We are sort of jumping in to the middle of Rawls’s theory. This can be a problem when he uses some terms that you might not find familiar, such as “original position.”
I think the notes I posted for my social and political philosophy class should help. Specifically, have a look at:
Prof. Green led things off by explaining what Rawls was doing. Officially, he was clarifying the meaning of the two principles of justice that he proposed to submit to the parties in the original position. Unofficially, he was arguing both that libertarianism is morally defective and also that only what he called “democratic equality” adequately addressed the moral problems with libertarianism.
We spent the most of our discussion talking about the graphical representations of Rawls’s difference principle on in figures 5–6 (Rawls 1999, 66–67). In a way, it was a class on how to read graphs.
The graphs are supposed to represent the shares of goods and opportunities held by the members of different social classes under different rules. The idea is that different rules with have different distributive effects. For example, rules restricting the supply of doctors will make most people worse off while making some much better off. Rules allowing private property make everyone much better off and some better off than others.
The axes are labelled x1 and x2; x1 and x2 refer to representative members of social classes. But what the axes really represent are greater or lesser shares of goods and opportunities for the people who belong to those social classes. It would be comical if x1 and x2 got bigger or smaller as you move along the axes.
Figure 5 represents the maximin rule. The only improvement from the point of view of justice comes from moving from a lower curve to a higher one. As far as justice is concerned, there is no difference between, x2 having a lot (being at a point very high on the y axis) or having an equal share (being at a point on the 45 degree line). Suppose the share held by x2 is near the top of the y axis. This would mean that the share going to x1 would be on the 45 degree line. If it is possible to move to a higher indifference curve, giving x1 more, that would be an improvement from the point of view of justice even if it meant that the share going to x2 would go down to a lower point on the y axis. In other words, the graph means that all that matters is raising the minimum as high as it can go.
Figure 6 represents the difference principle. It supposes that more goods will be produced if inequality is allowed. That is what the line OP represents: how much would be produced under different rules that result in x1 having more than x2. (Since they are below the 45 degree line, you know that x1 is getting more than x2.) Given the way the indifference curves are drawn, x1 is permitted to gain so long as x2 does as well. Point a is where this stops: any further gains going to x1 would not benefit x2 as well, so they are not permitted by the difference principle. The difference principle, then, allows inequalities only if doing so improves the position of the worst off class which, in this case, is x2.
As Professor Brown noted at the end of class, this means that Rawls abandoned the principle of efficiency. Suppose the OP curve in figure 6 were flat to the right of point a. That would mean that x1 could gain more than the share at point a without making x2 worse off. The principle of efficiency would count gains for x1 that do not make x2 worse off as an improvement. Rawls’s difference principle, however, does not do so. It views point a as superior to any point to the right on even a flattened OP curve.
Rawls, John. 1999. A Theory of Justice. Revised edition. Cambridge: Harvard University Press.
There was a handout for this class: 08.Rawls.handout.pdf