ITHACA, N.Y. – Lenore Durkee, a retired biology professor, was volunteering as a docent at the Museum of the Earth here when she was confronted by a group of seven or eight people, creationists eager to challenge the museum exhibitions on evolution.

They peppered Dr. Durkee with questions about everything from techniques for dating fossils to the second law of thermodynamics, their queries coming so thick and fast that she found it hard to reply.

After about 45 minutes, “I told them I needed to take a break,” she recalled. “My mouth was dry.”

That encounter and others like it provided the impetus for a training session here in August. Dr. Durkee and scores of other volunteers and staff members from the museum and elsewhere crowded into a meeting room to hear advice from the museum director, Warren D. Allmon, on ways to deal with visitors who reject settled precepts of science on religious grounds.

. . .

Dr. Allmon, who directs the Paleontological Research Institution, an affiliate of Cornell University, began the training session here in September with statistics from Gallup Polls: 54 percent of Americans do not believe that human beings evolved from earlier species, and although almost half believe that Darwin has been proved right, slightly more disagree.

“Just telling them they are wrong is not going to be effective,” he said.

Instead, he told the volunteers that when they encounter religious fundamentalists they should emphasize that science museums live by the rules of science. They seek answers in nature to questions about nature, they look for explanations that can be tested by experiment and observation in the material world, and they understand that all scientific knowledge is provisional – capable of being overturned when better answers are discovered.

Let me see if I understand. Someone questions some of the “settled precepts of science” by referring to “techniques for dating fossils” and “the second law of thermodynamics,” and how does the guide reply?

She pulls out her handbook for dealing with “religious fundamentalists” and gives pat answers about how “science museums live by the rules of science,” saying that “they understand that all scientific knowledge is provisional.”

It’s possible the “provisional” line is just meant to placate the religious nuts, but maybe some museum workers actually think something can be both a “settled precept” and “provisional.” If that’s the case, then I suspect the cracks in the hegemony are widening.

Since there is no content, there is no “controversy” to teach about in biology class. But here is a good topic for a high school course on current events and politics: Is intelligent design a hoax? And if so, how was it perpetrated?

But putting those aside, I think proponents of Intelligent Design should take seriously one of his main criticisms, namely that Intelligent Design has no positive explanatory power–it’s only nay saying.

Indeed, no intelligent design hypothesis has even been ventured as a rival explanation of any biological phenomenon. This might seem surprising to people who think that intelligent design competes directly with the hypothesis of non-intelligent design by natural selection. But saying, as intelligent design proponents do, “You haven’t explained everything yet,” is not a competing hypothesis. Evolutionary biology certainly hasn’t explained everything that perplexes biologists. But intelligent design hasn’t yet tried to explain anything.

At first it may seem absurd for him to claim that “intelligent design hasn’t yet tried to explain anything,” but it’s true–depending on how one defines her terms. For Dennett an acceptably “scientific” explanation must explain things solely in naturalistic terms. In other words, there cannot be any resort to mystery or what others have called the “God of the gaps.”

One invokes the “God of the gaps” if he pushes the causes for unexplained phenomena into the realm of the mysterious or supernatural. Critics of such a move have pointed out that causes of many seemingly inexplicable things have become clear with later science, so that what once seemed supernatural, after a while could be explained in materialistic terms. Also, scientific explanation is all about finding naturalistic explanations. To look for other explanations bucks the culture of scientific thinking from the last few centuries, these critics suggest.

And it’s there that I both agree with and part ways with Dennett. I agree that were we to stipulate 1) that all scientific explanations must be given in naturalistic terms and 2) that if no explanations are forthcoming we should assume they will eventually, then we would have to conclude that there is little room for a designer outside of nature. But I don’t know why we should make such stipulations. For one thing, what constitutes good science has been continually developing, and limiting its domain of acceptable explanations a priori seems terribly arbitrary. Dennett seemingly has great confidence in the permanence of contemporary scientific views:

First, imagine how easy it would be for a determined band of naysayers to shake the world’s confidence in quantum physics – how weird it is! – or Einsteinian relativity. In spite of a century of instruction and popularization by physicists, few people ever really get their heads around the concepts involved.

Dennett goes on to suggest that the only reason such nay sayers haven’t shaken our confidence in quantum physics is that there aren’t the other political and sociological interests in play in the Intelligent Design debate. But considering that many Newtonian notions, now rejected, had ascendancy much longer than those of Einstein, I would suggest that Dennett temper his confidence.

More importantly, I think that even while trying to find materialistic explanations, scientists can have reason to know that there are limits to those explanations. Curiously, even in this article Dennett gives us reason to think there might be. Here he explains why the eye was not designed:

Brilliant as the design of the eye is, it betrays its origin with a tell-tale flaw: the retina is inside out. The nerve fibers that carry the signals from the eye’s rods and cones (which sense light and color) lie on top of them, and have to plunge through a large hole in the retina to get to the brain, creating the blind spot. No intelligent designer would put such a clumsy arrangement in a camcorder, and this is just one of hundreds of accidents frozen in evolutionary history that confirm the mindlessness of the historical process.

Dennett’s argument assumes that science can evaluate claims of intelligence at work in nature. In the case of the eye, Dennett believes that the evidence points to the absence of intelligence. But if evidence can rule one way regarding the presence of intelligence, then it’s possible for it to go the other. In another situation, the same criteria Dennett here uses to rule out intelligence might at the least allow its possibility. I don’t think that’s just nay saying; as I understand some Intelligent Design proponents, the positive evidence is that naturalistic explanations at some points have discernible limits, limits evident in irreducible complexity, for example.

While scientists may disagree about how to properly apply criteria indicating intelligence, what they–and Dennett–can’t do is dismiss the enterprise out of hand. So rather than comparing Intelligent Design proponents to flat-earth believers, I suggest the scientific community should examine–and in that manner refute, if appropriate–the particular criteria and their applications that some believe indicate an intelligent Creator. If the naturalistic explanations’ hegemony is deserved, then its proponents have nothing to fear from such an examination.