In the first place, the topic of Karl Otto Apel's discourse ethic is exposed, including his criticism of Dussel. It is difficult to explain, in the first place, the philosophical reasonableness used by E. Dussel. In spite of everything, and unlike Marx, he recognizes the originality of E. Dussel in introducing into reason the exteriority of the oppressed other, the transontological origin, the extrahistorical one of unconditional vindicationof ethical reason. Then it becomes clear Dussel's approach to the ethics of liberation. Your criticisms of Apel. The formal reason of K.O. Apel is, in Dussel's opinion, incapable of being applied, since the reason of the affected participants, empirically and inevitably, is always in asymmetry with reality. In the third place, the points in which both authors agree coincide. Dussel and Apel are focused on several topics. The criticisms that have been made respectively the EdL and the ED are understandable, first view, given the different context in which they are born.