To turn to the political field, We observe many changes. In a number of countries all classes of citizens are taking a part in public life, and public authorities are injecting themselves more each day into social and economic matters. We are witnessing the break-away from colonialism and the attainment of political independence by the peoples of Asia and Africa. Drawn together by their common needs nations are becoming daily more interdependent. There is, moreover, an ever-extending network of societies and organizations which set their sights beyond the aims and interests of individual countries and concentrate on the economic, social, cultural and political welfare of all nations throughout the world.
As We pass all this in review, We are aware of Our responsibility to take up this torch which Our great predecessors lighted, and hand it on with undiminished flame. It is a torch to lighten the pathways of all who would seek appropriate solutions to the many social problems of our times. Our purpose, therefore, is not merely to commemorate in a fitting manner the Leonine encyclical, but also to confirm and make more specific the teaching of Our predecessors, and to determine clearly the mind of the Church on the new and important problems of the day.