ABSTRACT
Within the philosophical literature, libertarianism is typically understood as a theory of justice based on the allocation of two sets of robust individual rights. Ownership rights, both over the self and external resources, constitute the first and most basic set of libertarian rights. It is argued that the recognition of exception rights is necessary for avoiding what are usually perceived as the two main weakness of libertarianism: its distribution insensitivity and its consequence insensitivity. Exception rights only arise under special circumstances, and the costs that they imposed on others, although small, might not be trivial. In order to understand the central features of libertarianism, one might think about a situation of 'moral anarchy', that is, a situation where individuals do not observe any sort of moral constraint on their self-interested behavior. Exception rights only sanction the permissibility of a limited subset of potential infringements. The magnitude of those infringements is also strictly limited.
