This dissertation examines how we may meaningfully attribute explanatoriness to theoretical structures and in turn, how such attributions can, and should, influence theory assessment generally. In this context, I argue against "inference to the best explanation" accounts of explanatory power as well as the deflationary "answers to why questions" proposal of van Fraassen. Though my analysis emphases the role of unification in explanation, I demonstrate ways in which Kitcher's particular account i…
Read moreThis dissertation examines how we may meaningfully attribute explanatoriness to theoretical structures and in turn, how such attributions can, and should, influence theory assessment generally. In this context, I argue against "inference to the best explanation" accounts of explanatory power as well as the deflationary "answers to why questions" proposal of van Fraassen. Though my analysis emphases the role of unification in explanation, I demonstrate ways in which Kitcher's particular account is insufficient. The suggested alternative takes explanatory power to be a measure of theory intelligibility; thus, its value resides in making theories easy to probe, communicate, and ultimately modify. ;An underlying goal of the discussion is to demonstrate, even for a small set of examples, that not all components of rational assessment distill down, in one way or another, to evaluations of a theory's empirical adequacy. Instead, the merits of explanatory structures are argued to be forward-looking, meaning that they hold the potential to contribute significantly to theory development either by providing directives for theoretical modification, perhaps indirectly by guiding empirical investigation, or by facilitating various means of inferential error control. ;The dissertation's central case study concerns the development of twentieth century quantum mechanical theories of the chemical bond, provocative territory because of the diversity of models and representations developed for incorporating a computationally challenging, and potentially intractable, fundamental theory into pre-existing chemical theory and practice. Explicit mathematical techniques as well as various graphical, schematic, and diagrammatic models are examined in some detail. Ultimately these theoretical structures serve as the landscape for exploring, in a preliminary fashion, the influence of representational format on inferential capacities generally. Although the connection between representation and explanation is seldom emphasized, this dissertation offers evidence of the high cost of such neglect