Breadth in Scientific Explanation

Pence, Charles H. [UCL]

The literature on scientific explanation has often focused on various concepts of “depth” – it features in a series of foundational papers on causal explanation by Hitchcock and Woodward, is the title of Strevens’s magisterial 2008 book on the subject, and has been a frequent topic of discussion in the literature on scientific mechanisms, which has endeavored to describe the way in which nested hierarchies of such mechanisms could offer us an account of explanatory depth. In this talk, I want to take some first steps toward establishing a different kind of desideratum for scientific explanation: what I will call breadth. I take breadth to be importantly distinct from both “scope” and “abstraction”: it is more than simply the number of potential systems to which an explanation might apply, and it is more complex than just the removal of concrete, contingent detail from a particular explanation. It is, rather, the ability for an explanation to apply to systems which are diverse, for some discipline-relevant sense of diversity. In turn, these senses of diversity, and hence the quest for breadth, are the result of active choices by practicing scientists, and constitute another place where we can profitably explore the influence of epistemic and non-epistemic values on scientific practice. While I will develop this notion with particular reference to examples of explanation in the life sciences, I hope it will remain applicable to scientific explanation as a whole.