12/23/08

... solving a mystery is not the same as deducing from first principles. Nor does it amount simply to collecting a number of particular data from which to infer a general law. It means, rather, facing one or two or three particular data apparently with nothing in common, and trying to imagine whether they could represent so many instances of a general law you don't yet know, and which perhaps has never been pronounced. To be sure, if you know, as the philosopher says, that man, the horse, and the mule are all without bile and are all long-lived, you can venture the principle that animals without bile live a long time. But take the case of animals with horns. Why do they have horns? Suddenly you realize that all animals with horns are without teeth in the upper jaw This would be a fine discovery, if you did not also realize that, alas, there are animals without teeth in the upper jaw who, however, do not have horns: the camel, to name one. And finally you realize that all animals without teeth in the upper jaw have four stomachs. Well, then, you can suppose that one who cannot chew well must need four stomachs to digest food better. But what about the horns? You then try to imagine a material cause for horns-say, the lack of teeth provides the animal with an excess of osseous matter that must emerge somewhere else. But is that sufficient explanation? No, because the camel has no upper teeth, has four stomachs, but does not have horns. And you must also imagine a final cause. The osseous matter emerges in horns only in animals without other means of defense. But the camel has a very tough hide and doesn't need horns. So the law could be ..." "But what have horns to do with anything?" I asked impatiently. "And why are you concerned with animals having horns?" "I have never concerned myself with them, but the Bishop of Lincoln was greatly interested in them, pursuing an idea of Aristotle. Honestly, I don't know whether his conclusions are the right ones, nor have I ever checked to see where the camel's teeth are or how many stomachs he has. I was trying to tell you that the search for explicative laws in natural facts proceeds in a tortuous fashion. In the face of some inexplicable facts you must try to imagine many general laws, whose connection with your facts escapes you. Then suddenly, in the unexpected connection of a result, a specific situation, and one of those laws, you perceive a line of reasoning that seems more convincing than the others...

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