Tuesday, August 03, 2004

Hunter, Part One

Moving right along, the next essay in Uncommon Dissent that I read was “Why Evolution Fails the Test of Science” by Cornelius Hunter. Hunter holds a PhD in biophysics from the University of Illinois, making him the only contributor among those I have read so far to actually have some scientific credentials.

And it shows! Hunter's essay is very bad, as I shall show, but it is nonetheless a considerable improvement over the ones by Koons and Sisson that I have already considered. Hunter's tone is far more measured and respectful. His main goal is to persuade the reader not that evolution is demonstrably false, but that the evidence for it is not as strong as its defenders suggest.

Sadly, most of the essay is given over to arguments that are embarrassingly bad. One area where that is the case is his discussion of the fossil record, and I will address that here.

Hunter begins by providing a decent discussion of the reptile to mammal transition, and bear-like mammal to whale transition, both amply documented in the fossil record. Then comes this:


It is evidences such as these that give evolutionists their confidence. Evolution, they say, must be a fact. But how exactly does the proof proceed? A critical premise, it seems, is that similar species must be related via common descent. If we find similar desgins from the same time period, then they must share an evolutionary relationship. But in fact, this premise cannot be true, for there are many cases of similar species that evolutionsts do not believe serve as such strong proof. In the supposed reptile-mammal sequence and others, there are many similar fossil species that nonetheless do not fall into the reconstructed evolutionary sequence. It is, as one evolutionist put it, “notoriously difficult to decipher true ancestral-descendant relationships” amongst the boxes of fossil finds. Or as Douglas Futuyma put it: “The graudal transition from therapsid reptiles to mammals is so abundantly documented by scores of species in every stage of transition that it is impossible to tell which therapsid species were the actual ancestors of modern mammals.”(P. 206)


The idea that large numbers of transitional forms damages the case for evolution is a bit of intellectual perversity pioneered by Phillip Johnson. It's an argument reminiscent of the old Young-Earth claim that when fossil C is inserted in the gap between fossils A and B, the result is not progress, but merely two gaps.

Hunter is completely confused on this point. Let's consider the copious fossils cited by Futuyma as evidence of the reptile to mammal transition. The primary skeletal difference between reptiles and mammals is found in the strucutre of their jaws. Reptiles have three bones that connect their lower jaw to their upper jaw, while mammals have only one such bone. Two of the bones found in the reptilian jaw are nearly identical to two of the bones in the mammalian inner ear. If our hypothesis is that mammals evolved from reptiles, then there must at one time have been animals whose jaw structure was transitional between reptiles and mammals. There was a time when this hypothesis was considered so absurd that it was treated as prima facie evidence for the impossibility of evolution (I mean, if jaw bones became ear bones then the intermediates would have disfunctional jaws and disfunctional ears, right?)
Yet the fossil record documents that animals having the required features actually existed.

Similarly, if we are going to argue that whales evolved from bear-like ancestors or that humans evolved from ape-like ancestors, then there must have been a time when animals showing features transitional between these animals existed. The fossil record documents that such animals existed as well.

Evolution also implies that there should be a definite order to the first appearances of various species in the fossil record, an implication that is impressively borne out.

There is no reason outside of evolution to expect to find such fossils. There is no rival theory that makes the same predictions about the fossil record that evolution does. That is why the fossil record provides such good evidence for evolution. Hunter seems to have overlooked that point.

Instead he discusses the far thornier problem of inferring specific lines of descent among such fossils as we have. That is an intereting question, but one that has nothing to do with whether fossils provide strong evidence for common descent. Neither of the quotes he cites is helpful to his case.

That Hunter is confused on this point can also be seen from other comments he makes on this subject. For example, he writes:


With evolution we must believe that across the reptile-mammal transition, organisms evolved so rapidly that they appear fully formed and diverse in the fossil record, that there are large gaps between the reptiles and mammals, and that convergent evolution must have occurred many times. So too, the horse sequence turned out to be more problematic than evolutionists thought. It turned out that the species that were supposed to align in an evolutionary lineage actually persist unchanged and co-exist in the fossil record. As Niles Eldredge admitted:

“There have been an awful lot of stories, some more imaginative than others, about what the nature of that history [of life] really is. The most famous example, still on exhibit downstairs, is the exhibit on horse evolution prepared perhaps fifty years ago. That has been presented as the literal truth in textbook after textbook. Now I think that that is lamentable, particularly when the people who propose those kinds of stories may themselves be aware of the speculative nature of that stuff.” (P. 206-207)


Let's begin with the quote from Eldredge. It's taken from a 1985 article from Harper's magazine by Tom Bethell, a creationist. Rather lazy of Hunter not to go to Eldredge's own writings to learn his thoughts about fossil horses.

