|Bah, mortality. Damn spell checkers.|
Look at it this way, what is human? Is it just our DNA? If some hypothetical aliens adopted a human child would it be just as human as the rest of us? No; culture, beliefs, behaviors, norms, etc. that also defines our humanity. It’s not just our ability to reason that defines our humanity either, just our sentience.
Second, how would immortality affect our humanity? My argument is that it would destroy it. I had this argument on a transhumanist forum (don't ask) before so sorry I had just made a few assumptions before. This argument does differ slightly depending on the type of immortality we're talking about but I think the one with the least impact is downloading (why I mentioned it before) where your brain is essentially copied into a computer. Personally I don’t see the point cause even if it’s a perfect copy, its still a copy and ‘you’ still die. But the advantage there is you can live in any kind of virtual environment you want that is just as ‘real’ as you are, paradise. Another example that more commonly thought of and what ya’ll probably first think of is like Stephen Baxter’s ‘anti-senescence’ theory which stops the telomeres on you DNA from running out (or something like that, he does some really hard scifi). Basically you live forever or until the therapy fails. In his book the practical limit there is like 1,000 years although we’re talking about forever.
To answer the question though, its simple really. The average human lifespan is a little over 80 years, we have only that amount of time to do what we want and then its over. Our entire society is built around that, the fact that the people ahead of us eventually die is what allows us to go forward. How the hell do you compete against a person who has a 500 year head start on you? Free market my ass, you’re going to be stuck on the bottom. You might make the argument that in a perfect market it doesn’t matter how long someone has been working, if someone below them is better then they’re out. And we all know that’s bullshit, if Joe has been my vice-president of sales for the past 2 centuries and has done a good job, I don’t care how good that 70 year old youngster is, he ain’t getting the job. And that’s just socially, immortality would destroy the individual. Sure some would be fine, the super rich perhaps. But if we don’t have a decent idea when we’re going to die, how can plan our future? I like good honest labor but I don’t want to work for the next 1,000 years. You’ll be destroying families. I have 3 great-grandparents and I love them but if I had a great-great-great-grandparent, odds are I wouldn’t give a shit about them. You will never the ‘the’ head of a family and no matter what you do or how old you get; you’ll still be someone’s grandchild. So how do you escape that, by getting away. We each have our own lives to live and our own families to make but unless you get away from your ‘ancestors’ you’ll always be hamstringed. Even your parents, the simple concept of a son inheriting his fathers business will be thrown out the window. In the end, we truly won’t be human, at least not in any way that matters now. We’ll leave our parents ASAP, parents who probably won’t care about us as much as they can have massive families. You’d grow up without an education as the rational is you can get one later. Everything will be ‘later’; you’d be stuck in a dead end job for centuries waiting for your boss to die in an accident. Unless there is room for humanity to expand, every market niche would have been taken long ago. And even if we could expand to other worlds, others would have far better resources to exploit them. You couldn’t get very far up the latter, its dominated by the first immortals and the top 99% in intelligence, the other 98% of us would just have to settle for 2nd place, at best.
Finally, to make this argument complete, you have to ask yourself is humanity worth saving. There can’t be any half measures here, it’s either done or it isn’t. Naturally I wouldn’t live for humanity, but I would die for it but of course I already will. If anyone can come up with how our humanity can be preserved and we’d stay immortal, I’ve love to hear it but I don’t think there is one.