Interdisciplinary study of addiction is facilitated by relative unification of the concept. What should be sought is not formal unification through literal analytic definition, which would undermine practical flexibility within disciplines and intervention practices. However, leading controversies around whether addiction should be conceived as a ‘disease’, and over whether addiction is ‘chosen’ behavior, are made more difficult to resolve by failure to apply philosophical reflection on these general concepts. Such reflection should be sensitive to two kinds of constraint: coherence in description of empirical, including neuroscientific, observation, and utility in framing normative goals in treatment and policy design. Following review of various interpretations of addiction, disease, and choice across contributing disciplines, it is concluded that addiction is most plausibly viewed as a disease at the scale of public health research and policy, but not personal (e.g. clinical) management and intervention. Addicts must make choices to recover, and in that respect addiction is a ‘disorder of choice’. However, it is concluded that the most relevant sense of ‘disorder’ arises at the social rather than the personal scale.