“To justify inequalities of property, you must demonstrate that the poor have a duty to respect the rich’s property. How can this be done?”
Because it’s their property.
The claim is a specific application of the general principle that any given person is obliged not to take the fruits of another person’s labor from her. To do that is to treat her as if you had a right to force her to labor for your own profit. That is treating her as if she were your slave. But slavery is illegitimate. The proper question is not where she got a right to her property, but rather where you would get a right to live off her labor.
Note that this applies not only to the immediate wage or product of labor, but also to the things that she buys with them: helping yourself to someone’s larder, without her permission, is effectively forcing her to work for your benefit as much as taking her money directly is. After all, it is only for what she could buy with it that she was interested in the wages to begin with.
You might complain that not all property is gained by labor: sometimes people just have the good fortune of having natural resources or other valuable commodities on their land. But finding and gathering these resources are a form of labor like any other, and the land is a possession like any other. You cannot claim the right to exploit another person’s land without claiming a right to the labor she put into acquiring, using, and maintaining that land. And you cannot claim the right to take the windfalls without claiming the right to live off the labor involved in discovering and gathering them.
Further, this applies to gifts and inheritances, too. You cannot take a gift from someone without living off the labor of the gift-giver. If I want my friend to have a wrist-watch, and she wants to have it, then I have every right to give it to her for her to enjoy. She may not have received it through any labor of hers, but I acquired it through my own labor, and part of enjoying the fruits of my labor is being able to transfer them to other people as I see fit. Robbing from my beneficiaries means treating me as your milk-cow.
You might, finally, object that riches do not always come from any legitimate form of labor at all, but rather from conquest or plunder. Why should poor people respect the property claims of people who have accumulated their fortunes through gangsterism, or—what is no better, but far more common and more socially “respectable” in this day and age—through expropriating wealth in the form of tax subsidies, or “eminent domain” seizures and transfers, or by forcing would-be competitors out of business through government-backed monopoly privileges. Well, they shouldn’t. There is no duty whatsoever to respect the piratical titles of freelance or government-approved robber barons. And many libertarians (e.g. Murray Rothbard, Karl Hess, etc.) have openly recognized and argued for exactly this point.
I should note in passing that the Saudi “princes,” whose claim to the petrochemicals of Saudi Arabia rests entirely on conquest and shameless seizure, are clearly in this last class. (For what it’s worth, I am anti-copyright and anti-patent, so I regard both Bill Gates and Paul McCartney as being at least partial members of this last class as well. Whatever portion of their immense wealth is derived from the fruits of their honest labor is dwarfed by the wealth they have extracted through government grants of monopoly privilege over the use and distribution of software and music.)
“A cornerstone of Nozick’s libertarianism is the principle that we own ourselves, so that any effort to tell us what to do is a form of slavery. This principle, though, doesn’t justify inequalities of income, because incomes are jointly produced by individual talents and social circumstances. Thierry Henry’s skills as a footballer, Bill Gates’ as a software developer or Paul McCartney’s as a songwriter would have earned them little 100 years ago. Even if they own their talents, they’ve no right to the social conditions in which these talents can thrive.”
This is a bizarre red herring. Since when did Nozick or anybody else claim that Henry, Gates, or McCartney does have a “right to the social conditions in which these talents can thrive”? The claim is only that they have a right to enjoy such fruits as they can earn by those talents under social conditions as they are, not that they have some kind of right to force other people to sustain the conditions they enjoy.
Maybe you could explain a bit more what you mean here?
“These market failures are another case for redistribution as insurance. The trick is to design the redistribution so as to minimize the disruption to markets that work well.”
I think that the claims you make are economically absurd, and ignore a great deal of important left-libertarian work on the effects of government constraints on market economies. (Just as one example, the New Left historian Gabriel Kolko extensively documented how the “robber baron” capitalism of late 19th and early 20th century America promoted “Progressive” regulation as a means of gaining and controlling monopolies. The tendency of free markets at the time was towards greater decentralization and competition, not towards amalgamation and monopoly. Murray Rothbard, in “Left and Right,” Roy Childs, in “Big Business and the Rise of American Statism,” and Kevin Carson, in “Studies in Mutualist Political Economy,” have talked at length about this within the libertarian tradition.)
But suppose for a moment that these claims were true: suppose it were true that free markets sometimes tended towards inefficient centralization or greater overall poverty or greater precarity in most people’s economic prospects or whatever. Still, so what? Would that then give you the right to use violence to make other people dispose of their property differently, so as to get the better results? Since when did you get the right to coerce other people in order to secure a more comfortable standard of living for yourself, your family, your friends, or your neighbors?