Abstract

The structure of evolutionary theory has proved difficult to characterize. Most available analyses focus on the existence of evolutionary laws and on the axiomatizability of the theory; such analyses pay insufficient attention to mathematical evolutionary models and their structure, and to the structural complications arising from the variety of evolutionary sub-theories. ;The primary goal of this dissertation is to introduce and develop an analysis of the structure of evolutionary theory that is both precise and useful. The secondary goal is to offer further evidence of the appropriateness and utility of the semantic view of theories, as developed by P. Suppes, B. C. van Fraassen, and F. Suppe, in which the theory is viewed as a family of related mathematical models. ;After reviewing the semantic approach, I provide a formal framework for describing and distinguishing among population genetics models. The interrelations among the models are described through a set of notions developed and made precise through the analysis of several evolutionary sub-theories, including genic selection and species selection. The framework of model specification, combined with the notions describing formal relations among models, are offered as a system capable of describing any part or aspect of the structure of evolutionary theory. ;Finally, I present a view of confirmation that relies on the distinctions present in the above system of theory description. I argue that this view of confirmation has two advantages over a hypothetico-deductive view of confirmation. First, it is possible to establish the reasonableness of viewing a variety of evidence as a form of confirmation. Second, as I show in the analysis of a controversial model, distinctions can be made due to the subtlety of the view that do not appear under the usual approaches. ;I conclude that a semantic approach to the structure of theories offers a natural, precise framework for the characterization of contemporary evolutionary theory. As such, it may provide a means with which progress on outstanding theoretical and philosophical problems can be achieved