Wednesday, September 23, 2009

Understanding Natural Selection
T. Ryan Gregory's paper, online.
As is true with many other issues, a lack of understanding of natural selection does not necessarily correlate with a lack of confidence about one's level of comprehension. This could be due in part to the perception, unfortunately reinforced by many biologists, that natural selection is so logically compelling that its implications become self-evident once the basic principles have been conveyed. Thus, many professional biologists may agree that “[evolution] shows how everything from frogs to fleas got here via a few easily grasped biological processes” (Coyne 2006; emphasis added). The unfortunate reality, as noted nearly 20 years ago by Bishop and Anderson (1990), is that “the concepts of evolution by natural selection are far more difficult for students to grasp than most biologists imagine.” Despite common assumptions to the contrary by both students and instructors, it is evident that misconceptions about natural selection are the rule, whereas a working understanding is the rare exception.
Because you can't study this stuff enough...

5 comments:

Mike Flynn said...

A nice article, but it seemed to me that the author misunderstands teleology, which he seems to confuse with purpose, and essence, which he seems to confuse with uniformity. This is understandable, since both are based on conceptual foundations that have not been taught to most scientists for more than half a millennium.

John Farrell said...

Have you read Scott Turner's book The Tinkerer's Accomplice? Ed Feser recommended it to me. He's a physiologist and he looks at homeostasis as the foundation for a new approach to teleology.

Mike Flynn said...

No. But I can see how it might.

By me, the telos of evolution is the drive by any living organism to go on living, and thus to exploit whatever trait genetic mutation has given it. Whether a mutation is "harmful" or "beneficial" seems to depend as much on how the organism makes use of it. The end toward which evolution moves is better fitness in the niche - exactly the end Gregory describes in the paper. That's why I wondered if he understood telos.

The Deuce said...

The problem isn't that lots of knowledgeable people misunderstand natural selection, but rather that even people at the top of the field mean different things when they talk about it.

The confusion over intentionality in natural selection is built in to the natural selection concept rather than being the result of people not getting it.

To select something is to choose it, to intend it. Selection is an irreducibly intentional concept. Darwin used the term because he was trying to explain why biological structures look intended. On the other hand, the "natural" in natural selection was meant by Darwin to imply a lack of intention. Together, the words mean something along the lines of "like selection, only unintended" or "unintended intendedness". It's a contradiction in terms. There's no wonder it confuses people.

Gregory calls the "anthropomorphic" and "intentional" conceptions of natural selection misconceptions. But are they really?

Consider that in biology, the primary thing we are trying to explain is biological function. But function, like selection, is an intrinsically intentional concept. An object's function means, literally, what it was intended to do by the person who made it.

Therefore, if we take biological function to be a real, literal thing, then it logically entails that those biological structures were intended by an agent, which, if you take natural selection to be completely responsible for them, entails that the anthropomorphic or intentional concept of natural selection is actually true.

On the other hand, if we take biological function to be an illusion, then we don't need natural selection to explain it, which means that natural selection is practically out of a job. Illusions, after all, are only in your head. They're a job for a shrink to explain, not a physical scientist.

That's why you have philosophers of biology straining to come up with a non-intentional definition of "biological function" that isn't incoherent. And while T. Ryan Gregory says that natural selection officially lacks teleology, no less than Ernst Mayr ascribed the concept of "teleonomy" (which really just means "just like teleology but not") to the process, which is mighty close. And while Gregory approvingly quotes Dennett early in the paper, Dennett himself has ascribed a sort of "proto-intentionality" to natural selection, as part of his attempt to use it to explain (away) human intentionality with a naturalistic account. There are even debates among professional philosophers over whether Darwin destroyed teleology or made it part of science. Who's right, Gregory or these guys?

You can hardly blame students, then, for not understand something that even professional philosophers and top scientist haven't worked out amongst themselves. And you can't blame them for failing to "understand" incoherent concepts.

The solution to the confusion, in my opinion, is to drop "natural selection" from the vocabulary altogether, and use language that isn't intention-loaded, such as "environmental pressures" and "differential survival" instead.

Additionally, scientists ought to stop trying to address function altogether, and leave it to the philosophers, because the moment you bring function into the picture you bring intention with it, which confuses students who have not yet learned how to rationalize incoherent nonsense well enough to understand how something can be intended and unintended at the same time.

Of course, doing that would also make it mighty tough to use evolution as an argument against theism (particularly the part about God intending man) which might be a problem for some people we know :-).

John Farrell said...

Dennett's an interesting case. I'm reading his book now (inspired as much by Fr. Edward Oakes' and other philosophers' account of it as anything else). Much as the new atheists love to count him amongst the brethren the same voices also express their...um reservations about his book for precisely the reasons you point out. He clearly sees "Design Space" I think as something more than a convenient contrivance for explaining NS. And that bugs the "some people we know" too.