Sunday, July 24, 2005

Intelligent Design and the Argument from Incredulity

Something about Intelligent Design Theory has been bugging me, and I finally figured out what it is.

Intelligent Design Theory (IDT) is the latest ploy by opponents of Darwinian evolutinary theory to bring religious teachings into public school classrooms. Rather than embracing Christian fundamentalist doctrine directly, IDT is dressed up as a scientific hypothesis: life on Earth is too complex to have arisen by chance alone, so there must have been some sort of Designer.

This is hardly new, of course; it harks back directly to work in natural theology in the eighteenth and nineteenth centuries by prominent figures like Linnaeus and Paley.

It's also hardly scientific. It's easy enough to show that there cannot be a single shred of evidence that tells either for or against IDT. The theory makes no concrete predictions, it sets up no coherent research program, so it can be neither confirmed nor falsified. On those grounds alone, it is not a scientific theory.

That's not what really bugs me about it, though.

Casting around for the source of its irksomeness, I thought for a time that it rested in the not-quite-explicit appeal to an aesthetic judgment: life is too complex. By what standard? Does Darwinism just feel inadequate? Is excessive complexity in the eye of the beholder?

That's not it either. After all, respected (if slightly wacky) physicists appeal to "elegance" and so on as the mark of a good theory, and are looking for a beautiful theory to tie everything together. The cases are different in ways that are hard to put my finger on, but at least it seems fair to recognize that science is in some measure an aesthetic enterprise.

Yesterday, the source of my annoyance came to me. A few years ago, I coined a term for what struck me as an all-to-common but previously unnamed fallacy: the Argument from Incredulity. The fallacy works by mistaking a psychological inability (or unwillingness) to believe something for the lack of epistemological warrant, to wit, "I can't (or won't) believe it, therefore it is not true."

The simplest way for one to enact the Argument from Incredulity is to plug one's ears and say loudly, "la-la-la-la-la-la-la-la-la-la-la-I'm-not-listening-la-la-la-la-la-la-la-la-la," and so on, until the other person shuts up and goes away.

This, in effect, is what lies at the heart of Intelligent Design Theory:

"Darwinian evolution has the uncomfortable implication that humans have a common ancestor with apes (and voles, and newts, and oak trees and slime molds . . .), and that the emergence of the human species (like that of every other species) was radically contingent. We ID theorists refuse to believe that the emergence of the human species was radically contingent. So, the emergence of the human species was not radically contingent. Therefore, we must be the products of design.

"So there."

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