Often property is defined by the code of the local sovereignty, and protected wholly or more usually partially by such entity, the owner being responsible for any remainder of protection. The standards of proof concerning proofs of ownerships are also addressed by the code of the local sovereignty, and such entity plays a role accordingly, typically somewhat managerial. Some philosophers assert that property rights arise from social convention, while others find justifications for them in morality or in natural law.
Various scholarly disciplines (such as law, economics, anthropology or sociology) may treat the concept more systematically, but definitions vary, most particularly when involving contracts. Positive law defines such rights, and the judiciary can adjudicate and enforce property rights.
According to Adam Smith, the expectation of profit from "improving one's stock of capital" rests on private property rights. Capitalism has as a central assumption that property rights encourage their holders to develop the property, generate wealth, and efficiently allocate resources based on the operation of markets. From this has evolved the modern conception of property as a right enforced by positive law, in the expectation that this will produce more wealth and better standards of living. However, Smith also expressed a very critical view on the effects of property laws on inequality:
- "Wherever there is great property, there is great inequality … Civil government, so far as it is instituted for the security of property, is in reality instituted for the defence of the rich against the poor, or of those who have some property against those who have none at all." (Adam Smith, Wealth of Nations)
In his text The Common Law, Oliver Wendell Holmes describes property as having two fundamental aspects. The first, possession, can be defined as control over a resource based on the practical inability of another to contradict the ends of the possessor. The second, title, is the expectation that others will recognize rights to control resource, even when it is not in possession. He elaborates the differences between these two concepts, and proposes a history of how they came to be attached to persons, as opposed to families or to entities such as the church.
- Classical liberalism subscribes to the labor theory of property. They hold that individuals each own their own life, it follows that one must own the products of that life, and that those products can be traded in free exchange with others.
- "Every man has a property in his own person. This nobody has a right to, but himself." (John Locke, Second Treatise on Civil Government)
- "The reason why men enter into society is the preservation of their property." (John Locke, Second Treatise on Civil Government)
- "Life, liberty, and property do not exist because men have made laws. On the contrary, it was the fact that life, liberty, and property existed beforehand that caused men to make laws in the first place." (Frédéric Bastiat, The Law)
- Conservatism subscribes to the concept that freedom and property are closely linked. That the more widespread the possession of private property, the more stable and productive is a state or nation. Economic leveling of property, conservatives maintain, especially of the forced kind, is not economic progress.
- "Separate property from private possession, and Leviathan becomes master of all... Upon the foundation of private property, great civilizations are built... The conservative acknowledges that the possession of property fixes certain duties upon the possessor; he accepts those moral and legal obligations cheerfully." (Russell Kirk, The Politics of Prudence)
- Socialism's fundamental principles center on a critique of this concept, stating (among other things) that the cost of defending property exceeds the returns from private property ownership, and that, even when property rights encourage their holders to develop their property or generate wealth, they do so only for their own benefit, which may not coincide with benefit to other people or to society at large.
- Libertarian socialism generally accepts property rights, but with a short abandonment period. In other words, a person must make (more-or-less) continuous use of the item or else lose ownership rights. This is usually referred to as "possession property" or "usufruct". Thus, in this usufruct system, absentee ownership is illegitimate and workers own the machines or other equipment that they work with.
- Communism argues that only collective ownership of the means of production through a polity (though not necessarily a state) will assure the minimization of unequal or unjust outcomes and the maximization of benefits, and that therefore humans should abolish private ownership of capital (as opposed to property).
Both communism and some kinds of socialism have also upheld the notion that private ownership of capital is inherently illegitimate. This argument centers mainly on the idea that private ownership of capital always benefits one class over another, giving rise to domination through the use of this privately owned capital. Communists do not oppose personal property that is "hard-won, self-acquired, self-earned" (as the Communist Manifesto puts it) by members of the proletariat. Both socialism and communism distinguish carefully between private ownership of capital (land, factories, resources, etc.) and private property (homes, material objects and so forth).
Types of property
Most legal systems distinguish between different types of property, especially between land (immovable property, estate in land, real estate, real property) and all other forms of property—goods and chattels, movable property or personal property, including the value of legal tender if not the legal tender itself, as the manufacturer rather than the possessor might be the owner. They often distinguish tangible and intangible property. One categorization scheme specifies three species of property: land, improvements (immovable man-made things), and personal property (movable man-made things).
In common law, real property (immovable property) is the combination of interests in land and improvements thereto, and personal property is interest in movable property. Real property rights are rights relating to the land. These rights include ownership and usage. Owners can grant rights to persons and entities in the form of leases, licenses and easements.
Throughout the last centuries of the second millennium, with the development of more complex theories of property, the concept of personal property had become divided into tangible property (such as cars and clothing) and intangible property (such as financial instruments—including stocks and bonds—intellectual property—including patents, copyrights and trademarks—digital files, communication channels, and certain forms of identifier—including Internet domain names, some forms of network address, some forms of handle and again trademarks).
Treatment of intangible property is such that an article of property is, by law or otherwise by traditional conceptualization, subject to expiration even when inheritable, which is a key distinction from tangible property. Upon expiration, the property, if of the intellectual category, becomes a part of public domain, to be used by but not owned by anybody, and possibly used by more than one party simultaneously due the inapplicability of scarcity to intellectual property. Whereas things such as communications channels and pairs of electromagnetic spectrum band and signal transmission power can only be used by a single party at a time, or a single party in a divisible context, if owned or used at all. Thus far or usually those are not considered property, or at least not private property, even though the party bearing right of exclusive use may transfer that right to another.