I'm reading Korsgaard's The Sources of Normativity. Chapter 2 argues that substantive moral realism — the view that there exist entities which are intrinsically normative and that normative claims upon us originate from these entities — fails to answer the normative question: Why justifies the claims that morality makes upon us? She claims this is because substantive moral realism cannot convince the skeptic of morality; if I doubt that normative claims can be justified, the assertion that the justification exists just because some things are intrinsically good/just/obligatory is unsatisfying. I'm not sure I'm convinced by this objection. Wether normativity can be justified to the skeptic seems to me to have no bearing on wether it in fact exists as an intrinsic feature of objects/actions. What are people's thoughts?