Socialism's fundamental principles are centered on a critique of this concept, stating, among other things, that the cost of defending property is higher than the returns from private property ownership, and that even when property rights encourage the property-holder to develop his property, generate wealth, etc., he will only do so for his own benefit, which may not coincide with the benefit of other people or society at large.
Libertarian socialism generally accepts property rights, but with a short abandonment time period. In other words, a person must make (more or less) continuous use of the item or else he loses 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 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 private property (which in communist theory is limited to capital) should be abolished.
Both communism and some kinds of socialism have also upheld the notion that private property is inherently illegitimate. This argument is centered mainly on the idea that the creation of private property will always benefit one class over another, giving way to domination through the use of this private property. Communists are naturally not opposed to personal property which is "Hard-won, self-acquired, self-earned" (Communist Manifesto), by members of the proletariat

Various scholarly communities (e.g., law, economics, anthropology, sociology) may treat the concept more systematically, but definitions vary within and between fields. Scholars in the social sciences frequently conceive of property as a bundle of rights. They stress that property is not a relationship between people and things, but a relationship between people with regard to things.
Public property is any property that is controlled by a state or by a whole community. Private property is any property that is not public property. Private property may be under the control of a single individual or by a group of individuals collectively.[5] Some philosophers like Karl Marx use it to describe a social relationship between those who sell their labor power and those who buy

Modern property rights conceive of ownership and possession as belonging to legal individuals, even if the legal individual is not a real person. Corporations, for example, have legal rights similar to American citizens, including many of their constitutional rights. Therefore, the corporation is a juristic person or artificial legal entity, which some refer to as "corporate personhood".
Property rights are protected in the current laws of states usually found in the form of a Constitution or a Bill of Rights. The fifth and the fourteenth amendments to the United States constitution, for example, provide explicitly for the protection of private property:
The Fifth Amendment states:

Modern property rights conceive of ownership and possession as belonging to legal individuals, even if the legal individual is not a real person. Corporations, for example, have legal rights similar to American citizens, including many of their constitutional rights. Therefore, the corporation is a juristic person or artificial legal entity, which some refer to as "corporate personhood".
Property rights are protected in the current laws of states usually found in the form of a Constitution or a Bill of Rights. The fifth and the fourteenth amendments to the United States constitution, for example, provide explicitly for the protection of private property:
The Fifth Amendment states:

Various scholarly communities (e.g., law, economics, anthropology, sociology) may treat the concept more systematically, but definitions vary within and between fields. Scholars in the social sciences frequently conceive of property as a bundle of rights. They stress that property is not a relationship between people and things, but a relationship between people with regard to things.
Public property is any property that is controlled by a state or by a whole community. Private property is any property that is not public property. Private property may be under the control of a single individual or by a group of individuals collectively.[5] Some philosophers like Karl Marx use it to describe a social relationship between those who sell their labor power and those who buy

Property is any physical or virtual entity that is owned by an individual or jointly by a group of individuals. An owner of property has the right to consume, sell, rent, mortgage, transfer and exchange his or her property.[1][2][3] Important widely-recognized types of property include real property (land), personal property (other physical possessions), and intellectual property (rights over artistic creations, inventions, etc.), although the latter is not always as widely recognized or enforced.[4] A title, or a right of ownership, is associated with property that establishes the relation between the goods/services and other individuals or groups, assuring the owner the right to dispense with the property in a manner he or she sees fit. Some philosophers assert that property rights arise from social convention. Others find origins for them in morality or natural law (e.g. Saint

Sec. 2. The lands of the Cherokee Nation shall remain common property; but the improvements made thereon, and in the possession of the citizens respectively who made, or may rightfully be in possession of them: Provided, that the citizens of the Nation possessing 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 to 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, while 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.
Different societies may have different theories of property for differing types of ownership. 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

The two major justifications given for original property, or homesteading, are effort and scarcity. John Locke emphasized effort, "mixing your labor" with an object, or clearing and cultivating virgin land. Benjamin Tucker preferred to look at the telos of property, i.e. What is the purpose of property? His answer: to solve the scarcity problem. Only when items are relatively scarce with respect to people's desires do they become property.[6] For example, hunter-gatherers did not consider land to be property, since there was no shortage of land. Agrarian societies later made arable land property, as it was scarce. For something to be economically scarce, it must necessarily have the exclusivity property - that use by one person excludes others from using it. These two justifications lead to different conclusions on what can be property. Intellectual property - non-corporeal things like ideas, plans, orderings and arrangements (musical compositions, novels, computer programs) - are generally considered valid property to those who support an effort justification, but invalid to those who support a scarcity justification (since they don't have the exclusivity property.) Thus even ardent propertarians may disagree about IP.[7] By either standard, one's body is one's property.
From some anarchist points of view, the validity of property depends on whether the "property right" requires enforcement by the state. Different forms of "property" require different amounts of enforcement: intellectual property requires a great deal of state intervention to enforce, ownership of distant physical property requires quite a lot

Under United States law the principal limitations on whether and the extent to which the State may interfere with property rights are set by the Constitution. The "Takings" clause requires that the government (whether state or federal----for the 14th Amendment's due process clause imposes the 5th Amendment's takings clause on state governments) may take private property only for a public purpose, after exercising due process of law, and upon making "just compensation." If an interest is not deemed a "property" right, or the conduct is merely an intentional tort, these limitations do not apply and the doctrine of sovereign immunity precludes relief.[10] Moreover, if the interference does not almost completely make the property valueless, the interference will not be deemed a taking but instead a mere regulation of use.[11] On the other hand, some governmental regulations of property use have been deemed so severe that they have been considered "regulatory takings."[12] Moreover, conduct sometimes deemed only a nuisance or other tort has been held a taking of property where the conduct was sufficiently persistent and severe.[13

