A Theory of Justice tackles many things. But it’s fair to say that it has one dominant theme. It is an alternative to utilitarianism. The project is motivated by objections to utilitarianism and utilitarianism is the view that receives the most scrutiny by far.
The problem with utilitarianism is its tenuous connection with liberalism. This comes up most prominent in cases where the aggregate good of many people outweighs the good of a few individuals. In these cases, utilitarians seem committed to favoring the majority over the minority, even if doing so seems unfair or in violation of their basic rights and liberties.
The utilitarian retort should be obvious from Bentham. “Unfair? Basic rights and liberties? What are those? Mere holdovers from outdated and pernicious moral conventions. After all, why prohibit a society from producing as much good as it can? Isn’t it better to have more good rather than less?
It’s that kind of argument that Rawls was concerned to rebut. Why does it make sense to depart from utilitarianism? In particular, can we give a theoretically sophisticated alternative that is as rigorous and comprehensive as utilitarianism is while not having its undesirable moral consequences?
There are three layers of argument.
Rawls’s informal arguments come in the first part. He points out the conflicts between utilitarianism and most people’s beliefs about justice and fairness. He also offers an unflattering diagnosis of the appeal of utilitarianism. Utilitarianism is appealing because it takes over the model of making decisions that individuals would make concerning their own lives. The problem with applying this model to a society is that those who suffer from sacrifices do not always reap the rewards. Those often go to someone else.
The official argument is that the parties in the original position would prefer Rawls’s two principles to utilitarianism. It turns on a choice between two rules for making decisions under uncertainty: maximize expected utility or maximin.
The rule of maximizing expected utility tells the parties to do the following:
If that’s the rule they’re following, they will choose the option of maximizing average utilitarianism.
If the parties follow the “maximin” rule, they will choose the option with the best worst result. That is, they will do the following:
The psychological argument backs up the formal argument. It supports Rawls’s assertion that the parties in the original position would prefer his principles.
The idea of the psychological argument is that Rawls’s principles do not have the problem of the “strains of commitment” while utilitarianism does. Rawls maintains that people who grew up in a society governed by his principles would come to value the principles and try to comply with them. He is most concerned with those who are worst off. In a society governed by Rawls’s principles of justice, the worst off know that their society is committed to their being as well off as they possible can be. The same is not true of utilitarianism. Therefore, it is easier to feel allegiance to a society governed by Rawls’s principles than it is to feel allegiance to a society governed by utilitarianism. The parties in the original position know this and that gives them a reason to choose Rawls’s principles over utilitarianism.