Optimality Modeling and Explanatory Generality

The optimality approach to modeling natural selection has been criticized by many biologists and philosophers of biology. For instance, Lewontin (1979) argues that the optimality approach is a shortcut that will be replaced by models incorporating genetic information, if and when such models become available. In contrast, I think that optimality models have a permanent role in evolutionary study. I base my argument for this claim on what I think it takes to best explain an event. In certain contexts, optimality and game-theoretic models best explain some central types of evolutionary phenomena. 1 The Optimality Approach The optimality approach offers a way to model natural selection purely phenotypically, without directly representing the system of genetic transmission. This approach includes both optimality models and game-theoretic models, which are used when trait fitnesses are frequency-dependent. One determines the range of possible values for some phenotype and the fitness function relating these phenotypes to the environment. Based on this information, the model predicts which phenotypic value(s) will predominate in the population, given enough time in that environment. Many instances of long term evolutionary change can be modeled in this manner, resulting in information regarding the effect of the selection pressure(s) at work and any constraints arising from, e.g., the process of genetic transmission