot Be Purchased without Intelligence. It was written by H. Allen Orr, a professor of biology at University of Rochester. Orr addresses Dembski’s claims that mathematical theorems known as No Free Lunch (NFL) theorems illustrate that specified complexity must originate from an intelligence and not, as Darwinian evolution claims, from natural selection and genetic change. Having not read Dembski’s book and having no grounding in NFL theorems I will forego addressing those issues and deal, instead, with some missteps that Orr makes with regards to his interpretive methodology. I’ve written previously on the issue that ideas have consequences. A corollary to that could be that one’s worldview will structure how they tend to interpret data. My main arguments against evolutionary theory are typically not based on the data, as such, but on how the data is being interpreted. Orr addresses an illustration given by Richard Dawkins of how Darwinism works,
Now it's obvious how we go about making meaningful phrases: we use intelligence and crank them out at will. But how do biologists explain the complexity that resides in organisms? By Darwinism. To get a feel for what this means, consider the following caricature of Darwinism offered by Richard Dawkins and discussed at length by Dembski. Our target will be Hamlet's line, METHINKS IT IS LIKE A WEASEL. (Real evolution occurs in a sequence space that uses the four DNA "letters" A, G, C, and T but this is a distinction that doesn't make a difference.) First consider the odds of forming this target sequence by blind chance, i.e., with monkeys at word-processors. Draw a random letter from the alphabet for the first position in the phrase; now another for the second position, and so on. The odds that you've spelled out the phrase METHINKS… are essentially nil: in fact, with twenty-six letters plus a blank space, the odds of getting the word METHINKS alone are already less than one in 280 billion. But now consider the following "evolutionary algorithm." Start with a random sequence as before but i) randomly change each character that doesn't match the target sequence; ii) if a resulting character matches the target keep it and in the next round change only those characters that don't match. So, if we start with SATHINKS, at the next step we'll randomly change only the first two letters; and if those changes yield MQTHINKS, then at the next step we'll randomly change only the second letter. This two-step evolutionary algorithm of mutation plus selection arrives at the phrase METHINKS… with surprising speed.
Note that the odds of getting the phrase METHINKS by chance alone are not zero, but essentially zero. So although it is logically possible to attain the target phrase it is considered, for all intents and purposes, impossible. Also, note that the altered process, the evolutionary algorithm, uses a set of letters in which only the first two letters are off the target, and in which only the first two letters are allowed to change. Further, we should note that the phrase SATHINKS is meaningless (i.e., without function) and, per parameters Orr later describes, would not have any reproductive success. So, what we really need to find out is this: How can Darwinian evolution get from twenty-six letters plus a blank space (no meaning and no function) to METHINKS (meaning and function)? Orr ignores that question, or rather, he believes it is best approached by the concept of fitness function.
Fitness is a measure of quality; high fitness is good and low is bad. (In biology the only kind of quality that matters is how good you are at having kids. High fitness means you have a lot of kids and low means you have few.) A fitness function is just a mathematical function that assigns a fitness value to each possible sequence. In our Hamlet example, the best sequence is the phrase METHINKS…, so the fitness function assigns it the highest value. A sequence that matches METHINKS… at every position but one gets a slightly lower fitness, and one that matches METHINKS… at every position but two gets a yet lower fitness, and so on. A random sequence typically suffers a quite low fitness. If we now pretend that all possible sequences sit in a plane, we could plot their corresponding fitness values above this plane, forming a 3-D plot. Evolutionists thus sometimes speak of fitness "surfaces" or "landscapes." Because evolution always moves from a sequence to another having higher fitness, natural selection can be thought of as moving populations uphill on fitness surfaces. In Dawkins's example this process ultimately arrives at the sequence METHINKS…, which sits atop a fitness peak.
After describing how METHINKS is a target which equates to high fitness, and how evolution always moves from one fitness level to a higher fitness level, Orr then states that Darwinian evolution does not, in fact, have the capability to anticipate a desired outcome or to even specify a long-distance target of any kind.
