The veil of ignorance forces genuinely impartial rule-making

Rawls's signature thought experiment asks us to imagine designing a society's basic rules without knowing what position we'll occupy within it — wealth, talents, race, gender, or class are all hidden behind a veil of ignorance. This strips away self-interested bias: a rule-maker who might end up poor or a minority has strong reason to ensure rules treat those groups fairly, since they might be one of them once the veil lifts.

Rawls argues this produces a meaningfully different outcome than ordinary political bargaining, where those already advantaged have every incentive to entrench rules that favor their existing position. Behind the veil, rational self-interest itself becomes a force for fairness, because no one can rig the rules in their own favor without risking that the rigging harms them.

The device isn't meant as a literal historical event but as a standard for evaluating any proposed principle of justice: would you accept this rule if you didn't know where you'd land in the society it governs.

Takeaway: test any policy or rule by asking whether you'd accept it without knowing which position in society you'd occupy.