19 Finally, the vision of development as a vocation brings with it the central place of charity within that development . Paul VI, in his Encyclical Letter Populorum Progressio , pointed out that the causes of underdevelopment are not primarily of the material order. He invited us to search for them in other dimensions of the human person: first of all, in the will, which often neglects the duties of solidarity; secondly in thinking, which does not always give proper direction to the will. Hence, in the pursuit of development, there is a need for “the deep thought and reflection of wise men in search of a new humanism which will enable modern man to find himself anew” . But that is not all. Underdevelopment has an even more important cause than lack of deep thought: it is “the lack of brotherhood among individuals and peoples” . Will it ever be possible to obtain this brotherhood by human effort alone? As society becomes ever more globalized, it makes us neighbours but does not make us brothers. Reason, by itself, is capable of grasping the equality between men and of giving stability to their civic coexistence, but it cannot establish fraternity. This originates in a transcendent vocation from God the Father, who loved us first, teaching us through the Son what fraternal charity is. Paul VI, presenting the various levels in the process of human development, placed at the summit, after mentioning faith, “unity in the charity of Christ who calls us all to share as sons in the life of the living God, the Father of all” .
Source: Caritas in Veritate (Vatican.va)