Rawls' 1971 text links the idea of social justice to a basic sense of fairness that recognizes human rights and freedoms. Controversially, though, it also accepts differences in the distribution of goods and services—as long as they benefit the worst-off in society. To justify his theory, Rawls asks readers to indulge in a thought experiment where members of an imaginary society create their idea of justice behind a 'veil of ignorance'—not knowing where they would be placed in terms of class, wealth or intelligence. The result, Rawls argues, would be a society that offers basic liberties to all citizens, ensuring the greatest benefit for the least well off.