Man, in this earthly life, though he be capable of many evils, is not capable of them all at once, inasmuch as one evil corrects and counteracts another just as one poison frequently corrects another.
 James Joyce, A Portrait of the Artist as a Young Man (1916). copy citation

Context

“—Such is the threefold sting of conscience, the viper which gnaws the very heart’s core of the wretches in hell, so that filled with hellish fury they curse themselves for their folly and curse the evil companions who have brought them to such ruin and curse the devils who tempted them in life and now mock them in eternity and even revile and curse the Supreme Being Whose goodness and patience they scorned and slighted but Whose justice and power they cannot evade. —The next spiritual pain to which the damned are subjected is the pain of extension. Man, in this earthly life, though he be capable of many evils, is not capable of them all at once, inasmuch as one evil corrects and counteracts another just as one poison frequently corrects another. In hell, on the contrary, one torment, instead of counteracting another, lends it still greater force: and, moreover, as the internal faculties are more perfect than the external senses, so are they more capable of suffering.” source