Oh boy. I have a lot of thoughts here. Death has always been an interest of mine from a philosophical perspective.
It has even begun appearing in movies and science fiction literature as a norm of the far-future life. I, as a complete naturalist, am pretty confident that practical immortality will be achieved within, at most, a hundred years.
First of all, I find this hard to believe. I don't keep up with biotech at all, but there have been lots of times where we've thought we'd been in a certain place technologically within X amount of time, and it hasn't happened. Weather prediction is one such area where we thought we'd continue to get more and more accurate inexorably -- right until chaos theory taught us that such things are virtually impossible to predict. In any case, I'd be very surprised if we didn't hit a wall at some point on life extension techniques where they simply can't get us any further. I don't really have much backup for this opinion, but then again the mechanics are the least interesting aspect of it for me.
My question is, how would you feel about such a development? I would like you to forget about the obvious ramifications of immortality (overpopulation, crippling social change mechanisms, deeply disturbing understood economic paradigms, and so on) Imagine that those issues were overcome, and you can live your life more or less as you do now (family, work, study, travel, entertainment, etc).
I think it's interesting that you want to bracket off the larger social ramifications, since they're quite interdependent with the individual ramifications. Actually, I think immortality is a bad idea in both cases, and for much the same reasons. But you're right to point out that the wider ramifications of immortality would be catastrophic... the world is overpopulated already just for starters, not to mention that death has always been one of the primary mechanisms (if not THE primary mechanism) for social change. Older people become more rigid in their thinking, and if the old guard never died off and vacated their positions of authority and power, it'd be a lot harder to disseminate new ideas.
How would that affect your life? How would it change your views? Would you like it? Would you choose a different path in life? Would you reject it and opt for a normal life span?
When I pose this question to science oriented people, I typically get cautiously optimistic reactions. But I would like see the reaction of more mixed group of people. And please give this question some thought as how it would affect you. Not just a rushed "life has no meaning without death" impulse.
P.S. In this scenario, you have the choice of being fully immortal. That means you can't even die in an accident. Your brain contents are backed up every hour or so on a remote server, and the worst that can happen is losing an hour of continuity. Meaning, you can be perfectly reconstituted with your memory, consciousness, and personality fully intact.
First of all, I think a lot of people like the idea of immortality because as a species we generally want to live longer than the average person lives. And on our deathbed, we can always wish for a few more years. But when infinity stretches out before you, then it starts to become a different question.
The classic article written on this topic was written in 1973 by the philosopher Bernard Williams and titled "The Makropulos Case: Reflections on the Tedium of Immortality." I recommend it highly, as it's by far the most cited text on this subject (I can send a PDF copy to anyone who PMs me for it). And in fact, he poses much the same scenario as you do. He talks of a fictional character from a play (I forget which play) who is a 40-year-old woman with access to an elixir that will keep her alive indefinitely as long as she continues to drink it. After 300 years, she voluntarily stops.
Williams' basic argument is that all people develop a certain character, along with certain likes and dislikes, certain dispositions, etc, and that at a certain point, any person will have experienced all that a person of that character and disposition will wish to experience. They will be deeply, existentially bored -- not a boredom which still looks to tomorrow for alleviation, but a boredom which knows that there is simply nothing else anywhere that he or she wants to do. I have to say that I agree with Williams on this point. Sure, there will always be new people to meet, new injustices to fight, new basketball games to watch, new books to read. But seriously, how long could you go on doing the things you enjoyed until you had simply done them to death? A thousand years? Maybe. A million? Um... no.
Another curiosity would be to see how much religion would be diminished.. for obvious reasons.
I really think that religion can be seen as an attempt to answer the fact that everyone dies. The fact is that -- on the surface at least -- nothing you do will ultimately matter, because eventually you'll die and become nothing, and then even everyone who you directly affected will die. So why even bother living? No one really knows quite what to do with that question. But a lot of religions have tried.
