Rawls argued inequality is only fair if it leaves the worst-off better off than otherwise

In A Theory of Justice (1971), John Rawls proposed the 'difference principle': social and economic inequalities are only justified if they work out to the advantage of society's least well-off members. A wage gap that incentivizes productivity that ultimately raises the floor for everyone passes the test; one that doesn't, fails it.

— John Rawls, A Theory of Justice — Harvard University Press, 1971
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