Friday, April 22, 2005

California Wild Article, Update

In Monday's post I linked to, and quoted from, an article by Eugenie Scott published in the magazine California Wild. Some of the facts in the passage that I quoted are currently in dispute. For that reason I have decided to remove that post until the situation is resolved.

Wednesday, April 20, 2005

Evo-Devo in U.S News and World Report

I just came across this interesting article in US News and World Report about biologist Sean Carroll of the University of Wisconsin, Madison. Carroll's recent evo-devo book Endless Forms Most Beautiful is excellent. I will have more to say about it in some future post.

For now, here are two excerpts from the U. S. News article:

We're living at a strange moment in America. Once again, evolution is becoming a controversial topic. But while school boards are revisiting the 19th-century debate over whether evolution even happens, 21st-century scientists are beginning to show exactly how the natural phenomenon works. Using the powerful tools of molecular biology and comparative genomics, they're finding specific changes in the DNA that can account for 17,000 species of butterfly or why insects have only six legs instead of a dozen. And while some 55 percent of Americans balk at the idea that humans evolved at all, analysis of the genes that build our bodies shows our clear kinship not just to the apes but all the way back to bugs, worms, and beyond. Along the way, scientists are starting to find concrete explanations for everything from our large brains to just exactly how the fruit fly--or the leopard, for that matter--got its spots.

And later:

That discovery pointed to the deep connections between all animals and helped scientists work out the complex details of development. But it also raised a new problem: If key developmental genes have remained largely unchanged throughout evolutionary history, how can we account for all the differences, great and small, between different species? In some cases, the answer turned out to be a process of duplication and innovation. Several key points in animal evolution are associated with an increase in the number of developmental genes. The resulting redundancy in the control system, Carroll says, allowed evolution to “experiment” with new developmental programs and body forms, allowing vertebrates to develop distinctive features like skulls and jaws, for example, without hopelessly messing up other body parts.

Tuesday, April 19, 2005

Poll of Agronomists

The ID folks are crowing about a recent online poll about science education hosted by the American Society of Agronomy (ASA). Read William Dembski's take at his blog here, and Jonathan Witt's take over at the DI blog here.

The poll began: “Should K-12 students be taught in school:” Respondents the had five choices: Evolution, Alternatives (creationism, etc.), Both, Unsure and Other.

This was an online, voluntary response poll. It's day one of any statistics course that such polls are worse than useless, since the results of such polls are often very misleading.

Still, my initial response was that the ID folks had reason to crow. Out of 658 respondents, 338 chose “Both” while an additional 81 chose “Alternatives” (which presumably excludes evolution). Only 221 chose “Evolution.” That's a distressingly high percentage of respondents who favor creationism being taught in science classes.

Happily, even in the blogosphere initial responses don't always reign.

The only way the results of an online poll might be worth taking seriously is if the sample size was a significant fraction of the ASA membership. So I felt better when I noticed that the ASA and its affiliates have more than 11,000 members. If we call it 11,000 even, then 658 represents just under six percent of the total membership. And that six percent is composed of those people who both knew about the poll and cared enough to reply, a sampling that is sure to favor the minority of creationists within the group.

Then there are other issues. Of the 338 who chose “Both” how many actually support creationism? There are many people on my side of this who believe that various forms of creationism should be taught in science classes as a pedagogical tool. They believe that presenting both sides as favorably as possible will lead to students seeing that evolution is much the better explanation. I don't happen to endorse that view, but the people who do certainly have no qualms about evolution or its evidential support.

