I want to argue that, on the one hand, Kant is indeed one of the founding fathers of contemporary constitutivism, but that, on the other, he teaches us not to set too much score by constitutive arguments. Kant has a ready answer to the question why we should act morally and take care that the maxims of our actions are universally valid: Because this is just what acting amounts to. This is the type of answer a constitutivist might give to the fundamental question of ethics. But Kant himself did not seem to find this argument particularly convincing, as he saw the need to add further considerations in order “to obtain access for the moral law” (437). And these additional considerations are not conceptual, but practical. Thus, Kant’s final word on why we should act morally would not be because this is what acting implies, but because it is valuable.
