[Mithadan]

Please keep in mind that what I posted is my interpretation of Tolkien's writings. I know of others who would insist strongly that the Valar and Elves operated entirely through their own free will. I don't agree and think there is ample support for my interpretation in the Silm and HoME.

Notwithstanding what was fated expressly in the Music, there was ample room for the exercise of free will by both the Valar and the Elves. Yet their actions tended to "lock in" the paths that the future would take. Child, you mention the decision of the Valar to summon the Elves to Valinor. This appears to be an area where free will was exercised with dire consequences. In either Morgoth's Ring or War of the Jewels there is a snippet of "dialogue" between Manwe and Eru where Eru questions this decision but states that since the decision was made it was now fated to be so. From this decision, coupled with the "temporary" imprisonment of Morgoth, events led slowly but inexorably to the rebellion of the Valar. Morgoth's role in Arda as the corruptor and source of chaos was established by his own rebellion during the Music and his nature was set by the dissonance he created in the Themes. Manwe could not understand Morgoth's nature because he was fundamentally good and could not conceive of evil (See Osanwe-Kenta). The Noldor were innocents but corruptible and were twisted by Morgoth. This is the nature of Arda Marred.

I think Tolkien struggled a bit with the nature of the Half-Elves. Perhaps absent a "ruling" by the Valar (with the implied consent of Eru) their nature could not be established. Thus, until Earendil and Elwing, all of the nature of the half-elven remained undecided and all died young to avoid the determination of whether they would have the longevity of Elves. Perhaps this too was fate of a sort.