Modals vs. Morals : Supervenience and Conceptual Relativity

In order to critically scrutinize the well-known modal argument Simon Blackburn forwards against moral realism, I propose to distinguish weak and strong conceptual relativism: In contrast to the former, the latter takes into account all natural facts. Given the former, I want to show how moral realism can solve Blackburn’s problem while projectivism as endorsed by Blackburn cannot. Given the latter, I firstly attempt a consistent formulation of Blackburn’s challenge. Secondly, I argue that Blackburn’s version of projectivism cannot adequately deal with it. Thirdly, I uncover general difficulties for moral realism resulting from moral relativism.