How do you assert a graph? Towards an account of depictions in scientific testimony

Abstract I extend the literature on norms of assertion to the ubiquitous use of graphs in scientific papers and presentations, which I term “graphical testimony.” On my account, the testimonial presentation of a graph involves commitment to both (a) the in‐context reliability of the graph's framing devices and (b) the perspective‐relative accuracy of the graph's content. Despite apparent disagreements between my account and traditional accounts of assertion, the two are compatible and I argue that we should expect a similar pattern of commitments in a set of cases that extends beyond the graphical one. I end by demonstrating that the account resolves apparent tensions between the demands of honesty and the common scientific practice of presenting idealized or simplified graphs: these “distortions” can be honest so long as there's the right kind of alignment between the distortion and the background beliefs and values of the audience.