In A Theory of Justice, John Rawls states that his social contract theory builds on the work of such philosophers as Locke, Rousseau, and Kant. To develop his social contract, he goes back to an imagined or hypothetical state of nature. From this theoretical starting point, a group of people will attempt to fashion a just society.

This social contract is based on the idea that nobody will have any idea ahead of time what their position in the new society will be. Because of this position of blindness that Rawls calls ignorance, the people devising the social contract will be heavily inclined to emphasize fairness. Since any one of them might end up in the lowest position, each person will seek to protect that position as well as they can.

This social contract, as Rawls imagines it, will therefore have the three following components. First, it will grant liberty and equality to all people, no matter how lowly. It won't, for example, reduce any group to slavery for the good of the whole. Second, it will give people "fair" and "equal" opportunities, regardless of if they are rich or poor, highly intelligent, or in some way handicapped. Finally, this society will be weighted to protect its most vulnerable members, making it difficult for the privileged to abuse the underprivileged.

Rawls takes the concept of a social contract beyond Locke's idea of protecting property rights, Rousseau's idea of mutual protection, and Kant's idea of freedom in order to emphasize social justice.