The following extract is from the book “Catholic Apologetics” by the American priest John Laux, originally published by Benziger Brothers in 1928, republished by TAN Books in 2011, pages 28-30.
1. Man alone “thinks the thought of immortality.” This thought moves him to the deepest depths of his being, fills him with joy and fear. How could this thought affect our souls so deeply if they were not made for eternity? If there was not in us a spark of the Divinity, how could the thought of God and of union with Him for all eternity ravish our hearts? The belief in immortality is a characteristic feature of every religion. ‘The thought of eternity vibrates in the soul of humanity, in the hearts of the civilized and the uncivilized races.”
It is said that the hope of immortality is an instinct of humanity, If so, it is surely an instinct of man’s spiritual nature which bears witness against the testimony of the senses. The thought of immortality cannot come into the soul from the external world, where all is transitory and perishable. If in spite of the witness of nature to the contrary, the soul holds fast to the hope of immortality, the roots of this hope must be looked for in the nature of the soul itself. If no instinct in the animal kingdom is without purpose, can one of the most universal and persistent cravings of the human soul be a mere will-o’-the-wisp, a fata morgana?
2. The soul could perish only if God annihilated it.—But it is God who implanted in it the craving for eternity and imprinted upon it the splendor of His own image. Eternal Wisdom does not destroy His works; He perfects them, guides them to the end for which He made them. “Throughout the whole realm of nature no substance capable of existence ever perishes. Why should the soul prove an exception to this rule? Why should it alone suffer annihilation after a brief space of time, when every single atom lives on? What grounds have I for assuming that the spirit of man is a less enduring thing than an atom of oxygen or hydrogen?”
3. Man’s life here on earth is incomplete, and the more lofty his aims, the more worthy his labors, the more incomplete will it appear to be. Even the man who lives for fame, wealth, power, is not satisfied in this life, much less he who lives for the ideals of truth, beauty, goodness; for he lives not for time but for eternity; his ideals cannot be realized on this side of the grave. Unless these ideals are mocking visions, man has a right to expect the continuance of his life for its completion (A. E. Garvie).
4. Our conscience tells us that there is a Supreme Lawgiver who will reward the good and punish the wicked. In this lite the wicked often prosper and the righteous suffer. The justice of God, and our sense of justice, demand that there should be a future state in which this inequality is corrected.
5. Emerson declares that “the impulse to seek proof of immortality is itself the strongest proof of all.”—We expect immortality, he argues, not merely because we desire it: but because the desire itself arises from all that is best and truest and worthiest in ourselves. The desire is reasonable, moral, social, religious; it has the same worth as the loftiest ideals and worthiest aspirations of the soul of man. The loss of the belief in immortality casts a dark shadow over the present life. “No sooner do we try to get rid of the idea of immortality—than Pessimism raises its head … Human griefs seem little worth assuaging; human happiness too paltry (at the best) to be worth increasing. The whole moral world is reduced to a point. Good and evil, right and wrong, become infinitesimal, ephemeral matters. The affections die away—die of their own conscious feebleness and uselessness. A moral paralysis creeps over us.” (Natural Religion).
The Duomo in Florence. Image by Lawrence Lew OP, CC-BY-NC-ND 2.0 in 2019, here