Natural rights can justify legal rights to control and dispose of those resources exclusively – that is, rights of ownership. Ownership is justified on moral grounds when it seems likely in practice to help people acquire and use resources more effectively than alternate regimes would – especially, a system in which resources were open for everyone’s access and use and people enjoyed them with usufructs. This chapter studies four core or paradigm cases in which ownership facilitates use enough to be legitimate. One (associated with Aristotle) stresses ownership’s tendency to reduce disputes over property; another (associated with St. Thomas Aquinas) focuses on how ownership encourages careful management of resources; a third (Locke) focuses on how ownership incentivizes people labor and productivity; and the last (James Madison and other American founders) focuses on ownership’s securing privacy and autonomy for owners’ own preferred uses. This chapter considers egalitarian critiques of ownership, especially by Jeremy Waldron, Joseph Singer, G.A. Cohen, Liam Murphy, and Thomas Nagel. To define ownership, this chapter relies on conceptual work by A.M. Honore and J.E. Penner.

Ownership entitles owners to assign away some lesser property rights and retain other such rights. This chapter studies the cases for and against these lesser rights, called in this chapter “component” rights. Component rights may and should be limited when they help owners and the likely assignees of component rights use the resources more productively. The rights may and should be limited when they interfere with the clarity of property rights and when they interfere with opportunities of people who are not assignees to have sufficient access to resources. Property’s productive use requirement also justifies correlative doctrines between people who hold component rights in the same resource. This chapter studies leases, servitudes, security interests, present possessory estates, and future interests. To study limits on component rights, this chapter studies formalities requirements, standard terms of art for different component rights, the numerus clausus principle, the Rule Against Perpetuities, and the doctrine terminating servitudes for changed conditions. To study correlative rights, this chapter studies the doctrine of ameliorative waste.

This chapter studies the property’s analytical structure. The most basic concept for property is the concept of a usufruct. The conceptual model for usufructs describes informal property right and simple legal rights like easements and common law water rights. That model also describes the features of the natural rights that conventional property institutions should secure. Usufructs consist of in rem and immunized claim-rights in relation to separable resources, they possess institutional status, and they are structured to perform the function of facilitating productive use as studied in Chapters 4 and 5. The foregoing definition of a usufruct is a definition in relation to a focal or core case. This chapter contrasts its conceptual claims with exclusion theories and bundle of rights theories.

When natural rights justify ownership, the justification is only a prima facie justification. Ownership may justly be limited when it seems unlikely in practice to serve people’s interests in acquiring and using ownable resources. Each of the four elements of natural property rights highlights limits on ownership, and this chapter surveys a range of doctrines illustrating the relevant limits – limits on the scope of property in air columns via aerial trespass doctrine; adverse possession; doctrines enforcing limits on malicious conduct and abuse of right; remedial defenses for undue hardship in property disputes; public commonses; the necessity privilege in tort; rights of way to access public commons; common carrier doctrines; and progressive taxation, welfare, and other public assistance policies.

Chapter 2 introduces the normative theory on which the book relies. Principles of natural law are guides for practical human action. The principles are “natural” because they are knowable through human reason and valid guides to action whether they have been accepted in any community’s laws. They are “law” in that they supply reasons or justifications for action. Natural law theory focuses human action on survival and on flourishing understood rationally. Natural law justifies reasoning with interests, understood as distinct components of a person’s well-being. Natural law also justifies reasoning with rights, understood as entitlements to act and be free from interference backed by claims against others. Natural rights focus social and political life on desirable, low, and uncontroversial goals like survival and freedom. Natural rights also help specialize – around distinct fields of human activity organized around people’s bodies, their capacities to make livings, their capacities to associate, and their capacities to use property.

This chapter explains what property covers and what interest it serves. Property is the field for legal and social relations for separable resources. And property serves an interest people have in acquiring and using separable resources for survival or flourishing. This chapter relies on work by James Penner and Neil MacCormick to introduce separability. This chapter studies property in body parts, names, identities, and slaves.

This book introduces a normative theory of property. Property laws and social norms are justified by whether and how well they secure natural rights. The natural rights are justified by run-of-the-mill principles of natural law, which evaluate human action by whether it helps people survive or flourish rationally. The book studies how natural rights legitimate property law in general and in specific doctrines. It also studies the main topics in property law and policy – ownership, public commons, the appropriate design of property rights, rights less sweeping than rights of ownership, property torts, regulatory takings, and eminent domain. The book studies in particular the phenomenon of practical reasoning, the sphere of moral reasoning that converts fundamental moral goals into specific laws and policies to enforce in practice. A theory of natural rights contributes importantly to normative theory beyond the theories most respected today – egalitarian or progressive theories, law and economics, and approaches the book calls pragmatic.

This chapter concludes.

This chapter studies doctrines that consolidate different real-world resources into different res in property law. Some such doctrines classify individual real-world resources as separate res; others consolidate several resources into single res in law. The requirements for natural property rights, namely, claim communication and productive use, provide satisfying foundations for thing design doctrines. The doctrines are then implemented in law and policy via practical reason. This chapter studies doctrines associated with accession, specification, confusion, fugitive or fugacious minerals, the ad coelum maxim, the ratione soli maxim, and fixtures. This chapter also studies how property in land, water flow, and chattels all limit one another. This chapter also studies contemporary policy debates about hydraulic fracturing, including property in oil and natural gas trapped in shale or “tight” rocks.

In a rights-based legal system, a government may justly condemn property on two main distinct grounds. The eminent domain power authorizes governments to take private property upon payment of just compensation, if the taken property is going to be used by the government or by the public at large. Governments may also condemn and redistribute private property under the police power, primarily when doing so seems clearly likely to secure an average reciprocity of advantage to all the affected owners. If a government action does not satisfy either set of standards, however, it constitutes a violation of property rights. This chapter applies the justifications it studies to familiar disputes about irrigation systems, the creation of dams and mills, the acquisition of land for mining rights of way, urban renewal programs, the redistribution of land in Hawaii to deal with oligopoly, and the redistribution of land to facilitate economic development in Kelo v. New London (2005). This chapter also considers the skeptical view holding that it is impossible to distinguish between police regulation and eminent domain or between public and private uses.

This chapter studies the elements of an interest-based natural property right. To acquire a prima facie right in a resource, the claimant must use it productively and claim exclusivity to its use in terms others will understand. But the prima facie right may be overridden by either of two provisos. The sufficiency proviso limits property rights when a proprietor’s use of a resource does not leave others sufficient access to the same type of resource for their own needs. The necessity proviso limits natural rights when someone who does not hold property in a resource needs access to it to repel some serious threat to life or property. This chapter illustrates legal doctrines for capturing animals and other articles of personal property, occupying unowned land, and appropriating water flow by use. This chapter contrasts productive use with Locke’s treatments of labor, waste, and spoliation, and it contrasts claim communication with Pufendorf and Grotius’s treatments of possession. This chapter also considers familiar criticisms of rights-based property theories, involving hypotheticals with radioactive tomato juice or ham sandwiches embedded in cement.