ABSTRACT
Although the controversy over adaptationism has gone on for many years, several important issues have not been resolved. First, adaptationism has not been clearly defined. Second, it has remained unclear as to how adaptationism is testable, how the testing of specific optimality models is involved in that test, and how the test of a specific model should be structured in order to assess the hypothesis of optimality. We address these issues in this article. Some of our discussion of optimality models will focus on evolutionarily stable strategy (ESS) models because the relevant theory illustrates an important distinction we will make concerning different hypotheses about the power of natural selection. Despite this focus, our arguments apply to any optimality model and, more generally, to any model used to support the claim that natural selection is the only important cause of a trait.
