Once upon a time, there was a notion created that people could own things. Owning meaning that you controlled what ever it was in all fashions. This was one of the first ideas of property rights.
Property rights as defined by Armen A. Alchian in his paper "Property Rights" says as follows:
"A property right is the exclusive authority to determine how a resource is used, whether that resource is owned by government or by individuals."
While I do agree that in many situations that a government of a person has the authority to determine how a resource is used, that authority is not exclusive. I would say that at any time for any reason, by a multitude of forces, the determination of how a resource is used can change. Not only can it change, but to believe that any entity has complete control over a resource is ludicrous.
So insane is this notion is how many things it does not take into account. The forces of physics and biology constantly take the idea of property rights and smash it. One who owns food can never truly control the decay of the food, meaning its use by many a chemical and biological process was totally out of the control of the individual with so called "property rights".
To continue, the notion that another individual cannot exercise their being and wrest control of property from someone due to an enforced policy is as well boondoggling. It may provide a way to coerce people into doing it less by providing the negative incentive of legal action but it will never be able to actually stop it from happening. The only way you ever could stop it from happening is by divine intervention or using mind altering technology not known to popular science at the current time.
So this is why I say that property rights are an illusion. It is an abstract concept with no roots in reality, only in mentality. But then again most people are pretty mental.