Skepticism and Ontological Parsimony

External world skepticism is often thought to entail that we should suspend judgment about the existence of the external world. I challenge this orthodoxy by arguing that, when combined with a plausible principle of ontological parsimony, the skeptical challenge intensifies into an argument for outright disbelief in the external world. The principle in question instructs us to prima facie disbelieve in undetectable postulates. This bears on the skeptical challenge because, by the skeptic's lights, the external world and its constituents qualify as undetectable. This result poses problems for concessive responses to skepticism, such as entitlement‐based and pragmatic strategies.