“[T]he Golden Rule is theoretically inferior to the Impartial Observer Formula and Kant’s Consent Principle. But this rule may be, for practical purposes, the best of these three principles. By requiring us to imagine ourselves in other people’s position, the Golden Rule may provide what is psychologically the most effective way of making us more impartial, and morally motivating us. That may be why this rule has been the world’s most widely accepted fundamental moral idea.”

— Derek Parfit, On What Matters: Volume One (2011)