So I was reading Chesterton (uh oh) and a few things popped out at me as vaguely D&D-relevant:
Humility was largely meant as a restraint upon the arrogance and infinity of the appetite of man. He was always outstripping his mercies with his own newly invented needs. His very power of enjoyment destroyed half his joys. By asking for pleasure, he lost the chief pleasure; for the chief pleasure is surprise. Hence it became evident that if a man would make his world large, he must be always making himself small. Even the haughty visions, the tall cities, and the toppling pinnacles are the creations of humility. Giants that tread down forests like grass are the creations of humility. Towers that vanish upwards above the loneliest star are the creations of humility. For towers are not tall unless we look up at them; and giants are not giants unless they are larger than we. All this gigantesque imagination, which is, perhaps, the mightiest of the pleasures of man, is at bottom entirely humble. It is impossible without humility to enjoy anything...
This seemed surprisingly relevant to OSR philosophy - the value of playing ultimately rather small and human characters in a big world, the enjoyment of surprises from the random tables and exploratory play, the fundamental boringness of fighting monsters against which you are evenly matched ("not giants unless they are larger than we"), the boringness of having a nice planned story arc and very little going wrong and ultimately getting what you want that sometimes happens in more modern games.
Even at max-level in B/X or OD&D, you're only a baron, not a king or emperor. The feeling of being a small fish is still sort of there. And during the wilderness levels, when you're dealing with 30-300 orcs - "that few stood against many". Imbalanced combat-as-war is seldom heroic, but balanced encounters never are, because a requisite for heroism is fighting an enemy greater than you, which requires smallness.
But I deal here with what ethic and philosophy come from being fed on fairy tales. If I were describing them in detail I could note many noble and healthy principles that arise from them. There is the chivalrous lesson of "Jack the Giant Killer"; that giants should be killed because they are gigantic. It is a manly mutiny against pride as such.
This struck me as a very curious answer to the problem of justification of fighting sentient / humanoid monsters.
For the pleasure of pedantry I will call it the Doctrine of Conditional Joy. Touchstone talked of much virtue in an "if"; according to elfin ethics all virtue is in an "if." The note of the fairy utterance always is, "You may live in a palace of gold and sapphire, if you do not say the word `cow'"; or "You may live happily with the King's daughter, if you do not show her an onion." The vision always hangs upon a veto. All the dizzy and colossal things conceded depend upon one small thing withheld. All the wild and whirling things that are let loose depend upon one thing that is forbidden. Mr. W.B.Yeats, in his exquisite and piercing elfin poetry, describes the elves as lawless; they plunge in innocent anarchy on the unbridled horses of the air—
"Ride on the crest of the dishevelled tide, And dance upon the mountains like a flame."
It is a dreadful thing to say that Mr. W.B.Yeats does not understand fairyland. But I do say it. He is an ironical Irishman, full of intellectual reactions. He is not stupid enough to understand fairyland. Fairies prefer people of the yokel type like myself; people who gape and grin and do as they are told. Mr. Yeats reads into elfland all the righteous insurrection of his own race. But the lawlessness of Ireland is a Christian lawlessness, founded on reason and justice. The Fenian is rebelling against something he understands only too well; but the true citizen of fairyland is obeying something that he does not understand at all. In the fairy tale an incomprehensible happiness rests upon an incomprehensible condition. A box is opened, and all evils fly out. A word is forgotten, and cities perish. A lamp is lit, and love flies away. A flower is plucked, and human lives are forfeited. An apple is eaten, and the hope of God is gone.
This sort of magic-with-a-condition seems like it could be fun in games and certainly fitting to the literature but I don't think I've ever seen it used. It could get especially exciting if you start stacking up multiple taboos.
This is the tone of fairy tales, and it is certainly not lawlessness or even liberty, though men under a mean modern tyranny may think it liberty by comparison... Fairy godmothers seem at least as strict as other godmothers. Cinderella received a coach out of Wonderland and a coachman out of nowhere, but she received a command—which might have come out of Brixton—that she should be back by twelve. Also, she had a glass slipper; and it cannot be a coincidence that glass is so common a substance in folk-lore. This princess lives in a glass castle, that princess on a glass hill; this one sees all things in a mirror; they may all live in glass houses if they will not throw stones. For this thin glitter of glass everywhere is the expression of the fact that the happiness is bright but brittle, like the substance most easily smashed by a housemaid or a cat. And this fairy-tale sentiment also sank into me and became my sentiment towards the whole world. I felt and feel that life itself is as bright as the diamond, but as brittle as the window-pane; and when the heavens were compared to the terrible crystal I can remember a shudder. I was afraid that God would drop the cosmos with a crash.
This is what I have learned in some years in the field of computer security. The internet is brittle. The power grid is brittle (one well-placed nuke away from ceasing to operate, never mind hacking). All the wonders of our current way of life are brittle. But sadly we do not have the fairy tale's clear rules of The Things That Must Not Be Done.
I may express this other feeling of cosmic cosiness by allusion to another book always read in boyhood, "Robinson Crusoe," which I read about this time, and which owes its eternal vivacity to the fact that it celebrates the poetry of limits, nay, even the wild romance of prudence. Crusoe is a man on a small rock with a few comforts just snatched from the sea: the best thing in the book is simply the list of things saved from the wreck. The greatest of poems is an inventory. Every kitchen tool becomes ideal because Crusoe might have dropped it in the sea. It is a good exercise, in empty or ugly hours of the day, to look at anything, the coal-scuttle or the book-case, and think how happy one could be to have brought it out of the sinking ship on to the solitary island. But it is a better exercise still to remember how all things have had this hair-breadth escape: everything has been saved from a wreck. Every man has had one horrible adventure: as a hidden untimely birth he had not been, as infants that never see the light. Men spoke much in my boyhood of restricted or ruined men of genius: and it was common to say that many a man was a Great Might-Have-Been. To me it is a more solid and startling fact that any man in the street is a Great Might-Not-Have-Been.
Ode to the inventory. Choosing prudently what to bring with you when you can't carry much and it is all that you will have in a dangerous place. It's also been a long time since I shipwrecked some PCs, but on reflection a strict inventory would've been good there too.