Published online by Cambridge University Press: 01 January 2022
Skipper and Millstein analyze natural selection and mechanism, concluding that natural selection is not a mechanism in the sense of the new mechanistic philosophy. Barros disagrees and provides his own account of natural selection as a mechanism. This discussion identifies a missing piece of Barros's account, attempts to fill in that piece, and reconsiders the revised account. Two principal objections are developed: one, the account does not characterize natural selection; two, the account is not mechanistic. Extensive and persistent variability causes both of these difficulties, so further attempts to describe natural selection as a mechanism are also unlikely to succeed.
Thanks to William Bechtel, Nancy Cartwright, Marta Halina, Eric Martin, Roberta Millstein, and Jacob Stegenga for assistance with this project throughout the stages of its development. A version of this discussion was presented at the 2009 meeting of the International Society for the History, Philosophy, and Social Studies of Biology in Brisbane, Australia. Thanks to the audience for very helpful discussion, as well as to the conference organizers for supporting graduate student travel.