Fairly often, I’ve seen people misunderstand things about life expectancy. They would talk about the olden days  ( Rome, for example ) , when the average life expectancy ( at birth !) could be as low as 25 years.  They mistakenly thought this implied that people died around 25, that few people lived longer than that, that around 25 years your warranty ran out, like a salmon. Not so: most of the difference stemmed from higher infant mortality, and evil old farts existed and often played a key part in history.  Augustus died at the age of 75,  Tiberius at 77,  Claudius at 63, Galba at 72 ( murdered), while Vespasian became a god at 69, baby. Certainly some emperors  died young, of malaria or strangulation, but it was by no means rare for people to live into their 70s.

Narses started his successful military career at age 60, and lived to at least 86.

Even a very moderate knowledge of the past should have been sufficient to avoid this mistake: “three score and ten”, anyone?

I see a closely related mistake popping up in discussions during the current Time of Troubles.  S0me people have argued that if a population’s average life expectancy  is 80, while the average of those dying from coronavirus is 79 years, they’ve only lost a year of life. Not so: life expectancy at birth may be 80, but someone who is 79 has already survived all the slings and arrows that might have killed him earlier: on average he would live another 9 years or so.  Misanthropic Principle. People are not built like the wonderful one-hoss shay: problems accumulate with age, but most chronic diseases do not confer a clear expiration date ( some do: we could make a pretty accurate prediction if you had pancreatic cancer, or glioblastoma.)  When you hit the average life expectancy, does anything dramatic happen?  Do you turn into a pile of dust that looks as if it’s been ground in the mill? “All at once and nothing first, just as bubbles do when they burst”?  No way. You get up, go outside,  and tell those damn kids to get off your lawn.


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  1. Jim O'Sullivan says:

    Are there really a lot of people who fail to comprehend this?

    • gcochran9 says:

      I think so. The error about lifespan in ancient times is closely related, and I’ve run into it many, many times. I’m seeing the Wuflu version pretty often lately.

    • Just saying says:

      There are a lot of people on the internet saying the virus is not a big deal because of the fallacy he documented in this post.

      • Pincher Martin says:

        Yep. All those dying eighty-year-olds in Italy only had one year left to live anyway. The WuFlu just pushed them over an edge of an abyss they were already staring into. You know, on average.

        • reiner Tor says:

          However, there is a version of this which doesn’t utilize the fallacy.

          Roughly, that it only kills the very sick, and so, even though most 78-year-olds still have several years left in them, those who were killed only had a year or two, tops. Someone for example cited the example of the heat wave in France in 2003 (I didn’t check his data, and he only cited France, not other countries), where there was an extra mortality of tens of thousands, but then mortality dropped the next year – apparently because those who would’ve died in 2004 had already died in 2003.

          I don’t think it’s true of Covid-19, but the guy insisted on this explanation that “those who die probably only have one year or a few months left anyway.” Just looking at the statistics and the cases, it simply didn’t seem true, but who knows.

          • gcochran9 says:

            It needs to be true in order to support his argument, and that’s enough.

            • reiner Tor says:

              Obviously it’s difficult to disprove his assertion, though honestly I didn’t much try.

              But my point was, that at least it’s not the fallacy mentioned in the post, it’s just an unproven assertion.

    • Anonymous says:

      This must be the most common view among the general population. Some years ago I was watching a tv documentary about the grave of some 60yo lady who died in Venice during some plague. It was argued that she must have been suspected of being a witch since she was alive at that old age while average life span was whatever it was, they even had a scene with actors where Mathousalina is walking down the street while younger passers-by look at her suspiciously, so a bunch of people were involved but nobody got the mistake. I think this has to do with their projecting the modern condition of low childhood mortality uppon the past. Another thing I think most people get wrong about older times by projecting current trends is that once uppon a time reproductive output correlated positively with SES.

