Is Natural Selection a Population-Level Causal Process? - Mechanism and Causality in Biology and Economics - page 158

Chapter 9
Is Natural Selection a Population-Level Causal
Process?

Rong-Lin Wang

Abstract Recent discussions of natural selection focus on two questions: first, is
natural selection a causal process or is it a statistical consequence of lower-level
events? And second, is natural selection at the population level or at the level of
individuals? Bouchard and Rosenberg (Br J Philos Sci, 55:693-712, 2004) argue
that natural selection is causal and at the level of individuals, as opposed to Matthen
and Ariew (J Philos, 99:55-83, 2002) and Walsh et al. (Philos Sci, 69:452-473,
2002), who argue that natural selection is at the population level and purely
statistical. In addition to these two polar extreme positions, Millstein (Br J Philos
Sci, 57:627-653, 2006) tries to steer a middle course by arguing that natural
selection is a population-level causal process. I will make three points in this
chapter: first, Millstein's account of natural selection is incomplete, in the sense
that nowhere in her account can one find a place for cases of natural selection-of.
Second, we should prefer Brandon's account of natural selection and drift over
Millstein's, on the grounds that her account fails to meet a plausible requirement
that Brandon's account succeeds in meeting: namely, whenever natural selection
and drift operate together, a change in the strength of natural selection implies an
inverse change in the strength of drift, and vice versa. Third, the prospects of the
view that natural selection is a population-level causal process depend on a satis-
factory solution to both the epiphenomenon and the overdetermination problems.
With the help of an analogy, I will show how the two problems can be dealt with.

Recent discussions of natural selection focus on two questions: first, is natural
selection a causal process or is it a statistical consequence of lower-level events?
And second, is natural selection at the population level or at the level of

R.-L. Wang ( * )
Department of Philosophy, National Taiwan University, 1, Sec. 4, Roosevelt Rd.,
Taipei 10617, Taiwan
e-mail: [e-mail]