If reason is to be rescued, that is to say, if we want to be coherent with this energy that defines us, if we do not want to deny it, then its very dynamism forces us to affirm the exhaustive answer beyond the horizon of our life. The answer exists. It cries out through the entreaties that make up our being. But it cannot be defined by experience. It is there, but we do not know what it is....
The summit of reason's conquest is the perception of an unknown unreachable presence, to which all human movement is destined, because it depends upon it. It is the idea of mystery.
Luigi Giussani, The Religious Sense, ch. 11