Justice as Impartiality

Harsanyi uses the construction of an ‘original position’ for the purpose of letting individuals choose between alternative social systems from behind ‘a veil of ignorance’. They know the whole history of the world, but they do not know what their personal position will be under any system. They would have the same probability of taking the place of the worst-off or of the best-off or of any position in between: this is the equiprobability assumption. He asks himself: ‘which decision rule would rational individuals use in this model.’ Now suppose that an individual would have to choose between two social situations in complete ignorance of what his personal position would be in either situation and that he would have the same probability of occupying any of the available social positions, and then his choice would fully qualify as a moral value judgment. Obviously he would, utilitarians believe, choose the situation providing a higher level of average utility to the individual members of society. The utilitarian doctrine prescribes that we choose that alternative, of those available to us, which maximizes the preference-satisfaction, in sum, of all those affected by our action, considered impartially (the doctrine of equal concern). Social states must be compared and ranked and to that end social welfare functions must be constructed that are based on the ethical preferences of all individuals.