Abstract
The open-question argument (OQA) is an argument in meta-ethics that is used against ethical naturalism, the thesis that moral properties are identical to natural properties. This argument has been rightfully criticized, and one notable criticism is that it overlooks the sense-reference distinction, viz. the distinction between the concept that a term refers to and the sense in which it is being used. Ayn Rand's Objectivism rejects the sense-reference distinction, and this paper will present an argument that uses the OQA to argue against the underlying epistemological assumptions of Objectivism.