Friday, February 20, 2004

The Latin Word for the Opposite of Trivia

You learn something new every day or, if you don’t, you simply aren’t trying. What surprises me, though, is how often what I encounter isn’t simply novel but in one way or another fundamental, a concept and not just another detail supplying local color to some corner or other of the cosmos.

If you think of the universe as a big box with things in it, you expect to find a new bird, beast, or rock from time to time; but discoveries of that order can’t satisfy a serious curiosity. It’s more rewarding but also more difficult to allow yourself to discover that the box itself has dimensions you hadn’t noticed. One of the problems with the Internet is that it encourages the notion that learning is just a matter of accumulating information as if all information were intrinsically equivalent, interchangeable blades of grass upon which the cattle peacefully graze. In fact, to digest the foliage that actually nourishes, us cows need to ruminate. When do we let that happen?

These thoughts were occasioned by a piece I read on the Nature site about avalanches. Somebody bothered to test whether the strength of snow can be reliably predicted from its density. What they discovered was that columns of snow of the same density broke under very different weights. Biologists and psychologists have known for a long time that under carefully controlled laboratory conditions experimental animals do what they damned well want to, but it is a bit shocking that even the inorganic displays erratic behavior. Because I work for engineers, I hear a lot about failure—how to calculate its probability, how to prevent it, how to live with it—but I don’t recall having thought about it in quite this way and also I hadn’t known that the measure of the variability of failure under loading is the Weibull modulus. The bigger the modulus, the more consistent the behavior, so that a piece of steel that can be counted on to fail when you expect it to has a Weibull modulus of about 30 while packed snow is 1 or 2. Having encountered this bit, I will now gradually come to think about many things differently including what it means to define the strength of anything, how well we can predict the future, and even what is defensible and indefensible about the old metaphysical notion of cause and effect. And that news is of a different order than the fact, which I also discovered, that the Weibull modulus was defined by one Waloddi Weibull, a Swede who died in 1979.


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