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Tuesday, October 11, 2005                                                                                       View Comments

Intelligent Design 101: Short on science, long on snake oil

The irreducibly complex teeters on the verge of reduction. None of these difficulties were mentioned.
By James Curtsinger

Good morning, class. As you know, the local school board has decided that we must include “Intelligent Design” in high school biology, so let’s start with the work of Dr. Michael Behe, ID’s leading scientist. Dr. Behe, a professor of biochemistry, visited the U last week as a guest of the MacLaurin Institute.
I spoke with him at lunch, attended his public lecture and took notes for today’s class.

Dr. Behe opened his public lecture by showing two images: a mountain range and Mount Rushmore.

One had a designer; the other didn’t. In case anyone was uncertain which was which, Dr. Behe also showed a duck, and emphasized that if it looks like a duck, and it quacks like a duck, then it is a duck.

Ergo if something in biology looks designed, it is designed.

He reviewed “irreducible complexity,” the important notion that certain structures with intricately interacting parts cannot function if any part is removed. According to Dr. Behe, such structures could not evolve gradually, as standard Darwinian Theory supposes; they must be the handiwork of a designer.

Well-known examples include mousetraps, the blood-clotting cascade, the vertebrate immune system and the bacterial flagellum. All of this was covered in his 1996 book, “Darwin’s Black Box.” Dr. Behe spent quite a bit of time talking about reviews of his book, and his responses to reviews.

Surprisingly, he had nothing to say about new developments in ID. Surely this revolutionary approach to biology has produced important scientific insights in the last nine years. Let’s use the Web to discover what they are.

Use Google to find “Entrez PubMed,” which will take you to a database of 15 million peer-reviewed publications in the primary scientific literature. The site, maintained by the National Library of Medicine, allows users to enter a search term and retrieve references to relevant publications.

For instance, enter “natural selection” in the search box and click “go”; about 14,000 references will be found. “Mutation” gets 40,000. “Speciation” gets 5,000. “Human origins” gets 22,000. “Behe intelligent design” gets … zero.

Not one publication in PubMed contains the terms “Behe,” “intelligent,” and “design.” The same holds for “Behe irreducible complexity.” A less restrictive search for “intelligent design” finds 400 papers, but many are not relevant because the words are common in other contexts.

To get more useful information, enter “intelligent design” in quotation marks, which searches for the two words together. When I searched last week, this produced 25 references, of which 13 were irrelevant to this discussion, five were news articles, six were critical of ID, and one was a historical review. “Irreducible complexity” in quotes gets five hits, one irrelevant and the others critical of ID.

Exact numbers change daily as new publications are added to the database, but the pattern is clear. Where are the scientific papers supporting ID?

Perhaps Dr. Behe publishes research papers that support intelligent design without using those terms. Searching PubMed for “Behe MJ” and sorting the results by date, you will find 11 publications since 1992, when the good professor converted to his new Ideology. Several are just letters to the editor.

The most recent (Behe and Snoke, 2004 and 2005) suggest that certain events in molecular evolution have low probability of occurrence.

This falls far short of the claim that a designer must have intervened, but what the heck, let’s put all 11 in the ID column.

Under these rather generous assumptions, ID’s leading light has produced fewer than a dozen peer-reviewed papers for the cause, none of which explicitly mentions ID. That number is substantially less than PubMed finds for “voodoo” (78), and pales in comparison with “diaper rash” (475).

Perhaps when the number of supporting publications rises to the level of “horse feces” (929) the professional community will grant ID some respect.

Cynics will suggest that ID is intentionally excluded from the peer-reviewed literature. It’s possible; the system strives for objectivity, but any human endeavor is potentially subject to bias.

This argument fails, however, when we consider that other revolutionary ideas have successfully crashed the party. Plate tectonics, major meteoritic impacts, and the bacterial origin of mitochondria are important ideas that were initially regarded with skepticism but are now accepted by the professional community.

Non-Darwinian molecular evolution, so-called “neutral theory,” was despised when it was first proposed in the late 1960s, but within a decade it became a standard part of the literature.

The historical evidence suggests that scientists can be persuaded to new views, given appropriate evidence. The primary literature is particular, but not rigid.

While you’re at PubMed, try searching for “bacterial flagella secretion.” One of the resulting papers, by SI Aizawa (2001), reports that some nasty bacteria possess a molecular pump, called a type III secretion system, or TTSS, that injects toxins across cell membranes.

Much to Dr. Behe’s distress, the TTSS is a subset of the bacterial flagellum. That’s right, a part of the supposedly irreducible bacterial “outboard motor” has a biological function!

When I asked Dr. Behe about this at lunch he got a bit testy, but acknowledged that the claim is correct (I have witnesses). He added that the bacterial flagellum is still irreducibly complex in the sense that the subset does not function as a flagellum.

His response might seem like a minor concession, but is very significant. The old meaning of irreducible complexity was, “It doesn’t have any function when a part is removed.” Evidently, the new meaning of irreducible complexity is “It doesn’t have the same function when a part is removed.”

The new definition renders irreducible complexity irrelevant to evolution, because complex adaptations are widely thought to have evolved through natural selection co-opting existing structures for new functions, in opportunistic fashion.

The story is incomplete, but it is a perfectly reasonable hypothesis that the bacterial flagellum evolved first as a secretory system, and later was adapted by natural selection for locomotion.

This scenario for gradual evolution of a complex molecular machine is bolstered by recent reports that some bacterial flagella do, in fact, have a secretory function (and now you know how to find those papers).

The irreducibly complex teeters on the verge of reduction. None of these difficulties were mentioned in the public lecture.

It seems that a new image should be added to Dr. Behe’s public presentation, one that represents the scientific status of intelligent design: a duck on its back, feet in the air, wings splayed.

If it looks like a dead duck, and it smells like a dead duck, it is a dead duck.

James Curtsinger is a University professor in the department of ecology, evolution and behavior.