Logic & Philosophy of Science Colloquium


Timothy Shanahan
Loyola Marymount University

"Why Don't Zebras Have Machine Guns? Recent (and Not so Recent) Work on
Adaptationism and Constraint


Like Darwin, contemporary biologists struggle with the problem of understanding why natural selection is able to forge such exquisite adaptations in some cases, but not in others. One commonly accepted solution focuses on the idea of "constraints". Whereas selection explains adaptive fit between living things and their environments, constraints are said to explain non-adaptive traits, why some lineages exhibit significant stasis over evolutionary time, and why many regions of morphospace remain (perhaps necessarily) unoccupied. In this view, constraints constitute an alternative explanation of biological form. This paper explores some of the central conceptual issues concerning adaptation, selection, and constraints, and argues that some of the constraints often juxtaposed and contrasted with selection are in fact explicable in terms of selection. Despite significant scientific advances since Darwin, questions like the one posed in the title of this essay are best answered in terms that Darwin himself would have been familiar with.

Friday, October 8, 2004
SST 777
3 pm

Refreshments will be served