ABSTRACT
A libertarian theory of justice conceives justice in terms of property rights. It holds that persons are self-owners and have the moral power to acquire property rights in initially unowned external resources. Different variants of libertarianism can be distinguished according to their stance on the famous Lockean proviso. Libertarianism is not the only theory of justice that takes private-property rights seriously. This chapter shows that if one embraces a libertarian theory of justice due to the project pursuit rationale, that is, if one embraces self-ownership and the natural right to the practice of private property and gives them considerable weight, then one should also embrace a sufficientarian proviso. The proviso does not apply to specific acts of appropriation but to the practice of private property as a whole. Private property is justified because private property is necessary for project pursuit, but practices of private property should work for all. They should enable everyone to actually live as a project pursuer.
