The American philosopher John Rawls uses the idea of the "veil of ignorance" to promote impartial decision making. The "veil of ignorance" is a thought experiment that involves imagining that people are choosing principles for society from behind a veil that prevents them from knowing their ethnicity, social status, gender, and other factors that could bias their choices. This exercise is called the "original position".
Rawls uses the idea of the "veil of ignorance" to argue that fair and just distribution can be defended on rational grounds. For example, if someone decides on abortion laws, they would have to face the possibility that they themselves will end up as a woman with an unwanted pregnancy.
Rawls theorized that by being ignorant in this way, people can more objectively consider how societies should operate. He says that if a person keeps themselves under the "veil of ignorance", they would come up with just distribution, fair laws, and policies that would affect the whole society.
The idea of the "veil of ignorance" is central to Rawls, and figures prominently in his 1971 book, A Theory of Justice.