最近在看著名的英國天主教作家 G. K. Chesterton ，然而不是看他的護教學經典 Heretics, Orthodoxy, 或 The Everlasting Man ，卻是看他用以賺取收入的 Father Brown (布朗神父)系列的偵探小說。
但 Chesterton 卻不放棄在小說中表達他的信仰，以下是在 Father Brown 首次出場時，跟假扮成神父的大盜 Flambeau 的對話：
[The fake priest Flambeau:] “Ah, yes, these modern infidels appeal to their reason; but who can look at those millions of worlds and not feel that there may well be wonderful universes above us where reason is utterly unreasonable?”
“No,” said the other priest; [Father Brown] " reason is always reasonable, even in the last limbo, in the lost borderland of things. I know that people charge the Church with lowering reason, but it is just the other way. Alone on earth, the Church makes reason really supreme. Alone on earth, the Church affirms that God himself is bound by reason."
The other priest raised his austere face to the spangled sky and said:
“Yet who knows if in that infinite universe——?”
" Only infinite physically," said the little priest, turning sharply in his seat, " not infinite in the sense of escaping from the laws of truth."
" Reason and justice grip the remotest and the loneliest star. Look at those stars. Don’t they look as if they were single diamonds and sapphires? Well, you can imagine any mad botany or geology you please. Think of forests of adamant with leaves of brilliants. Think the moon is a blue moon, a single elephantine sapphire. But don’t fancy that all that frantic astronomy would make the smallest difference to the reason and justice of conduct. On plains of opal, under cliffs cut out of pearl, you would still find a notice-board, ‘Thou shalt not steal.’"
(The Innocence of Father Brown / The Blue Cross)
作者藉 Father Brown 道出了天主教信仰一個重要的信念：道德的普遍性。一如 Father Brown 說，無論到了那論「毋偷盜」這規誡都是合理及需要遵守的。他甚至指出，天主自己也被「理智」所規限著。
這就是其中一樣，基督信仰和伊斯蘭教 (起碼是遜尼派, Sunni Islam) 不同的地方。基督信仰中，理智是必然的，因為這是天主「思想」的軌跡，這是天主自己所定的法則，天主的本性。天主不會違反自己的本性而言。
但以筆者的認知﹝歡迎交流﹞，在遜尼派伊斯蘭教中，阿拉可不會被理智所侷限，因為他們認為這是使神變得不再是全能。阿拉的行徑是人所不能預測的；祂全能，只要祂願意，(Power and Will) 就能作；理智並不侷限阿拉的所為。
然而在基督信仰中，天主雖是全能的天主，但祂的核心本質是「愛」及「理智」 (Love and Reasons) 。天主的全能在於祂是愛、在於祂是合理的。世界是有秩序的，因為天主愛這世界、按天主既定的計劃而行；人能夠相愛，因為這當中有天主為人啟示了法則 (聖詠 98:2)，這是人能夠相愛的方法 (若望福音 15:12)。人可以理解他人，可以去愛，因為天主是理智的 (若望福音 1:1)，天主是愛 (若望一書 4:8)。
最後， Father Brown 解釋他為何能夠確認面前的這位神父是假扮的：
“Oh, by being a celibate simpleton, I suppose,” he said. “Has it never struck you that a man who does next to nothing but hear men’s real sins is not likely to be wholly unaware of human evil? But, as a matter of fact, another part of my trade, too, made me sure you weren’t a priest.”
“What?” asked the thief, almost gaping.
“You attacked reason,” said Father Brown. “It’s bad theology.”
好的神學是不會違反理智的。當然我們從上文見到， Chesterton 所指的理智不單是認識自然科學，更是認識倫理法則。好的神學是不會違反倫理法則的。正如聖詠 147:19-20 說：
他向雅各伯曉示了自己的言語，他向以色列啟示了自己的誡律。 他從未如此恩待過其他任何民族，也沒有向他們宣示過自己的法律。
這是天主自己的法律，我們應該因能夠認識天主的法律而感到高興，因為這確是天主的恩待。
