Freedom, Markets, and Well-being Fall 2019

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 come up with apparent exceptions to the utilitarian principle, but it’s difficult present 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.

What Rawls means

Rawls’s principles govern what he calls the basic structure of society. He’s concerned with institutions, such as the education system, legal system, tax system, central banking system, and so on. So none of this is about what individuals should do. It’s about how society’s institutions should work.

Rawls measures the welfare of the members of a society by their share of what he calls primary social goods. Primary social goods are goods that are needed to realize any rational plan of life. Money, for instance, is a primary social good.

Rawls believes that individual liberties and the right to vote should be distributed equally: everyone should have the same liberties and votes as everyone else.

Jobs and incomes will be unequal. Rawls assumes that any society would require at least some degree of inequality. For instance, a society that lets people keep a disproportionate share of what they make will be more productive than one that redistributes everything equally. This is so because people will work harder if they get to keep more of what they create through work. Since inequality is necessary for societies to be wealthy, he assumes all societies will have inequality.

Things that are distributed unequally, like jobs and incomes, are governed by two principles: fair equality of opportunity and the difference principle. Fair equality of opportunity means that every member of society has the same opportunity to get the best jobs as everyone who has the same natural talents; no one’s life will be determined by the social class of their parents. A society satisfies the difference principle if the inequalities in primary social goods maximally benefit the worst off class.

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, which he calls “fair equality of 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 between devoting resources to equalizing opportunity or to improving the position of the worst off class, it has to devote them to equal opportunity. It can send them to the worst off class only after fair equality of opportunity has been 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?

Now, there are very important reasons why a society would want to develop the talents of its talented but socially disadvantaged members. One reason why it would do so is to reap the benefit of their using their talents. Think of all the surgeons, inventors, doctors, and teachers that we have not had because he don’t do this. We let a lot of human talent go to waste and we are much poorer than we could be as a result.

But achieving what Rawls calls fair equality of opportunity would be fantastically difficult and expensive. He’s committed to trying to achieve it even when the costs of doing so exceed the benefits in increased social productivity and wealth. It’s that part of his view that I think he can’t defend.

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