Comment by mechanical_fish | Hacker News Reader

Comment by mechanical_fish | Hacker News Reader

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mechanical_fish

How is "curing aging" necessarily going to help? If, tomorrow, we magically doubled everyone's life expectancy, the age distribution of the population would remain exactly the same. The X axis (time) would just be twice as long.

There might be a short-term blip of excess births as we all get used to the new equilibrium. That is sort of how we ended up with an excess of old people today. But since the magic that doubled our life expectancy probably didn't also double our food, oil, and fresh water supplies, we'd soon see birthrates drop to maintain equilibrium.

But why settle for doubling? Why not make humans immortals? Oops! Now you have abolished children! Sell that Toys R' Us stock.

Or is the idea that our Philosopher's Stone will enable us all to live the healthy lives of twenty-year-olds up to age 150, at which point everything collapses at once and we die in one instant, like the wonderful one-hoss shay? Um, good luck with that.

In summary: changing the nature of life expectancy will change the nature of our demographic weirdness, but is unlikely to produce anything less complicated.

Why not make humans immortals?

Sounds good.

Oops! Now you have abolished children!

Several possible solutions come to mind. A ridiculous solution, which would still be a tremendous improvement over the status quo, would be to institute a Logan's Run policy where you get 100 years of good health and are then painlessly euthanized. But really, I think concerns like that are analogous to the doomsayers 120 years ago who predicted that given current trends New York would be waist-deep in horse manure by 1950. More likely, I would expect a temporary drop in the birth rate, while we get serious about colonizing space (which we should do regardless, on the egg/basket principle).

In summary: changing the nature of life expectancy will change the nature of our demographic weirdness, but is unlikely to produce anything less complicated.

Things would be different, yes. And given that right now aging is responsible for an impending fiscal train wreck, as well as incalculable suffering and destruction of human potential, we badly need something different.

Actually, even if no one dies, we can still all have children without creating infinite population, as long as we have, on average, less than 2 per couple (1 per person).

For example, if we have 1 billion people who suddenly all become immortal, and each couple has, on average 1.8 children, we asymptote towards a world with 10 billion immortals. Everyone could have offspring, though the actual number of young people would be continuously decreasing...

If $p0$ is the starting population, and $a$ is the number of children per person (number per couple divided by two), we have

  p = p0 * sum_{i=0...inf} a^i = p0 / (1-a)

Curing aging doesn't necessarily mean changing lifespan, although that's usually taken as a given, but what it really means is not degenerating with passing years.

In that case - even if people still live roughly 65-90 years, the age distribution of the population stops being such a matter of importance. If, at 80 you still feel and heal like a 50 year old there's much less problem with a) who is going to work and b) who is going to look after you, since you can work and you don't need anyone to look after you.

And isn't that the main concern of this kind of examination of age distribution?

That is sort of how we ended up with an excess of old people today.

Excuse me? "excess"?

But since the magic that doubled our life expectancy probably didn't also double our food, oil, and fresh water supplies, we'd soon see birthrates drop to maintain equilibrium.

Yes, and that would be fine.

Why not make humans immortals? Oops! Now you have abolished children!

What do you mean "oops"? Also, people would still die from other causes.

In summary: changing the nature of life expectancy and changing the nature of aging are different things. Anti-aging research isn't supposed to be focused on the "surviving 90 times round the sun" bit, but on the "chronic disease, weakness, and disability" that comes with it.

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