Self-ownership theorists argue that many of our most morally urgent and enforceable rights stem from the fact that we own ourselves. Critics of self-ownership argue that the claim that people own their bodies commits self-ownership theorists to several implausible conclusions because self-ownership theory relies on several vague moral predicates, and any precisification of the required predicates is seemingly too permissive (because it allows people to impose deadly risks on innocent bystanders for no reason) or too restrictive (because it prohibits people from polluting or even interacting with others at all). I argue that this line of criticism does not undermine the case for self-ownership theory because self-ownership theory does not require precisification of each moral concept that it is based on and, even if it did, the theory’s alleged extensional inadequacy does not undermine its justification.