This paper establishes a retrospective history of the new economic theories of justice alive today. Focusing on the historical influences between the diverse branches of normative economics resulting in the new economic theories of justice, it presents an articulated yet restricted historical overview of the evolution of welfare economics through the XXth century.
The paper confirms the distinction between four successive periods: (1) the utilitarian legacy; (2) the old welfare economics; (3) the new welfare economics divided into (3a) the British approach, and (3b) the American approach; (4) the post-arrovian period in which diverse developments are maintained seperate, among which cost-benefit analysis, social choice theory and equity theory. The paper claims that, although nowdays developments in normative economics are totally maintained separate, they constitute heritages of three distinct branches of the historical welfare economics. (4a) It is standard to say that the British school of the New Welfare Economics is at the origin of cost-benefit analysis, although (4a') the new cost-benefit analysis also inherited from equity theory. (4b) The Old Welfare economics is shown to be the closest to Sen's influences on the rehabilitation of interpersonal comparisons of utility and the development of non-welfaristic approaches. (4c) The American school of the New Welfare Economics is the main inspiration of Fleurbaey's proposals in which normative issues and ordinal preferences are taken seriously.