Inevitability of death (revisited)

[Pitchwife]

Thanks to everybody for some interesting and inspiring posts up to now, and special thanks to Galin for clarifying quotations!

As for seasons, I'd think there can't have been any in Aman during the age of the Trees - at least if we stick to the old, 'classic' Silmarillion cosmology and assume that the Sun didn't exist before the death of the Trees (strangely, this would mean there can have been no seasons in Middle-Earth, either, at that time!). The blossoming and fading periods of the Trees seem to have been pretty regular, at least Tolkien doesn't tell us anything about seasonal variations as far as I've been able to discover (having consulted HoME X in the meantime). After the death of the Trees and the making of Sun and Moon it seems probable that Aman would have been subject to seasonal change like the rest of the world, and being caused by the same Sun, their seasons would be of the same length as ours.

There remains, however, the question of death in Arda Unmarred. As Ibrin has pointed out,

Melkor marred the Music even before Ea was created. If Ea, and Arda, are indeed the Music made manifest, precisely as it was sung, then it never was "perfect."

But was death part of Eru's original design, the theme of the Music, before Melkor added his dissonances? There's a tiny bit of dialogue in the Athrabeth:

[Andreth:]'Many of the Wise hold that in their true nature no living things would die.'
'In that the Eldar would say that they err,' said Finrod,

but he gives no reason why. However, it just occurred to me that, if Eru had planned from the beginning that Men would finally inherit Arda from the fading Elves, he may have planned for all living things to age and die in a time span that would be in accord with the lifetime and temporal perception given to Men, as it was for the Elves in Aman.
(Obviously, this idea runs counter to Legate's point that Men are only guests in that world and probably not meant to feel at home there. Hmmm... I need some more time for reading and thinking. Enough for today.)