Amartya Sen's readers were expecting the second volume of a series of two devoted to rationality, freedom and justice. Surprisingly The Idea of Justice is not exactly the book announced by Sen (2002); it offers a new perspective of Sen's enterprise. Calling economic orthodoxy into question is not enough; Sen envisages calling philosophical orthodoxy into question too. This review essay will focus on four salient points of the book: the partition of the different approaches of justice in two traditions; the concept of "positional objectivity" to serve impartiality; the will to reconcile reason and sentiments; the capability approach as important but not exclusive.