    • Anonymous says:

      Wasn’t Narses a eunuch though? Hence not the greatest example of not-rare longevity.

    • False Profiteer says:

      I’ve heard some variation on this a number of times when people are talking about divorce. “Well, marriage was never meant to last 40+ years. After all, life expectancy used to be only 25 years old.”

      • Related to that is the idea I’ve heard expressed on occasion that in Olden Times people got married at 16 or 13 or whatever because they were going to be dead before they hit 30. In reality, average ages at first marriage in Northwest Europe (early modern, late medieval) were commonly early twenties, or even mid twenties. You know this if you keep up with historical demography, or read hbd chick.

    • dearieme says:

      Lots of people misunderstand it. I used to read posts on a pensions forum: the blunder was common there, among people who had an incentive to get it right.

    • Philip Neal says:

      I haven’t got the reference, but Isaac Asimov said something similar in one of his pop science pieces. Referring to Nestor, of whom the Iliad says that two generations of Pylians died during his rule and he was now reigning over the third, Asimov argued that the real Nestor would have been about sixty and regarded as immensely old at a time when life expectancy was so much lower. Asimov was scientifically educated and a member of Mensa.

  2. James Thompson says:

    Bills of mortality show that even at very old age, you always have a little more left. Always.

    • The 50-50 “die in the next year” mark doesn’t happen until you are 101. Certainly that means at 99 or 100 it’s in the 40+% range, so this is mostly a story about numbers, not people. Still, it’s worth keeping in the back of your mind when discussing anyone getting C19 at age 86. It doesn’t mean they were likely to die in the next year or even four.

  3. mapman says:

    The whole life expectancy thing boils down to this: if you survived past ~ 15 years, all that the modern medicine does for you is to extend your expiration date by ~10 years. “On average”. YMMV. By a lot. Somewhere in the bible it says “the human age is 70 years”. Well, it’s now more like 80, but that’s all there is.

  4. Polynices says:

    I have routinely seen people making that life expectancy mistake who really should know better. It’s a huge pet peeve of mine. One of those errors that makes you doubt everything else coming out of a person’s mouth.

    • rgressis says:

      I’ve also seen the weather mistake–someone thinks a 30% chance of rain means that it’ll rain for 30% of the day.

    • The Monster from Polaris says:

      I’ve also been annoyed by that mistake for a long time.
      Sometimes humans can be infuriatingly dumb.

      • marcel proust says:

        Yeah. And then there are the people who think that it will rain all day but only in 30% of the area being forecast about.

  5. Jacob says:

    “Some people have argued that if a population’s average life expectancy is 80, while the average of those dying from coronavirus is 79 years, they’ve only lost a year of life.”


    I always love an excuse to bring up Proverbs 27:22, which I think sums up many details of your public intellectual life: even more so now that everyone and their mother has opinions about WuFlu.

  6. Anonymous says:

    Age is a proxy for underlying health. The Wuflu is more likely to kill the old because they are less healthy than the young. At any given age the people succumbing to this virus are, on average, less healthy than those surviving. At any given age those dying from the virus would have died sooner than the survivors, on average. The immediate loss in life-years is smaller than you would calculate using the average life expectancy at a given age. Survivors may have their ultimate lifespan reduced though, so the loss in life-years over the long term could be higher.

    I am 100% in favor of the lockdown/quarantine by the way. No misanthropy here.

  7. swampr says:

    According to one source, the earliest indisputable case of someone living near to 100 was English MP John Holland (1603-1701). His disease environment and health care (such as it was) couldn’t have been much better than antiquity.,_1st_Baronet

  8. Martin says:

    Glioblastoma and pancreatic also have the most “prionesque” properties of the known cancers…

  9. EdP says:

    Sure. But expected years left at 80 conditional on dying from wuflu is going to be much lower than the unconditional expectation.

