Some understand utopia as an ideal society in which everyone would be thoroughlyinformed by a moral ethos: all would always act on their pure conscientiousjudgments about justice, and so it would never be necessary to provideincentives for them to act as justice requires. In this essay I argue that sucha society is impossible. A society of purely conscientiously just agents wouldbe unable to achieve real justice. This is the Paradox of PureConscientiousness. This paradox, I argue, can only be overcome when individualsare prepared to depart from their own pure, conscientious, judgments ofjustice.