The distinction between discussion and negotiation tends to fade, in ordinary use as well as in political discourse. But this distinction is not only a grammatical matter of different language uses, it deals with the foundation of ethics, in so far as it is a condition for the constitution of a secular and postmetaphysical moral world founded on universal values, in a modern society where relations are agonistic and values heterogeneous. Can this world still be ours ? This is the core question of the following text.