This dissertation aims to critique and extend upon Christine Korsgaard’s theory of agency. Unlike much of the burgeoning literature engaging with Korsgaard’s work that addresses the metanormative ambitions of her argument, the scope of the present analysis is her first-order metaphysical account of agency. Instances of so-called “disorders of agency,” and “socially displaced agency”—exemplifying the problem of defective actions—are examined, and evidence for considering these cases as genuine instantiations of agency is presented and discussed. The conclusion is that Korsgaard’s constitutive norms of agency seem to be neither necessary nor sufficient to properly account for them, which points to the need for a clarification of the metaphy...