David Hume on the Evil Within OurselvesDialogues Concerning Natural Religion (Bobbs-Merril Co, Inc : 1970; orig. 1779), pt. X, pp. 84-85. The "great poet" is John Milton, the quotation from Paradise Lost, bk. XI.
But though these external insults, said Demia, from animals, from men, from all the elements, which assault us form a frightful catalogue of woes, they are nothing in comparison of those which arise within ourselves, from the distempered condition of our mind and body. How many lie under the lingering torment of diseases? Hear the pathetic enumeration of the great poet.
Intestine stone and ulcer, colic-pangs
Demoniac frenzy, moping melancholy,
And moon-struck madness, pining atrophy,
Marasmus, and wide-wasting pestilence.
Dire was the tossing, deep the groans: Despair
Tended the sick, busiest from couch to couch.
And over them triumphant Death his dart
Shook: but delay’d to strike, though oft invok’d
With vows, as their chief good and final hope.
The disorders of the mind, continues Demea, though more secret, are not perhaps less dismal and vexatious. Remorse, shame, anguish, rage, disappointment, anxiety, fear, dejection, despair — who has ever passed through life without cruel inroads from these tormentors? How many have scarcely ever felt any better sensations? Labor and poverty, so abhorred by everyone, are the certain lot of the far greater number; and those few privileged persons who enjoy ease and opulence never reach contentment or true felicity. All the goods of life united would not make a very happy man, but all the ills united would make a wretch indeed; and any one of them almost (and who can be free from every one), nay, often the absence of one good (and who can possess all) is sufficient to render life ineligible.