[hfinney]

Let's step back for a moment and think about what our goal should be in medicine. Suppose we could extend everyone's healthy life by 10 years. How much have we gained? Say there are 7 billion people. Have we added 70 billion man-years of healthy life? Not necessarily. After all, every year people experience 7 billion man-years of life. After 10 years, we'll have added 70 billion. So this great medical advance is the same as waiting 10 years! All we are really doing is speeding up the rate of accumulation of man-years. And even that is only temporary. After 10 years people will again be dying at the rate they are today (just 10 years older).

You could get the same speed-up of accumulating man-years by increasing the birth rate - more happy humans racking up experiences. But wait, the birth rate is falling! Is that a moral catastrophe? Yes, if you want to maximize the rate of accumulation of healthy man-years.

So these issues are complicated. It's too easy to focus on this personally. Sure, I want to live forever, and I'm taking steps to do so. But for the population as a whole, the calculus works out rather differently.