Freedom, Markets, and Well-being Fall 2018

Rawls’s Difference Principle


I started off by explaining how today’s reading fits into Rawls’s theory.

Rawls’s goal was to establish a theoretically rigorous alternative to utilitarianism. It’s easy enough to make ad hoc exceptions to the utilitarian principle, but hard to come up with a unified alternative. Rawls’s theory is that the way to identify the fundamental principles for society is by asking what the parties in what he calls the original position would prefer. And he maintained that they would choose his two principles of justice instead of utilitarianism.

In the reading for today, Rawls explains exactly what his two principles mean. This is completely independent of the main theory about what the parties in the original position would decide, but it is tremendously interesting in its own right. In particular, Rawls confronts some genuine difficulties with equal opportunity that our other authors have neglected.

Equal Opportunity

I made the case for what Rawls calls “Natural Aristocracy.” What that means is that I argued that Rawls didn’t really have a good reason for giving lexical priority to equal opportunity over the difference principle as he does. Let me explain that.

Rawls walks us through four different societies that have different ways of understanding what it means for inequalities in wealth and the social hierarchy to be “to everyone’s advantage” and “open to all.” We start with libertarianism (natural liberty). Rawls thinks his readers will find this objectionable because it does nothing to correct either the natural or the social causes of inequality. Since it is “morally arbitrary” that some people are born into wealthy families or with desirable natural features, society should do something about these causes of inequality.

One thing society can do is to try to eliminate the social influences on one’s prospects in life. As a goal, society could aim to ensure that people of equivalent natural ability have equivalent chances in life, regardless of their social class. That is Rawls’s understanding of equal opportunity.

Of course, that would leave inequalities to be caused by differences in natural ability. To compensate for that, Rawls proposes the difference principle. A society that complies with the difference principle will allow inequalities only to the extent that they benefit the worst off class.

Rawls favors both equal opportunity and the difference principle. More precisely, he gives equal opportunity “lexical priority” over the difference principle. That means that if a society has to choose to devote resources to equalizing opportunity or to improving the position of the worst off class, it has to devote them to equal opportunity until it is fully achieved.

I expressed doubt about whether Rawls could explain that. After all, equal opportunity means equalizing the chances in life for people of equivalent natural talents. The naturally talented will rise above their social class and the naturally talentless will sink below theirs. But why should we care about that? Natural talents are just a morally arbitrary feature of a person according to Rawls. So why should society give priority to sorting people according to this feature?

Kamyab said that one reason is that doing so means developing the talents of the most productive members of your society. That is an important point. But my complaint is that if we give equal opportunity the kind of priority that Rawls gives it, we will be committed to pursuing it even when doing so costs more than it gains in greater productivity. Why not develop the talents that you need for a productive society and then stop when it gets too expensive? I don’t see that Rawls has an answer.

I should hasten to add that this isn’t necessarily my opinion. I like equal opportunity just as much as the next person. I’m only saying that I don’t think Rawls can explain why it is important. And, I have to confess, my own confidence that I understand what equal opportunity is has been shaken a bit. I’m not sure that I like equality opportunity quite as much as I thought I did when I think of it as putting so much weight on natural abilities.

Rawls’s Figures

After I did my bit, Professor Brown took a hard look at Rawls’s figures (Rawls 1999, 66–67). These fall into an uncanny valley for economists: they are a lot like the figures that economists use but they are different enough to be slightly disturbing. Anyway, Prof. Brown explained what Rawls was up to while translating his figures into language that would be more familiar to a student of economics.

In particular, you should know why the indifference curves for utilitarianism go from northwest to southeast with a slope of -1 (see Figure 8). And you should know why Rawls’s difference principle settles on point a in Figure 6.

Finally, you should know why it’s probably inappropriate to describe Rawls as using indifference curves in Figure 6. The answer is that society isn’t actually indifferent about all the points on the horizontal lines in that figures. It prefers the points closer to the 45 degree line over those that are farther to the right on the x axis (or higher on the y axis).


Rawls, John. 1999. A Theory of Justice. Revised edition. Cambridge: Harvard University Press.


There was a handout for this class: 10.Rawls.handout.pdf