Ugh, for some reason I read "perhaps if you specify how your fairies have given us Social Utility" as "perhaps if you specify how your fairies have given us Social Security". No idea why. Apologies.
Anyway, I agree with you that it's not clear that rights come from social utility (whatever that really means). I also don't think it's clear they come from individual utility. I think they are complicated beasts that evolved partly from empathy and other feelings, partly from the values held by dominant groups, and partly from a number of religious and non-religious ideologies that piled up over the centuries.
Why would you ever consider those rights "natural", though? They are entirely defined by society, and the real world out there doesn't care about them at all. Kevin does have his opinions about where institutional rights come from, and I don't quite agree with him, but that wasn't the main thrust of his argument. His point was that natural rights don't exist. Institutional rights and natural rights are two completely different things.
They are natural rights because they flow naturally from the nature of humanity. Human nature is to observe, to process, to reason. Humans think, work, create.
A natural right, for instance, is freedom of thought. Humans each observe a slightly different to very different set of events and experiences, and each process it differently. Therefore, the freedom to our own unique thoughts is a natural right - it exists whether the law says that it is legal or not. While 'thought crimes' at various points in history have existed, it has never been possible to remove this right.
From this flows the human rights of freedom of expression and freedom of belief (frequently named freedom of religion). Expression is the sharing of thoughts between individuals. This individual right allows each individual to share his thoughts, to refine them with others. Belief is more or less a combination of expression and thought, and therefore is a human right as well.
Estate is another right. Each person can work, and almost all will work. The freedom of estate allows each person to possess goods and property. Each person labors to create, and each may possess goods.
Many times has the freedom of estate been limited. Marxists, for instance, believe that possessions were a grant of society - they assigned property instead of granting each person the freedom of ownership. All that happened was that people used other means to trade for property. The black market, and the resulting collapse of their entire labor and production system as a result of revoking this freedom - a revocation which ultimately failed.
From this flows the right to labor where one wills. The right to own the products of one's labor, and trade them to others for recompense. The right to equal opportunity - any may trade with another. Once again, many societies have restricted these rights, and each time, individuals suffer and the restrictions chaff and fail.
Kevin's proto-marxism and slightly creepy anal fetish aside, these rights exist naturally because of the nature of humanity. Were we the sort of species that could not think independently, we would not have freedom of thought. But we are, and we have it. We have rights that flow from that freedom, independent of what a 'society' deems reasonable.
Society, of course, exists for a purpose. Some times these rights collide, and society negotiates them. There's large value to everyone for everyone to have 'common property' (imagine, for a moment, a separate water network for each person in America, or a separate road system). While it's easy to say that each person has the right to property, a judicial system and police force are necessary to enforce that right. Society even has to sometimes negotiate the difference between a single individual right and a large collective right (the individual right to labor in the homemade bomb making industry kind of conflicts with our individual right not to get blown up (frequently called the 'right to life' although that term is a tad hijacked at the moment). Similarly, taxes are a compromise that allows us to pay for these services which we all benefit from.
But Kevin's ideas that social utility is the determining factor is nonsense. Eventually someone will decide that social utility calls for restricting the freedom of thought, or the freedom of property, or the freedom of belief. And they'll have plenty of convincing reasons why. Hell, look at Kevin's call to restrict the freedom to own one's labor in the name of some 'social utility' that occurs when no one can profit from creative endeavors!
