I've given a certain amount of thought over the years as to what the particular charms of "otherworldly fantasy" as compared to those of other types of fantastic fiction. I've coined my own word for such fiction-- "the metaphenomenal," which I sometimes toss out in my film-reviews-- but I'll avoid that theoretical briar-patch here.
I mentioned in that initial post that I believed Tolkien would have many if not all the answers. But now that I've reread it, I think the essay offers some interesting points, but it doesn't solve all the problems.
"On Fairy Stories," as Tolkien himself says on his first page, is entirely about identifying the nature of the genre Tolkien advocates. This is essentially an insular endeavor, one not concerned with drawing comparisons to other genres. Once or twice Tolkien makes reference to fantasy's "rival" (my word) science fiction, but he doesn't offer a sustained comparison between the two. He makes some isolated comments about how fantasy differs from naturalistic fiction as well, but Tolkien is also not particularly interested in these differences except insofar as they help him define the genre of "faery stories"-- which in his mind would seem to include THE HOBBIT, completed a few years before the essay. By extension, that would imply that he deemed the rest of his works to be in the same genre as well, though few moderns would refer to LORD OF THE RINGS and SILMARILLION as "fairy stories.".
So as I pick my way slowly through the various complexities of Tolkien's most famous essay in future posts, I will do so with the knowledge that Tolkien was manifestly NOT interested in what interests me in the definition of fantasy: i.e., what makes it different from other forms of fantastic fiction.
More to come.