When philosophers consider fi ctions or fi ctional representations in science, we typically have in mind some canonical cases: idealized models, simulations, thought experiments, or counterfactual reasoning. The issue raised by scientifi c fi ctions may also seem straightforward. Sciences aim to discover actual structures and behaviors in the world, and to represent and understand them accurately. A role for scientifi c fi ctions provokes the question of how fi ctional representations, or, more provocatively, misrepresentations could contribute to scientifi c understanding of how the world actually is.