Our challenge for the twentyfirst century consists in showing how to construct a global ethics and in trying to discover a rational foundation for it, which may be used as guidance for action and as a norm for the criticism of specific situations. I argue that four tasks must be accomplished to construct a global ethics: (1) Construct that global governance or that world government that makes cosmopolitan citizenship possible. (2) Foster the joint work of bioethics, economic and business ethics, and development ethics ? areas of applied ethics, each one of which on its own has reached the global level. (3) Discover a rational basis for a global ethics, which has a universal normative force, but assumes cultural differences. (4) Develop and promote a dilaogical ethics of cordial reason, which renders one capable of compassion and care.