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Comment by curiousgeorgio | Hacker News Reader

> Longer lives translates into fewer deaths per year.

Are you sure about that?

When the population is growing, yes. A bit of hand-wavy calculation to illustrate the phenomenon: if people die at 80, then people dying today are those born in 1931, if they died at 85 it would be people born in 1926, which were less numerous => less death. (Of course, not every one die at the same age and all, but you get the idea)

All else being equal, then very clearly yes. You could perhaps try to incorporate predictions of more indirect effects of longer lives (like increased reproduction rates and population) to argue that it could somehow cancel out, but that would take a lot of work to be convincing.

I think their point was that if everyone lives to 150, the rate of deaths per year will eventually converge to the same as if they live to 50. Lengthening the pipe doesn’t mean more water flows through it per minute.

Not true.

If there are 9 billion people (just to keep the numbers round), and they all live to 50, then every year 9 billion / 50 = 180 million people die (and the same number are born). But if they all live to 150, then every year 9 billion / 150 = 60 million people die (and the same number are born).

Only if the birth rate proportionally drops, which seems unlikely.

On the other hand, if the birth rate remains steady then the percentage of people alive that die in a given year decreases, which is maybe the more relevant metric as it seems like there’s less death around.

>just to keep the numbers round

That's not "just keeping the numbers round", that's putting a huge assumption on a complex system (births = deaths, no change in overall population over time).

The 9 billion was just to keep the numbers round. 8 billion would be a more accurate number, but it's not divisible by 3, and therefore not divisible by 150.

What you seem to be quibbling with is the assumption that the population was steady. That's an assumption that could be argued with, but it's not the "keeping the numbers round" part.

Fair enough

I mean your technically right to question because the only thing which can increase deaths are births ultimately as everything else 'just' moves them forward, but I think it was quiet clear what they meant.

Think of how many lives we could save if we could just reduce births!

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