Friday, 28 January 2005
Misunderstandings about Fitness, Variance, and Skew
Jessica Pfeifer
Univiversity of Maryland,
Baltimore County
12:05 pm, 817R Cathedral of Learning
Abstract: The widely accepted propensity account
of fitness has recently faced criticism from its previous defenders
due to Gillespie's (1974 & 1977) findings that variance can
affect selection and Finsen and Beatty's (1989) similar finding
with respect to skew. Some believe that these results merely
require a revision of the mathematical formulation of fitness (Beatty
& Finsen 1989; Brandon 1990), though these mathematical reformulations
do entail that fitness can only be defined schematically, since
it must be defined differently in different circumstances. This
has led Rosenberg to
argue that the schematic definition is, therefore, no real definition
at all, and this provides additional reason to reject the propensity
interpretation of fitness. Sober (2002) argues that the revisions
have even more profound implications for the metaphysics of fitness
attributions. Given that the revised definitions require reference
to population size and since population size is extrinsic to the
organism, Sober argues that “an organism’s fitness is
not a propensity that it has” (2002, 320). In the paper,
I argue that these concerns are misplaced and that even the mathematical
revisions may not be necessary.
