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Abstract
The dissertation is a critical examination of theory evaluation in population genetics. There are three main philosophical approaches to theory evaluation in philosophy of science: (1) confirmation and hypothesis testing, (2) scientific change, and (3) experimentation. Accounts that champion each of the main philosophical approaches to scientific theory evaluation are represented in philosophy of biology: (1) confirmation and hypothesis testing by Elisabeth A. Lloyd, (2) scientific change by Lindley Darden, and (3) experimentation by David W. Rudge. I argue that each of the main approaches is insufficient for evaluating population genetics theories. However, the accounts I critique are not fundamentally incompatible. I modify, unify, and extend them into a comprehensive account of theory evaluation for population genetics.
My philosophical analysis is driven by a complex, important, and ongoing controversy in population genetics, viz., the R. A. Fisher-Sewall Wright controversy in population genetics. I use my historical case study to assess the adequacy of both the extant philosophical analyses of theory evaluation and my own account. Between 1929 and 1962 Fisher and Wright debated the main differences emanating from their alternative approaches to evolutionary theorizing. The debates between Fisher and Wright functionally ended with Fisher's death. However, Wright continued to clarify his position in the controversy until his death in 1988, and other biologists have continued work on the core debates.
Recently, four scientific papers led by biologists Jerry A. Coyne and Michael J. Wade have been key in revisiting and rekindling the Fisher-Wright controversy with analyses of old theoretical and empirical issues as well as new developments that have spun off the older work. Four decades after the debates between Fisher and Wright, these papers have staked out, with substantial disagreement, claims about the evaluative status of the two predominant population genetics approaches to evolution in the field. A further task of this dissertation is to provide a non-partisan evaluation of the last 40 years of work on the controversy, i.e., the controversy since Fisher's death in 1962. It is hoped that such a critical analysis of the controversy will advance it to some extent.