…Darwinism isn't trying to reach a prespecified target. Darwinism, I regret to report, is sheer cold demographics. Darwinism says that my sequence has more kids than your sequence and so my sequence gets common and yours gets rare. If there's another sequence out there that has more kids than mine, it'll displace me. But there's no pre-set target in this game. (Why would evolution care about a pre-set place? Are we to believe that evolution is just inordinately fond of ATGGCAGGCAGT…?) …Dembski even quotes Richard Dawkins at length, who, it turns out, warned all along that his METHINKS… example is …misleading in important ways. One of these is that, in each generation of selective "breeding," the mutant "progeny" phrases were judged according to the criterion of resemblance to a distant ideal target, the phrase METHINKS IT IS LIKE A WEASEL. Life isn't like that. Evolution has no long-term goal. There is no long-distance target, no final perfection to serve as a criterion for selection….In real life, the criterion for selection is always short-term, either simple survival or, more generally, reproductive success.
So if Darwinian evolution uses no prespecified target, then why does Orr use the example in which METHINKS is a target? He uses it because he believes that the concept of fitness function is quantitatively different from that of a prespecified target. You see, the only target allowed by evolutionists is a short-term target, that is, reproductive success. But the rub is that the evolutionist is admitting that the odds of attaining a long-distance target (e.g., complex, functional information such as METHINKS) by chance is zero and, therefore, that it is only a short-term target (e.g., reproductive success) that is accessible by chance. This points to the crux of the problem facing the evolutionist. The problem is they tend to ignore the teeny-weeny fact that the organisms traversing the peaks and valleys of a fitness function are already functional (i.e., they have already attained a long-distance target of complex information). Those without function, such as SATHINKS, should not even have a chance to appear on the fitness function graph. Remember that functional fitness applies to short-term goals and, therefore, would tend to favor stability within an organism’s pre-existing functional boundaries. Nothing in the examples given indicate that additional function or features could be advantageous to reproductive success unless they were added in one fell swoop. Yet such an event would equate to achieving a long-distance target. In order to make the leap of faith from changes that provide functional stability to changes that create functionality the evolutionist must extrapolate the data to render it capable of performing acts they’ve never witnessed or specifically modeled. With regards to extrapolation, Orr states:
…Dembski's anti-extrapolationist view leads him into some formal muddy waters. If, as he oddly continues to claim, the NFL theorems pose a problem for Darwinism, why don't they pose a problem for a little Darwinism? The NFL theorems don't say anything about scale. To say then, as Dembski does, that a little bit of Darwinism is okay (despite NFL) but a lot is bad (because of NFL) is to say something odd. Dembski comes precariously close here to saying that while there's no such thing as a free lunch, you can help yourself to brunch. Last, surely it's the refusal to extrapolate Darwinism from the small to the large scale that needs justifying. If Darwinism can explain small changes in organisms over the last fifty years (antibiotic resistance, say), surely it can explain progressively bigger changes over the last 500, 5000, or 50,000 years. The cumulative effects of mutation and selection aren't going to get smaller. Dembski's anti-extrapolationism seems a lot like saying that, while Kepler's laws might hold on any given day, they don't hold over whole years. Such a position is, I suppose, formally possible but it—and not extrapolation—requires special justification.
Orr’s “if, then” statement is logically incoherent. Listen carefully to what he’s asking of you: You are to believe that, for instance, a land dwelling wolf-like creature can, in time and through mutational change, result in an ocean dwelling whale. You are to believe this extrapolation is justified based on the fact that, say, bacteria develop resistance to antibiotics. A whole lot of small changes just gotta add up to some mighty big changes! Right? Typically an evolutionist will then direct us to the fossil record and note that it indicates a progression from simplicity to complexity with the very types of species occurring in the very order that evolution would predict. One problem with this type of reasoning is that it tends to be circular. Remember now, it is the very phenomenon of the fossil record that we are trying to explain. Orr extrapolates that minor changes over short periods of time can produce major changes over long periods of time. This is evidenced, per the evolutionist, by the fossil record. But how can we use the fossil record as evidence to explain the phenomenon we see in the fossil record? What we need is evidence that the natural selection / genetic mutation mechanism can produce the types of changes that evolutionists have extrapolated. Another problem with this type of reasoning is that it ignores, knowingly or unknowingly, the fact that the data could just as well be explained by intelligent action. That’s all for part 1 of my critique.

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