Ordinarily this is the point where I would accuse Hunter of removing Eldredge's quote from its proper context. In this case, though, I think Eldredge's intention is perfectly clear, it's just not the point Hunter attributes to him.

Eldredge is not objecting to the idea that the extensive collection of fossil horses provides strong evidence of common descent. He is not even objecting to the horse exhibit at the American Museum of Natural History (where Eldredge works). His objection is to the misleading impression that some people get from viewing such exhibits. The horse exhibit, which lines up four distinct fossil horses from four different time periods, suggests that there was a simple, linear progression from some ancient proto-horse to modern horses. Eldredge is merely pointing out that the processes of evolution are more complicated than what is suggested by the exhibit.

Don't believe me? Here's Eldredge from his book The Triumph of Evolution, and the Failure of Creationism, commenting on a similar abuse of his ideas presented by creationist Luther Sunderland:


The dead horse that Sunderland and all other creationists beat is, of course, not stasis versus gradualsim, but the existence of anatomical intermediates, especially if they exist in perfect stratigraphic order. I am here to tell you that my predecessors had indeed unearthed and mounted a wonderful series of skeletons, beginning with the Eocene Hyracotherium (the so-called dawn horse), with its small size, four toes on the front feet, five on the back feet, shortened face, and generalized perisodactyl teeth suitable for browsing, not grazing. Climbing up the Tertiary stratigraphic column of the American West, we find the horses becoming progressively bigger, with fewer toes (modern horses have but one on each foot) and more comlicated teeth. The horses of the Pliocene are essentially modern,

This is not a made-up story. The fossils are real. They are in the proper order, and they are a spectacular example of anatomical intermediates found in the exact predicted sequence in the rock record. They are every creationist's nightmare.

No, horse evolution was not in the straight-line, gradualistic mode. But to state or imply that the horse evolution exhibit was somehow arranged to support an evolutionary story - to imply that the old museum curators deliberately misled the public by arranging the order of these horse fossils as they saw fit - is a damn lie. (Emphasis in Original) (P. 133).


The rest of Hunter's paragraph is no better. In writing about the reptile-mammal transition he asserts that convergent evolution must have happened many times. I can't imagine what he's talking about. The fossils show us there were many reptile species existing at the time when the transition was taking place. No doubt they all inherited their common features from common ancestors. Where's the convergence there? Does he mean that since more than one species possessed the bizarre amalgam of reptilian and mammalian jaw features indicative of the reptile-mammal transition that these species must have converged on that particular jaw structure? Surely not, for that would just be too stupid. Yet I can't see any other way to infer that convergent evolution happened many times.

And what's the alternative to fossils appearing fully formed? Partially formed fossils? Every fossil represents an animal that was making a living at some earlier time and in some earlier environment. Partially formed animals are not usually successful in that regard. What does that have to do with the interesting melange of anatomical features possessed by the fossils under discussion?

Hunter has written two books on the subject of evolution. It is something he has evidently thought about and read about for some time. And yet he's making arguments based on elementary misunderstandings of paleontology.

The usbtitle of Dembski's book is “Intellectuals Who Find Darwinism Unconvincing”. Apparently intellectual and smart are two different things.

4 Comments:

At 9:48 AM, Anonymous Anonymous said...

Actually, Bethell would have gotten the Eldredge quote from an interview that Sunderland conducted. So Hunter is even further removed from the original source if he cites Bethell as the source for his quotation.

Wesley R. Elsberry

 
At 10:46 PM, Anonymous Anonymous said...

Comments:
My reply to Jason Rosenhouse is at the ISCID Brainstorms:

http://www.iscid.org/ubb/ultimatebb.php?ubb=get_topic;f=6;t=000540

 
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At 9:04 AM, Blogger John Woods said...

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