Personal Beliefs’ Impact Upon the Synthesis

Synopsis: Was a selectionist model of evolution favored over a stochastic model due to the worldviews of the Synthesis’ architects? Particularly Fisher’s eugenics and wish to “improve” humanity as well as Julian Huxley’s progressivism and evolutionary humanism?

I was suggested Vissiliki Betty Smocovitis’ Unifying Biology by Sage Ross as an introduction to Modern Synthesis history. Her thought provoking history was thankfully not just a textbook history but also a discussion of its philosophical roots and of the architects’ personal beliefs. One argument in particular caught my attention and that is what I will briefly discuss below – why did a selectionist/adaptationist model of evolution win over a stochastic model?

Smocovitis claims a selectionist/adaptationist view of evolution was partly borne out of the worldviews of the Synthesis’ architects, especially RA Fisher and Julian Huxley. Fisher and Huxley believed knowledge and understanding of natural selection could help humanity “improve” itself (i.e., eugenics) and “progress” forward to some goal. This was of special concern following the horrors of World War II.

Of course, evolution is not “progressive,” and Huxley had to strike a “middle ground – deterministic enough to make predictions, but having enough indeterminism… which made possible a meaningful life with humans as agents of their own free will” (131). Furthermore, Smocovitis thinks that a stochastic process where genetic drift was supreme would have been unpalatable to the optimistic Americans. Indeed, “so powerful would be the felt need for a progressive, selectionist, and adaptationist framework that in the 1940s even Dobzhansky and Wright would come to adopt more strongly selectionist models” (131).

Was selectonism/adaptationism a result of Fisher’s eugenicist beliefs and Huxley’s evolutionary humanism (which Smocovitis argues was adopted and expressed by Carl Sagan)? Smocovitis’ argument is one I have not encountered before reading Unifying Biology and I unfortunately do not have the time to read the works of the Synthesis’ architects. Does anyone know more about this?

Smocovitis cites articles by John Beatty (“Dobzhansky and Drift: Facts, Values, and Chance in Evolutionary Biology” from Probabilistic Revolution, pp. 271-311) and by William Provine (“The Development of Wright’s Theory of Evolution: Systematics, Adaptation and Drift,” from Dimensions of Darwinism, pp. 43-70). I’ll check these out when I can, but if anyone can offer input here, it will be greatly appreciated!

(I should note that Smocovitis only spends a page or two on this subject so how strongly she favors this argument or not is uncertain. I’m more or less posting this to provoke some thoughts and record what I have read.)
Smocovitis, Vassiliki Betty. Unifying Biology: the Evolutionary Synthesis and Evolutionary Biology. Princeton, NJ: Princeton UP, 1996. Print.

3 thoughts on “Personal Beliefs’ Impact Upon the Synthesis

  1. The “synthesis” view was more sophisticated than that. Note that Fisher did not popularize any view of evolution. The popularizing was done by Dobzhansky, Mayr, et al. They really created the synthesis. And they did NOT propose that evolution resulted in a single best genotype with all others eliminated. Instead, they argued that “evolution” is shifting from one complex multi-locus equilibrium to another.

    This solved 2 problems. First, it allowed them to rebut the Mendelians’ stochastic view and claim that “evolution” (shifting gene freqs) is deterministic (i.e., given a not-small pop with abundant variation, the way it gets sorted out is largely repeatable– see the Nature paper by Burke, et al that just came out).

    Second, it allowed them to score big points in political correctness in a world reeling from racism and WWII. The acme of evolution (they said) is not a single master race. Instead, there are no winners and losers– every allele has a place in the big frequency distribution.

    That’s my take on the Mod Synthesis, anyway.


    • Thank you for the comment!

      I should note that Smocovitis’ book is a social history of science and does not discuss the science itself in any great detail. As a result, her framework is a bit different than normal history of biology.

      Can you recommend a good source for the science of the Modern Synthesis? I was thinking of reading stuff by Mayr but he exhibits some strong bias…


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