All sciences, except the science of Religion, have their certainty in themselves; as far as they are sciences, they consist of necessary conclusions from undeniable premises, or of phenomena manipulated into general truths by an irresistible induction. But the sense of right and wrong, which is the first element in religion, is so delicate, so fitful, so easily puzzled, obscured, perverted, so subtle in its argumentative methods, so impressible by education, so biassed by pride and passion, so unsteady in its course, that, in the struggle for existence amid the various exercises and triumphs of the human intellect, {254} this sense is at once the highest of all teachers, yet the least luminous; and the Church, the Pope, the Hierarchy are, in the Divine purpose, the supply of an urgent demand. Natural Religion, certain as are its grounds and its doctrines as addressed to thoughtful, serious minds, needs, in order that it may speak to mankind with effect and subdue the world, to be sustained and completed by Revelation.