Here is an clever excerpt out of The Philosophy of Tolkien: The Worldview Behind The Lord of the Rings by Peter J. Kreeft - which I thought all avid readers of the trilogy might find interesting.
Emboldenings from me, not the author.
How its philosophy makes it great
"Every story, long or short, has five dimensions. They are usually called its 1) plot, 2) characters, 3) setting, 4) style, and 5) the theme. We could call them, respectively, the story's (1) work, (2) workers, (3) world, (4) words, and (5) wisdom. "Philosophy" means "the love of wisdom". So a story's philosophy is one of its five basic dimensions.
Which "dimension" sold The Lord of the Rings? All five. To be great, a work of art must be great in not just one dimension but all, just as a healthy body needs to be healthy in all its organs, a healthy soul in all its powers (i.e. mind, will, and emotions), and a morally good act in all its dimensions (i.e. the deed, the motive, and the circumstance).
A great story must have, first of all, a good plot, a great deed, a good work, and something worth doing. You cannot write a great story on saving the button of a sweater and nothing more. You can, however, write a great story about saving the world, which is what Tolkien did.
Second, a great story must also have great characters or at least one great character (greatly drawn, at leat) for readers to identify with, to find their identity in. We become the characters--in spirit, in imagination. No story is great unless it sucks us in, takes us up out of our bodies, and gives us an out-of-body experience, an ek-stasis, standing outside yourself in another. Great stories give us the grace of a mystical experience, on the level of the imagination.
Nearly all of Tolkien's characters are identifiable-with, even Ents. Who would have believed that any author could conjure up, in adult human beings, literary belief in talking trees? And Hobbits: What other author has ever successfully created a whole new species? And who else has ever given us more credible Elves? We know there are real elves; we must have an innate Elf detector, an innate Jungian archetype of true Elvishness. Even inanimate things--forests, horns, swords--are characters with memorable, credible personalities.
Third, a great story also should have a great setting, and interesting world. Sometimes it is a familiar part of thie world, sometimes an unfamiliar part of this world, and sometimes another world. The Lord of the Rings' setting is not another world, but [was meant to be] a historically unfamiliar portion of this world: its mythical past. "Middle-earth" is an old name for "the third rock form the Sun". " (end-quote)
This book then goes on and discusses anthropology, philosophical theology, cosmology, epistemology, the philosophy of a history, aesthetics, the philosophy of a language, political philosophy, angels, ethics & the war of Good and Evil, the "hard" virtues, and the "soft" virtues.
.....and how all of those 12 things tie in with the content of JRR Tolkien's Middle-earth canon.