How is the Creation/Evolution Debate in respect to Middle Earth?

According to the people of Asgard, middle earth won't be reached until valhalla fills up.

It is completely creationist. All of which is covered in the Silmarillion

I *think* it's backwards. Tolkien adopted 'traditional' mythological reasoning for his works, taking his inspiration from what he knew best - Norse and Anglo-Saxon mythology. One could even say he cheated - you can find several names in his works that are duplicated in the already mentioned mythologies.

Mythology is essentially an ancient societies take on what they see around them, built up over centuries. The best example of this that I can think of is the basis for societal 'advance' in Greek mythology.

The ancient Greeks had a mythology that, as Hesiod explained in 'Works and Days' relied on the Four Ages of Man, these being Golden, Silver, Bronze, and Iron (with the Age of Heroes coming just after Bronze). The Golden Age is both the oldest and greatest, followed by ages that become 'lesser' as the ages pass. Thus Silver is a 'lesser' time than Gold, Bronze is a 'lesser' time than Silver. The Iron Age is stated by both Hesiod and Ovid as the one they live in, and is regarded as the worst. In part at least, this is where we get our idea of a 'Golden Age' (however it is applied).

Tolkien's mythology takes a very similar line. The oldest legends, merely hinted at in LOTR, are filled with greater characters, greater evils, greater dangers and greater heroism. The people of LOTR, however noble (for example, Aragorn), are shadows of some of their forebears. Sauron, however nasty, is a lesser evil than his boss, Melkor. Shelob is a lesser Great Spider than her mother, Ungoliant. The greatest elven characters in LOTR (with the possible exception of Galadriel) pale in comparison to Feanor and Glorfindel.

In every case, the 'now' is less than the 'then', but (and this is important) Tolkien does seem to pursue some relativism throughout his Middle Earth mythology. Frodo is no less 'heroic' than others of greater stature who have gone before him. In fact, his heroism could be said to be greater, as he himself is less than most (if not all) the heroes of the past.

So Tolkien's work really rather takes a 'creation' based, Greek-alloyed mythology instead of holding to any scientific principle, although evolutionary theory would have been long accepted by the time he was writing. With this in mind I don't think we should forget Tolkien's firmly held Catholic faith, which is a step too far to go into here and now. I think I'll come back to this and edit it once I've had a chance to think about it some more. Excellent question.