What's wrong with inequality? This is the question posed by Oxfam's claim that eight men have as much wealth as the poorest half of the world's population.

Of course, you can quibble with this: if we look only at net financial wealth, someone starting work at Goldman Sachs with lots of student debt is one of the world's poorest people and poorer than an Indian beggar who's just got one rupee. Such quibbles, however, are irrelevant. As Oxfam point out, a lot of the indebted are genuinely poor. And if we consider human capital as wealth (as we should) there remain massive inequalities, not least between our Goldmans trainee and the world's poorest.

So, what's wrong with this? We should distinguish between economic and moral arguments against inequality. The economic objections are that high inequality is often a sign of economic dysfunctions such as malfunctioning markets, restrictive intellectual property laws and crony capitalism or that it can be a cause of worse economic performance and increased distrust.

I suspect, though, that the strongest argument against global inequality isn't so much the economic as the moral one. Global inequality - especially when accompanied by absolute poverty - means that people are suffering through no fault of their own but simply because of the bad luck of being born in the wrong place. Someone born in sub-Saharan Africa will earn much less than someone of similar talent born in the UK; as Herbert Simon argued, most of our incomes we owe to the good luck of being born in the right place. And they face greater health risks too, especially if they are a woman.

Such inequalities violate the principle of luck egalitarianism. And given the shortened and impoverished lives the worst victims of such back luck suffer, they might well represent a violation of human rights (big pdf).

The case for global redistribution is simply that it is a means of rebalancing such bad luck. Those of us who won the birth lottery should share our good luck with those who lost - not least because the losers never asked to enter the lottery in the first place.

This, though, is exactly what we don't see. One way to pool such luck is overseas aid. But there's recently been a backlash against this in the trash papers. This isn't, I think, because people believe Rawlsian law of the peoples-type arguments (pdf) for prioritizing domestic over global redistribution*. Most people who are opposed to higher global redistribution don't favour greater domestic redistribution. Instead, the Daily Mash called them right:

We need to look after our own first, say people who would never help anyone

But there's another way of balancing the massive differences in global luck - open borders. Allowing people to move from poor to rich countries would greatly relieve their poverty. But again, we're seeing a backlash against this.

Now, I can of course see practical objections to open borders and global redistribution - I'm not completely stupid - but I'm not at all clear how robust the moral objections are.

In fact, what such objections amount to is a belief that one's fate in life should be determined by one's birth. This is a form of feudalism. Unless public attitudes change very much in the west, feudalism might outlive capitalism.

* Even Rawls believed we have a duty to help "burdened societies".