Qualitative Theory and Chemical Explanation

Roald Hoffmann and other theorists claim that we we ought to use highly idealized chemical models (“qualitative models”) in order to increase our understanding of chemical phenomena, even though other models are available which make more highly accurate predictions. I assess this norm by examining one of the tradeoffs faced by model builders and model users — the tradeoff between precision and generality. After arguing that this tradeoff obtains in many cases, I discuss how the existence of this tradeoff can help us defend Hoffmann’s norm for modelling. ∗Many thanks to Michael Friedman, Robin Hendry, Ben Kerr, Deena Skolnick, Peter Godfrey-Smith, and Michael Strevens for extremely helpful comments on earlier drafts of this and related papers. John Brauman, Marc Feldman, Paul Needham, Joan Roughgarden, Janet Stemwedel, and Ward Watt also provided helpful comments in conversations about these themes. Most of all I would like to thank Roald Hoffmann who has been an inspiring mentor and who’s reflections on the philosophical aspects of chemistry stimulated my interest in this topic. This research was partially supported by a National Science Foundation Pre-Doctoral Fellowship.