Final answer:
Nozick's theory of property ownership is his entitlement theory, based on libertarian principles and individual liberty, contrasting with Locke's natural law-based rights and Proudhon's rejection of ownership.
Step-by-step explanation:
According to Nozick, the only theory of property ownership that is justified is his entitlement theory. This theory is based on libertarian principles and holds that a person who acquires a holding in accordance with the principle of justice in acquisition, justice in transfer, and rectification of injustice, is entitled to that holding.
Nozick’s approach opposes patterns of distribution and large, redistributive roles for the state, contrasting with notions such as Proudhon's "property is theft." Instead, it champions individual liberty and the creation of wealth through personal labor.
This theory is sharply distinct from those of Locke, who believed in property rights originating from labor and natural law but limited by the consideration that one could not acquire property to the detriment of others, and Proudhon, who ultimately rejected the concept of property ownership altogether, advocating for worker cooperatives and the product of labor directly rewarding the worker.