African ethicists have so far not agreed on a single, precise, secular and comprehensive basic norm, an Afro-Grundnorm, which captures the core values of Ubuntu sub-Saharan African cosmopolitanism. This article constructs and proffers the ‘double-dignity’ Grundnorm that partly shares with Western stoic cosmopolitans the view that our common human ontological capacity for autonomy identifies us as members of the human species. This capacity grants our first dignity, inherent dignity. Inherent dignity only grants our universal basic (security and subsistence) rights. Our (...) duties to care of each other derive from the second dignity, acquired dignity. Acquired dignity itself derives from our second ontological capacity, our capacity for communion. Unlike inherent dignity, acquired dignity is neither universal nor automatically present in us. It is earned when we commune with others in fostering harmony as we earn ‘full personhood’. Since fostering harmony starts with nurturing communal identities and solidarities, Ubuntu entails efficiency-model moderate cosmopolitanism which permits prioritizing serving our immediate associates or compatriots not because of their special moral worthiness but because we more efficiently serve humanity at large when we do so. (shrink)