Metaphysics of the Music, part 28
One dimension to the Vision’s superiority over the Music is theological or revelatory: although the Music itself had been a means by which the Ainur could grow in their knowledge of Ilúvatar, in the foreknowledge of the Children of Ilúvatar afforded in the Vision, by contrast, the Ainur are able to see “the mind of Ilúvatar reflected anew, and learned yet a little more of his wisdom, which otherwise had been hidden even from the Ainur” (Silmarillion 18). Through the Vision, in short, the Ainur receive a greater revelation of the Creator than what the Music alone had provided, a progression that, once more, makes little sense when interpreted according to the Neoplatonic principle that every later stage or emanation of reality results not in an increased but a diminished capacity to reflect the divine. Related to this is the greater theodical power the Vision also wields in comparison to the Music, providing the Ainur with a greater disclosure of Ilúvatar’s ability to bring about good from Melkor’s evil. Again, and as we have already seen, the issue of theodicy is already present in the Ainur’s Music, where the Ainur witnessed “the most triumphant notes” of Melkor’s rebellious music being continually taken up by Eru’s music “and woven into its own solemn pattern” (17). Yet it is in the Vision that the Ainur first witness in a concrete way the Creator’s power to subvert and transform Melkor’s corrupted themes. As Ilúvatar explains to Melkor after the closing of the Music, in the Vision he will
see that no theme may be played that hath not its uttermost source in me, nor can any alter the music in my despite. For he that attempteth this shall prove but mine instrument in the devising of things more wonderful, which he himself hath not imagined… And thou, Melkor, will discover all the secret thoughts of thy mind, and wilt perceive that they are but a part of the whole and tributary to its glory. (S 17)
In addition to the Vision containing things which the Ainur had not thought, it also reveals to them the ultimate truth of those things which they previously had thought. It is not the prior Music, in sum, that embodies the essential truth of the later Vision, but rather the later Vision that embodies the essential truth of the prior Music. The later encompasses and thus gives added meaning to the earlier.
 As Tolkien stresses in his letters, it is precisely because the Ainur had so little to do with that portion of the Music and Vision corresponding to the Children of Ilúvatar that makes the latter so intriguing and desirable to the Ainur: “The Children of God are thus primevally related and akin, and primevally different. Since also they are something wholly ‘other’ to the gods [i.e., the Ainur], in the making of which the gods played no part, they are the object of the special desire and love of the gods” (Letters 147). In another letter Tolkien stresses the “primeval kinship” of the Ainur and the Children of Ilúvatar in these words: “The uncorrupted Valar, therefore, yearned for the Children before they came and loved them afterwards, as creatures ‘other’ than themselves, independent of them and their artistry, ‘children’ as being weaker and more ignorant than the Valar, but of equal lineage (deriving being direct from the One); even though under their authority as rulers of Arda” (285).