Abstract
This article examines compulsory vaccination from the perspective of Nozick's theory of rights. It argues that the unvaccinated are a threat, even if unintended, to the rights of others. The reasons Nozick provides for when such threats may be forcibly prevented, such as the identifiability of the rights violator, general fear of the risky activity, probability of harm, and the general benefits of the activity, are examined, and it is argued that those reasons weigh in favour of prohibition of the threat and hence in favour of compulsory vaccination. It is also argued that anyone opposed to compulsory vaccination on Nozickian grounds faces a dilemma: if they reject compulsory vaccination, they also risk rejecting the very foundations of the legitimacy of the state.