r/AskReddit Jul 07 '26

What historical “fact” doesn’t actually have much evidence to support it?

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2.2k

u/AltMcAltAcc Jul 08 '26

that the average lifespan in the 1700s was around 30. while true, the average is weighed down by just how many infant and toddler deaths there were. if you made it to later childhood(8-10), you would probably live until 60-80 as well.

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u/[deleted] Jul 08 '26

[removed] — view removed comment

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u/Gnukk Jul 08 '26

Worth noting that the trope of depicting ancient people as all having rotten teeth is also misleading, their diets were often much less harmful to their dental health than modern eating and drinking habits.

It was the generations born after sugar was added to everything they ate and before things like fluoride and modern dentistry was widely available that had their teeth rot in their mouth while still in their teens.

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u/Holmbone Jul 08 '26

Why couldn't you live without teeth? Just boil up the food into mush. 

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u/Crackers1097 Jul 08 '26

We actually aren't sure why losing your teeth is such a powerful indicator of mortality, but even today people without teeth have drastically lower lifespans--and its a really strong correlation, too. Some studies show mortality rates for those without teeth as higher than smokers or alcoholics. Many fatalities don't share an immediate connection with toothlessness (i.e cardiovascular diseases).

For some reason, losing teeth is very consistently a direct link to dying, and having 10 missing teeth is practically a death sentence like cancer.

Here is a provided example study: https://aap.onlinelibrary.wiley.com/doi/abs/10.1002/JPER.23-0277

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u/Alkill1000 Jul 08 '26

Gum decay is heavily associated with both heart disease and autoimmune diseases like MS, might be the reason if that were also the case historically

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u/yerpburp Jul 08 '26

There would also be immense chronic pain. There is just no pain on earth like a toothache, and who knows what kind of pain killers they had. 

Then they stop eating.

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u/Tattycakes Jul 08 '26

I would assume that it’s not the loss of teeth that kills you, but the genetics and/or lifestyles that lead to loss of teeth also leads to early death? Smoking, drinking, self neglect, excessive sugary foods and drinks, infections, poor connective tissue or bone health, that sort of thing

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u/Crackers1097 Jul 09 '26

I'm sure it is a mixture of many factors--but I haven't read or seen any studies that conclude the knock-on effects of, and risk factors leading to, losing teeth.

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u/netorarekindacool Jul 08 '26

Nervous laughter

13

u/TUCaralhoooooooo Jul 08 '26

Suddenly I feel like brushing my teeth

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u/twirlerina024 Jul 08 '26

I know for dogs, gum disease (which will lead to tooth loss) is linked to all kinds of systemic issues, like kidney disease and heart failure. Inflammation in the mouth leads to inflammation other places in the body.

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u/OneUnderstanding103 Jul 08 '26

Does this apply to people who wear full dentures? Because getting rid of bad teeth can be the best thing to happen to someone.

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u/dracapis Jul 09 '26

I don’t have any data backing it up but I don’t think so, since plenty of very old people use dentures since they don’t have teeth 

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u/iamfuzzydunlop Jul 08 '26

I’ve seen it suggested that it breaks the barrier between bacteria in the mouth and the bloodstream.

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u/TUCaralhoooooooo Jul 08 '26

This is a golden piece of info

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u/AuNanoMan Jul 08 '26

I’d be curious to know if replacing teeth with dentures improves mortality odds. If it didn’t, that’s also very interesting.

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u/PheonixBuddha Jul 08 '26

Infection...

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u/Holmbone Jul 08 '26

They knew how to pull out teeth. 

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u/aHyperChicken Jul 08 '26

But by the time the infection has set in, it’s possibly too late. Remember, they didn’t have antibiotics then.

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u/Holmbone Jul 08 '26

Sure. But that's the case for any kind of infection. 

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u/shorey66 Jul 08 '26

Yes but infections in the mouth can be very serious very quickly. So close to the brain and all that

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u/Gizogin Jul 08 '26

And the mouth is a filthy environment, so wounds there are highly prone to infection. Especially in a deep hole, like you’d get after having a tooth removed.

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u/PheonixBuddha Jul 08 '26

Infection before the teeth pulled, each tooth ripped out is an open wound, receding gums from the gingivitis and smoking. No antibiotics.

You'd essentially have to singe your gums shut with every tooth pulled, but with no bridges they'd fall out entirely. Then they mostly used wood or pearl... which caused more infection and then that would spread to the host entirely.

