structural:expansion, linguistic:paraphrasing
Theories

There exist many theories of property. One is the relatively rare first possession theory of property, where ownership of something is seen as justified simply by someone seizing something before someone else does. Perhaps one of the most popular is the natural rights definition of property rights as advanced by John Locke. Locke advanced the theory that God granted dominion over nature to man through Adam in the book of Genesis. Therefore, he theorized that when one mixes one's labor with nature, one gains a relationship with that part of nature with which the labor is mixed, subject to the limitation that there should be "enough, and as good, left in common for others." (see Lockean proviso)

In his encyclical letter Rerum novarum (1891), Pope Leo XIII wrote, "It is surely undeniable that, when a man engages in remunerative labor, the impelling reason and motive of his work is to obtain property, and after that to hold it as his very own."

Anthropology studies the diverse ownership systems, rights of use and transfer, and possession under the term "theories of property". As mentioned, western legal theory is based on the owner of property being a legal person. However, not all property systems are founded on this basis.

In every culture studied, ownership and possession are the subjects of custom and regulation, and "law" is where the term can meaningfully be applied. Many tribal cultures balance individual rights with the laws of collective groups: tribes, families, associations, and nations. For example, the 1839 Cherokee Constitution frames the issue in these terms:

Sec. 2. The lands of the Cherokee Nation shall remain common property. Still, the improvements made thereon, and in possession of the citizens respectively who made, or may rightfully own them: Provided, that the citizens of the Nation possessing the exclusive and indefeasible right to their improvements, as expressed in this article, shall possess no right or power to dispose of their improvements, in any manner whatever, to the United States, individual States, or individual citizens thereof; and that, whenever any citizen shall remove with his effects out of the limits of this Nation, and become a citizen of any other government, all his rights and privileges as a citizen of this Nation shall cease: Provided, nevertheless, That the National Council shall have power to re-admit, by law, to all the rights of citizenship, any such person or persons who may, at any time, desire to return to the Nation, on memorializing the National Council for such readmission.

Communal property systems describe ownership as belonging to the entire social and political unit. Common ownership in a hypothetical communist society is distinguished from primitive forms of common property that have existed throughout history, such as Communalism and primitive communism, in that communist common ownership is the outcome of social and technological developments leading to the elimination of material scarcity in society.

Corporate systems describe ownership as being attached to an identifiable group with an identifiable responsible individual. The Roman property law was based on such a corporate system. In a well-known paper that contributed to the creation of the field of law and economics in the late 1960s, the American scholar Harold Demsetz described how the concept of property rights makes social interactions easier:

In the world of Robinson Crusoe, property rights play no role. Property rights are an instrument of society and derive their significance from the fact that they help a man form those expectations which he can reasonably hold in his dealings with others. These expectations find expression in society's laws, customs, and more. An owner of property rights possesses the consent of fellowmen to allow him to act in particular ways. An owner expects the community to prevent others from interfering with his actions, provided that these actions are not prohibited in the specifications of his rights.

Different societies may have other theories of property for differing types of ownership. For example, Pauline Peters argued that property systems are not isolable from the social fabric, and notions of property may not be stated as such but instead may be framed in negative terms: for example, the taboo system among Polynesian peoples.