This work elucidates the theological and philosophical backgrounds of the ethics of solidarity in official Catholic social thinking, with a focus on John Paul II s social encyclicals. His concept of solidarity springs from a complex combination of history, tradition and philosophy. This study not only illustrates these backgrounds, but also the basic hermeneutical conditions for a reappraisal of the concept of solidarity in Christian social ethics and in contemporary debates. While recognising the fluidity, which characterises the articulation of this concept, it underscores an orientation to...