This paper defends a Kantian constructivist understanding of normative authority as rational authority, by invoking a distinctive cognitivist argument that offers a dialogical conception of constitutive rational norms. G.A. Cohen raises doubts about the logical status of constitutive norms. Insofar they are unconstructed starting points of practical reasoning, the question arises whether constructivism is coherent. A reply to this objection requires an account of the constitutive role of normative principles of construction. The argument proposed here does not commit to social constructivism or ontological agnosticism, but it purports to identify a distinctive conception of rational agency, based on a dialogical conception of reasoning where the relevant interlocutors are regarded as peers. This view takes seriously the possibility of peer disagreements as well as the quest for objective standards of normative authority. It responds to such a quest by rejecting sterile idealizations and focusing on practices of mutual respect and recognition.
