Is there any evidence in Tolkien's writing, notes or letters pointing to the planned future development of Arda?
More specifically, did he envision the Age of Man to usher in the industrial progress a la our Earth, or a forever-feudal Lords-and-serfs society?
I'm only interested in data from source materials, not idle "laws of history" speculations.
Tolkien intended Arda to be an ancient form of our Earth. From The Letters, Letter #211
I imagine the gap to be about 6000 years [destruction of the Ring ~ modern ): that is we are now at the end of the Fifth Age, if the Ages were of about the same length as 2nd Age and 3rd Age. But they have, I think, quickened; and I imagine we are actually at the end of the 6th Age, or in the 7th.
In fact, Tolkien maintains that Hobbits still exist. From Fellowship of the Ring, Prologue:
Hobbits are an unobtrusive but very ancient people, more numerous formerly than they are today; for they love peace and quiet and good tilled earth: a well-ordered and well-farmed countryside was their favourite haunt. They do not and did not understand or like machines more complicated than a forge-bellows, a water-mill, or a hand-loom, though they were skilful with tools. Even in ancient days they were, as a rule, shy of 'the Big Folk', as they call us, and now they avoid us with dismay and are becoming hard to find. They are quick of hearing and sharp-eyed, and though they are inclined to be fat and do not hurry unnecessarily, they are nonetheless nimble and deft in their movements. They possessed from the first the art of disappearing swiftly and silently, when large folk whom they do not wish to meet come blundering by; and this an they have developed until to Men it may seem magical.
Since Arda is in fact intended to be our Earth, it can be deduced that it was eventually industrialized, with or without Tolkien's planning. :)
One other thing: Tolkien himself began work on a sequel to Lord of the Rings tentatively titled The New Shadow, which took place during the reign of Eldarion Telcontar (Aragorn's son). Placing it at least 120 years into the Fourth Age. Tolkien said:
"I did begin a story placed about 100 years after the Downfall, but it proved both sinister and depressing. Since we are dealing with Men it is inevitable that we should be concerned with the most regrettable feature of their nature: their quick satiety with good. So that the people of Gondor in times of peace, justice and prosperity, would become discontented and restless — while the dynasts descended from Aragorn would become just kings and governors — like Denethor or worse. I found that even so early there was an outcrop of revolutionary plots, about a centre of secret Satanistic religion"
The 15 or so pages that he wrote appears in chapter 16 of The Peoples of Middle Earth.
Tolkien wasn't a great fan of industrialization, as we can see from his descriptions of both Isengard and the Shire thanks to Saruman's meddling.
It's not clear how he envisaged the time between the events of LotR and the modern day, though. He briefly sketched out a sequel, which was to take place after Aragorn's death in the time of his son, Eldarion, when Men were already beginning to turn back to evil, but he abandoned it early on.
We do know that he considered the time of the Elves to be passing, and Men would inherit. Saruman says as much, according to Gandalf, when he originally tried to subvert him:
'The Elder Days are gone. The Middle Days are passing. The Younger Days are beginning. The time of the Elves is over, but our time is at hand: the world of Men, which we must rule.'
But perhaps the best clue to how Tolkien thought of the future comes in the conversation between Gimli and Legolas when they first enter Minas Tirith:
'It is ever so with the things that Men begin: there is a frost in Spring, or a blight in Summer, and they fail of their promise.'
'Yet seldom do they fail of their seed,' said Legolas. 'And that will lie in the dust and rot to spring up again in times and places unlooked-for. The deeds of Men will outlast us, Gimli.'
'And yet come to naught in the end but might-have-beens, I guess,' said the Dwarf.
'To that the Elves know not the answer,' said Legolas.
