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