No levels, no Hit Points, only epic conflicts between ages-old sorcerers: this is Tolkien’s antidote to Hard Magic.
Tolkien employed a notoriously vague, soft magic system in The Lord of the Rings. You might guess at the wizarding hierarchy of Middle Earth, but you can’t quantify it. The power of his soft magic system consists more of hints than on-page battles.
Compare the Wizards
Just how powerful are Gandalf and Saruman? What is the difference in their use of magic? Gandalf uses butterflies to message the eagles. Small magic, but very useful. He breaks the bridge in Moria and throws the balrog down a pit. But the fight they have at the bottom? As vague as the wars between the gods in Greek mythology.
Sauron lost physical form when Isildur cut the One Ring from his hand, then spent the next four thousand years rebuilding his dark realm in the barely-corporeal form of a flaming, lidless eye. If Sauron recovers the ring, it will restore his physical form. We think. But to any other wearer, it’s a ring of invisibility and a homing beacon pinging the Dark Lord himself.
Elven bread? Magic. Elven cloaks? Magic. Tom Bombadil? Magic. Beorn the were-bear? Magic.
Whatever you want
The power of Tolkein’s soft magic system is that it’s anything the reader wants it to be. No rules, no detailed explanations we can pick holes in. You can’t argue that it doesn’t work if Tolkein never explained it.
Did Tolkien define and codify it while writing the story? I suspect not. Why not? Because such rules weren’t relevant to the plot. Magic provided the framework, not the story itself. Tolkien cared about characters and their actions. Could Tom Bombadil, the most magical being in all of Middle Earth, pop over to Mordor and take out Sauron? Probably. But that’s not what he’s there for. I’m not actually sure what he’s there for, but not that.
The point is, Tolkein used magic to evoke a sense of the mythic, of supernatural forces beyond our understanding; a sense of wonder. I don’t believe he intended for us to understand it. Tolkien harked back to a time before modern science and engineering that enabled the salughter he witnessed in the Great War. He wants his characters as far from all of that as possible.
Middle Earth exists in a swirling mist of creation and destruction myths, of powerful but indescribable soft magic. So is this a problem? No more than the pliable soft magic of Homer, the Mahabarat, Milton, or Spenser’s Faerie Queen.
Tolkien didn’t write with a tabletop role-playing game in mind. He couldn’t conceive of the card-based Magic: The Gathering. I suspect he’d hate the levelling-up shenanigans of Massively Multiplayer Online Role-playing Games.
All of those Hard Magic systems impose limits and constraints on story-telling. Tolkien would see Brandon Sanderson’s many worlds of Hard Magic as small and mundane, lacking in mystery and wonder. They are the product of obsessive puzzle-solving, collecting and classifying. Sanderson’s hard magic is the butterfly caught, categorized and labelled. Tolkien’s soft magic is the butterfly messenger on the wing that cannot be caught and cannot be known.