I don't know which way human psychology will go wrong. We have a world in which there is uncertainty. There are new technologies. And one of the prob… - Kenneth Arrow

I interpret moral obligation as the carrying out of agreements which may, however, be implicit. Thus, a society in which everyone immediately executed his aggressive impulses would be untenable. Therefore, there is an agreement that I will refrain from aggressive actions, which in themselves give me satisfaction, in return for your not taking aggressive action against me. However, conscious agreements to achieve these ends are much too costly in terms of information and bargaining. Therefore, as societies have evolved they have found it economical to make these agreements at an unconscious, implicit level. Internalized feelings of guilt and right are essentially unconscious equivalents of agreements that represent social decisions.

To the extent that individuals are really individual, each an autonomous end in himself, to that extent they must be somewhat mysterious and inaccessible to each other. There cannot be any rule that is completely acceptable to all. There must, or so it now seems tome, be the possibility of unadjudicable conflict, which may show itself logically as paradoxes in the process of social decision-making.

Let us turn from the epistemological problems of the current decision-maker for society to those in the original position. Individuals are supposed to know the laws of the physical and the social worlds, but not to know who they are or will be. But empirical knowledge is after all uncertain, and even in the original position individuals may disagree about the facts and laws of the universe.