Related Ideas

The veil of ignorance plays an important role in Rawls' theory. It is intended to guarantee impartiality by restricting what people in the original position know about themselves and their situation in real life. They cannot contrive principles of justice that will favor people like themselves because they do not know what sort of people they will be outside the original position.

Some sort of principle of impartiality has been important to many moral philosophers, and they have used different devices and restrictions to dramatize or guarantee such a result. Some philosophers have referred to an ideal observer whose judgments are to be followed. As R. M. Hare tells us in his review of Rawls' Theory, such an observer is typically very different from the people in the original position. Instead of being ignorant and self-interested like the parties in the original position, the ideal observer is fully knowledgeable and universally benevolent. In his own theory, Hare tries to guarantee impartiality by insisting that moral rules be "universalizable" and also requiring us to make moral judgments about "reverse-role" situations. (Thus, for example, a white segregationist must be willing to agree that if it were discovered that one of his grandparents was black, he should be segregated in the same way that blacks are segregated.

Reference: See R. M. Hare "Rawls' theory of Justice" in Daniels, Reading Rawls, p. 89, 93.