Yes, the argument is that as time passes, particularly multiple millennia, less information survives
So no new arguments, then.
The counter-argument is that as books are published in greater and greater numbers and the technology to copy them becomes easier and easier, the total loss of one becomes less and less likely. Have you any idea how many copies there are of the
Encyclopedia Brittanica, 15th ed.? (I don't. I tried googling it, but failed. But it must be hundreds of thousands or millions).
A second counter-argument is that deliberate attempts to preserve knowledge will take the problems of accidental and deliberate destruction into account and take measures to counteract them.
- especially if:
a) the information was destroyed (accidentally or deliberately, near the time or since)
The information is already stored in multiple copies and formats.
b) the information was recorded in a language/format that is no longer intelligible eg Phaestos/computer disc
Language:
Rosetta Project. Format: Reconstructing unknown formats is what cryptographers do for a living.
c) the information was recorded on media that are impermanent (so that no originals survive) eg everything recorded today apart from headstones and foundation stones
Impermanent under what conditions? Stored by a library or a museum or a private collector or a bank? Etched on glass discs and hidden in a time capsule?
With many millions of books to start with, some are bound to survive.
d) any copies made of the originals may be lost or tampered with
They may indeed, but as I've pointed out a couple of times already, you need to lose
every copy without new copies being made. Not going to happen in the TU. (I'm referring to a general knowledge base of the 20th Century, not any particular datum).
e) material may not be considered worth copying or saving - it's not viable to copy everything
f) people with their own agendas/indoctrinations decide what is copied and/or saved
And when you've convinced all people of Charted Space to tamper with all extant copies of all encyclopedias, history books, and library data collections, what will you do for an encore?
Much depends on how important the event has seemed to be during the intervening time. If it's deemed inconsequential it runs the risk of being forgotten, but if it's vitally important it runs the risk of being distorted or suppressed.
The event? The original question was if Terra really knew anything about 1969 AD. How did you go from that to the singular?
Depends. Your examples happen not to have emotional meaning for the descendants, but there are alternative examples. There are Germans denying certain events of just over half a century ago, there are Americans arguing daily about who actually shot a president just under half a century ago, there are Irish who are deeply upset about events that happened to their ancestors 400 years ago, and there are whole races (half a planet) perpetually warring about whether a certain individual 2000 years ago was divine or merely a prophet.
And yet there is no shortage of Bibles and Korans in the world today.
As for 1969, what if the Vilani wanted to suggest that the Terrans didn't discover spaceflight for themselves, but reverse-engineered a Vilani probe...? How accurate would your records on Capital be then?
The Vilani? All of them? And why in the Universe would they want to do that? Deny that the Terrans invented the jump drive, that I can see, but what's so special about space travel?
Anyway, they wouldn't be able to tamper with the lovingly preserved copies of various 20th Century encyclopedias in the Emperor's private collection.
There are people publishing stuff even now that claims much of our technology is a result of reverse-engineering from Roswell. Stuff that will be stored and copied time after time.
And I'm positive that there are going to be crackpot Vilani supremacists publishing stuff about how the Terrans didn't actually invent the jump drive. Crackpot Vilani supremacists with the resources to tamper with every library collection in Charted Space, on the other hand, I'm equally positive won't exist. If they did, they'd be much better off using those resources to take over the Imperium.
Suppose the 51st Century historian holds two electronic extracts (5000th generation copies) from the New York Times and three extracts (3000th generation copies) from the Fortean Times.
Those are the only sources of information available to him? I'll try.
...
Nope, sorry. I can't manage to make that assumption.
Yes, we are storing a lot of information just now, but we're also storing a lot of crap and it's all on impermanent media. Will the future (hopefully honest) historian be able to distinguish one from the other?
Will he know anything about 1969 AD? Yes, he will. Will he know everything? Of course not. Will some of what he knows be false? Almost certainly -- no, make that completely certain. Will
most of what he knows be reasonably accurate? Yes, it will.
Hans