272 As believers, we are convinced that, without an openness to the Father of all, there will be no solid and stable reasons for an appeal to fraternity. We are certain that “only with this awareness that we are not orphans, but children, can we live in peace with one another”. For “reason, by itself, is capable of grasping the equality between men and of giving stability to their civic coexistence, but it cannot establish fraternity”.
Source: Fratelli Tutti (Vatican.va)