Justice in the World?

There are two concepts of justice: 1. equality of outcomes: everyone gets the same things, regardless of ability, skills, perseverance, needs and preferences; 2. equality of opportunity and preference: everyone gets what they can achieve and prefer to have to the extent mathematically feasible. (For example, you may prefer to have two wives and to share neither of them with other men, but this preference is mathematically unfeasible in a just world. There are roughly as many men as women, and they each prefer to have a partner, so the math is simple: no-one can be entitled to two. Which means your preference is unjust and won't be granted. Find other preferences that are mathematically feasible, and you won't be disappointed. Prefer to have two houses, work hard and earn them.)

The first kind of justice is formal and may apply within homogenous categories, such as an employer. People doing the same job with similar experience and performance should be paid the same wage – despite the fact that you could always argue that they are different in some way. Everyone is different, but the same company should pay the same wage for the same work, because in this case individual differences are not relevant. This requirement doesn't apply across employers though, because they each have a different market position, productivity, competitiveness, etc. The problem is that it's hard to decide when differences do matter and when they don't. It's a rather intuitive decision and is thus open to debate. An open public dialogue is required and even so, the perception of justice is a moving target.

Justice in the world is dynamic, there is no formula that would lead to a lasting perception of justice. Worse, every relatively just solution can be challenged easily and must be defended with arguments. But since that's the best available approach, it should be appreciated.