This is the final version. Available on open access from Springer via the DOI in this recordPaleobiologists (and other historical scientists) often provide simple narratives to explain
complex, contingent episodes. These narratives are sometimes ‘one-shot hypotheses’ which are
treated as being mutually exclusive with other possible explanations of the target episode, and
are thus extended to accommodate as much about the episode as possible. I argue that a
provisional preference for such hypotheses provides two kinds of productive scaffolding. First,
they generate ‘hypothetical difference-makers’: one-shot hypotheses highlight and isolate
empirically tractable dependencies between variables. Second, investigations of hypothetical
difference-makers provision explanatory resources, the ‘raw materials’ for constructing more
complex—and likely more adequate—explanations. Provisional preferences for simple, one-shot
hypotheses in historical science, then, is defeasibly justified on indirect—strategic—grounds. My
argument is made in reference to recent developments regarding the K-Pg extinction.John Templeton Foundatio
