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I was dumbfounded, and didn’t even know where to begin to respond. We had just leapt from science to faith, and although those two spheres weren’t always in conflict, I could tell that in this instance, they would be.

“Okay, forget the fossil record,” I said. “Let’s talk about modern humans, people who have lived within the past two hundred years. People whose birth dates and death dates we know. The Terry Collection at the Smithsonian contains nearly two thousand human skulls, belonging to individuals born as far back as the early 1800s. Here in Neyland Stadium, in the UT collection, we have about six hundred skulls so far, belonging to individuals born as recently as twenty or thirty years ago. Comparative measurements of those twenty-five hundred skulls show that in just the past two hundred years, the average jaw is getting smaller, and the average cranium is getting bigger. We think of evolution as something occurring over thousands or millions of years, but this is an example of evolutionary change that’s almost fast enough to see in our own lifetime.”

Just as he was winding up to reply, I saw another hand go up at the back of the room. Grateful to shift interrogators, I pointed. “Yes, there in the back?”

“You mentioned ‘dumb design.’ What’s dumb about having fewer teeth?”

“Good question. There’s nothing dumb about having twenty-eight teeth instead of thirty-two, or forty-four. The way we eat nowadays, we could probably get along just fine with twenty, or even twelve. What’s dumb, or inefficient, or problematic, is that our jaws are shrinking more rapidly than our tooth count is. The two evolutionary changes are not in sync. So we wind up with too many teeth in too little space. That’s why so many of us have to have our third molars-our wisdom teeth-yanked when we’re fifteen or twenty or thirty years old. Which is a bad thing for most of us, but a good thing for those of you who are heading for dental school.” I noticed a few smiles, which I guessed might belong to pre-dent students.

“Enough about teeth,” I said. “Let’s talk about a couple of other design flaws. I won’t embarrass anybody by asking who’s had either of these problems, but I would bet some of you have, and I guarantee that more of you wilclass="underline" hernias and hemorrhoids. A hernia is a failure-a blowout, you might say-in the abdominal wall. Back when we moved around on all fours, our internal organs had it easier. I’ll show you why.” I clambered onto the table at the front of the auditorium on my hands and knees. “You see how my belly is hanging down here?” I heard a few good-natured “oohs” and “yucks” from the students. “The point is, when you’re in this position, the abdomen makes a nice, roomy sling, like a hammock, for the organs.” To underscore the point, I swayed back and forth a few times. Then I stood up on the table and put my hands on my belly. “But when we went vertical, what happened? Anybody?”

“Everything sank down to the bottom,” ventured a girl on the front row.

“Exactly,” I said. “And that increases the pressure on the lower abdominal wall. So it’s more prone to tear. Same thing with hemorrhoids. The lower end of the large intestine gets more pressure now than it did in our four-footed ancestors, so it’s more susceptible to blowouts, too, which is basically what hemorrhoids are.” I heard more exclamations of disgust. “Varicose veins-how many of you have seen varicose veins?” A lot of hands went up. “Now that we’re upright, the heart has a lot more work to do. It has to pump blood with enough force to push it from the bottom of your feet all the way up to the top of your head, a distance of five or six feet, or even more. That’s a lot tougher than pumping it three feet uphill, which is about how tall we are when we’re on all fours. It’s interesting,” I said. “To try to compensate for the circulatory problem we created when we stood up, we’ve evolved this complex system of tiny flaplike valves in our veins, whose job is to keep the blood from flowing back downhill in the pause between heartbeats. But as we get older, those little valves tend to leak a bit, so blood pools in the legs, and the extra pressure makes the veins swell up and sometimes burst.”

An especially tall young woman-she was one of the star players on the Lady Vols basketball team-raised her hand. I pointed to her. “Yes?”

“So do other mammals-dogs and lions and whales-not have those little valves in their veins?”

No one had ever asked that before. I had never asked it myself. “To be honest,” I said, “I don’t know. I’ll find out before our next class. Good question.” She beamed; it was considered a coup to stump me.

“Okay, now let’s talk briefly about the pelvis and the spine,” I said. “Some of you women will doubtless have babies at some point. The good news is, obstetric medicine is getting better all the time.”

“What’s the bad news?” a female voice called out.

“The bad news is, babies’ heads are getting bigger and bigger,” I said.

“Ouch, man,” the same voice said. “C-section, here I come.”

“Lots of women are having cesareans these days,” I agreed. “Purely as elective surgery, not because there’s any medical complication that calls for it. And frankly, skittish as I am about the idea of having my belly sliced open, if I were a woman, I might consider it, too.”

“If you were a woman, Dr. Brockton,” called out a guy who had emerged as the class clown, “I don’t think pregnancy would need to be high on your list of concerns.” Much laughter ensued, including my own.

“Okay, last dumb-design feature,” I said, opening the box I had brought with me. “There are others, but we’ll stop with this.” I reached into the box and fished out an articulated pelvic girdle, the bones held together with red dental wax. The pubic bones arced together in the front; in back, the sacrum-the fused assemblage of the last five vertebrae-angled between the hip bones. “Notice the shape of the sacrum,” I said. “As you get down to the end of the spine, the vertebrae get smaller and smaller. So it’s shaped like a triangle, a wedge. Now, what do you use to split firewood?”

“Um, an ax?” offered someone.

“Well, yes, but I was thinking of a wedge. When you apply pressure to a wedge, it tends to force things apart, doesn’t it? You see where the hip bone, or the ilium, joins the sacrum here on each side? That joint is called the sacroiliac joint. When you put pressure on this wedge, the sacrum-with the weight of your entire upper body-it pushes down, and it tends to force these hip bones apart, and strain that sacroiliac joint. That’s a common cause of lower-back pain in people my age and older.”

I looked directly at the intelligent-design proponent in the third row. “So you see,” I said, “there are all sorts of structural features in the human body that suggest slow, imperfect evolution, rather than instantaneous, intelligent design.”

He raised his hand, his face showing a mixture of regret and defiance. “But think about the eyeball, and the brain, and the heart. Those are complicated and amazing structures. The eyeball is a marvel of optical engineering. The brain is more sophisticated and powerful than any computer on earth. The heart makes any man-made pump look flimsy and crude.” I nodded, trying to acknowledge that we shared an admiration for those organs. “Besides,” he challenged, “what’s wrong with teaching both theories? Isn’t that what education is all about? Let both sides of the controversy make their case, and let people make up their own minds?”

“There is no controversy,” I thundered. “Evolution is no more controversial than the Copernican theory of the solar system, or the ‘theory’ that the Earth is round. Just because a few people make an opposing claim, loudly and often, that doesn’t make the issue a legitimate scientific controversy. There is nothing scientifically testable or provable about creation theory. Hard-core creationists claim the fossil record-fossilized evidence showing that animals and plants evolved over many millions of years-was created right alongside Adam and Eve. That’s hocus-pocus, a fictional geologic backstory, conjured up out of nothingness: ‘Fossilized remains just look millions of years old’-you said as much yourself not thirty minutes ago-‘because God made them look millions of years old.’ Logically, you can’t argue with that. It’s perfectly circular reasoning, the ultimate ‘because God said so.’ Only it’s not really God who’s saying so. It’s people claiming to speak for God. Well, maybe God spoke to me this morning as I was reading the paper, and told me to tell everyone that Charles Darwin was right, and that anybody who says otherwise just isn’t paying good attention.