It's surprising that we don't work harder on fixing this. 10x what we're spending on AIDS might be a good place for a start. Imagine what humanity could accomplish if the standard life-span was just 200 instead of 70. Imagine what you personally could accomplish.
Plus, they're more likely to accept the world as it is now instead of moaning about how much better everything was fifty years ago... (I think there's some kind of statistic or history tracking that has shown that in the mind of society, everything has always been better fifty years ago. I recall reading something about how the young are only interested in partying and fighting - written by a monk two hundred years or so ago).
Choosing limited lifespan to achieve a particular political balance strikes me as a truly bizarre approach.
As far as science...just take care that smart people have as many kids as they ever do, and we'll be okay.
The people that I consider the most intelligent and/or smart in various general and specific ways also seem to be the most given to not want children (and some go so far as to get operations that effect this biologically). Many others further down the distribution of "smart people" are inclined to have fewer children, and have them later.
In other words, in my personal life experience there is a very strong inverse correlation between the intelligence of people and the amount of children they have or will tend to have, and that's assuming they have children at all. The intelligent folks I have met seem to be the only group where a total rejection of childbearing exists to a statistically non-negligible degree, to put it mildly.
No, not politically correct at all, and, perhaps unsupported by bodies of evidence other than my own (mis?)perceptions.
But I don't think I'm the only one who has noticed this.
This doesn't necessarily mean that more intelligent people will have fewer children, as it's more of a question of prioritization than of ability. It does probably imply a weak correlation (smarter people tend to like to use those smarts), but there are certainly many intelligent people out there who value their children more than they value their personal ambitions. (While this is certainly not a given... consider your parents!)
This is a wildly different situation than existed even 100-200 years ago. Gregory Clark has some historical data on the industrial revolution, if you're interested.
We're apparently struggling to feed six billion now, which problably means that we'd need to get rather creative to feed eighteen billion.
It's also predicated on the assumption that it's actually bad for long-lived people to get a little stuck in their ways. This may not be true either; society is unstable, in the physics sense of the term, what with the constant influx of new naive people. Adding some more "momentum" into the system may be safer and better. Again, I'm not saying this is true or false, only that the casual assumption of the truth is unjustified.
Having 120-year-old youth will be a genuinely new phenomenon, and nobody knows what that means. Preventing such technologies from being used or developed (or even arguing against it) based on such terrible arguments would be a terrible thing to do.
I never said that it's bad to be stuck in your ways: what I said (or tried to say) was that not being stuck in your ways makes it easier for you to come up with novel solutions to problems.
Having a certain amount of momentum in society is definately a good thing, but having too much of it means that society will respond too slowly to a changing environment. In my opinion, our current momentum doesn't make us too volatile. That's just my opinion, though, but that might just be a reflection of me being fairly young.
I'm only 30 myself, which definitely moves me out of the flush of 18-24 but hardly qualifies me as an old fart. I sometimes think that going a bit slower could be helpful to society, but the truth is that we don't have forever to dilly-dally where we are. If we're going to win the sustainability race with the high-technology solution [1], we need to get there before the resources run out.
With a 200 year lifespan, we would have people trying to enforce cultural norms from 180 years ago. In 1829, women couldn't vote, slavery was common, imperialism was considered good foreign policy, it was common sense that women and blacks were incapable of complex tasks or higher level reasoning, and forcible relocation of American Indians was being practiced. Meanwhile, the steam engine was considered pretty hot shit.
To ask someone who grew up in that era to accept the son of an African immigrant as president, gay marriage, streaming pornography, the fall of the European empires, globalization, and software startups as facts of life is absurd. Likewise, if we lived long enough to build the world of 2189, it would have the same petty biases and taboos that we have today.
It's important sometimes for generations to forget bygone eras and move on.
My grandparents are all dead, but I suspect that few of them would be pleased with the prospect of a black president. Even my parents would be less than pleased to learn that I was bisexual.
Your grandparents may be more open minded than mine, and that is a credit to them. But for every one of them there's ten old people who don't keep up as well.
{edit} Just to add, I think this is because newer generations are growing up in a world where things are increasingly in flux; whereas older generations grew up in much more stagnant times (with respect to social and technological progress). {/edit}
How does it make sense to talk about how 'well off' humanity is outside the context of living people?
We might find that we can't accomplish much, as older, more set-in-their-ways voters choke off support for innovation in favor of being supported in their old age. (We could give the United States as a partial example of a country where this is already national policy.) Note that I am not grinding axes for young people here--I am probably already more than half-way through my lifespan, and definitely a good bit older than most HN participants.
But, due to the nature of the problem, that sort of thing is unlikely. Fixing old age will necessarily involve making us healthier.