Certainties of Very Low Probability Edward W. Constant II (bio) Oxymorons are paradoxes gone bad, as our title attests. We learn simple causal relations with great facility. As Clark Glymour has observed, even infants know this: to get the pacifier, tug on the blanket it lies on. But we have a harder time getting our minds around the meaning of very small probabilities over very long time scales, likely because our hominid ancestors never lived long enough to have to worry about them. Some years ago, when I was in graduate school at Northwestern University, we had a Friday noon seminar on aspects of science and technology. I recall one meeting that featured a paper on high-energy physics. One of the senior physicists, Arnold Siegert, who had been a student of Heisenberg's, got into an argument with a charming but not overly reverent mathematician (whose name I regrettably don't remember) about the physical interpretation of mathematical formalisms. It was the ancient quarrel about whose reality was better, the mathematicians' Platonic idealism or the physicists' experimental materialism. At issue was some particle-decay process with a probability of ten to the minus something or other, which, when translated, meant that it should occur approximately once every thirty or so billion years, or once in twice the believed age of the universe. Finally, the mathematician, in some exasperation, asked, "Arnold, what would you do if you observed this phenomenon?" There was a silence. Then Siegert replied, almost impishly, "Not tell anyone." It's a splendid stratagem for improbable events in subatomic physics, but it doesn't scale well for hurricanes. Too big. What's striking about Hurricane Katrina is that, like the nuclear physicists, everybody knew it was going to happen—sooner or later. Certainly anyone who'd lived in New Orleans or in Louisiana or on the Gulf Coast for very long knew. My grandmother was born and raised in New Orleans, in what's now more hopefully than veridically called the Garden District, and [End Page 249] I grew up with the folklore of the River and hurricanes. Later, when I was at Tulane, we lived in an apartment building that faced South Claiborne Avenue, but backed up to the old Sugar Bowl. Between our building and the stadium were the university's practice fields, five or six of them. On each side of each regulation 100-yard field were two or three gently contoured, sodded sumps, perhaps 30 yards long and 10 yards wide, maybe 4 or 5 feet deep, with a large drain at the bottom. When the cloudbursts came, which was often, the sumps would rapidly fill up. South Claiborne is about 60 yards wide at that spot, with two lanes in each direction separated by a broad grass esplanade, which covers one of the several major canals that drain New Orleans. From our sixth-floor apartment we could see the end of South Claiborne as it curved around, and we would watch for the pumps down there to come on. Sooner or later we'd see the smoke from the big diesel engines that drove the pumps, and pretty soon the water in the sumps would go down, usually in only ten or fifteen minutes. When it was later rather than sooner, there wasn't much mystery about what would happen if it were ever never. I also remember one blurry morning sitting in Jackson Square, as gentle night gave way to merciless day, watching the strippers go home, now tired and droopy and flat-footed. I had one of those "what's wrong with this picture?" moments as it dawned on me that the hull of the freighter I was looking up at was visible above the top of the levee. We clambered across the railroad tracks behind the old Jax brewery (in those less troubled days the night watchman only fussed at us a little) and up onto the levee. Sure enough, the river stage was a good 20 or 25 feet higher than where I'd been sitting in Jackson Square. The river levees at New Orleans are challenged, severely, at least once a year, usually more often, and the...
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Sep 1, 2008
Usama El Shamy + 1
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