Theory in Service of Narratives in Evolution and Ecology.

Considering the role of theory in ecology and evolution, we argue that scientific theorizing involves an interplay between narratives and models in which narratives play a key creative and organizing role. Specifically, as scientists, we reason through the use of narratives that explain biological phenomena by envisaging, or mentally simulating, causal paths leading from a plausible initial state to an outcome of interest. Within these narratives, some parts may appear clear, while others may appear puzzling. It is at these tenuous junctions-junctions where reasoning is made challenging by conflicting possible outcomes-that we often build mathematical models to support and extend, or reject and revise, our narratives. Accordingly, models, both analytical and computational, are framed by and interpreted within a narrative. We illustrate these points using case studies from population genetics. This perspective on scientific theorizing helps to clarify the nature of theoretical debates, which often arise from the narratives in which math is embedded, not from the math itself. Finally, this perspective helps place appropriate creative weight on the importance of developing, revising, and challenging narratives in the scientific enterprise.