@damian @Puddle @orathaic
I think the discussion about the state of nature is tangential—if it is even related—to the matter at hand. I ain't sign no social contract.
But I think the issue Puddle was trying to raise is similar to one I described in my longer post: that if rights only exist because they are means to an end, then if they are ineffective means, they should not be used. Using the state of nature is here is not an attempt to justify rights or morals, but a proposal for a consequence of the absence of rights. He (or she) is asking why there is any incentive to respect social mores if it is to his or her disadvantage. In short, Puddle is objecting to a utilitarian conception of rights, and not the presence of society.
With regard to universalisation, I shall illustrate my point with an example. Imagine you're sheltering a child from some bad guy (the specifics here are not terribly important). You have a reasonable expectation that this bad person will do harm to the child, so you allow the kid to hide in your basement. If the bad guy comes to the door and asks if you have seen the child, do you tell him? Upon consulting the categorical imperative, you realise that lying is wrong because it leads to a contradiction. But telling the bad guy the truth will lead to him harming the child.
I doubt very many people would let the bad guy get the kid, and rightly so. If you have a reasonable expectation of the consequences of your action, you have to take that into consideration when you make a moral evaluation. As I wrote above, the categorical imperative is great for figuring out if something is wrong in the abstract. Outside of material circumstances, lying is wrong. But in this particular scenario, it isn't wrong. And therein lies the weakness of a purely Kantian moral framework: it doesn't account for the practical limitations of the real world.
To bring this back to my original question, as to the justification of private property, I don't think we've quite come to an answer. (Don't worry, there's no definitive answer out there anyway). I asked after the moral justification of having private property, especially with regard to an absolute right. You've replied with a notion of rights that considers them only abstractly, independent of material outcomes. But, if I may put this bluntly, this formulation of right and wrong is out of touch with the real world: the homeless man on the street doesn't care if your universal maxims don't result in a logical contradiction. All he knows is that he's hungry and cold, and there's something that you and everyone else can do about it. He sees a society that values individualism and the equal moral worth of everyone, and a world that refuses to help him, justifying inaction as the most moral thing to do.
I'm not 100% in favour of a consequentialist moral philosophy either, but I acknowledge that to some extent outcomes do matter. We live in the material world and we can’t just ignore the results of our actions. Intentions are not the entirety of morality, and neither are outcomes. There is room for nuance and none for absolutes.