From Chapter VI of Orthodoxy by G. K. Chesterton ( Dodd, Mead & Company, Copyright 1908)
This is what I have called guessing the hidden eccentricities of life. This is knowing that a man's heart is to the left and not in the middle. This is knowing not only that the earth is round, but knowing exactly where it is flat. Christian doctrine detected the oddities of life. It not only discovered the law, but it foresaw the exceptions. Those under-rate Christianity who say that it discovered mercy; anyone might discover mercy. In fact everyone did. But to discover a plan for being merciful and also severe--that was to anticipate a strange need of human nature. For no one wants to be forgiven for a big sin as if it were a little one. Anyone might say that we should be neither quite miserable nor quite happy. But to find out how far one may be quite miserable without making it impossible to be quite happy--that was a discovery in psychology. Anyone might say "Neither swagger nor grovel" ; and it would have been a limit. But to say "Here you can swagger and there you can grovel"--that was an emancipation. . . .
This is the thrilling romance of Orthodoxy. People have fallen into a foolish habit of speaking of orthodoxy as something heavy, humdrum, and safe. There never was anything so perilous or so exciting as orthodoxy. It was sanity: and to be sane is more dramatic than to be mad. It was the equilibrium of a man behind madly rushing horses, seeming to stoop this way and to sway that, yet in every attitude having the grace of statuary and the accuracy of arithmetic. The Church in its early days went fierce and fast with any warhorse; yet it is utterly unhistoric to say that she merely went mad along one idea, like a vulgar fanaticism. She swerved to left and right, so as exactly to avoid enormous obstacles. She left on one hand the huge bulk of Arianism, buttressed by all the worldy powers to make Christianity too worldly. The next instant she was swerving to avoid an orientalism, which would have made it too unworldly. The Orthodox Church never took the tame course or accepted the conventions; the Orthodox Church was never respectable. It would have been easier to have accepted the earthly power of the Arians. It would have been easy, in the Calvinistic seventeenth century, to fall into the bottom-