About the degradation of the physical bodies

[Avian]

This is something that I couldn't really figure out properly. It is stated that if they stay in Middle-Earth for too long, the elves' bodies start to get physically weakened and degraded until they become like wraiths due to the marring of Arda caused by Morgoth. But their bodies will stay forever young if they are in Aman.

So, is it the same for the men as well? Would their bodies remain physically young without degrading until they die if Morgoth didn't poison the physical world?

 

[Eldacar]

You mean that they wouldn't really age until they drop dead at one point? At least this was kind of a reality for Numenoreans.

"[...] the Numenorean span was brought about by assimilation of their mode of life to that of the Eldar: [...] they [...] had been granted only an extension of the period of their vigour of mind and body. Thus (as the Eldar) they grew at much the same rate as other Men, but when they had achieved 'full-growth' they then aged, or 'wore out', very much more slowly. The first approach of 'world-weariness' was indeed for them a sign that their period of vigour was nearing its end. When it came to an end, if they persisted in living, then decay would proceed, as growth had done, no more slowly than among other Men." (Unfinished Tales - The Line of Elros)

Decay seemed to be a natural part of (mortal) life even for blessed people. But the elves are not only aging and fading in Middle-Earth as far as I know and not only because of the marring of Arda. At least from what I've read in the Nature of Middle-Earth, they most certainly age a lot faster in Middle-Earth with mature elves aging 100 times faster as they would have in Aman. But they would still age and fade there, even though much slower. Hofstetter states, that it isn't certain if this type of fading was an intentional design by Eru or a punishment for the sins of the Eldar. Are there other texts that state or suggest differently?

To answer your question: No, I don't think men would have stayed in full youth and vigour up until their death if it wasn't for Morgoth. This process seems to be perfectly natural to me.

 

[TokingTolkien]

I can't remember clearly but it's either Morgoth's Ring or The War of the Jewels in which Christopher Tolkien discusses his father's evolution of the concepts of fëa (spirit) and hröa (body), and the differences in each in Elves and Men.

I cannot do the explanation justice but I definitely recommend reading the relevant chapters.

 

[Eldacar]

I've read a significant portion of HOME but seldom in any meaningful order or the books in full. It's always a discussion like this that makes me look into them for answers, learning something unrelated along the way. I'll spend some time on it. Maybe today, maybe in a week or so.

 

[Amalcarin]

Hofstetter states, that it isn't certain if this type of fading was an intentional design by Eru or a punishment for the sins of the Eldar.

I suppose you are referring to this sentence from text II of Elvish Life-cycles:

The Eldar were “fading”: whether this was by the original design of Eru, or a “punishment” for the sins of the Eldar, is not certain.

But it is not a statement by Carl Hostetter, as it is found in the text that Tolkien himself wrote.

In any case, this matter is treated more thoroughly in note 7 on the Commentary to the Athrabeth Finrod ah Andreth (MR/342–3), which says that the Eldar believed that the “fading” was not natural to them and remained in hope that Eru would heal it:

‘Not natural’, whether it is due wholly, as they earlier thought, to the weakening of the hröa (derived from the debility introduced by Melkor into the substance of Arda upon which it must feed), or partly to the inevitable working of a dominant fëa upon a material hröa through many ages. (In the latter case ‘natural’ can refer only to an ideal state, in which unmarred matter could for ever endure the indwelling of a perfectly adapted fëa. It cannot refer to the actual design of Eru, since the Themes of the Children were introduced after the arising of the discords of Melkor. The ‘waning’ of the Elvish hröar must therefore be part of the History of Arda as envisaged by Eru, and the mode in which the Elves were to make way for the Dominion of Men. <...>)