Metaphysics of the Music, part 44
In his various commentaries on or summaries of the Ainulindalë found in his letters and elsewhere Tolkien repeatedly emphasizes the dialectic between the merely mental existence of the Music and Vision taken together, and the later, real existence enjoyed by the created physical world. In one letter, for example, Tolkien analyzes his creation narrative in terms of the “story” of the world as contained in the Music and the Vision on the one hand, and the story as it later becomes “realized” in the creation of the physical world (Letters 235-6). In another letter he similarly speaks of the Music and Vision together as a “cosmogonical drama” which is “perceived… as in a fashion we perceive a story composed by some-one else,” to which he contrasts the world we see “later as a ‘reality’” (146). In yet another letter, Tolkien passes over the Vision entirely to speak of the Ainur’s Music as their
work of Art, as it was in the first instance, [and the Valar] became so engrossed with it, that when the Creator made it real (that is, gave it the secondary reality, subordinate to his own, which we call primary reality, and so in that hierarchy on the same plane with themselves) they desired to enter into it, from the beginning of its “realization.” (259)
Here Tolkien goes so far as to suggest—again, contrary to the metaphysically tragic reading—that the independent existence of the physical world actually makes it more like the spiritual being of the Ainur than the purely mental and hence derivative being of the Music: the physical world enjoys the same kind of “primary reality” which places it on “on the same plane” as the Ainur. The same point is made in another letter which describes the Music and Vision as a “Design” communicated to and then “interpreted” by the Ainur, “propounded first in musical or abstract form, and then in an ‘historical vision,’” after which “the One (the Teller [of the story]) said Let it Be, then the Tale became History, on the same plane as the hearers…” (284). Tolkien goes on to contrast the story of the Music as “it ‘exists’ in the mind of the teller, and derivatively in the minds of hearers, but not on the same plane as the hearers,” with the realized world which the hearers “could, if they desired, enter into” (emphasis original). And in his commentary on the Athrabeth, Tolkien likewise juxtaposes the “Great Music, which was as it were a rehearsal, and remained in the stage of thought or imagination,” with the “Achievement” it receives in the fifth and final act of the creation drama when it is at last made real (Morgoth’s Ring 336).
 “According to the fable Elves and Men were the first of these [divine] intrusions, made indeed while the ‘story’ was still only a story and not ‘realized’; they were not therefore in any sense conceived or made by the gods, the Valar, and were called the Eruhíni or ‘Children of God’…” (L 235-6).