Keitaro, I wouldn't waste your time arguing with people on the internet about whether this is a good idea. Often, these sorts of discussions follow a pattern: Those out there whom are just being critical for its own sake will just keep pouring on arguments that, usually, are easy enough to counter that a rebuttal pops into your head the instant your eyes cross over the words. But actually going through and replying to each one usually just leads them to respond with something just as well thought out, and now you've wound up debating with people whom are unsure about... whether it is preferable to be alive instead of dead? Yeah. That's a good sign that it's time to talk to someone else.
People who initially take an opposite role will usually do so to the end, man, and will do all sorts of mental gymnastics to keep themselves there. Most people out there are not willing to search for a way through the obstacles -- something that have taken some scientists years -- to achieve the end result you hope for. Usually its just to spill forth the first argument that comes to mind and hope the other person gets tired of replying.
My advice is, seek out discussion with individuals who are adequately willing to find some way to achieve whatever ends (or as close as possible) through the snags and obstacles, but who are critical and unwilling to ignore said snags and obstacles. If you run into an argument that is genuinely worth answering, the answer won't come to mind instantly. Otherwise, don't waste your time, they're probably not gonna make the effort either.
There's a problem with thinking in absolutes like that. We're in the fortunate position here of examining a hypothetical - for the moment - scenario and making sure we've addressed the basics. If you think "whether to be alive or dead" is the only question to be answered, that it's really that black and white, you're missing at least part of the point. I'll demonstrate momentarily why.
Let's for a moment imagine what would happen if those who first discovered oil had the luxury of 20/20 foresight. They'd likely still go ahead, knowing it would bring us to this current technological plateau. Wouldn't they have also made certain, when the opportunity existed, to say 'we've taken this as far as we can without doing more harm than good, let's focus on different technology'. This is what 20/20 hindsight gives us now, what 20/20 foresight would have given them then.
Key question: Was it absolutely, unequivocally worth it, oil? Well, to a certain degree it was. Not bad at all, but not the be all and end all.
In context of this here question of whether being alive is always preferable to being dead. It might look black and white with a very easy answer of, "of course it's always better to be alive than death, anyone who thinks differently isn't worth wasting your time entering into a discussion with." And you'd make a grave mistake (pun unintended) of missing a key element of what most humans value more than life itself: quality of life.
I'm tabling for a moment my reservations on the moral judgment call of bringing people back against their will:
a) We've, through this very debate, Keitaro and I, come to the conclusion these nanobots can make a very decent decision as to whether people want to be brought back
b) It's possible in the future we may find another empirical way to answer questions like that in an objective way
c) It's not necessary to make my next point
So say for a moment there's no inherent problem with bringing people back from the dead and resurrecting them in the present. That is the present at the time this technology is invented, to avoid paradoxes. Then what?
Well, given most humans are keen on quality of life - at least I know of few who prefer to be miserable - let's further take it as read that we'd be able to give them an awesome healthy body that would never get sick, or that even if they did, we'd be able to provide them with a fresh clone.
Still looks like always being alive rather than dead holds true, right? Except we're talking here about transplanting people into the future, saving everyone who has ever lived. How well exactly would someone from 120k years ago fare in this day and age? They'd just adapt overnight without going insane, feeling entirely lost or helpless? We'd still, without any question whatsoever, be doing these people a favour? Because it's always better to be alive than dead, right? We come along in our hubris, take someone who's led a perfectly happy life and may well condemn them to a second life of misery. How generous of us.
That's the kind of thing dealing in absolutes gets you.
Hopefully having illustrated that this entire debate Keitaro, others and I have been having wasn't an exercise in futility, but that there are worthwhile questions to be asked (even in for the moment hypothetical scenarios), we can ask how we then might solve these problems.
Do we say, "don't bring back anyone who's been dead for more than 50 years, because chances are greater they'll be miserable than adapt and be happy?" With 50 years being an arbitrary number.
We could also speculate on whether this technology alone is enough and if we might not need a companion technology, to help these people acclimate to the future.
Let's posit a companion technology, for the moment equally futuristic, in which we have a massive simulation, compartmentalised into several eras. Each person would be brought back to life in a simulation first, no more than a psychologically safe number of years ahead of their original time. They'd live another life in this simulation and be reborn again in the next simulation, all the while holding on to the memories of their previous existence. Eventually, when they're ready to face 'reality', they might be brought forward in a leaps of 100 or 200 years at a time, as long as the simulation can tell the person would be able to handle it without going insane or plain miserable.
Eventually they'd be in a simulation that matches the timeline of this invention. This might take several lifetimes for them, but could take a few days or weeks in realtime. They'd then be ready to join us in the real world, whether that's still a physical reality, or whether we're ourselves simulated entities by then traveling between the stars in self-replicating machines.
But we've now examined a question at least as important: "What's the point of bringing people back if they're going to be miserable?" Saying life is always preferable to death just doesn't take enjoyment into account, which, last I understood is something people care a little about...
Anyway, I don't consider our (Keitaro's and mine) back and forth to have been adversarial. We've stumbled across questions and answers that would have been asked anyway if this technology ever came to pass. I think it's also established we shouldn't rush headlong into everything we invent, just because we can, without at least thinking through the possible scenarios. Would that we had with oil.
It's been very interesting and worthwhile indeed, or at least I think it has been. It's nice to engage with passionate, intelligent people, remaining for the best part civil throughout.
As for mind uploading and Jff3's scenario, Cory Doctorow wrote a freely downloadable novel
a while ago with a very similar idea.
This amount of awesome cannot be from concentrate.