 Other thought experiments are scoped more narrowly; for example, scientific thought experiments are intended to allow people to explore nomic possibilities. Galileo (On Motion) famously offered a thought experiment that disproved Aristotle’s theory of motion, which predicts that heavier objects fall more quickly. In this thought experiment, Galileo asked people to imagine the falling of a composite of a light and heavy object versus the falling of the heavy object alone. When one runs the thought experiment—that is, when one elaborates on the starting point of this imaginary scenario—one notices an incoherence in Aristotle’s theory: on the one hand, it should predict that the composite would fall more slowly because the light object would slow down the heavy object; on the other hand, it should also predict that the composite would fall more quickly because the composite is heavier than the heavy object alone. While it is incontrovertible that imagination is central to thought experiments, debates remain on whether imagination can be invoked in the context of justification (Gendler 2000b; Williamson 2016) or only in the context of discovery (Norton 1991, 1996; Spaulding 2016).