The idea which I intend to discuss is not one which has been, to the best of my (admittedly very limited) knowledge, outside of a libertarian context, but which I shall show has strong implications for how even those who disdain libertarianism ought to think about distributive justice. This idea, known as The Wilt Chamberlain example, comes from as passage entitled "How Liberty Upsets Patterns" and runs as follows. Suppose you have a society which enjoys perfect distributive justice. This might be perfect equality, it might be in exact accordance with some measure of desert - you name it. Nozick's argument is intended to be perfectly general.
Now Wilt Chamberlain, the legendary basketball player, is willing in his spare time to play basketball for the entertainment of other people; a million other people, in turn, are each willing to pay him $1 for the privilege of watching him. If these trades are allowed to happen then Wilt ends up vastly richer than other people in society. Hence either there can be no solid principle of distribute justice, or, in Nozick's words, "an egalitarian society would have to forbid capitalist acts between consenting adults". There's a bit more to it than that, but only in order to tighten up the details; the entire essence of the problem is contained in this paragraph.
This is a very persuasive argument. It's hard to argue against the freedom to make trades in which no-one is made worse off, but - suitably idealised - this is the whole process of modern capitalism. Must we accept libertarianism?
No, actually. There's a remarkably simple solution, which I'm amazed hasn't become the mainstream interpretation of where this argument ought to go. In a word: sufficientarianism.
Sufficientarianism is the view that equality per se is not what matters in terms of distributive justice; rather, we ought to care simply that each person has enough. What we mean by "enough" is a matter of some debate - it seems like every sufficientarian theorist has their own definition, none of which I am fully persuaded by. I won't pretend it has no difficultes, either - should we make the poverty of many people direr in order to bring a single person up to the line of sufficiency, as some formulations suggest? But it provides an easy, obvious answer to Nozick's argument. Our original stipulation was that everyone had enough. given that distributive justice had been achieved. Assuming no-one is putting himself below the line of sufficiency by buying basketball tickets, which seems to me a reasonable assumption, there is no reason why the distribution of resources should be objectionable after people have paid to see Wilt playing basketball.
We can have a view of distributive justice which does not hold it to be acceptable for people to be starving in the street, without having to interfere. Nozick's argument fails to establish libertarianism, but it functions as a strong piece of evidence in favour of sufficientarianism being superior to egalitarianism.