What significance do dualities play for the interpretation of string theory? Dual theories appear to represent objects in radically different spacetime backgrounds. Dualities have been taken as examples of underdetermination, but we argue that this view is flawed. We argue instead that the dual formulations cannot be thought of as already having physical interpretations. They are instead “mathematical scaffolding” used to formulate a theory. This theory should then be given a physical interpretation on its own terms, for example by recovering classical spacetime in an appropriate limit.