A few other tidbits. Here's Dembski's description of the poll:

Why is this significant? Consider the following numbers: out of 658 ASA members who responded before the poll results were removed, 33% favor teaching evolution only in K-12, 12% favor teaching alternatives (e.g., ID), 10% are unsure, and a full 50% favor teaching evolution as well as alternatives. It’s this last number that’s shocking. If these numbers are representative of the organization as a whole, half of this professional scientific society does not think that conventional evolutionary theory is sufficiently well supported to deserve a monopoly in science education. As this happens more and more across professional scientific societies, evolution’s monopoly over the teaching of biological origins will disintegrate. (Emphasis Added)

As I've already noted, it is very unlikely that the handful of respondents to the poll represent the society generally, and Dembski has no basis for concluding that the “Both” respondents have any qualms about the evidential basis for evolution.

But it's that bold-face phrase that caught my eye. The actual response option, as I described above, was “Alternatives (creationism, etc.)” Contrary to Dembski's description, there was no mention of ID. Since Dembski usually goes to great lengths to distance ID from creationism, it's rather convenient for him to use them interchangably here. This either reflects Dembski's instinctive dishonesty, or, more likely, it reflects the fact that Dembski doesn't really believe there is any important difference between ID and creationism.

Finally, we should also point out that the official position of the Discovery Institute is that they do not want to teach either ID or creationism in science classes. If we take them at their word (never a good idea), they simply want to teach more about Darwinism. By this they mean they want favorable coverage of the brain-dead, trumped-up anti-evolution arguments they're always going on about. The results of this poll are contrary to the officially stated position of the DI.

Sunday, April 17, 2005

Nelson on Sober on Gould

Our story begins with this article from The Missoulian, a Montana newspaper. The subject is a talk given by philosopher Elliott Sober at the University of Montana:

“The theory of evolution is not an atheistic doctrine,” Sober said. “It's about life once it gets started. How the universe began is not a problem for biologists. It's a problem for physicists.”

Sober presented two famous cases against and for God's involvement in designing the world.

In what he called “the panda's thumb,” Sober recounted science writer Stephen Jay Gould's observation that the small knob of bone on a panda's wrist, which it uses to prepare bamboo for eating, is so inefficient that it argues against an “intelligent designer's” involvement.

That argument is false, Sober said, because it assumes we know what God was trying to do with the panda's thumb. Nature is full of imperfect creations as well as remarkable ones. But we have no way yet of learning God's motives, if there are any.

It's always difficult to glean what somebody said from a brief newspaper account. As it happens, however Sober has elaborated on this point in other writings. (PDF format)

Sober's broad point is correct. If we hypothesize a deistic God who created the world but no longer interacts driectly with it, then it is impossible to know anything about His motives.

The problem with Sober's argument is that Gould pretty clearly was not trying to make an argument for atheism. Here's what he actually wrote:

Our text books like to illustrate evolution with examples of optimal design--nearly perfect mimicry of a dead leaf by a butterfly or of a poisonous species by a palatable relative: But ideal design is a lousy argument for evolution, for it mimics the postulated action of an omnipotent creator. Odd arrangements and funny solutions are the proof of evolution--paths that a sensible God would never tread but that a natural process, constrained by history, follows perforce. (Emphasis added)

Those bold-faced portions are important. By using the term “postulated” Gould is making it clear that he is, indeed, making certain assumptions about God. Those assumptions are that God is all-powerful (stated explicitly) and all-loving (implied throughout the essay). These are very common assumptions to make about God. And given those assumptions, the odd-design of organisms becomes something that is awkward for theists to explain.

On the other side of the coin, if we hypothesize that complex structures arise by gradual accretion and natural selection, then we would expect those structures to bear evidence of history. A panda with a fully opposable thumb that is lacking in its nearest relatives is hard to explain via evolution. But a panda whose thumb is cobbled together from bones serving other purposes in the panda's closest relatives is exactly what you expect from evolution.

