Political Philosophy Spring 2019

The Argument for Rawls’s Principles


Rawls’s official argument is that the parties in the original position would prefer his principles of justice to utilitarianism. Since the decision by the parties in the original position is guaranteed to be fair, Rawls maintains, the fact that they favor his principles shows that those are the principles of justice.

Today we discussed Rawls’s case for thinking that the parties would choose his principles. Next time, we will talk about his reasons for thinking they would reject utilitarianism.

In the end, it all comes to pretty much the same thing: his case for thinking the parties would take his principles is that they would prefer them to utilitarianism.

Choosing the Best Worst

The core of Rawls’s case is that the parties will prefer his principles over utilitarianism if they look at the worst possible outcome under each set of rules. That is, they should look at the worst possible lives under each set of rules and choose the system with the best worst outcome. This is the essence of the so-called maximin rule.

To make his argument work, he needs to explain why the parties should give that much weight to the worst possible outcome. Why shouldn’t they take all of the other outcomes into account too? After all, we do not normally make decisions by comparing only the worst possible results of different choices.

Rawls maintains there are three features of the decision to be made by the parties in the original position that make it rational for them to focus on the worst possible outcome.

  1. They cannot estimate the probabilities of being in any particular social position: they don’t know how likely it is that they are in the worst position, the middle, or the top.

  2. They do not care very much about getting more than they could get in a society governed by Rawls’s principles.

  3. They find the worst position in a society governed by utilitarianism to be unacceptable.

I said we would talk about the point about probabilities next time.

I also said that I did not know how we could know that the second point is true. Rawls himself says that he will supply the argument for this conclusion in a subsequent part of his book. Since it is very long and relies on detailed psychological theories, we do not have the time to assess it.

I have read it and, in my opinion, the answer is that the parties cannot know that the people they represent do not care much about getting more than they could get in a society governed by his rules. We know that everyone cares at least a little about getting more than the minimum: the things they get are primary social goods and, by definition, these are things that everyone wants. Who is to say that many people do not care a lot, especially if they think that they could make their standard of living significantly higher without the Difference Principle? There are lots of people who want lots of different things. For example, maybe you think anything less than a state religion is intolerable. Or maybe you want to be an entrepreneur and you would chafe under the restrictions on economic liberty in a Rawlsian society. So I don’t see how the parties in the Original Position could know that they people they represent don’t care about gains above the minimum.

The Third Point

In my opinion, Rawls’s best argument is that the parties know the people they represent would find the worst possible outcomes under utilitarianism unacceptable and that they would not find the worst possible outcomes under Rawls’s principles unacceptable.

The point is pretty simple. Utilitarianism could allow almost anything: slavery, medical experiments, summary executions, you name it. If it could be needed to bring about the greatest overall good, utilitarianism would have to be for it. So the worst possible outcome under utilitarianism will be pretty bad. By comparison, the worst possible outcome under Rawls’s principles is pretty nice: extensive protection of personal liberty, equal opportunity, and a significant guaranteed income.

Given that the choice is between utilitarianism and Rawls’s principles, why run the risk of being made a slave? That’s a pretty good question, in my opinion.

We will, obviously, return to this next time. One thing to think about is why utilitarianism would ever allow slavery or the other horrible stuff. What does life have to be like for that to be an option for a utilitarian? And how likely is that anyway?

Our discussion

Adam made a very interesting point. He asked why the parties in the original position need to know anything about the people they represent in order to form coalitions. Here’s what that means. Last time, I said that the reason he puts so much information behind the veil of ignorance is that he thinks that he has to do that in order to keep the decision fair. If people knew there were nine right handers for every lefty, they might decide to discriminate against the left handers. To prevent that, we deny them the information about their odds of being right or left handed.

But, Adam said, the parties could just form coalitions anyway. Say someone in the original position says “everyone on the right side of the room join me; we’ll have a small majority and we’ll use that to favor ourselves.” They don’t need to know anything about the parties they represent to favor them; they just need to be able to write rules that will favor their parties.

Jasper was suspicious of this and, having thought about it, I think he’s right. The parties aren’t allowed to write rules that favor particular people: see the “formal conditions on ethical principles” on the original position handout. Also, they are required to make a unanimous decision (Rawls 1999, 106). So I don’t think they could make Adam’s scheme work. But I love the thought!

Bex asked what would happen if the parties in the original position compared Rawls’s principles against a modified version of utilitarianism: utilitarianism with a floor. What’s the floor? Prohibit everything that the parties would find unacceptable, such as slavery, medical experiments on people, deprivation of the right to vote, and so on. The idea is that with the floor in place, the modified utilitarian minimum isn’t so bad; all the unacceptable stuff would have been ruled out. And the utilitarian part would give the parties a higher expected utility than they would get under Rawls’s principles. To put that another way, people would, on average, be better off under utilitarianism than they would under Rawls’s principles.

Main Points

These are the points you should know or have an opinion about from today’s class.

  1. Why Rawls says the parties in the original position would focus on the worst possible outcomes.
  2. Why he thinks they would prefer his principles to utilitarianism.


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


There was a handout for this class: 25.RawlsTwoPrinciples.handout.pdf