Monday, December 04, 2006

Demarcation, Falsification, and Intelligent Design

Janet, over at Adventures in Ethics and Science, has a nice discussion going about intelligent design, the line between science and pseudoscience, and Karl Popper's criterion of falsificationism. According to Popper, a theory is scientific if and only if one can show what possible observations would render the theory false. Science is not the seeking of confirmation for one's beliefs, but the robust search for counter-evidence that would undermine them. Doc Free-ride takes the standard line that a theory is scientific just in case it is falsifiable, creationism and intelligent design are unfalsifiable, therefore they are pseudoscientific.

I've long thought that Popper was exactly the wrong line to take in considering intelligent design. On the one hand, banking on the impossibility of falsifiable propositions from intelligent design is put one's eggs in a poorly made basket. There are some very smart (albeit misguided) folks on the ID-team working very hard with things like information theory to show how one could have derivable results that are potentially falsifiable. Suppose they succeed? No reason to think that it is impossible. To be honest, I don't think it should make much difference. There is so much in terms of biological, geological, and archaeological evidence that is so nicely and cleanly subsumed under the evolutionary explanations that is not accounted for by the creationist approach that hinging everything on the falsifiability of intelligent design seems to be misplacing the concern.

On the other hand, there are certainly aspects to every theory that would be called scientific with no objection, including evolutionary theory, which are placed beyond falsification. Consider a famous episode in the history of biology. Two biologists, Cain and Shepard, tried to explain the distribution of snails with markings on their shells in terms of natural selection, they argued that certain banding patterns made some snails easier to see in the woods by birds who fed on them. A competitor, Lamott argued that their work was faulty, but in doing so, he didn't contend that their central axioms were false, only misapplied. Falsification, should Lamott have been correct, would not have been taken as grounds upon which to reject the basic notions of evolution theory. We have real science going on here, but falsification was nowhere to be found. As Pierre Duhem pointed out long ago, it is always possible to save any given part of a theory if you are willing to pfutz with the rest of it and we do take central axioms and put them out of bounds.

All of this was pointed out by Popper's student Imre Lakatos who presents what I would contend is a much better way of looking at the evolution/ID debate. He argues that all scientific theories have an unfalsifiable hard core and a protective belt of auxiliary hypotheses. On this view, both evolutionary biology and ID would be scientific -- BUT, theories can be judged relative to one another on the way they have developed historically and whether they account for a broad spectrum of phenomena with little significant alteration (he deems there progressive research programmes) or whether they need major renovations and ad hoc patches to account for things as they pop up (he terms these degenerating research programmes). If a theory can remain little changed with a sleek, streamlined structure while accounting for more and phenomena -- especially phenomena that the theory wasn't initially conceived of in order to explain -- then you have a good theory. If you have a theory that gets more and more clunky just to hold on to the few things it thought it could already explain, then you've got a dog of a theory.

I have no problem saying that there may be formulations of creationism or intelligent design theory which may be scientific (of course, there are versions which are pseudoscientific by any measure, but to avoid building a strawman, I have no problem allowing that some may not be). But the problem with intelligent design is not that it is unscientific, the problem is that it is a degenerating research programme for a set of phenomena for which we have an incredibly successful alternative that is amongst the most progressive research programmes going. I see little problem in letting ID into the ring, when there is no way it wins a fair fight.

Allowing that it may be possible to formulate creationism or intelligent design in a way that crosses the line of demarcation between science and pseudoscience does not mean that it should be allowed into the science classroom any more than we should "teach the controversy" between phlogiston theory and the statistical mechanics, or between Aristotle's physics and relativity theory. There is no controversy there, but that is better accounted for by leaning on Lakatos, the student, rather than Popper, the teacher.