Lewontin on Gould

David Sloan Wilson recently interviewed Richard Lewontin for the website, This View of Life: “The Spandrels Of San Marco Revisited: An Interview With Richard C. Lewontin”. Lewontin is an evolutionary biologist and geneticist who spent a long career at Harvard University until his retirement in 1998. He has just turned 86 years old.

I wanted to share a quote from the interview about Stephen Jay Gould, which is insightful about Gould’s role in evolutionary biology. The interview begins with Lewontin’s recollection of the famous paper, “The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme”, which he wrote with Stephen Jay Gould in 1979. That paper evocatively presented a critique of the study of adaptation, arguing that biologists should devote more attention to nonadaptive factors such as genetic drift, structural and developmental constraint.

The paper is remembered (and assigned to students today) for its style of argument. In the interview, Lewontin reflects on how Gould approached these issues:

Now I should warn you about my prejudices. Steve and I taught evolution together for years and in a sense we struggled in class constantly because Steve, in my view, was preoccupied with the desire to be considered a very original and great evolutionary theorist. So he would exaggerate and even caricature certain features, which are true but not the way you want to present them. For example, punctuated equilibrium, one of his favorites. He would go to the blackboard and show a trait rising gradually and then becoming completely flat for a while with no change at all, and then rising quickly and then completely flat, etc. which is a kind of caricature of the fact that there is variability in the evolution of traits, sometimes faster and sometimes slower, but which he made into punctuated equilibrium literally. Then I would have to get up in class and say “Don’t take this caricature too seriously. It really looks like this…” and I would make some more gradual variable rates. Steve and I had that kind of struggle constantly. He would fasten on a particular interesting aspect of the evolutionary process and then make it into a kind of rigid, almost vacuous rule, because—now I have to say that this is my view—I have no demonstration of it—that Steve was really preoccupied by becoming a famous evolutionist.

There is a role for provocative argument in science. Without a clear statement of an idea, other scientists cannot evaluate it. Extreme descriptions can be very helpful, and often surprisingly hard to reject. When we cannot reject the extreme version of an idea, that should tell us something important about the (poor) quality of the evidence.

I also think that scientists should be advocates for their ideas. That doesn’t mean I think that we should cling to ideas that have been proven wrong. But usually it is not so easy to say that an idea is wrong: New evidence may weigh against the extreme version of a hypothesis, but a slight change to the hypothesis may save it. It is worth exploring those changes fully, especially if the hypothesis seems to be supported by other sources of data, because nature often isn’t simple. Debate helps us to draw out the consequences of models that we might not think about without such a challenge. To test an idea seriously requires exploring its implications for some time, really becoming an expert on its intricacies and the strengths and weaknesses of evidence. Good scientists will take their time to do that, and by systematizing the variations on an idea, they serve the cause of science—even if the idea turns out to be incomplete or wrong.

There’s no question that Gould was a provocateur, and many would argue that he went too far toward advocating ideas that were extreme. But in general I think that provocateurs play an important role in science, and should be recognized for it.

Still, I was never really a fan of Gould. I discovered his writing not long before I entered paleoanthropology, and I found that he was consistently wrong about human evolution. Although he mainly addressed the issue superficially in a few of his Natural History columns and book reviews, his writing had a broad influence among the public at a time when few anthropologists had such prominent venues for publishing their ideas. I don’t fault him for writing about the field in provocative terms, but I’m glad that today people have so many more places to read about human evolution, from actual experts in the field.