Fingernail Denial

Evolution deniers have a tough job. In order to believe primitive folk-tales about a magical angry giant creating the world in 144 hours, they have to reject the entire sum of collective human knowledge in biology, genetics, anthropology, geology, physics, astronomy, chemistry, geography and ecology.

Well, actually they don’t, because for the most part evolution deniers don’t seem to actually know anything about those topics, or at least nothing beyond what they’ve been told by their preachers, priests, witchdoctors, right-wing pundits, or other self-assigned demigods. But they try awfully hard to pretend they know something about science. Sort of like how a six year old will pretend to be a fireman.

It’s interesting to consider just how far reality-deniers have to go to maintain their illusions. Would they go so far as to deny their own fingernails? Let’s see.

Plate tectonics is the study of how continental expanses of rock can float around the Earth’s surface, buoyed on a mantle of dense, hot, ductile rock below. Continental plates seem to be fixed in place, over a human lifetime, but are actually in constant motion over millions of years. The evidence for this is all around us, in the forms of mountains, oceanic trenches, volcanoes, deep-sea hydrothermal vents, global fossil distributions, locations of sedimentary rocks, and paleomagnetic imprints in seafloor volcanic rock. Even the shapes of the continents form a crude jigsaw puzzle, allowing the coastline of Africa to broadly fit into the embrace of North and South America, if you could erase the Atlantic Ocean that separates them.

How fast do crustal plates move? Pretty slowly, but fast enough to track. It’s possible – and today done routinely using GPS and lasers bouncing off satellites – to directly measure plate motions. Plates move about as fast as your fingernails grow, or around 2.5 cm per year, plus or minus. Now, if you believe the world is only 10,000 years old, then you’d have to believe there hasn’t been enough time for much plate tectonics motion to occur. At most, the plates could have moved about 25,000 cm, or 250 meters, since Yhwh the magical angry giant created the world.

Maybe the plates used to move faster in the old days. We know that plate tectonics was going on at least as early as 4 billion years ago, since which time the supercontinents of Rodinia and Pangaea came and went. To assume all that accumulated global plate motion happened in only 10,000 years would require that ancient Middle-Eastern goat herders lived in a world where the plates were screaming past each other at about 100 feet per day. You’d think someone would have noticed. And at what point did it slow way down? Is there a giant switch somewhere below the North Pole?

Perhaps the world was created with the plates already en route at a few centimeters per year, 10,000 years ago. Which brings me back to fingernails. Unlike continental divergence, you don’t need billions of dollars worth of satellite laser GPS technology to measure how fast your fingernails grow. Just forget to clip them for a month, and you’ll notice a difference. Go out of your way to not clip or gnaw your nails for a year, and you’ll have some wicked claws to try and type with. Everyone accepts this because it’s easy to observe. The evidence is easy to collect, if you’re strange enough to collect your nail clippings. You probably have independent confirmation of evidence for fingernail growth, such as your spouse or roommate complaining that you left your nail clippings all over the carpet and would you please vacuum them the hell up? You also could make predictions about your nails, if you wanted to. You could predict, for example, that if you don’t take nail clippers with you on a month-long backpacking trek into the Alaskan backcountry, you might have trouble tying your shoes toward the end of the trip.

Evidence: nail clippings all over the carpet every two weeks. Conclusion: my nails grow. Not conclusion: my nails are fixed in length, and have never grown, and those nail clippings where planted in the carpet by Satan.

As I sit here at my keyboard, I don’t perceive my nails growing. The very idea is absurd… my fingernails, growing? I’m looking right at them, right now, and I can’t see anything happening. Clearly they never grow. Except… there’s all the evidence to the contrary, a lifetime of evidence and repeated observations and independent confirmation of my observations and physical detritus. So, how are my fingernails any different from crustal plates? If I can accept the evidence at hand (sorry) that my fingernails grow, can’t I accept all the evidence that the world is very old, and plate tectonics has been going on a long time, and that life has evolved? Evidence is evidence, as long as it can be measured repeatedly, independently observed, tested, and holds up to rational scrutiny.

Maybe neither happened, and my fingernails were put on my hands last Tuesday by an invisible angry giant, and they never grow, and anyone who says otherwise is an agent of Satan. Maybe my fingernails only appear to grow because angels pull on them and stretch them. My thinking so clearly establishes a fundamental controversy in the medical establishment, so we should teach both sides of this controversy to our kids in school, and let them decide.

Or maybe the evolution deniers should just grow the hell up and stop pretending to be firemen.


~ by Planetologist on September 4, 2008.

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