Dr. Vaughan once taught a whole seminar on theories of property, but I didn't get to take it. I heard it was pretty interesting, though. I seem to remember Locke (Second Treatise) defining property as something like nature (land, plants, rocks) invested with labor (a garden, tomato sauce, horseshoes), which makes it "mine." I totally buy that notion, but history (at least the people in it) doesn't really seem to (see "slavery," "conquest," "colonialism," and the like).
Property or ownership is partly nominal, as in "I claim this land for the King of France" or a deed to a house. But I think the real essence of property is physical force. If someone resists the King of France's claim to ownership, he will be arrested or killed. Having seen this transaction, the next guy who wants to resist will respect the King's speech act of claiming property. The same thing seems to be going on in our more enlightened times, as well. Say I have a deed to a house, and everyone (government, contractors, tenants, neighbors) agree the property is "mine." Rather than killing each other, we settle any disputes through legal proceedings. However, all of our laws are only meaningful insofar as they imply a threat to person or property: if you break the law, you will lose "your" stuff or be locked up. Sure, the threat is more humane than rape and murder has been more or less agreed on by the participants in the society, but it is a threat all the same. The difference, then, between Alexander's plundering Persia, my buying a car, and the government's claim of eminent domain is one of degree, not kind.
I was reminded of issues like these when I saw the guy who owns the moon on Conan O'Brien (I'll try to find a link to his website later). He found a loophole in all of the existing laws regarding ownership of stellar bodies, and has laid legitimate, legal claim to the Moon, Mars, and other planets. He makes a fortune selling lunar real estate (lots of celebrities buy, but hotel chains are some of his biggest customers). Right now, he is just a kooky fella who has found a scam, and The Man lets him have his fun. However, if the Moon ever actually becomes easy to get to or needed for some military installation, that guy will have no chance whatsoever of resisting the King's claim.
So, it seems to me that, as awful as it sounds, all property is simply on loan from whoever has the strength to take it away, whether it is barbarian invaders, Medieval Crusaders, my mortgage lender, the State of Ohio, or Uncle Freakin' Sam.
