Tuesday, December 06, 2005

Fisking Bethell

With the conservative Charles Krauthammer bashing ID in The Washington Post and the liberal Bob Beckel dissing evolution in USA Today, I was beginning to fear I might have to revise my views on politics and evolution.

But now things seem to be returning to normal. National Review Online has recently run this awful article from Tom Bethell, author of The Politiclly Incorrect Guide to Science. It goes without saying that no one with actual scientific credentials would publish a book with so hackneyed a title.

After plugging his book and describing the rift among conservatives on this subject (in which a generally anti-evolution rank-and-file is pitted against the pro-evolution “chattering classes”), Bethell gets down to business. First up is antibiotic resistance, briefly mentioned by Krauthammer. Bethell writes:

But what actually happens in the Petri dish? Some of the bacteria are naturally equipped with enzymes that give them immunity to the antibiotic. So they survive, while most of the bacteria die. Nutrients remain in the dish, and the resistant strain now has an ample food supply and multiplies. Before, it could hardly compete with the far more abundant strain, now wiped out. So the (pre-existing) resistant strain becomes more numerous. There is a multiplication of something that already existed. But as the famous geneticist Thomas Hunt Morgan said about 100 years ago — he spent years studying fruit flies at Columbia University and was rewarded with the Nobel Prize — evolution means making new things, not more of what already exists.

Nonetheless, if you define evolution as a change of gene ratios, well, yes, there has been such a change of ratios in the population of bacteria. So, if your definition of evolution is sufficiently modest, then you can call evolution a fact. Others define evolution as “change over time.” That's a fact, too.

It is around here that an experienced reader begins to suspect that Bethell doesn't really know what he is talking about. His second paragraph directly contradicts the first. Even in the narrow situation he described in his first paragraph, selection has, indeed, made something new. It has tranformed a population of non-resistant bacteria into a population of resistant bacteria.

In a single round of variation and selection like this you obviously won't see major changes taking place. But the variations preserved by selection in this round will serve as a platform for subsequent variations that do not yet exist. Of course selection by itself can only cause preexistant variations to become more numerous. Who ever said otherwise? It's the genetic variations themselves that are constantly being created anew.

Consider the evolution of the eye. The familiar scenario is that some primitive organism possessed a simple light-sensitive spot. Over the generations selection preserved a long series of genetic variations that improved the ability of the spot to draw information about the environment from the available light. Eventually this led to modern eyes. No doubt Bethell would take each step in isolation and remark that, in every case, selection merely caused preexisting variations to become more numerous. But the fact remains that most of the variations that led to the eye did not exist when the process began. The end result of all this variation and selection was something entirely new.

Bethell talks about hypothetically defining evolution as a change in gene ratios, as if anyone has ever defined it as anything else. Even Darwin, who did not know about genes, described evolution as descent with modification. The thing being modified, as he makes clear in The Origin of Species, were the average characteristics of a population. Nowadays that average is expressed in terms of genes.

Bethell has other arguments, of course. Apparently fossil bats are hard to come by:

So let's look at the evidence adduced for evolution. The fossil record is sparse. Bats, for example — the only mammals capable of powered flight — appear suddenly in the fossil record, with their sonar systems already fully developed. “There are no half bats,” as a world expert on bats once said. The experts have no idea what animal gave rise to the first bat.

As I've said before, what's significant about the fossil record is that with tens of millions of fossils dug up and categorized, not one is out of place from an evolutionary standpoint. To put in language Bethell might understand, we have examples of creatures that are half-fish, half-amphibian; half-amphibian, half-reptile; half-reptile, half-mammal; half reptile, half-bird; half-land based carnivore, half-whale; and, of course, half-ape, half-human. We have impressively gradated sequences of fossil horses, elephants and rhinos. And these are just the high profile examples that don't include less glamourous creatures like trilobites and snails. In Bethell-land we're supposed to ignore all this because bats don't fossilize well.

And then there's all that complexity anti-evolutionists are so fond of:

The creatures that evolution purports to explain are fantastically complex. The cell, thought at the time of Darwin to be a “simple little lump of protoplasm,” is as complicated as a high-tech factory. We have no actual evidence that it evolved — and yet we are asked, indeed obliged, to believe that it did.

