Lewontin's revisition of the Spandrels paper with D.S. Wilson

By Roberta Millstein

About a month ago, David Sloan Wilson posted a transcript of a wonderful phone conversation that he had with Richard Lewontin concerning the (in)famous paper that Lewontin co-authored in 1979 with Stephen Jay Gould, The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme, a paper that attracted a lot of attention from biologists but also from philosophers of biology (too many to cite here). The attention was, and continues to be, both positive and negative, i.e., the paper is a bit of a lightning rod.

I recommend the interview in full, as it has a lot of wonderful nuggets in it, but here are the things that stood out to me:

• Lewontin denied that the paper was primarily aimed at sociobiology, suggesting that it was just aimed at the practice of telling "just so" evolutionary stories, which he found to be widespread in evolutionary biology more generally, and not just in sociobiology. I was surprised by this and I am not sure what to think, so I'll just note that Lewontin was writing other critiques of sociobiology around the same time, see e.g., Sociobiology - A Caricature of Darwinism.
• Lewontin said that Gould wrote most of the paper, but that he (Lewontin) wrote the section where "the various factors and forces of evolution" were discussed. That interested me because that has always seemed to me to be the most important part of the paper and the heart of the advice that Gould and Lewontin were giving. The section identifies five alternatives to the claim that there was direct selection for a trait's current function (on the assumption that it has one):
  1. No adaptation and no selection at all (here they describe various roles for random genetic drift).
  2. No adaptation and no selection on the part at issue; form of the part is a correlated consequence of selection directed elsewhere.
  3. The decoupling of selection and adaptation, either (i) selection without adaptation or (ii) adaptation without selection.
  4. Adaptation and selection but no selective basis for differences among adaptations.
  5. Adaptation and selection, but the adaptation is a secondary utilization of parts present for reasons of architecture, development or history ("spandrels").
  The lesson that Lewontin (and Gould) gives here is a methodological one, that we should be pluralists about the processes of evolution and consider (no really, actually consider, and not just give lipservice to) the various alternative ways that traits can come to be prevalent in a population. This has very much shaped my own thinking about evolution and my own work on distinguishing the concepts of random genetic drift and sexual selection from natural selection.  Some people think the paper was making a claim about the prevalence (or lack thereof) of selection, but I think that that reading is mistaken.
• Wilson asks Lewontin a very direction question about whether adapationist hypotheses are the best place to start (as Wilson himself believes – note again that this is a question about methodology) and Lewontin's reply is equally direct – he says that the right way to start is with the sentence: "We do not have any hard evidence of the forces leading to the following evolutionary change."  Lewontin then states: "There has to be a prelude to the discussion of evolutionary change to make it clear that although the theory of natural selection is very important and happens lots, there are other forces, or other mechanisms, that lead to change and we are not obliged by being Darwinians and being evolutionists to invent adaptive explanations for all changes. Then, as either a philosopher or biologist, ask in a particular case what is the direct evidence, besides the desire that we want to find something, that a particular story is true or not true." I read this as saying that not only is Lewontin a pluralist about evolutionary explanations, but also that he does not think that any one type of explanation should be our starting point, and moreover, that it is important for us to be humble and honest about what we've shown and about other possible alternatives. This is good advice, it seems to me.

Anyway, I am curious what other people think of the above or of the interview more generally (there are some remarks about Gould wanting to be a famous evolutionist, but in my mind that does not distinguish him from a lot of people). Thoughts?