 Kantian constructivism is defended in a variety of ways, but its distinguishing feature is that it understands the nature of moral and normative truths based on considerations about the basic features of rational agency. On this view, reasons for being moral do not spring from our interests or desires; instead, they are rooted in our nature as rational agents. Insofar as moral obligations are justified in terms of rational requirements, they are universally and necessarily binding for all rational beings. Because of its claim about the universal authority of reason and obligations, Kantian Constructivism is regarded as the most ambitious form of metaethical constructivism. In this section, we will consider three main varieties, starting with the constructivist interpretation of Kant’s ethics.