The Death of Melkor and the Life of the Elves

Thus spake Mandos in prophecy, when the Gods sat in judgement in Valinor, and the rumour of his words was whispered among all the Elves of the West. When the world is old and the Powers grow weary, then Morgoth, seeing that the guard sleepeth, shall come back through the Door of Night out of the Timeless Void; and he shall destroy the Sun and Moon. But Eärendel shall descend upon him as a white and searing flame and drive him from the airs. Then shall the Last Battle be gathered on the fields of Valinor. In that day Tulkas shall strive with Morgoth, and on his right hand shall be Fionwë, and on his left Túrin Turambar, son of Húrin, coming from the halls of Mandos; and the black sword of Túrin shall deal unto Morgoth his death and final end; and so shall the children of Húrin and all Men be avenged.

            (The Lost Road 333) 

I have always taken great pleasure in the story that in the final battle at the end of time Túrin will return from Death to kill Melkor, avenging his family and all Men. Nor am I alone in this. The prophecy of Túrin's return rings so true with so many because in it we hear the Final Chord of Ilúvatar resounding on the Fields of Time. Yet when composing The Silmarillion for publication, Christopher Tolkien chose to leave it out because he felt that, when writing the Valaquenta in 1958, his father had abandoned the so-called 'Second Prophecy of Mandos' in which this claim appeared (LR 333; Morgoth 204). He points out that his father had crossed it out in the manuscript. For this decision Douglas Charles Kane in his book Arda Reconstructed has faulted him (236-238). Kane argues, quite reasonably, that Tolkien did not cross out the entire Second Prophecy, and that he left the part which pertains to Túrin. Thus, Kane believes, the story of his returing and killing Melkor should have been preserved and printed in The Silmarillion. 

I can't really disagree with Kane's argument, but I believe there may be another, more metaphysical, reason for why Tolkien might have chosen to shelve the Second Prophecy. A letter of Tolkien's, which also comes from 1958, provides a clue:

That Sauron was not himself destroyed in the anger of the One [at the drowning of Númenor] is not my fault: the problem of evil, and its apparent toleration, is a permanent one for all who concern themselves with our world. The indestructibility of spirits with free wills, even by the Creator of them, is also an inevitable feature, if one either believes in their existence, or feigns it in a story.

            Letters no. 158 p. 280

This is consistent with something Tolkien wrote in The Book of Lost Tales a generation earlier. There the narrator explains that, when Melko (as he's called early in the legendarium) was taken captive by the Valar to protect the newly awakened Elves from him, he could not be put to death because "the great Gods may not yet be slain" (LT I 104). Notice that word "yet," which seems to suggest that a time may come when they might be slain? Well, that word wasn't there in the original text (LT I 104 n. 4). Tolkien added it, perhaps because he was anticipating the story that in the final battle Melko would in fact be slain. Not by Túrin, however, though he is present (LT I 219; LT II 281-282). So, it seems that Tolkien initially had an opnion resembling what he says in the 1958 letter, but changed his mind. Killing Melko was just too appealing an idea at the time, and even more so when Tolkien decided that Túrin really ought to be the one to do it. 

Yet by the 1950s, right about when Tolkien crossed out some, but not all, of the Second Prophecy of Mandos, Tolkien appears to hold an opinion that clashes with the part of the Second Prophecy he did not cross out. But if even God cannot destroy spirits possessing free will, what does that mean for the Elves, whose lives are said to end when Arda ends? One way out is to argue, as some have done, that Elves do not have free will. Or perhaps it means, as Finrod speculates -- prophesies even -- in the Athrabeth Finrod ah Andreth that the Elves will somehow survive the end of Arda. He also foresees that Eru himself will one day enter Arda to heal its hurts, which at least at first glance does not harmonize well with the vengeance of Túrin. The Athrabeth is of course also a work of the mid to late 1950s, when Tolkien wrote the letter quoted above and crossed out some of the Second Prophecy. Did he cross out all he meant to at that moment? Or did he allow metaphysics to trump myth hereafter?