Actually, there is very clear evidence that the modern eukaryotic cells (the ones with well-defined nuclei and all those amazing organelles) evolved from simpler precursors. We can be pretty certain that the mitochondria and the chloroplasts arose via symbiosis, for example. But the cell is hardly the main focus of evolution. The first cell, after all, came into existence billions of years ago. Explaining its existence is the job of origin of life researchers, not evolutionists.

But once again we see the familiar style of argument. We have vast amounts of evidence from fossils, anatomy, biochemistry, genetics and so on that tells us that evolution happened. In many cases we can provide convincing explanations for how specific structures evolved. Bethell would have us dismiss all that because certain aspects of the cell are a bit mysterious. This is a luxury that armchair science critics have that actual scientists do not.

Apparently having run out of mysteries for evolution to solve, Bethell decides to widen his search:

In the human body, there are 300 trillion cells, and each “knows” what part it must play in the growing organism. To this day, embryologists have no idea how this happens — even though they have been trying to figure it out for 150 years.

This is hardly an evolutionary question at all. Once we have a better grasp on the mechanism by which cells differentiate themselves in the course of embryological development, then we'll worry about explaining the evolution of that mechanism.

From here Bethell spends most of the his remaining space waxing poetic about the marvelous things that living creatures do. Since there is no discernible argument in any of this gushing, I will not respond to it here.

What becomes clear from all this is that Bethell is content to point to a few biological mysteries, and on that basis conclude that evolution should be thrown out the window. As I said, he has that luxury because no one expects him to enter a laboratory and come out with actual results.

Actually, Bethell does have one additional argument to make. It's a creationist classic! Bethell argues that natural selection is a meaningless tautology. Natural selection is sometimes defined as the survival of the fittest, you see. But the fittest individuals are simply the ones that survive. It's just a a tautology! QED!!

One wonders how scientists have overlooked for so long this simple logical fallacy. Actually, this argument is singularly brain-dead. But it is also interesting enough to merit it's own blog entry. Stay tuned!


At 6:18 PM, Anonymous Anonymous said...

This is just an impression, but in reading Bethell's comments on the development of resistant bacteria, it occurred to me that it would take a pretty limited imagination to find his argument convincing. It's kind of depressing, actually. He's talking about changes taking place within a single generation, but apparently he lacks the wit (or the honesty) to extrapolate that process over many thousands of generations, and to imagine the profound changes that would result.

Of course I can't know if Bethell himself is dense or dishonest, but it is a stark reminder that creationism appeals to some of the worst traits of our species: anti-intellectualism, fear of the unknown, and the smug sense of absolute certainty that you can only get by shutting off your imagination.

At 6:31 PM, Blogger Lee J Rickard said...

"In the human body, there are 300 trillion cells, and each “knows” what part it must play in the growing organism. To this day, embryologists have no idea how this happens — even though they have been trying to figure it out for 150 years."

Ah, so Bethell does indeed come from Mars. Otherwise, how could he have missed the publicity for and commentary on (not to mention the excellent content of) Sean Carroll's Endless Forms Most Beautiful?

At 6:36 AM, Blogger Craig Pennington said...

I wrote on this a few days ago. I didn't know at the time, but Bethell has been publishing anti-evolution tripe since at least February 1976 when he penned an article titled "Darwin's Mistake" for Harper's. I find it difficult to grant the benefit of incompetence to someone who's been writing on a topic for thirty years and yet fails so completely to understand a topic; I suspect he is simply dishonest.

At 8:28 AM, Blogger Mark said...

Well, he got part of it right--selection for resistance--but he just couldn't take the next small, imaginative step. I wonder if all of his knowledge is so bounded and segregated. By being so limited in thought, he appears to be a dumb as a pile of sawdust.

At 4:00 PM, Anonymous Anonymous said...

Has Bethell never heard of bacteria which have evolved to metabolize some types of plastics (nylon)? See http://www.nmsr.org/essay3a.htm

Interesting how could this new "information" have been added? Oh yeah, because Dembski's wrong!

At 5:14 PM, Blogger John Farrell said...

Craig, man, if you only knew. Bethell's opposition to Darwin is just the tip of the iceberg. Add hostility to Einstein's relativity and his belief that of course the plays of Shakespeare were written by the Earl of Oxford, and you definitely have a case.


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