Many things have existed that did not have an owner, sometimes called the commons. The term "commons," however, is also often used to mean something quite different: "general collective ownership" - i.e. common ownership. Also, the same term is sometimes used by statists to mean government-owned property that the general public is allowed to access. Law in all societies has tended to develop towards reducing the number of things not having clear owners. Supporters of property rights argue that this enables better protection of scarce resources, due to the tragedy of the commons, while critics argue that it leads to the exploitation of those resources for personal gain and that it hinders taking advantage of potential network effects. These arguments have differing validity for different types of "property" -- things which are not scarce are, for instance, not subject to the tragedy of the commons. Some apparent critics actually are advocating general collective ownership rather than ownerlessness.
Things today which do not have owners include: ideas (except for intellectual property), seawater (which is, however, protected by anti-pollution laws), parts of the seafloor (see the United Nations Convention on the Law of the Sea for restrictions), gasses in Earth's atmosphere, animals in the wild (though there may be restrictions on hunting etc. -- and in some legal systems, such as that of New York, they are actually treated as government property), celestial bodies and outer space, and land in Antarctica.
The nature of children under the age of majority is another contested issue here. In ancient societies children were generally considered the property of their parents. Children in most modern societies theoretically own their own bodies -- but they are considered incompetent to exercise their rights, and their parents or guardians are given most of the actual rights of control over them.

The two major justifications given for original property, or homesteading, are effort and scarcity. John Locke emphasized effort, "mixing your labor" with an object, or clearing and cultivating virgin land. Benjamin Tucker preferred to look at the telos of property, i.e. What is the purpose of property? His answer: to solve the scarcity problem. Only when items are relatively scarce with respect to people's desires do they become property.[6] For example, hunter-gatherers did not consider land to be property, since there was no shortage of land. Agrarian societies later made arable land property, as it was scarce. For something to be economically scarce, it must necessarily have the exclusivity property - that use by one person excludes others from using it. These two justifications lead to different conclusions on what can be property. Intellectual property - non-corporeal things like ideas, plans, orderings and arrangements (musical compositions, novels, computer programs) - are generally considered valid property to those who support an effort justification, but invalid to those who support a scarcity justification (since they don't have the exclusivity property.) Thus even ardent propertarians may disagree about IP.[7] By either standard, one's body is one's property.
From some anarchist points of view, the validity of property depends on whether the "property right" requires enforcement by the state. Different forms of "property" require different amounts of enforcement: intellectual property requires a great deal of state intervention to enforce, ownership of distant physical property requires quite a lot, ownership of carried objects requires very little, while ownership of one's own body requires absolutely no state intervention.

Among contemporary political thinkers who believe that human individuals enjoy rights to own property and to enter into contracts, there are two views about John Locke. On the one hand there are ardent Locke admirers, such as W.H. Hutt (1956), who praised Locke for laying down the "quintessence of individualism." On the other hand, there are those such as Richard Pipes who think that Locke's arguments are weak, and that undue reliance thereon has weakened the cause of individualism in recent times. Pipes has written that Locke's work "marked a regression because it rested on the concept of Natural Law" rather than upon Harrington's sociological framework.
Hernando de Soto has argued that an important characteristic of capitalist market economy is the functioning state protection of property rights in a formal property system where ownership and transactions are clearly recorded. These property rights and the whole formal system of property make possible:
Greater independence for individuals from local community arrangements to protect their assets;
Clear, provable, and protectable ownership;
The standardization and integration of property rules and property information in the country as a whole;
Increased trust arising from a greater certainty of punishment for cheating in economic transactions;
More formal and complex written statements of ownership that permit the easier assumption of shared risk and ownership in companies, and insurance against risk;
Greater availability of loans for new projects, since more things could be used as collateral for the loans;
Easier access to and more reliable information regarding such things as credit history and the worth of assets;
Increased fungibility, standardization and transferability of statements documenting the ownership of property, which paves the way for structures such as national markets for companies and the easy transportation of property through complex networks of individuals and other entities;
Greater protection of biodiversity due to minimizing of shifting agriculture practices.
All of the above enhance economic

property not as a physical object, but rather as a relationship between people with respect to an object. Thus, saying one owns a glass of water is merely verbal shorthand for I may justly gift or trade this water to another person. In essence, what one owns is not the object but the value of the object. By "value," Bastiat apparently means market value; he emphasizes that this is quite different from utility. "In our relations with one another, we are not owners of the utility of things, but of their value, and value is the appraisal made of reciprocal services."
Strongly disputing Proudhon's equality-based argument, Bastiat theorizes that, as a result of technological progress and the division of labor, the stock of communal wealth increases over time; that the hours of work an unskilled laborer expends to buy e.g. 100 liters of wheat decreases over time, thus amounting to "gratis" satisfaction. Thus, private property continually destroys itself, becoming transformed into communal wealth. The increasing proportion of communal wealth to private property results in a tendency toward equality of mankind. "Since the human race started from the point of greatest poverty, that is, from the point where there were the most obstacles to be overcome, it is clear that all that has been gained from one era to the next has been due to the spirit of property."
This transformation of private property into the communal domain, Bastiat points out, does not imply that private property will ever totally disappear. This is because man, as he progresses, continually invents new and more sophisticated needs and desires