The great positive argument in favor of this hypothesis is, that rational nature necessarily seeks God as its ultimate object, and therefore longs for that clear, intellectual vision of him called the beatific. If this be true, the question is settled for ever. Those who seek to establish its truth state it under various forms. One way of stating it is, that reason seeks the universal, or the explanation of all particular effects, in the _causa altissima_, This is the doctrine of St. Thomas. God is the _causa altissima_, the universal principle, and therefore reason seeks for God. Again, it is affirmed that there is a certain faculty of super-intelligence, which apprehends the super-intelligible order of being, not positively, but negatively, by apprehending the limitation of everything intelligible. Intelligence is therefore sensible of a want, a vacuum, an aimless, objectless yearning for something unknown and unattainable; showing that God has created it for the purpose of satisfying this want, and filling this void, by bringing intelligence into relation to himself as its immediate object, in a supernatural mode. In a more popular mode, this same idea is presented under a countless variety of forms and expressions, in sermons, spiritual treatises, and poems, as a dissatisfaction of the soul with every kind of good attainable in this life, vague longing for an infinite and supreme good, a plaintive cry of human nature for the beatitude of the intuitive vision of God. "Irrequietum est cor nostrum donec requiescat in te"--"Our heart is unrestful until it finds repose in thee," is the language {154} of St. Augustine, which is echoed and reechoed on every side. These considerations are not without great weight; nevertheless, they do not appear to us sufficient to prove conclusively the hypothesis in support of which they are adduced, or to over-balance other weighty considerations on the opposite side. Reason seeks for the _causa altissima_, but it remains to be proved that it seeks for any other knowledge of it but that which is attainable by a mode connatural to the created spirit. Reason is conscious of its own limitation. But this does not prove that it aspires to transcend this limitation. Beatified spirits are conscious of their own limitation. Those who are in the lowest grade are aware of numerous grades above them, and the highest are aware of their inferiority to the exalted humanity of Jesus Christ, united to the divine nature in his person. All together, including Jesus Christ himself, as man, are aware of an infinite incomprehensibility in the divine nature. In the words of the greatest of all mystic theologians, St. John of the Cross: "They who know him most perfectly, perceived most clearly that he is infinitely incomprehensible. To know God best, is to know he is incomprehensible; for those who have the less clear vision do not perceive so distinctly as the others how greatly he transcends their vision." [Footnote 33]