Coyne on Natural Selection

Jerry Coyne offers some further thoughts on the Richard Lewontin essay I discussed in yesterday’s post. Specifically, he addresses the question of why natural selection deserver pride of place among evolutionary mechanisms. He writes:

First of all, yes, it’s true that the evidence for natural selection as the cause of most evolutionary change in the past is not as strong as the evidence that evolutionary change occurred. It cannot be otherwise. We can see evolution happening in the fossil record, but it is infinitely harder to parse out the causes of that change. We weren’t around when it occurred, so we must rely on inference. This difficulty is one reason why it took biologists much longer to accept natural selection than to accept evolution. But to say that the evidence for selection is weaker than for evolution does not mean that the evidence for natural selection is weak, a conclusion I fear that creationists will extract from Lewontin’s comment.

I think you could quibble over whether we actually “see” evolution in the fossil record (it’s going to depend on how you define “evolution”), but Coyne’s point is well-taken. He backs it up further with six good reasons for accepting natural selection as an especially important evolutionary mechanism.

I also liked this:

What about my supposed double standard about accepting natural selection for many traits but being skeptical when it comes to evolutionary psychology? This is a reasonable tactic for one important reason: we have many more alternative theories for the appearance of human behavioral traits than we do for morphological adaptations in other species. How many alternative theories do we have for the appearance of flippers in proto-whales, or for the movement of their nasal passages to the top of their heads? In contrast, there are many alternative theories for the appearance of traits like human rape, depression, music, art, religion, etc. Blowholes aren’t likely to be spandrels; the appearance of music and poetry might well be. Humans have culture and rationality to a degree possessed by no other animal, and can learn many things not permitted in species having smaller (or no) brains. That’s why we need to be more cautious about imputing selection to human behaviors than to blowholes.

Well said! I would add that the price for being wrong is greater when studying human psychology than it is when studying the blowholes of whales (a point also made by philosopher Phillip Kitcher about sociobiology). An erroneous understanding of blowhole origins is not likely to lead to bad public policy. An erroneous understanding of human nature, on the other hand, could do precisely that.

Natural selection gets it from both directions. On the one hand people point to various complex structures and assert that there is no way to explain something so magnificent by reference to gradual accretion. But when a scientist then comes up with a plausible, step-by-step account for how the structure could have formed, suddenly the criticism is that you can come up with a story to explain anything.

If you have ever attended a creationist conference, there is a good chance that you have even heard both of those arguments made in the same talk.

Comments

  1. #1 Wes
    May 12, 2009

    Well said! I would add that the price for being wrong is greater when studying human psychology than it is when studying the blowholes of whales (a point also made by philosopher Phillip Kitcher about sociobiology). An erroneous understanding of blowhole origins is not likely to lead to bad public policy. An erroneous understanding of human nature, on the other hand, could do precisely that.

    I totally agree (and Kitcher’s book is one of the best on the topic of sociobiology).

    However, we should keeping in mind that eliminating promiscuous selectionism from our notion of human nature does not eliminate the danger of flawed policy based on erroneous understanding of human nature. Marxists such as Lewontin and Gould have just as flawed an understanding of human nature as evolutionary psychologists. I mean, let’s be frank here: dialectical materialism is a bogus pseudoscience. I don’t see any reason to mince words in that regard. Marx was wrong.

    What irks me is that the Marxists have illegitimately seized control of the moral high ground in the sociobiology debate, when they don’t have any better an understanding of human nature than E O Wilson or Leda Cosmides. Evolutionary psychology makes the mistake of presupposing every trait is a genetic adaptation, when that is clearly not the case. Marxists make the mistake of ignoring the fact that human beings are indeed biological organisms which evolved primarily by natural selection.

  2. #2 araujo
    May 12, 2009

    The criticism of evolutionary psychology are unfair. See the work of John Tooby and Leda Cosmides, in the Center for Evolutionary Psychology, David Buss and many others. See many articles in < http://www.epjournal.net/>

  3. #3 araujo
    May 12, 2009
  4. #4 John Farrell
    May 12, 2009

    I thought Larry Moran would weigh in on this soon, and he has.

  5. #5 Jason Rosenhouse
    May 12, 2009

    John –

    Thanks for the link, I had missed Larry’s post. I just left a comment over at his blog.

  6. #6 John Farrell
    May 12, 2009

    Great! Kick his butt. Okay, seriously…I enjoy Larry’s posts a lot. If it wasn’t for his critical eye, I would never have appreciated the differences professional biologists have, not only over natural selection vs. variations, but junk DNA, science journalism in general, etc.

  7. #7 giyim
    June 2, 2009

    thank you

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