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How many people have ever lived on Earth?

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Re: How many people have ever lived on Earth?

#41

Post by jcranmer »

justinclift wrote: post #27

> Average life expectancy in Iron Age France (from 800 B.C.E. to about 100 C.E.) has been estimated at only 10 or 12 years. Doesn't that sound extremely weird? Like, how does puberty, and 9 months to have a baby, fit in with a 12 year total life expectancy? Maybe I need more coffee or something...

This is a common misconception about how life expectancy works. If you have 10 children, 9 of them die at age 5, and the 10th dies at age 55, the life expectancy of your children is 10. Those 9 children who die early aren't going to go through puberty and become parents, but the life expectancy of those who do reach that stage is decently long. Low life expectancy doesn't mean you're considered some decrepit geriatric at age 12; it means that you get to grow up with lots of siblings who didn't make it.

When you look at pre-modern societies (essentially until around 1900 or so), there are four large causes of low life expectancy that don't really exist anymore. Infant mortality was extremely high (a quarter or so of live births didn't make it more than a few days). Then child mortality itself was high (you had perhaps a 50-50 chance of making it to puberty). For young women, there's an extra hit to life expectancy due to risky childbirth (you have about a 10% lifetime chance of dying in childbirth). For young men, they get extra risk due to endemic warfare--the baseline casualty rate of premodern warfare is basically WW2-levels of total war. Of all these factors, the infant mortality is the heaviest drag on life expectancy, as dying at age 0 really pulls down the average lifespan.

Re: How many people have ever lived on Earth?

#42

Post by jcranmer »

yreg wrote: post #22
kurosawa wrote: post #21

Wondering how many will ever be born here, if it lasts until the sun dries out for example

The Doomsday Argument[0] relates to this. It says that since the reader is born in the current times with there being X billion humans so far, statisticslly there shouldn't be too many more (not say tens of trillions). I don't think the logic is too sound though. Or rather that the premises should be taken for granted. [0] https://en.wikipedia.org/wiki/Doomsday_argument

I like Randall Munroe's summary of the argument (https://what-if.xkcd.com/65/):

> Almost everyone who hears this argument immediately sees something wrong with it. The problem is, everyone thinks it's wrong for a different reason. And the more they study it, the more they tend to change their minds about what that reason is.

Re: How many people have ever lived on Earth?

#43

Post by Towaway69 »

delgaudm wrote: post #36
lyu07282 wrote: post #33

Makes me wonder how many more billions will have to die before we bother to put some actual effort into ending death, but I know that's a very obscure opinion. https://nickbostrom.com/fable/dragon

Why would you want to end death?

I think it was Ayn Rand who said that with her death all life ends. Well it did for her thankfully not for the rest of us.

Re: How many people have ever lived on Earth?

#44

Post by doodlebugging »

And dopplegangers are living proof that God does recycle faces. Somewhere out there in amongst all the people who have ever lived are people who look just like you.

I distrust numbers like the ones they use in this analysis. There are so many unknowns and unknowables that the best we can hope for is to SWAG (Scientific Wild-Ass Guess) a few numbers and call it good. I think that is what we have here. It serves a purpose even if it is more likely to be wrong.

Re: How many people have ever lived on Earth?

#45

Post by orwin »

jcranmer wrote: post #41
justinclift wrote: post #27

> Average life expectancy in Iron Age France (from 800 B.C.E. to about 100 C.E.) has been estimated at only 10 or 12 years. Doesn't that sound extremely weird? Like, how does puberty, and 9 months to have a baby, fit in with a 12 year total life expectancy? Maybe I need more coffee or something...

This is a common misconception about how life expectancy works. If you have 10 children, 9 of them die at age 5, and the 10th dies at age 55, the life expectancy of your children is 10. Those 9 children who die early aren't going to go through puberty and become parents, but the life expectancy of those who do reach that stage is decently long. Low life expectancy doesn't mean you're considered some decrepit geriatri…

I think the 10% death at childbirth was only for the first child. Or is that the average?

Re: How many people have ever lived on Earth?

#46

Post by bohadi »

Buttons840 wrote: post #6
tjpnz wrote: post #3

Why do I keep (mis)remembering a fact that most members of the human race are alive right now?

It's not most, but it's still remarkable that about 5% of humans who have ever lived haven't died.

Even more remarkable is that by the estimate in Table 1, the percentage is increasing over time.

If this trend continues over the centuries it is conceivable that >=50% of all human beings to ever exist could be extantly alive. Either growth rate exploded or death rate arrested.

It recalls to mind Fyodor the one-time teacher of Tsiolkovsky of the rocket equation, who conceived a kind of akashic immortality project he called the Common Task. So like maybe this Kaneda-Haub statistic asymptotically approaches 100%.

Supposing a starting population of 2 we can call Adam and Eve divided by 0 dead ancestors do note it started at infinity before dropping precipitously near 0 for a 202k year exponential climb to today's ~7%. Fwiw I consider such plot affirmative evidence assuming the demographic inputs are not wildly inaccurate.

Re: How many people have ever lived on Earth?

#47

Post by wiseowise »

delgaudm wrote: post #36
lyu07282 wrote: post #33

Makes me wonder how many more billions will have to die before we bother to put some actual effort into ending death, but I know that's a very obscure opinion. https://nickbostrom.com/fable/dragon

Why would you want to end death?

Because not all want to die.

Re: How many people have ever lived on Earth?

#48

Post by TheCoelacanth »

orwin wrote: post #45
jcranmer wrote: post #41

Earlier quoted context omitted.

This is a common misconception about how life expectancy works. If you have 10 children, 9 of them die at age 5, and the 10th dies at age 55, the life expectancy of your children is 10. Those 9 children who die early aren't going to go through puberty and become parents, but the life expectancy of those who do reach that stage is decently long. Low life expectancy doesn't mean you're considered some decrepit geriatri…

I think the 10% death at childbirth was only for the first child. Or is that the average?

10% cumulatively across their whole lifetime. In other words, of all women who died, 10% of the deaths happened during childbirth.

Re: How many people have ever lived on Earth?

#50

Post by irrational »

lyu07282 wrote: post #33

Makes me wonder how many more billions will have to die before we bother to put some actual effort into ending death, but I know that's a very obscure opinion. https://nickbostrom.com/fable/dragon

Yes, because I totally want to continue working to pay taxes, rent, utilities, clothing, food, etc. forever. Frankly, I am not trying to hasten my death, but I am looking forward to it. Finally a break from the eternal go go go go, just to maintain life.
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