And in fact, when religions are viewed from the perspective of trying to answer our questions about death, I think that's where Christianity and Islam stand out as particularly lame. They seem to sidestep the issue rather than address it by simply saying that we continue on living in some other realm. Besides stretching creduality (as an aside, odd that only humans get to live forever, right?), this view has all sorts of negative implications. First and foremost, it belittles our existence here on earth, which then becomes little more than a pre-game, or a test. It makes us undervalue physical bodies in deference to our supposed "spiritual/incorporeal" sides. It gives us license to continue exploiting the earth as we have been. And in the end, it's all so VERY ego-centric. Why the hell is any person so important that he or she must live on FOREVER? Hate to burst you bubble, but there have been billions and billions of people before you, and there will be more billions after you. No one's so special that they should live on for eternity. I'm sure the new generation will do quite well without us.
In any case, setting aside some of the more selfish reasons, I tend to think people believe in afterlife either because they'd like to imagine their loved ones going on in some way, or because they simply can't wrap their head around a world that doesn't have them in it (or both).
To be fair, really no one can imagine his or her own non-existence -- the best we can do is either imagine the world in the case where our physical self is absent, or just imagine black nothingness. But in both cases we are still conscious of thinking about blackness, or thinking about our absence. The existential truth of death from any finite perspective is not just of the self dying, but of THE UNIVERSE ending. When we die that is the END, and there is NOTHING. That's not something that anybody's mind can grasp, but just because we can't grasp it doesn't mean that we get to live on somehow.
And as for lost loved ones (and ourselves), Epicurus' statement from more than 2000 years ago still holds water: "Death is nothing to us, since when we are, death has not come, and when death has come, we are not." In other words, death is simply non-existence, and so it seems hard to construe it as bad for the dead person, because the dead person no longer exists to care that he or she is dead. And while the living may mourn them, death is not ultimately such a bad thing. Don't get me wrong, I very much enjoy living, but I don't see myself as so important that I need to believe that I go on forever. Lots of other will come after me, some better and some worse -- and I don't need to be hanging out in a peanut gallery up in the clouds while these others go about living. The work of others and whatever small legacy I leave behind to help (or hinder) them should be more than enough.
One more observation. Questions about death are tied up very closely with questions of personal identity, so much so that we might call them one and the same question. When we die, what is it that actually dies?
Of course, there are at least two different kinds of self. There is first the active, reflective ego-self or subjective self, and second is the objective (or perhaps "objectifiable") historical self. So what does it mean to say that "I am AtheistPreacher"? On the usual reading, both the proper name "AtheistPreacher" and the personal pronoun "I" -- at least when AtheistPreacher is speaking it -- rigidly denote the same person. Yet as Mark Johnston points out in his book
Surviving Death, I can imagine being someone else, like FDR, and then being killed in an event that wiped out all of human life, so that AtheistPreacher never existed. As Johnston summarizes it: "While knowing that I am Johnston, I can, without semantic incoherence and without ignoring the structure of the fact that I am Johnston, imagine myself [the ego-self] existing without Johnston [the historical person] existing."
What exactly does this idea tell us? Precisely that the subjective self is empty of content. Which historical person it happens to be does not matter to the ego-self -- by itself it's like a picture frame in want of a photograph to fill it. It is simply, as Johnston puts it, quoting Wittgenstein's Tractatus, "the limit of the world, not a thing in it."
Unless I misunderstand, this is a rather Buddhistic reading of the self. But in any case I find it a compelling one. And the take-home message is, once again, that our subjective selves aren't even really worth saving. There are billions of subjective selves out there, and while there may be small differences in sense organs that will then make us perceive the world differently, the vast portion of our differences arise from our social and historical context, the historical details of our lives. It is our historical and objective selves that actually matter in the wider context. But of course, we need not worry about saving them, because the fact is that we all leave legacies behind, and the next generation will take what is good about us -- those actions and ideas which help to enrich the world -- while they will leave our self-centered actions and ideas buried with our corpses. That sort of objective immortality is a fact, even if subjective immortality is a misguided pipedream.
I may eventually respond to some of the other points in this thread, but for now I think I've written enough. Fascinating question, though.