  10. István Nagy says:

    I would like to mention Enrico Dandolo the 41st Doge of Venice. Born in Venice 1107, died in Constantinople 1205, at age 98…
    Dandolo was the famous conqueror of Byzantine Empire, including Constantinople. From there he had many items of value sent back to Venice, including the four Horses of St. Mark that decorate the Venetian cathedral to this day. Dandolo died in 1205 and he was the only person to be buried in the Hagia Sophia in Constantinople.

  11. Pete says:

    Whilst the average life expectancy of an 80 year old may be another 9 years. Those dying of coronavirus at that age are in the less healthy half (maybe quarter), they probably would only live another year or two anyway.

  12. BB says:

    For those of us of meager intelligence, this is all hard to comprehend. I don’t want to see mom die but I don’t want to see my kids starve or be torn to bits by looting People of Walmart over the last bag of rice. Mom would rather die than see that.

    • Starvation takes a long time. People were already poor and went hungry and had their long-term health impacted during the Great Depression, but they didn’t starve. No one is going to starve other than anorexics. The societal breakdowns that lead to looting are tied to cities in political protest or in natural disasters, and even then don’t involve bags of rice. TVs is what they’re after. Many ugly things will be said, and there may even be some increased crime, but be at peace about this, my friend. That’s not going to happen.

    • sinij says:

      I read today that there are rotting corpses in the streets of Guayaquil in Ecuador. That type of systemic collapse would result in lack of food. It isn’t that there is shortage of food, but collapse of distribution network to urban centers. So if you live in 1mil+ city, starvation is not entirely impossible.

      • j says:

        Temperature in Guayaquil 100 F and people are expecting the City to collect the corpses. Cholera or something may be the next.

  13. gothamette says:

    I know a fair amount of people in their seventies who have no comorbidities and who are in fantastic shape. I would like to know if they have a greater chance of surviving Wufloo than a younger person who is obese or asthmatic or diabetic. Look at Prince Charles. He seems to have come through quite nicely. Tom Hanks, who has diabetes, but he and his wife survived. (If you really believe they had it…)

  14. mtkennedy21 says:

    My mother was born in 1898 and died in 2001. She lived in three centuries. My wife’s mother lived to 100. Both were sickly children. My mother had a tracheostomy for diphtheria at age 2, on her mother’s kitchen table. My wife’s mother had tb as a child. Good genes, probably.

  15. Karl Narveson says:

    My uncle said that if he was around at all the next time Halley’s comet returns, he would be “too old to buy green bananas”, but he knew he was joking.

  16. sinij says:

    Sorry for the unrelated question. What are out chances of avoiding 1930s-style economic collapse in late 2020 to early 2021?

    • lg says:

      Good question – i think the parallels to depression/ww2 are missing that the catalyst of industrial production for war was very important as an economic driver. maybe a gigantic infrastructure plan can serve as a similar peace dividend. the current infatuation for “SBA loans” to businesses with no revenue seems to me a kind of madness. return to normalcy with masks seems like the best chance to avoid depression.

  17. Easy Goer says:

    The author misses the point, distracts from the real issue debated: namely, the longevity topic is generally misunderstood but the point remains. What is going on is that the “elderly” are leaning on everyone else extraordinarily to keep them alive, economically, physically, mentally, etc — instead of taking the skin in the game, themselves. That’s what the point of all this is. And Roman Emperors and Venetians didn’t do that, because they didn’t need to. And they couldn’t force others to do it on the basis of political gain, the way it is done easily now.

  18. aromanoff says:

    So what was the answer to A Somewhat Similar Case, March 25?

  19. Robert McLindasy says:

    At each year of a person’s life there’s a probability that they will survive to the next year. To calculate the age they will live to on average you have to integrate the probability times age from that age to infinity. Kind of like finding a centre of mass. Right?

  20. saintonge235 says:

    Did a quick websearch, found

    TL,DR, at age 80, people have an average life expectancy of 8-9 years if they live in the developed world, and 4-5 in the worst third-world countries.

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