Constraints and spandrels in Gould's Structure of Evolutionary Theory

Gould's Structure of Evolutionary Theory argues that Darwinism has undergone significant revision. Although Gould succeeds in showing that hierarchical approaches have expanded Darwinism, his critique of adaptationism is less successful. Gould claims that the ubiquity of developmental constraints and spandrels has forced biologists to soften their commitment to adaptationism. I argue that Gould overstates his conclusion; his principal claims are compatible with at least some versions of adaptationism. Despite this weakness, Gould's discussion of adaptationism - particularly his discussions of the exaptive pool and cross-level spandrels - should provoke new work in evolutionary theory and the philosophy of biology.