This article presents the notion of justice of Amartya Sen and explains its main elements. We analyze Sen's critique to the proponents of an ideal or “trascendental” theory of justice. We argue that Sen's work is mainly based on two principles that go beyond the merely empirical and which seem to fall under the label of "transcendentalism". This principles are: the importance of human freedom understood under the "capabilities approach" and a consensual and procedural conception of practical reason. We conclude that the major deficiency of Sen’s work is that he denies implicitly the idea that the question of justice is intrinsically linked to the question of human nature and the good life.