Imagining Mechanisms with Diagrams
Philosophy of science has long focused on how scientists achieve successful explanations of a phenomenon. But much of scientific work is aimed at something more basic: successfully and coherently imagining how a phenomenon might be explained—for example, hypothesizing a mechanism that could possibly produce the phenomenon. This chapter examines the graphics and diagrams that scientists in the field of circadian biology have generated and used to externalize and stabilize their imaginative reasoning. In particular, it examines how scientists revise their graphics as they sharpen and constrain their imaginative construal of a hypothetical mechanism. This analysis examines published diagrams that reflect the community’s developing understanding of the mechanism responsible for circadian rhythms in cyanobacteria and zeroes in on unpublished graphics from a single lab as they developed one operation in the mechanism. The goal is to understand how circadian biologists rely on graphics to overcome the difficulties of imagining the complex working of hypothetical mechanisms over time. Throughout, the chapter emphasizes that pursuing imaginative success is a scientific endeavor governed by its own internal norms, distinct from the norms of successful explanation. The aim is to direct philosophical analysis to scientists’ imaginings and to encourage integrating this understudied dimension of scientific practice with traditional philosophical analysis of normativity in scientific practice.