I notice that Sober has mostly acknowledged this point:

Gould’s argument, I hope it is clear, is a likelihood argument. I agree with what he says about evolutionary theory, but I think his discussion of the design hypothesis leads him into the same trap that ensnared Paley. Gould thinks he knows what God would do if he built pandas, just as Paley thought he knew what God would do if he built the vertebrate eye. But neither of them knows anything of the sort. Both help themselves to assumptions about God’s goals and abilities. However, it is not enough to make assumptions about these matters; one needs independent evidence that these auxiliary assumptions are true. Paley’s problem is also Gould’s. (Emphasis in original)

As I have already shown, Gould was perfectly aware that he was making assumptions about God's character; he has not been ensnared in any trap. Sober has no basis for saying that Gould thought he knew what God would do.

We could go on for many pages on this subject, but let's bring Paul Nelson into this. Some years ago Nelson managed to con the editors of the academic journal Biology and Philosophy into publishing a bit of poorly-reasoned tripe called “The Role of Theology in Current Evolutionary Reasoning.” The focus of this paper was Gould's essay.

Commenting on Sober's Montana appearance, Nelson writes:

The scientific establishment retails a great deal of high-minded advice about the proper relationship of science and theology. Typically this advice recommends a “non-overlapping spheres” model, according to which theologians with good manners stay on their side of the playground, in a thin strip of weeds near the gymnasium wall, while scientists stay on their side, which turns out to be the rest of the playground. Stephen Gould’s “non-overlapping magisteria” (NOMA) framework is an instance of this notion, and one wishes Gould had followed his own advice. But he played in the theologians’ tiny patch of weeds as well. Threw his weight around, in fact.

Sober rightly indicts Gould for this deep inconsistency. The panda’s thumb argument amounts to a hopelessly contradictory methodology. “Strict NOMA for you, but any argument I like for me, including helping myself to that theology buffet over there.”

We should begin by pointing out that no one has actually said that last sentence. Nelson places it in quotation marks for no reason at all.

We should also observe that you will search Sober in vain for any indictment of deep inconsistencies on Gould's part. Sober is not faulting Gould's consistency, he is faulting his logic (rather unfairly, as I have argued). Sober was not discussing the proper relationship between science and theology, but rather the strength of certain versions of the design argument.

As for NOMA, Gould's point was that theologians should not make pronouncements about natural history becuase they have no evidential basis for doing so. Meanwhile, scientists should not turn their theories about and observations of nature into worldviews or systems of morality, because the facts of nature tell us nothing about proper behavior. Is that so complicated?

And the phrase “The panda's thumb argument amounts to a hopelessly contradictory methodology” is one of those masterpieces of nonsense only a creationist could write. There is no methodology under discussion here. And there is no contradiction either; what Nelson describes in his final sentence, if it were accurate, would amount to hypocrisy, not contradiction.

Gould's point was very simple and obviously correct. A certain class of observations we make about nature, exemplified by the panda's thumb, are easy to explain as the products of evolution but hard to explain as the products of an omnipotent, omnibenevolent designer. That's it. Only overzealous philosophers or creationist leeches could find something to argue with here.

Nelson has had this pointed out to him before. Here's Robert Pennock, in his book Tower of Babel

However, Nelson's argument improperly conflates the positive argument for evolution with Gould's negative argument against creationism. Nelson's confusion is not surprising given that on the dual model view creationists presuppose that rejecting the one is equivalent to proving the other. If Gould's comment about what a sensible God would never do were meant to be taken as part of a scientific argument, then Gould has indeed improerly violated methodological naturalism in his negative argument, for science has no way to test what would or would not be sensible from God's point of view. But ruling out this argument does not affect the positive argument. The reason that odd arrangements and makeshift adaptations are evidence of evolution is that these constitute a kind of pattern that is an expected effect of evolutionary processes, which must work at any given moment within the constraints imposed by previous evolutionary development.

At the end of the day the situation is very simple. ID proponents, almost without exception, believe in the Christian idea of an all-powerful, all-loving God. It is for them to explain why such a God afflicts his creations with such obvious examples of poor design. So far they have been completely unable to do so. The few suggestions they have made are laughably inadequate. But that is a subject for another post.