Responding to LA County Natural History Museum Scientist Kirk Fitzhugh
In a prior post, we saw how the LA County Museum of Natural History (LACMNH) contributed to the pressure on the California Science Center to cancel a pro-ID event sponsored by American Freedom Alliance. But there's a little story to tell here about a fairly vocal anti-ID scientist at the LACMNH. When I was an undergraduate, a friend gave me a packet titled "Classification: Graduate Student Project," which explained various methods of building phylogenetic trees. The packet is a three-ring binder collecting the pages of a project completed in 1983 by a then-graduate student at George Washington University, Kirk Fitzhugh. His name came up as I was reviewing e-mail correspondence related to the California Science Center's cancellation of its contract to screen the pro-ID film Darwin's Dilemma. Some of the emails were authored by Dr. Fitzhugh while others were addressed to him. But I'm getting ahead of myself.
Over the years, I've occasionally referred to the Classification packet with amusement. Why? Because the exercises use an intelligently designed, artificial dataset of little drawings of hypothetical text-based creatures, each given a unique set of traits and characters. The student is supposed to analyze the dataset, compare the characters, and use various methods of tree-construction to reconstruct the evolutionary relationships for the creatures. Given that this dataset is intelligently designed and that the creatures in fact do not share a common ancestor, the exercise reminds me of how easy it is to construct evolutionary trees that have nothing to do with evolution history.
For example, you could go to the local gym, empty out each locker and catalogue the contents, and then use these methods to compare characters and construct some hypothetical phylogenetic tree showing how this pair of shorts is related to that t-shirt, how this hair dryer shares ancestors with that antiperspirant spray, and so on. Though the resulting tree might result from careful application of the methods of systematists, it would be pure nonsense. Could this happen in this construction of real phylogenetic trees of living organisms?
Let's say you take a hypothetical set of intelligently designed organisms whose similarities are not the result of common descent. By assuming common descent, you can still concoct a perfectly good evolutionary tree. Yet the tree would be a mere construct based upon assumptions -- and completely false.
The packet's assumption is that biological similarity implies common inheritance (except when it doesn't) -- an assumption ubiquitous throughout the field of systematics. As one article states:
molecular systematics is (largely) based on the assumption, first clearly articulated by Zuckerkandl and Pauling (1962), that degree of overall similarity reflects degree of relatedness. This assumption derives from interpreting molecular similarity (or dissimilarity) between taxa in the context of a Darwinian model of continual and gradual change. Review of the history of molecular systematics and its claims in the context of molecular biology reveals that there is no basis for the 'molecular assumption.' ... For historians and philosophers of science the questions that arise are how belief in the infallibility of molecular data for reconstructing evolutionary relationships emerged, and how this belief became so central ...The packet even ignores characters purportedly resulting from convergent evolution -- as the packet repeatedly reminds the reader, "convergent characters have no place in taxonomy." The packet has thus served as a reminder to me of the assumption-based and weak methodology underlying all phylogenetic trees.
(Jeffrey H. Schwartz, Bruno Maresca, "Do Molecular Clocks Run at All? A Critique of Molecular Systematics," Biological Theory, Vol. 1(4):357-371, (2006).)
Further responses to Dr. Fitzhugh's arguments against intelligent design will come in a couple forthcoming posts.