Philosophy
Nozick's Entitlement Theory and Libertarian Property Rights
Quick fact
Robert Nozick's entitlement theory holds that a distribution of holdings is just if each person is entitled to what they have, regardless of how unequal the overall pattern becomes—so even a wildly unequal outcome can be perfectly just as long as it arises from just acquisition and voluntary transfer.
Why this is interesting
Imagine you have a jar of cookies. You take a few, and then you trade some with a friend. At the end, the jar's contents might look uneven—but does that mean the distribution is unfair? Robert Nozick would say no, and he has a famous argument to prove it.