Tuesday, January 09, 2007

Because Y Is a Crooked Letter

From Phil:

“I maintain there are, in fact, no such things as 'why's, just 'how's. Or to put it another way, all 'why' questions are meaningless. So as a challenge I would ask: Are there any 'why's?”
Good thing you brought this question here to the “why’s” guys.

I suppose the first question that pops to mind is, “Why do you believe that there are no why questions?” Done.

But to be less of a smart ass...Before we can say whether there are any legitimate why questions, we first need to determine what why questions are asking. Turns out that there are several different types of information you could be requesting with “why questions.” One is intent. “Why did you buy that hybrid?” “Because I wanted to drive a car that gets good mileage.” Another is explaining the factual basis for your choice of tactics in trying to achieve an intended goal. “Why did you choose that Thanksgiving promotion?” “With God as my witness, I thought turkeys could fly.”

Now, both of these require intentions and when we look at science, there is no such thing. Phil’s sense that why questions in science are nothing but a hold over from previous times in which questions about the structure of nature were really nothing but questions about the Divine will places him in good company. In one of my favorite pieces, Bertrand Russell argues that when we ask why questions we are looking for causes, but contends that the notion of cause, like the British monarchy, is obsolete but kept around only because it is wrongly thought to do no harm. Russell sees modern science as substituting the notion of a differential equation for the concept of cause. Like Phil, Uncle Bertie sees science as describing, not explaining.

But there do seem to be two ways in which we can formulate meaningful scientific why questions. One is in the case of subsuming a phenomenon under a law of nature or a law of nature other than the one that is expected. “Why did that helium balloon float towards the front of the airplane cabin when the plane took off?” “Because the cabin is accelerating and by the principle of equivalence, an accelerating reference frame is equivalent to a local gravitational field and helium balloons in air and gravitational fields go away from the source of the gravitational field.” Or “Why did that heavy metal disk not fall to the ground since it is being pulled by gravity?” “Because there was a strong magnetic field that produces a stronger pull in the other direction.”

The other sort of why question in science is the case of a functional explanation. “Why do giraffes have long necks?” “Because a long neck conveys a survival advantage in gathering food which made those early giraffes with longer necks more likely to achieve reproductive success.” There is not intent here, since there is no mind to form an intent but there is still a part of an organism that performs a goal-oriented function and we can ask why it’s there.

I suppose if one were clever enough, one could always frame the request for the same information with a sentence that started with the word “how” instead of “why,” but it does seem that asking “How did the giraffe get it’s long neck?” is not identical to “Why do giraffes have long necks?” and the latter seems a perfectly legitimate scientific query.

Meet the challenge?