[4] Thomas Mertens says Rawls believes that the principles of society are chosen by representative citizens on "fair" terms.
[9] By guaranteeing the worst-off in society a fair deal, Rawls compensates for naturally occurring inequalities (talents that one is born with, such as a capacity for sport).
Rawls justifies the difference principle on the basis that, since fair equality of opportunity has lexical priority, the just choice from Pareto optimal scenarios which could occur would be that benefiting the worst-off rather than the best-off.
A key component of Rawls' argument is his claim that his principles of justice would be chosen by parties in the original position.
This choice is made from behind a veil of ignorance, which would deprive participants of information about their particular characteristics: his or her ethnicity, social status, gender and, crucially, their conception of the good.