Tolkien came to regard the tale of Beren and Tinuviel as 'the first example of the motive (to become dominant in Hobbits) that the great policies of world history, the wheels of the world, are often t...
Has a knee-jerk tendency to avoid extremes as implausible, but ‘fantasy’ actively embraces them. It magnifies and clarifies the human condition.
To put the last point another way, writers such as Graves, Sassoon, and Owen saw the Great War as the disease, but Tolkien saw it as merely the symptom.