The Church is convinced that work is a fundamental dimension of man’s existence on earth. She is confirmed in this conviction by considering the whole heritage of the many sciences devoted to man: anthropology, palaeontology, history, sociology, psychology and so on; they all seem to bear witness to this reality in an irrefutable way. But the source of the Church’s conviction is above all the revealed word of God, and therefore what is a conviction of the intellect is also a conviction of faith.