Mozart - An Unanswerable Question?

In 1906, the great American composer Charles Ives gave us a short piece for an ensemble group titled " The Unanswered Question." It deals with the three elemental queries; specifically, Who Am I? What Am I? Why Am I Here? Of course, no answer is forthcoming.
Well, an equally engrossing question connects me with the 18th century titan Mozart. For years, I had been discussing the imponderable question, both with myself and a number of my students; a question wrestling with a feeling that always pervaded my consciousness every time I listened to Mozart - why is it that with this composer, and no other, the uncanny feeling that the music was already in existence - it was merely waiting for a medium (Mozart?) to appear and commit it to paper, rendering it a secret no longer? That question has been with me for as long as I can remember.
Recently, in going over the letters written by Mozart, I came across one I had somehow overlooked during all these years of study. It was a letter written by the genius to his father, and these are his words:
"the music is already here - it just needs to be written down."
Another Unanswered Question - certainly unanswerable to me...