[burrahobbit]

You seem to be implying that Arda is 'nothing but' the Music made manifest - I don't read it that way.

'Behold your Music!' And he showed to them a vision, giving to them sight where before was only hearing; arid they saw a new World made visible before them, and it was globed amid the Void, and it was sustained therein, but was not of it. And as they looked and wondered this World began to unfold its history, and it seemed to them that it lived and grew. 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.'

Again I ask, why bother creating the world at all if its to be nothing but a literal manifestation of what was already set out?

I don't know, why?

I get to ask a question again too. How exactly does a person change the performance of a song if he wasn't in the room with the other people playing? How can I change what an orchestra does in New York if I live in Oklahoma? Even more, how would I change that orchestra in New York if it happened 50 years before I was born?