Moral constitutivism purports to explain moral normativity by appeal to the nature of either agency or rational powers. Ambitious constitutivism aspires to ground the categorical authority of morality and to derive the content of the basic moral norms while avoiding the problems of moral realism. As a general strategy, moral constitutivism faces three serious challenges. First, the shmagency challenge. The worry is that the authority of the norms derived from the nature of agency is only conditional on having a reason (...) to be an agent rather than some other kind of subject, a shmagent or an alienated agent. Constitutivists usually reply by appealing to the inescapability of agency. Second, there is a worry that agency is too thin a basis for the derivation of the substantive content of moral norms. Finally, there is the worry that constitutivism might be unable to make room for bad actions. The entry considers possible responses by moral constitutivism to these concerns and whether, if these responses are unsatisfactory, moral constitutivism might still have some explanatory power but of a less ambitious sort. (shrink)