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The Neo-Darwinian Synthesis: A Fable Told by Ernst Mayr

Michael Flannery

Ernst Mayr

Editor’s note: This essay is adapted from an article by Michael Flannery, “Toward a New Evolutionary Synthesis,” in the journal Theoretical Biology Forum.

A number of biologists such as Joseph Henry Woodger (1894-1981), Theodosius Dobzhansky (1900-1975), and Julian Huxley (1887-1975) (grandson of Thomas Henry Huxley [1825-1895]) helped establish the neo-Darwinian synthesis (NDS), the linking of common descent by means of natural selection with Mendelian genetics. But it was Ernst Mayr (1904-2005) who became the grand architect of the historical and philosophical narrative that went along with it. 

Starting with his introduction of the biological species concept in Systematics and the Origin of Species (1942), Mayr worked tirelessly to establish a synthesis bearing the unmistakable stamp of positivism. By 1959 he made it clear that NDS absolutely rules out teleology or any kind of “mysterious” finalistic or vitalistic force. Mayr further praised Darwinism for supplanting what he called the five recurrent themes in Western thought: creationism and natural theology (Christian dogma-guided science), anthropocentrism (human-centric thinking), essentialism (Platonic or neo-Platonic typological forms), physicalism (Newtonian physics-derived certainty versus a more probabilistic and emergence type of thinking), and teleology (purpose and/or guidance in nature). It is clear that Mayr’s agenda was much more than advancing the “science” of biology, it included branding the discipline with a philosophical stamp that included methodological naturalism. By the end of his career Mayr could confidently proclaim that between 1937-47 “consensus among previously feuding schools of evolutionists” and the “various branches of evolutionary biology, such as anagenesis and those studying cladogenesis” had been achieved and rested secured.

A Misleading History

In fact, Mayr systematically reconstructed a misleading history of evolution, an “Essentialism Story” that branded all pre-Darwinian naturalists as reactionary Scripture-struck species fixists, despite the fact that this synthesis history bore little resemblance to the truth. To add an element of drama, NDS leaders supposedly rescued Darwinism from certain oblivion as biology careened into chaos, although facts suggested otherwise. In 1931, the supposed nadir of Darwinism, paleontologist Robert Broom found the Zoological Section of the British Association in London well populated with Darwin enthusiasts at its annual meeting. Mayr always portrayed Darwinism in a state of decline, if not collapse, a condition from which Mayr helped rescue it in the nick of time with NDS. But Nicholas Rasmussen is less convinced of this Mayr-driven and Peter Bowler-promoted “eclipse of Darwin” thesis, and Mark A. Largent has his doubts about Darwin’s rescue at the hands of the neo-Darwinists, calling Bowler’s approach “old-fashioned history of ideas” and evincing “a deep tendency to explain the past in terms of the present.” Nevertheless, this Essentialism Story became “the central pillar” of Mayr’s self-fulfilling propaganda campaign. Günter Wagner has agreed and thoroughly rejects Mayr’s “cartoon version of the history of biology.”

A Progressive and Beneficent Mask

Mayr’s triumphalist NDS account wears a progressive and beneficent mask that disguises or sometimes tacitly endorses its underlying positivism. But such a biased rendering of this philosophical investment cannot be taken at face value, and should be judged on the assumptions of positivism and its permutation into the Vienna Circle. Positivism’s weaknesses (its questionable hard verificationism, its rejection of all metaphysics except its obvious blindness to its own, its historical reductionism, and its inherent scientism, indeed its reification of science itself) have been discussed for many years, and despite all its faults, has had a much stronger influence in biology than it ever had in philosophy (see Hilary Putnam’s discussion). No wonder that physicist Werner Heisenberg had little use for positivist claims to resolve the scientist’s deepest questions (e.g., the origin of life, the nature of consciousness, the appearance of form and atrophy/death in a temporal world, etc.):

The positivists have a simple solution: the world must be divided into that which we can say clearly and the rest, which we had better pass over in silence. But can anyone conceive of a more pointless philosophy, seeing that what we can say clearly amounts to next to nothing? If we omitted all that is unclear, we would probably be left with completely uninteresting and trivial tautologies.

NDS left us with a discipline, in historian V. B. Smocovitis’s words, “centrally situated within the positivist ordering of knowledge.” Rejecting creationism, essentialism, and vitalism, the modern synthesis, according to Smocovitis, proclaimed that “emergent evolution is the Declaration of Independence for biological sciences.” But can such a “declaration” be any better than the flawed philosophy that underpins it? Is NDS a value-free “fact only” assessment of the complexities of life? It would appear the answer to both questions is no. 

As we will see in a subsequent post, Ludwig von Bertalanffy might well suggest a way out.

Photo: Ernst Mayr, by University of Konstanz [CC BY 2.5 ], via Wikimedia Commons.