moth sitting on a piece of wood

Weird Science?

A Darwinian Debate Continues Published at Christianity Today

From Christianity Today: “Last week, we posted a letter from scientists Kevin Padian and Alan Gishlick in response to a piece by Jonathan Wells in the September/October issue of Books & Culture, dealing with the notorious peppered moth experiments. This week, we have given Wells an opportunity to respond. At stake are fundamental questions about truthfulness in debatematters on which there should be consensus among all parties to the debate over Darwin’s legacy.”

In Of Moths and Men, Judith Hooper charges that defenders of the peppered myth have “marginalized” and “demonized” scientists who challenge them. Here Kevin Padian and Alan Gishlick obligingly prove her charge beyond a reasonable doubt.

According to the myth, light-colored peppered moths resting on pollution-darkened tree trunks are preferentially eaten by birds; the resulting natural selection explains why better-camouflaged dark moths became more common during the industrial revolution. The myth was largely exploded in the 1980s, however, when scientists discovered that peppered moths don’t normally rest on tree trunks. Yet many biology textbooks still illustrate natural selection with staged photos of moths on tree trunks — usually made by pinning or gluing dead moths in place. The New York Times recently featured such photos as a now-classic example of “scientific fakery” (October 15, 2002).

Yet Padian and Gishlick continue to defend the discredited myth, claiming that a quarter of peppered moths rest on tree trunks and insisting that their claim is “based directly on the scientific literature.”

A 1998 book by peppered moth expert Michael Majerus reported that between 1964 and 1996, scientists spotted 47 peppered moths resting in the wild, including 12 on tree trunks. Padian and Gishlick simply divided 12 by 47 to obtain their statistic. Yet many thousands of peppered moths lived and died during that period, and the fact that so few were found resting anywhere led experts to conclude that most of them hide under horizontal branches high up in the trees, where they can’t be seen. Majerus himself concluded that “peppered moths do not naturally rest in exposed positions on tree trunks.”

Now, 12 divided by thousands is not a quarter. As I pointed out in my review of Hooper’s book, the statistic is bogus.

But Padian and Gishlick don’t stop there — and here’s where the fun begins. They liken me to the protagonist of the film The Talented Mr. Ripley, who lies about being a Princetonian as he ruthlessly climbs the social ladder and even commits murder. What’s fascinating (and revealing) is what Padian and Gishlick omit from the quotation from their review of my book when they cite it in their letter to Books & Culture. The ellipsis stands for: “Its author, Jonathan Wells, appears to come from an unusually strong academic background, but the truth is more complex.” They go on to claim that during my post-doctoral research appointment at Berkeley “[Wells] seems to have performed no experiments” and “no peer-reviewed publications resulted from Wells’s 5-year stint.”

Since doing research as a “post-doc” is part of the process scientists go through to become fully credentialed, Padian and Gishlick are implying that I (like Mr. Ripley) have lied about my academic credentials — a serious charge indeed.

In response to their charge, a Berkeley professor wrote to them pointing out that during my post-doc I performed experiments in her lab and co-authored two peer-reviewed publications. She asked Padian and Gishlick to retract their false and defamatory claim, but they refused to do so. Books & Culture readers who are interested in this controversy can read their review of my book and my response, “Critics Rave Over Icons of Evolution.”

Ultimately, however, character assassination cannot take the place of logic and evidence. This is well illustrated by Padian and Gishlick’s parting shot, in which they warn readers of Books & Culture of my “confessed religious mission against evolution.” In other words: “Jonathan Wells is religiously motivated; therefore, peppered moths do rest on tree trunks.” QED.