In the work of Rawls, the metaphorical description of the barrier against using special concerns in order to assess principles of justice. The veil of ignorance defines the original position . It is as if the parties have to contract into basic social structures, defining for example the liberties that their society will allow, and the economic structure it will recognize, but not knowing which role in the society they themselves will be allocated. Only if a social system can rationally be chosen or contracted into from this position, does it satisfy the constraints on justice. See also difference principle.
Philosophy dictionary. Academic. 2011.