 Contractarians seek to show that without rules of justice for cooperation, persons are worse off by their own lights. Hence it is rational to adopt some rules for morality and justice. These two aspects of the contractarian individual—self-interest and the ability to benefit from interaction with others—along with the conditions of moderate scarcity imply what Rawls following Hume called the “circumstances of justice”: the conditions under which rules for justice could be both possible and necessary (1971, 109–112). Justice, and a social contract, is only possible where there is some possibility of benefit to each individual from cooperation.