Sunday, June 6, 2010

What to Do with "Against Darwin"?

Jerry Fodor, Philosophy prof at Rutgers, has jumped into the evolution debates with a book that I don't have time to read, but I just got my hands on an essay that is 1.) Free and 2.) Shorter than a book, and therefore I can look over his argument. It looks like this distills the argument pretty cogently, in any case. The essay itself is here.

Fodor argues against natural selection and "adaptationism." He doesn't have any real bone to pick with evolution per se as far as I can tell, but he is fed up with evolutionary psychologists. And I'm with him on that. In psychology and literature in particular, egregious sins against reason are being committed by hand-waving "just-so" stories that boil motivations and choices down to evolutionary pressures to survive or reproduce. Fodor insists rightly that intentions and aims need to be preserved for psychology to make sense (although, as an atheistic naturalist, I wonder where he proposes we get this free will from that is so important to his field; from what I can tell he doesn't go for free will and argues that we are in a mire of unknowingness that we must summarize as "intention").

It's easy to pick on the evolutionary psychologists, and kind of fun, but Fodor doesn't stop there; he expands his critique to evolutionary biology, arguing that not only can't natural selection explain brain states and intentions but it can't even explain biology. This is what he's getting all the attention for, and this is where the argument either stands or falls. This is also where I part company with him.

Fundamentally, what you have in this essay is a Philosopher critiquing Biology for not being Physics (without any consideration of Chemistry at all). Fodor claims that the "law" of natural selection is not really a law of science in any useful way. I agree that it's not a law like the law of physics or the law of gravity, but his chipping away at natural selection doesn't include any positive value for actually doing biology. (What am I, a biochemist, supposed to do with it beyond being careful when I make historical arguments?) Fodor points out quite rightly that evolutionary biology is closer to historical narrative than it is to physical law. But then he claims that because historical narratives can't be reduced to repeatable laws, then there's no place for the law of natural selection in biology.

Well, what is biology then? You've basically defined biology out of science and into history with a narrow Procrustean philosophical definition of what a scientific law is. This has everything to do with a philosophical argument and nothing to do with actually doing science or describing the world at a biological level. The definition of "science" is so tight that it can hardly be applied to the past at all. I think it's a well-written piece of sophistry on the level of Xeno's paradox. Yes, you always have to cross half the distance to a certain point before you actually get there. Yet -- it moves!

The missing link here is chemistry. It troubles Fodor that biological laws are context-dependent, as if the fact that the environment (chemistry!!) matters to biology is somehow embarrassing. (I know chemists are embarrassing sometimes but let us in on the conversation occasionally!) The chemical link between the environment and evolution is a major feature of the RJP Williams books I keep harping on about, so I guess I've got some more to talk about to get those ideas in the exchange. In fact, the role of the second law of thermodynamics and evolution in RJP Williams's books may provide exactly the physical level of rigor that Fodor demands.

Fodor also will often focus on a single organism for his argument as if the interaction between organisms is not important. There's one graph in particular of pigments like chlorophyll that shows how all the pigments overlap to capture all available visible light from the sun. This kind of connection, in which any single pigment doesn't make a pattern but all pigments together make a pattern, doesn't find a place in Fodor's argument. He just argues that it's hard to imagine how frogs snapping at flies or spiders weaving webs could evolve. But if it's all a drive for food and sticky things in general catch more food, I have no problem with the examples he provides. The complex sticky structures easily could result from simpler easy structures. It makes biological sense. I'm not sure it's the only thing but it's better than saying it just is.

(Another specific side point: There indeed ARE historical counterfactuals; maybe not philosophically coherent counterfactuals, but I think that means the philosophy is too rigid, not that the counterfactuals don't exist.)

What's strange is to see a leading atheistic philosopher taking some of the same myopic arguments against evolution as people with theological objections to evolution. Of course the intelligent designists and others are all over this, but they should look closer. Fodor is arguing against biological explanation, not against evolution itself. He's arguing against arguing, in a sense. And one thing I've learned from science is that the universe had a beginning, time had an origin, and time carries us all in a direction. Because of that I think it's all historical narrative at a level, and some stories of evolution are nice historical narratives just like stories from the ancient Hebrews are nice historical narratives. If you adopt Fodor's view you begin to argue against science itself (or at least against biology itself). We do actually live in an understandable world, in which narratives have explanatory power, and it is heading in a direction, and repeating experiments will tell us something about how it works, even in biology! Just because some people have ridden that horse too far doesn't mean we should stay off that horse -- just that they should take it slower ("Hey, man, stop hogging the horse!").

Fodor has a point. So, evolutionary psychologists, stay off Fodor's lawn. But Fodor, stay off the biologists's lawn (and the undergirding chemistry) until you have a critique that matches how that particular science actually works.

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