Qiaoying Lu

In The Knowledge Machine, Michael Strevens challenges traditional views of the scientific method and defends the “iron rule of explanation.” This commentary introduces an evolutionary game perspective to explore the emergence and sustainability of the iron rule. Modeling the dynamics of theory-competing strategies in a population of theorists demonstrates that whether following the iron rule is rational depends on the frequency of iron-rule players one encounters. The study suggests that the social constraints of localized networks for iron-rule followers are critical factors in transitioning from a philosophical-dispute equilibrium to a scientific-dispute equilibrium.

In The Knowledge Machine, Michael Strevens challenges traditional views of the scientific method and defends the “iron rule of explanation.” This commentary introduces an evolutionary game perspective to explore the emergence and sustainability of the iron rule. Modeling the dynamics of theory-competing strategies in a population of theorists demonstrates that whether following the iron rule is rational depends on the frequency of iron-rule players one encounters. The study suggests that the social constraints of localized networks for iron-rule followers are critical factors in transitioning from a philosophical-dispute equilibrium to a scientific-dispute equilibrium.

Advocates of Extended Evolutionary Synthesis claim that the gene-centric framework of Modern Synthesis (MS) inadequately addresses epigenetics and extended heredity. Historically, epigenetic inheritance relates to Lamarck's inheritance of acquired characters, which was widely accepted before the dominance of MS. In this talk, I argue that the challenge posed by epigenetic inheritance to the gene-centric view arises partly from the ambiguous use of "gene," "phenotype," and "environment" concepts. A functional analysis of the gene concept played in the formal evolutionary models shows that the gene can include materials like exogenes, demonstrating the flexibility of evolutionary theory beyond the verbal MS. Properly understanding the evolutionary gene concept reveals that incorporating epigenetic inheritance does not demand a radical revision of the contemporary evolutionary theory.

Advocates of an ‘extended evolutionary synthesis’ have claimed that standard evolutionary theory fails to accommodate epigenetic inheritance. The opponents of the extended synthesis argue that the evidence for epigenetic inheritance causing adaptive evolution in nature is insufficient. We suggest that the ambiguity surrounding the conception of the gene represents a background semantic issue in the debate. Starting from Haig’s gene-selectionist framework and Griffiths and Neumann-Held’s notion of the evolutionary gene, we define senses of ‘gene’, ‘environment’, and ‘phenotype’ in a way that makes them consistent with gene-centric evolutionary theory. We argue that the evolutionary gene, when being materialized, need not be restricted to nucleic acids but can encompass other heritable units such as epialleles. If the evolutionary gene is understood more broadly, and the notions of environment and phenotype are defined accordingly, current evolutionary theory does not require a major conceptual change in order to incorporate the mechanisms of epigenetic inheritance. _1_ Introduction _2_ The Gene-centric Evolutionary Theory and the ‘Evolutionary Gene’ _2.1_ The evolutionary gene _2.2_ Genes, phenotypes, and environments _3_ Epigenetic Inheritance and the Gene-Centred Framework _3.1_ Treating the gene as the sole heritable material? _3.2_ Epigenetics and phenotypic plasticity _4_ Conclusion

Heritability estimates obtained from genome-wide association studies are much lower than those of traditional quantitative methods. This phenomenon has been called the “missing heritability problem.” By analyzing and comparing GWAS and traditional quantitative methods, we first show that the estimates obtained from the latter involve some terms other than additive genetic variance, while the estimates from the former do not. Second, GWAS, when used to estimate heritability, do not take into account additive epigenetic factors transmitted across generations, while traditional quantitative methods do. Given these two points we show that the missing heritability problem can largely be dissolved.