Philosophers are a useless bunch. They don't know if other minds exist, they don't know if the external world exists (we could be minds in vats or something) and they don't know if the sky will still be blue tomorrow. So what should we do? We toddle along believing in other minds, the world and tomorrow's blue sky unperturbed. Not to do so would literally be insane.
Many philosophers agree that we have free will but when they explain exactly what they mean by that you will (if you are anything like me) be left feeling confused and unsatisfied. Some people worry about free will because, if we don't have it then how can we punish criminals for their actions? It's not fair! Some worry, but most don't. Not believing in free will might not be insane, but it's still a little weird.
But these philosophers are serious, clever people and should be taken seriously. In the same way that you can start to question the existence of free, you can start questioning whether anybody can ever deserve more income than anybody else.
A person's income is determined by a host of factors; how hard they work, how talented they are and luck. People don't deserve the luck they get and they have nothing to do with how talented they happen to be, so at first glance people only really deserve the part of income they get from hard work. But, someone's willingness to work depends on a combination of innate inclination and upbringing, neither of which she controls. So maybe we don't deserve that bit of income either. It will always be unfair for one person to earn more than another, so the only just way to organize society is to enforce strict material equality.
This is a serious argument in political philosophy and I can see its appeal, but why is it so different from the other examples I gave? It all looks like the same philosophical weirdness to me, but we dismiss the other examples without a second thought.
While I can?t really comment on the substance of any of these issues I can offer a though on free will and responsibility. Even in a world without free will, the threat of punishment is one of the factors that influence a decision to commit a crime. More crimes would be committed without the punishment. So the punishment may not be ?deserved? but it still serves the valid function of deterrence. Thinking like this takes the emphasis away from retribution and views punishment as a necessary evil rather than an end in itself. Also, some people do not respond to the threat of punishment no matter how great it would be. These people are considered insane and are treated differently. Their actions are not considered freely chosen in the same way that a normal person?s would be (even in a world without free will). One way to think of free will is the way that we respond to incentives.