Talk of “levels” can be found throughout the sciences, from “levels of abstraction”, to “levels of organization”, to “levels of analysis”. This has led to substantial disagreement regarding the ontology of levels, and whether the various senses of levels each have genuine value and utility to scientific practice. In this paper, I propose a unified framework for thinking about levels in science which ties together the various ways in which levels are invoked in science, and which can overcome the problems (...) that different senses of levels have faced. I argue that levels can best be understood as choices scientists make regarding what sort of information to foreground in their models and theories, and what sort of information to push into the background. To change levels is to change the foregrounding and backgrounding of information for different representational and pragmatic purposes. (shrink)