You have to remember that we're not just dealing with a timeline of past-present, but with the timeline of Tolkien's development of his ideas and world. You can see it in the Book of Lost Tales, one of the first compilations that Christopher Tolkien worked on his father's earliest unpublished manuscripts, as you can see in the preface:
The Book of Lost Tales was the first major work of imagination by J.R.R. Tolkien, begun in 1916-1917 when he was 25 years old, and left incomplete several years later. It stands at the beginning of the entire conception of Middle Earth and Valinor, for the Lost Tales were the first form of the myths and legends that came to be called The Silmarillion.
In here, Tolkien imagines an English sailor by the name of Eriol, or Ælfwine, who sails westward and makes his way to Tol Eressëa, the Lonely Isle, where the elves still dwelt, and hears from them the ancient stories of the First Ages. These tales are early and undeveloped versions of the ones we know from the Silmarillion: Names are a bit different (Melkor is Melko, the Noldor are Gnomes(!)) and the words and syntax of the Elvish tongues have changed, but the basic ideas are there.
So, to actually get back to the OP, at some point, Tolkien envisioned our present - or at least a version of it - to be the "future" of Middle Earth. But this was an early concept that he entertained in his youth, and it seems that by the time he fully fleshed it out, he abandoned this idea.
Tolkien imagined Arda to transition into the modern day as we know it, with the seventh age corresponding to the Gregorian Calendar.
In 1958 Tolkien wrote a long letter to Rhona Beare answering several questions she had posed. Towards the end, when explaining some inconsistencies between the book and our world, Tolkien explains it to the long time gap and talks a bit about the future. Estimating that another 6,000 years have since passed putting us in the sixth or seventh age.
I could have fitted things in with greater versimilitude, if the story had not become too far developed, before the question ever occurred to me. I doubt if there would have been much gain; and I hope the, evidently long but undefined, gap* in time between the Fall of Barad-dûr and our Days is sufficient for 'literary credibility', even for readers acquainted with what is known or surmised of 'pre-history'
* I imagine the gap to be about 6000 years : that is we are now at the end of the Fifth Age, if the Ages were of about the same length as S.A. and T.A. But they have, I think, quickened; and I imagine we are actually at the end of the Sixth Age, or in the Seventh.
October 1958 letter to Rhona Beare - The Letters of J.R.R. Tolkien #211
Two years later, in a writing titled "The Awaking of the Quendi & position of Ingwë/Finwë/Elwë etc.", Tolkien lengthed that time gap (to about 9,300 years), and clarified that the dates of the seventh age corresponded to the Gregorian calendar, "we being in 1960 of the 7th Age".
If they awoke in VY 1050 that would give 40 VYs, or 5,760 Sun Years in which Melkor could have dealings with them and corrupt them, before his captivity. The Atani entered Beleriand in 310 Bel. That is in the 22nd Sun-year of VY 1498. Men had then existed for 448 VYs + 22 SYs: i.e., 64,534 Sun Years, which, though doubtless insufficient scientifically (since that is only – we being in 1960 of the 7th Age – 16,000 years ago: total about 80,000), is adequate for purposes of the Silmarillion, etc.
The Nature of Middle-earth - "The Awaking of the Quendi"
1) We seem to be in the future of Middle-earth, since Tolkien started a story involving a man of today traveling in time to Numenor at the time of its downfall.
2) Two quotes from The Return of the King, chapter 6 (Many Partings):
'Never is to long a word even for me,' said Treebeard. 'Not while your kingdoms last, you mean; but they will have to last long indeed to seem long to Ents.'
'The New Age begins,' said Gandalf, 'and in this age it may well prove that the kingdoms of Men shall outlast you, Fangorn my friend.'
and, a bit later:
[Treebeard: ] 'For the world is changing: I feel it in the water, I feel in the earth, and I smell it in the air. I do not think we shall meet again.'
And Celeborn said: 'I do not know, Eldest.' But Galadriel said: 'Not in Middle-earth, nor until the lands that lie under the wave are lifted up again. Then in the willow-meads of Tasarinan we may meet in the spring. Farewell!'
(another reference to that Second Prophecy of Mandos)
