Métaphysique et effet papillon...

[Aglarond]

Je pense que Laegalad fait allusion à ce passage de l'Ainulindalë :

'And thou, Melkor, shalt 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 when the Ainur had gazed for a while and were silent, Ilúvatar said again: 'Behold your Music! This is your minstrelsy; and each of you shall find contained herein, amid the design that I set before you, all those things which it may seem that he himself devised or added. And thou, Melkor, wilt 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.'

Cela dit, une lecture attentive du conte ne me donne pas à penser que les Ainur ne se soient pas vus eux-mêmes. Il est dit en tout cas qu'ils ont vu l'arrivée des Enfants d'Iluvatar (Elfes et Hommes).
Le libre-arbitre est effectivement la notion clé, et la deuxième partie de la citation que je donne l'illustre bien, à mon sens.