The difference between population concepts and “population thinking”

The late Ernst Mayr is remembered for many things, but a number of his historical and philosophical claims are unravelling. The very clever and perspicacious Rutgers geneticist, Jody Hey, has published a paper in the Quarterly Review of Biology on one of these. Jody is a very good reader of history as well as being a leading geneticist, and he made an observation to me that I followed up in my book, that the “species problem” is a post-Mendelian invention, and that what the pre-Mendelians had was a “species question” – what was the origin of novel species?

Here is the abstract of his paper:

Ernst Mayr said that one of Darwin’s greatest contributions was to show scholars the way to population thinking, and to help them discard a mindset of typological thinking. Population thinking rejects a focus on a central representative type, and emphasizes the variation among individuals. However, Mayr’s choice of terms has led to confusion, particularly among biologists who study natural populations. Both population thinking and the concept of a biological population were inspired by Darwin, and from Darwin the chain for both concepts runs through Francis Galton who introduced the statistical usage of “population” that appears in Mayr’s population thinking. It was Galton’s “population” that was modified by geneticists and biometricians in the early 20th century to refer to an interbreeding and evolving community of organisms. Under this meaning, a population is a biological entity and so paradoxically population thinking, which emphasizes variation at the expense of dwelling on entities, is usually not about populations. Mayr did not address the potential for misunderstanding, but for him the important part of the population concept was that the organisms within a population were variable, and so he probably thought there should not be confusion between population thinking and the concept of a population.

I think Jody is being too nice. Statistical thinking originated with Adolphe Quetelet, the Belgian astronomer, in the 1830s, and his ideas are very far from the notion of variability relied upon (and also not original to) Darwin. If anything, the notion of a statistical population is indirectly the result of Darwin, via Galton, which is what Jody argues in this paper.

All I can add is my explanation of why this and so many other claims arose unjustifiably about Darwin’s originality in all fields. Every fifty years since Darwin’s death, on the anniversary of the Origin in 1908/9, 1958/9 and 2008/9, there are, understandably, celebrations and conferences held. These tend to ramp up in the preceding years. Now, few scientists are as well studied or understood as Darwin – even Newton is not as well studied – so it is hard to find more to say. One trick is to make Darwin seem to have covered every base, philosophical as well as scientific. So he gets all kinds of ideas ascribed to him that he did not overtly, and often likely not even covertly, held. As I argued in my paper “Not Saint Darwin” during the last round, Darwin is good enough for what he did achieve. Let’s not make him out to be the sole source of scientific progress in biology as well.

Jody Hey (2011). Regarding the confusion between the population concept and Mayr’s “population thinking” Quarterly Review of Biology, 86 (4), 253-264

11 thoughts on “The difference between population concepts and “population thinking”

  1. My understanding is that Darwin and Russel derived their notion of natural selection from an idea of Malthus, specifically the idea that a burgeoning population always outstrips the food supply an environment can provide.

    1. Wallace (Russel is his middle name) did not rely upon Malthus, although Malthusian economics were widespread at the time due to David Ricardo’s influence on the theory of rents. But both converged upon the idea that competition under limited resources could drive change, independently, so far as I know.

  2. Darwin might have put his twos and twos together, but he hasn’t formed the outcome of how species are human or other, there is some other force that has determind shape and form and mind, and the eliments that are used to bring them about.

  3. In a sense, the statistical sampling of a population that allows us to describe the population with statistics that are estimates of the parameters of the population is similar to the reproductive process that samples local biological populations to “describe” them to the next generation. (I think there’s enough overlap to reduce the worry – I’m more concerned about molecular biologists who have no concept of population, either statistical or biological.)

    1. That’s a somewhat rarefied notion of population, although I think it’s a damned good explication of the notion. However, Darwin simply needed some occasional “error” in subsequent populations, and hence variety. It was Galton who described and developed the fundamental ideas that led Fisher et al. to produce proper statistics. Mayr claimed that Darwin was conceptually innovative; I think he was at best using existing notions of variation, and that even if he had come up with the notion of a population in the statistical sense, Quetelet beat him by some margin, and with actual figures. What Darwin was concerned with was the differential of traits at a time and across generations.

  4. John
    For the last week or so, there has been nowhere to click to read
    the ‘comments’ section.
    Some readers may not realize the need to click the title to read comments.

Leave a Reply