Genetic explanation of complex human behavior presents an excellent test case for pluralism. Although philosophers agree that successful scientific investigation of behavior is pluralistic, there remains disagreement regarding integration and elimination—is the plurality of approaches here to stay, or merely a waystation on the road to monism? In this paper we introduce an issue taken very seriously by scientists yet mostly ignored by philosophers—the missing heritability problem—and assess its implications for disagreement among pluralists. We argue that the missing heritability problem, (...) which isn’t going anywhere any time soon, implies that pluralism in behavior genetics is both practically ineliminative and theoretically non-integrative. (shrink)

A strong case has been made for the role and value of mechanistic reasoning in process-oriented sciences, such as molecular biology and neuroscience. This paper shifts focus to assess the role of mechanistic reasoning in an area where it is neither obvious nor expected: population genetics. Population geneticists abstract away from the causal-mechanical details of individual organisms and, instead, use mathematics to describe population-level, statistical phenomena. This paper, first, develops a framework for the identification of mechanistic reasoning where it is (...) not obvious: mathematical and mechanistic styles of scientific reasoning. Second, it applies this framework to demonstrate that both styles are integrated in modern investigations of evolutionary biology. Characteristic of the former, applied population genetic techniques provide statistical evidence for associations between genotype, phenotype, and fitness. Characteristic of the latter, experimental interventions provide causal-mechanical evidence for associations between the very same relationships, often in the same model organisms. The upshot is a richer perspective of how evolutionary biologists build evidence for hypotheses regarding adaptive evolution and a general framework for assessing the scope of mechanistic reasoning across the sciences. (shrink)