Abstract
Metaethical constructivism holds that a judgement is normatively compelling for an agent if that judgement follows from within the standpoint of the judging agent. Christine Korsgaard, a Kantian constructivist, holds that there are constitutive standards of agency––the categorical and hypothetical imperatives––and that, due to these constitutive standards, substantive moral values follow necessarily from the standpoint of agency. In contrast, Sharon Street argues for a Humean constructivist view, which denies that substantive moral values follow from the standpoint of agency. Thus the debate between Humean and Kantian constructivists revolves around the question of whether anything substantive follows necessarily from the standpoint of any agent who takes something or other to be of value. This thesis is primarily an examination of the debate between the Humean and Kantian constructivist. Chapter 1 introduces and analyses the arguments of Korsgaard and Street. Chapter 2 extends upon Street's argument by assessing two different Humean accounts of reasons: first, a strong Humean theory of reasons whereby an agent is only held to have a reason R if that agent has a desire which reason R directly promotes; second, Mark Schroeder's hypotheticalism. Chapter 3 engages with Humean and Kantian accounts of agency, asking whether the Kantian constitutivist account is plausible. Whereas the first three chapters of this thesis are broadly linked, in that each extends upon the ideas of the previous one, the arguments of Chapter 4 are largely independent from those of the preceding chapters. Chapter 4 has two main themes: first, it argues that Korsgaard's work can be used by Rawlsians to respond to critics who claim that the theory is implausible in virtue of its Kantian assumptions about the nature of persons; second, it elucidates a tension between Korsgaard's metaethical thesis and her defence of pure proceduralism in politics and society.