Types and tokens: Model transfer and the strategy of explanatory unification

This paper focuses on an issue in the epistemology of interdisciplinary model transfer: how can model transfer between distinct domains of study make an epistemic contribution to science? I argue that there is an underappreciated but epistemically-significant difference between two modes of reasoning in model transfer, and which epistemic contributions model transfer can make depends on which mode is present. Existing discussions of interdisciplinary model transfers from one scientific discipline to another typically focus on analogy and analogical reasoning. By contrast, in what I'll call "type-token" reasoning, model transfer from one scientific system to another is motivated not by analogies or similarities but instead by the idea that different systems are tokens of a type. While analogies render phenomena more intelligible, type-token explanations aim at a certain kind of ontological unification.