The limits of libertarianism.

Libertarianism is the political theory that the legitimate role of the state is limited to the protection of negative rights to life, liberty and property. The most important of these rights is the rights to property; the libertarian argument for a minimal state requires the claim that individuals have ownership rights in external goods which as sufficiently extensive to preclude the possibility of enforceable moral demands over and above those duties entailed by libertarian negative rights. I argue that these ownership rights are not supported by libertarian principles against aggression, and hence the libertarian cannot explain why anyone should be thought to have ownership rights. Without these ownership rights a libertarian political thesis cannot be sustained. The most plausible motivation for libertarianism is the conception of a person that underlies libertarian objections to consequentialism. This is the conception of a person as having the capacity to choose her own ends, and to constrain her behaviour in accord with those ends. I identify this capacity with a capacity for autonomous choice. This conception of a person gives prima facie support for a libertarian principle against aggression. The main contenders for a principle against aggression are a right not to be harmed, a right to liberty, and a right of self-ownership, which entails in others a duty to refrain from coercive interference. I argue that none of these principles can support any substantive conception of ownership rights. Hence libertarian attempts to link ownership rights with a principle against aggression fail. This is not surprising, since property rights themselves can be thought of as licensing aggression others. Although libertarian arguments for ownership fail, there is nonetheless an important connection between individual ownership rights and the conception of a person that I take to provide the most plausible support for libertarianism. An institution of private property is better able than alternative social arrangements to protect people's interest in choosing autonomously. However, the considerations that support private property also support restrictions on ownership, especially restrictions entailed by individual positive rights. Hence the concept of ownership that emerges is considerably weaker than the libertarian conception