Solidarity, essential for social cohesion in diverse societies, has many definitions. This chapter examines solidarity as a dynamic concept, balancing individual autonomy with collective responsibility through the negotiation of ‘I,’ ‘we,’ and ‘they.’ While interdependence, shared norms, struggles, and encounters foster solidarity, they also risk utilitarian or tribalistic outcomes in pluralistic settings. The chapter discusses Durkheim’s mechanical vs. organic solidarity, Honneth’s recognition theory, Rorty’s empathetic understanding of suffering, and Kymlicka’s bounded and unbounded solidarity. It argues that universal principles grounded in human dignity must transcend exclusionary tendencies if they are to safeguard democratic ideals. Solidarity can be learned in various ways, but primarily it is developed by participation in learning environments where it is explicitly promoted.