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Comment by inglor_cz | Hacker News Reader

People don't generally understand premodern demography. We have fairly good demographic record of England, where detailed birth and death records were kept.

As of the 18th century, about 30 per cent of people died before reaching adulthood, but this percentage seems to be much higher in urban areas, which acted like population sinks. (Pathogens were really concentrated there.) Once you lived to be 20, you had more than even chance to live to 40, and a good (AFAIK over 35 per cent) chance to live to 60, but the drop-off after that was steep, 70 y.o.s were already uncommon and 80 y.o.s very rare.

Interestingly, cardinals and popes lived significantly longer, 70-somethings were a common sight in conclaves. Easier life, no military threat, good water, almost no risk of famines.

I am writing this from the top of my head, so precise values may differ from my handwaving. But I believe that the values are roughly correct.

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Looking at deaths globally by age as a distribution shows how the average can mislead https://www.google.com/search?q=deaths+globally+by+age&rlz=1...

Hmm based on your comment, I think people understand better than you think. Obviously if the life expectancy is 40, then some people live longer. Half of all people who live to 20 dying before 40 is probably what most people think of when they think about a 40 year life expectancy.

From my experience, people think most people back then lived around 40 years, while some lived less and some lived more.

I don’t know specifically about that time period, but there have been dips and peaks in life expectancy over time. In the latter half of the 19th century in England, life expectancy at adulthood was the same or better than it is today.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2672390/

There was actually a major, severe DECLINE after that associated with globalization, trade, and further industrialization, which is where many charts begin.

Think about how incredible that is - nothing we would recognize as modern medicine, but adults living just as long. I can’t think of any greater indictment of our health in modern civilization, especially given the amount of resources we expend. I mean, just think about - aside from the improvements in child mortality which are almost entirely just from now nearly century old antibiotics and vaccines technology, we spend 20% of our GDP to achieve the same results as the 1850s English who got them for next to nothing in comparison. Progress!

If you want to look at the silver lining, we have much easier lives and access to a tremendous number of cheap, rich foods (albeit unhealthy) and plenty of cheap recreation and drugs. We have worse living habits than them and spend much more time in sedentary positions. It’s probably impressive we can keep the same life expectancy with all those factors.

> we spend 20% of our GDP to achieve the same results as the 1850s English who got them for next to nothing in comparison.

I have to assume that our lives are overall much easier medically, though. Breaking a limb (or even losing one) is not nearly as big of a deal now than it probably was then, for instance.

IIRC bulk of the gain in average life expectancy over the last 2 centuries came from reducing infant mortality, which had outside impact on the aggregate mean.

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