Thoughts in a Haystack

Having just discussed "scientism," it is only right and just to discuss what doesn't fall under that category. Here is yet another example of the kind of disingenuous pabulum that will be foisted on unsuspecting schoolchildren if the Discovery Institute's "strengths and weaknesses" ploy get widely disseminated in public education. One Lee Harvill of Stafford, Texas has a letter to the editor in the Houston Chronicle about the Texas State Board of Education's vote in favor of eliminating the phrase from the science standards:

It did not succumb to science; it succumbed to scientism and the fear that somehow admitting a weakness in the Darwinian theory would lead to the teaching of religion in public schools.

Although there are numerous scientifically based weaknesses in the Darwinian theory of gradual evolution (redundancy intended) of organisms, I will cite only one that every high school biology student should be taught.

Amphibians and reptiles have three-chambered hearts, and birds and mammals have four-chambered hearts. The gradualism part of the theory requires that the change from three-chambered to four-chambered hearts came about by a long series of micromutations. Our students should be permitted to ask: "Where is the evidence of a three and one-half chambered heart?" And, the teacher should be permitted to reply: "That is a weakness in the theory."

Creationism versus secular humanism aside, the objective discussion of strengths and weaknesses of all theories should not be discouraged in our schools.

It should come as no surprise that this supposed "weakness" is featured in the Disco' 'Tute's ersatz "textbook," Explore Evolution and even less a surprise that the "weakness" is not what it seems. The National Center for Science Education has a nice explanation of the misdirection involved.

I'd like to focus on something else, namely the confusion of Mr. Harvill about what constitutes a "weakness" in a theory. The absence of evidence for or against any particular prediction or expected result of a theory is not a weakness, unless or until there is such an absence of evidence in favor of the theory across the board that it is obvious that it should not have been called a theory in the first place but should have been classed as a hypothesis or worse. What constitutes a weakness in a theory is the existence of phenomena that it should be able to encompass within its framework and cannot. This sort of conceptual difficulty is what Intelligent Design Creationists aspire to achieve with "irreducible complexity." Of course, once confronted with conceptual pathways to the evolution of any supposedly IC trait, they immediately switch tactics and demand an empirical demonstration that such a pathway was the one actually taken, papering over the fact that the IC argument was that there was no such conceptual pathway to begin with.

It is obvious that Mr. Harvill is engaging in this same sort of game. First evoking a supposed conceptual difficulty between "gradualism" and evolution of a four chambered heart (with a visit at the old "half a wing" fallacy) and, perhaps sensing that scientists may have a conceptual answer, demanding either evidence of a particular pathway occurred or an admission of a "weakness."

It is not scientism to say that a mere lack of complete evidence of the evolution of every organism and trait fails to constitute a weakness in a theory. It is not science to tell children that any gap in our knowledge calls into question evolution, despite the massive amount of evidence we do have supporting it and the lack of any conceptual difficulties in the theory sufficient to call its basic tenets into question.
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Update: John Lynch points to another treatment of Explore Evolution by Brian D. Metscher at Evolution & Development:

The latest out of the Discovery Institute is 159 glossy pages of color-illustrated creationist nostalgia ... All the old favorites are here—fossils saying no, all the Icons, flightless Ubx flies, irreducible flagella, even that irritating homology-is-circular thing. There are no new arguments, no improved understanding of evolution, just a remastered scrapbook of the old ideas patched together in a high-gloss package pre-adapted to survive the post-Dover legal environment. The whole effort would be merely pathetic if it did not actually represent a serious and insidious threat to education.