Niklas Parwez
Heinrich-Heine-University
The concept of ‘fitness’ has been the subject of a long-standing debate in the philosophy of the life sciences. Authors, including Popper (1974), have objected that its traditional definition as a measure of actual reproductive success might render evolution’s central “law” – the principle of natural selection – and, thereby, evolutionary explanations trivial. Several philosophers have addressed these issues in light of the propensity interpretation of fitness (PIF) (Brandon, 1978; Mills & Beatty, 1979). The basic idea of PIF is that fitness should not be defined by an organism’s actual reproductive success but by its probabilistic disposition or propensity to reproduce. The strength of this propensity can be measured by calculating its expected number of offspring. However, due to a series of counterexamples, PIF’s mathematical and ontological foundations have been redefined or abandoned altogether (Pence & Ramsey, 2013). In this talk, I will argue that most of the alternatives offered are unsatisfactory to a certain extent and suggest a revision of PIF, which I call the normic-dispositional interpretation of fitness (NIF). NIF understands fitness as a functional property real-
ized under evolutionary ‘normal’ conditions in the sense of Schurz (2001). While other readings of PIF have struggled to make sense of the claim that fitness is a propensity (Sober, 2013; Drouet & Merlin, 2015), NIF is naturally embedded into a long-run interpretation of propensities (Gillies, 2000). Integrating these results into a causal Bayes nets analysis (e.g., Pearl, 2000; Gebharter, 2017) of the standard equations in evolutionary modelling will yield the opportunity to shed new light on the debate between statisticalist and causalist interpretations of evolutionary fitness (e.g., Otsuka, 2011; Walsh et al., 2017). Finally, I will generalize this approach to the theoretical framework of cultural evolution by claiming its validity for both biological and cultural domains.
Chair: Josef Kohlmaier
Time: September 8th, 12:00-12:30
Location: SR 1.007
SOPhiA 2026 