The Structure of Evolutionary Theory: Beyond Neo-Darwinism, Neo-Lamarckism and Biased Historical Narratives About the Modern Synthesis

Abstract

The last decades have seen frequent calls for a more extended evolutionary synthesis (EES) that will supposedly overcome the limitations in the current evolutionary framework with its intellectual roots in the Modern Synthesis (MS). Some radical critics even want to entirely abandon the current evolutionary framework, claiming that the MS (often erroneously labelled “Neo-Darwinism”) is outdated, and will soon be replaced by an entirely new framework, such as the Third Way of Evolution (TWE). Such criticisms are not new but have repeatedly re-surfaced every decade since the formation of the MS, and they were particularly articulated by developmental biologist Conrad Waddington and paleontologist Stephen Jay Gould. Waddington, Gould, and later critics argued that the MS was too narrowly focused on genes and natural selection, and that it ignored developmental processes, epigenetics, paleontology and macroevolutionary phenomena. More recent critics partly recycle these old arguments and argue that non-genetic inheritance, niche construction, phenotypic plasticity and developmental bias necessitate major revision of evolutionary theory. Here I discuss these supposed challenges, taking a historical perspective and tracing the arguments by critics back to Waddington and Gould. I dissect the old claims by Waddington, Gould and more recent critics that the MS was excessively gene centric and became increasingly “hardened” over time and narrowly focused on natural selection. Recent critics have consciously or unconsciously exaggerated the long-lasting influence of the MS on contemporary evolutionary biology and have underestimated many post-Synthesis developments, particularly Neutral Theory, evolutionary quantitative genetics and the power and generality of the Price Equation. Critics have also painted a biased picture of the MS as a more monolithic research tradition than it ever was and have downplayed the pluralistic nature of contemporary evolutionary biology, particularly the long-lasting influence of Sewall Wright with his emphasis on gene interactions and stochasticity. I argue that some of the criticisms of the MS and contemporary evolutionary biology are primarily meta-scientific, revealing the underlying identity politics of critics when pushing their alternative research agendas. It is still unclear what their proposed alternative research frameworks would entail and why the existing theoretical framework is insufficient. Finally, I outline and visualize the conceptually split landscape of contemporary evolutionary biology, with four different stably coexisting analytical frameworks: adaptationism, mutationism, neutralism and selectionism. I suggest that the field can accommodate the challenges raised by critics, although structuralism (“Evo Devo”) and macroevolution remain to be conceptually integrated within mainstream evolutionary theory.