Wikipedia says of Chesterton that, “in this book he tries to illustrate the spiritual journey of humanity, or at least of Western civilization.”
That’s about right. Chesterton is best not when he’s defending Christianity in particular, but when he’s criticizing others who miss the spiritual side of man.
He’s also a damn good writer, so I’m basically turning it over to him:
If there is one fact we really can prove, from the history that we really do know, it is that despotism can be a development, often a late development and very often indeed the end of societies that have been highly democratic. A despotism may almost be defined as a tired democracy. As fatigue falls on a community, the citizens are less inclined for that eternal vigilance which has truly been called the price of liberty; and they prefer to arm only one single sentinel to watch the city while they sleep.
More on democracy:
Democracy is a thing which is always breaking down through the complexity of civilization. Anyone who likes may state it by saying that democracy is the foe of civilization.
. . .
the broad truth is that barbarism and civilization have always dwelt side by side in the world the civilization sometimes spreading to absorb the barbarians, sometimes decaying into relative barbarism, and in almost all cases possessing in a more finished form certain ideas and institutions which the barbarians possess in a ruder form; such as government or social authority, the arts and especially the decorative arts, mysteries and taboos of various kinds especially surrounding the matter of sex, and some form of that fundamental thing which is the chief concern of this inquiry; the thing that we call religion.
If the world becomes pagan and perishes, the last man left alive would do well to quote the Iliad and die.
I wish I’d written that.
He has a long and only-somewhat-persuasive argument that the field of “comparative religion” is bunk:
Those religions and religious founders, or rather those whom we choose to lump together as religions and religious founders, do not really show any common character. . . . Confucianism and Buddhism are great things, but it is not true to call them Churches; just as the French and English are great peoples, but it is nonsense to call them nomads. . . . But in reality the rivers mythology and philosophy run parallel and do not mingle till they meet in the sea of Christendom. Simple secularists still talk as if the Church had introduced a sort of schism between reason and religion. The truth is that the Church was actually the first thing that ever tried to combine reason and religion. There had never before been any such union of the priests and the philosophers.
On the myths of civilizations:
There comes a time in the routine of an ordered civilization when the man is tired at playing at mythology and pretending that a tree is a maiden or that the moon made love to a man. The effect of this staleness is the same everywhere; it is seen in all drug-taking and dram-drinking and every form of the tendency to increase the dose. Men seek stranger sins or more startling obscenities as stimulants to their jaded sense. They seek after mad oriental religions for the same reason. They try to stab their nerves to life, if it were with the knives of the priests of Baal. They are walking in their sleep and try to wake themselves up with nightmares.
. . .
Nobody understands the nature of the Church, or the ringing note of the creed descending from antiquity, who does not realize that the whole world once very nearly died of broad-mindedness and the brotherhood of all religions.