ViennaSausage:
From my understanding, in an ideal anarchcap world, everything would be privately owned. The forests, the oceans, land, perhaps even animals to an extreme. Two questions.
1) Can someone own the Sun? If so, I claim it for myself, and I lease it to everyone for free;). But seriously, how does the Sun and more generally Nature play into private ownership?
2) How does one claim ownership in general? By utilization? What if the utilization is just to let a property sit?
John Locke's labor theory of property (not to be confused with Karl Marx's labor theory of value) suggests that one can legitimately claim ownership of an unowned resource by exerting labor upon it and adding to it's value or making it more desirable*. You claim ownership of the resource so as to safeguard the value you have created against expropriation.
For example, you may find an abandoned lot of land and grow something on it, or build something on it, increasing the value of the land. You may then fence the land to protect the value you have created from being stolen or destroyed by other people (or wild animals, for that matter).
Nobody can take ownership the sun, because,
a) it is not unowned--living things have been using it for eons.
b) you cannot substantially increase its value
c) any attempt to deny others use of the sun would be considered initiation of force and subject to retaliation.
Does that make sense?
*Admittedly, I made up the part about adding value to something. I found it necessary to answer the question of what is considered "labor".
"We have thus stepped back from the position our ancestors occupied; for we allow under the flag of justice, and consecrate in the name of the law, what was imposed on them by violence alone."