Sunday, September 30, 2007
The Demise of Design: A Review of "Edge of Evolution"
About a week ago I picked up Behe's book, in hopes of reading it and reviewing it, and seeing if the arguments were any good. In his book, Behe argues that Common Descent is a fact, and so is Natural Selection, but he's not so sure about Random Mutation. He admits that it happens, but his point in the book is mainly that random mutation cannot account for what we see today. Unfortunately, Behe didn't sell me on intelligent design, and there were quite a few errors that need to be corrected within the book. Forgive me if this review is messy, Behe's book was was almost like a biology book, a bad theology book, a Lee Strobelesque intelligent design book all thrown in together.
The first, and probably by far the dumbest error I want to refute is this:
"Sickle hemoglobin can inarguably be explained by mutation and selection, the bacterial flagellum cannot." (p.104)
No, it's not out of context, he really said it. Ken Miller showed him that the flagellum was not irreducibly complex, but not how it evolved. Did he miss Nick Matzke's Essay on the Evolution of the Flagellum? He must have heard about it somewhere! This sort of thing is common knowledge to people who hold interest in evolution! There's even a video on youtube showing how the flagellum evolved.
He again makes the same mistake with the cilium, saying that Ken Miller "offered no Darwinian explantion for the step by step origin of the cilium" and that [the situtation of] "Missing Darwinian explanations of the cilium is utterly unchanged." (p.95)
Click here to read Panda's thumb talk about this mistake.
Now, onto Behe's main arguments:
1. Mutation and Selection are often destructive, not constructive
The example he gives us is with the evolution of disease and of the immune system. He points out that genes are often times broken so that the organism can survive. What I think he forgets is that the evolution of life in general would not have been like this. You wouldn't expect evolution to be consistently degenerative, obviously developing strong fins like the Tiktaalik did would not be destructive. My article entitled "Evolution cannot add new information" addresses this and shows evolution is not necessarily destructive. Abigail Smith also viciously refuted this point on her blog.
2. "That looks complicated, how could nature do it?"
He doesn't come out and say this, but that is the implication in chapter 5. He throws out descriptions of lots of complex molecular machinery, and then expects the reader to come to the conclusion that "randomness" couldn't have produced such a thing.
3. The Two Binding Site Rule
Basically the argument is that two protein protein binding sites evolving at the same time would be practically impossible, and since most molecular machines are "irreducibly complex", this couldn't happen. Note that he doesn't come out and say "irreducibly complex", but rather he says,"stupendously complex structures such as the cilium, the flagellum, and the machinery that builds them are beyond Darwinian evolution" and in conclusion states that the reason for this is that "most proteins in the cell work as teams of half a dozen or more." Indeed, this is just a thinly veiled irreducible complexity argument. Jerry Coyne refutes this assertion on Talk.Reason:
"Behe's probability calculations, on which his entire argument rests, are flatly wrong because they assume that adaptation cannot occur one mutation at a time. He uses chloroquine resistance of malaria (CQR) as an example, saying that the parasite always must have two mutations arising together to evolve resistance. As Ken Miller shows, this assumption is false, because one of the two mutations that Behe claims are "required" for CQR is not actually required (Chen et al. 2003, reference accidentally omitted from Miller's piece). It is therefore bogus to take the 1/10 to the 20th power number as the estimate of the probability of the evolution of a single binding site for CQR. And it is even more bogus to use this as a generic estimate for the evolutionary probability of getting any protein-protein binding site.
The probability calculations are also wrong because Behe's argument is based on specifying a priori exactly which mutations have to occur to be adaptive: the identical pair of mutations that occur in chloroquine-resistant malaria. He neglects the possibility (indeed, the certainty) that many other mutations that cause interactions between proteins and other molecules can also be adaptive.
Behe argues that the evolution of a single protein-protein binding site requires more than 2 simultaneous mutations -- more like 3-6 of them. He adduces no evidence for this major claim, nor does he give a single example of any case in which two or more binding sites must evolve simultaneously for an adaptation to arise. The reviews by Ken Miller in Nature and Sean Carroll in Science cite several examples of the gradual origin of adaptations via the step-by-step accumulation of point mutations in proteins."
4. Random Intelligent Design Arguments
This is probably the worst, and least thought out, part of the book. Behe argues that the getting a habitable universe, planet, starting life and then it evolving to today's complexity is so improbable that it requires a designer. Let's start out by examining the argument for the fine tuning of the universe. It has been discovered that the constants of our universe (i.e. gravity) are at just the right value to allow life to thrive. If Behe had read The God Delusion or God: The Failed Hypothesis, or even bothered to research the "Theory of Everything" he would have known this argument is wrong since the laws of physics are interrelated. As for a habitable planet, that might be fairly rare. Richard Dawkins had written an estimate of just how many planets in the universe are actually habitable, it was about 1 billion (out of 100 billion or more planets in the universe, not including moons and clouds of gas that can possibly host life). Behe also goes into improbable events that allowed our planet to be habitable. For example, he cites the fact that our moon stabilizes the earth's tilt, which in turn keeps our planet from undergoing life-destroying temperature fluctuations. But take, for example, Europa, one of Jupiter's moons. The tidal tugging that Jupiter exerts on Europa keeps it warm enough to possibly allow water to stay melted, thus making it habitable. I wonder if creatures that live on that planet talk about the exquisite and improbable design it took to position their home close enough the water below the surface wouldn't freeze, but far enough that it wouldn't vaporize. Do you think the IDers of that planet use this as one of their main arguments?
Now for the origin of life: Is life extremely improbable? The truth is we don't know. No one's ever demonstrated it in a lab, so all we can do is speculate. However, fossils show that life has been here for 3.8 billion years, and probably longer when you consider:
* The rarity of fossilization
* Older fossils which existed may have been destroyed
* We probably would not have fossils from the first organisms, because it would be unlikely for us to have fossils until the time that a population had grown very large.
I would estimate that the replicating molecule that led to life formed about 4 billion years ago. Consider the fact that our early planet was bombarded by meteorites during its early history (which would have annihilated these molecules if they were near) we can deduce that life shouldn't be astronomically unlikely. After all, if it was, shouldn't it have taken longer to happen?
Was the evolution of life grossly improbable? Well, Behe sure didn't construct any arguments to make me think so. I'd like to call your attention to Sean Carroll's book, The Making of the Fittest. In this book, he calculates that one specific mutation (he uses the example of light colored mice developing a dark coat) in a population of 10,000 would occur and spread between 20-100 times in 1 million years. Of course, Earth's population has probably not been down to 10,000 since shortly after the origin of life, and life has had about 3,800 times more years to evolve. We also have to consider that many mutations would be useful and would arise in this time frame and spread besides this specific one. Is evolution impossible? You be the judge.
In conclusion, this book is the death of intelligent design. There are so many more points I would like to go into, and so many examples of bad logic which I do not have the energy to type. If you want to learn more, read the following reviews, or buy the book, but keep the receipt so you can return it.
One of my favorite (non-famous) reviewers.
Richard Dawkins' review
Jerry Coyne's review