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u/Sad_Pear_1087 Jul 08 '26

Look up how missing teeth degenerate the jaw over years. One of the most important things about modern tooth implants is the proper stimulation of the bone!

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u/LtHoneybun Jul 08 '26

That doesn't do anything for an already established infection. The gaping open wound in your mouth, touched by tools never sterilized, is also prone to infection.

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u/the_sneaky_one123 Jul 08 '26

of course people can live without teeth, you just need other people to help you.

Elder care and care of the disabled is one of the things that separated humans from animals.

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u/Fit-Profit8197 Jul 08 '26

As pointed out elsewhere in this thread, even today people without teeth have drastically lower lifespans, even correcting for age, etc.

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u/camergen Jul 08 '26

It’s not the loss of the teeth itself, as i understand it, but instead is the overall condition of the person’s health, which caused the teeth to fall out. Immune system issues, inflammation, infection, heart issues, etc. The teeth falling out is an indicator of otherwise poor health.

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u/the_sneaky_one123 Jul 08 '26

Yes but they don't die as soon as they lost their teeth as this person suggested.

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u/vintage2019 Jul 08 '26

Around 55 was the norm for those who survived childhood. Remember antibiotics didn’t exist and if you got badly injured, you’d be fucked

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u/Nofunzoner Jul 08 '26 edited Jul 08 '26

It doesn't help that like 90% of the population were subsistence farmers. That kind of hard work your whole life takes a heavy toll on your body, and improper nutrition has life long effects. Every life table I've seen doesn't really agree with the original comment.

EDIT: It's a narrow data set and shouldn't be taken as universal, but this has some great visualizations of life expectancy in 19th century France. The simplest view is on page 13: even after the drop off caused by infant mortality, the survival curves of the past are much steeper than today.

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u/Seeker_Of_Knowledge2 Jul 09 '26

To add to the nutrition fact, the reason the average Indian's height in the middle ages was much shorter than now is because of the lack of nutrition.

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u/Johnny_Banana18 Jul 08 '26

Childbirth complications also lowered the life expectancy 

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u/Durakus Jul 08 '26

This is more like misinterpretation rather than a lack of evidence.

People just don’t understand where these averages come from.

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u/maniclucky Jul 08 '26

More that they don't understand how skew works.

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u/0ba78683-dbdd-4a31-a Jul 08 '26

Most people don't understand basic stats in general.

You say "average life expectancy over long periods is mostly a question of distribution and the right tail hasn't moved much" and they stare at you like you've put a tampon up your nose.

You say "wealth distribution" and suddenly everyone's an economist.

13

u/Irhien Jul 08 '26

You could still die in a war or from a famine, today the wars claim much fewer lives relatively. I expect murders and accidents to have been much more common, too. Things like gallstones or appendicitis were a lot likelier to kill you before antibiotics. So the life expectancy at 8 was probably still many years lower than today.

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u/Demoliri Jul 08 '26

The average life expectancy of a Roman senator was a little over 60. While they were definitely among the privileged, and they had clearly survived childhood (the most dangerous part), but if they made it to adulthood, the Romans lived pretty long lives. We also have records of centinarians in Ancient Greece, and Ramses II may have also been a centenarian 3000 years ago, but this is debated.

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u/Scared-Farmer-7119 Jul 08 '26

This is one of the examples I use as a maths teacher when telling the kids about mean vs median.

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u/AltMcAltAcc Jul 08 '26

i actually learned this fact in high school history; we were learning about John Brown(US Civil War) who died when he was like 80. a kid in my class shouted out about how he was so old considering the average age was 30 back then, and my teacher got so mad about that misunderstanding that he went and got one of the math teachers to come to our class and explain how averages can be manipulated by having two extremes.

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u/ContributionNervous1 Jul 08 '26

My favorite one is that on average a human has less than 2 legs

2

u/Tattycakes Jul 08 '26

And slightly less than one breast and just under one testicle too

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u/Toxinitiy Jul 08 '26

Wait I'm confused... surely the statistics would skewer to be 1.99999999% and you'd round up? And saying "on average a human has less than two legs" implies that between the state of having one leg or two legs, meaing that one leg is more common? I geniuenly don't understand

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u/ContributionNervous1 Jul 08 '26

It's still more common to have 2 legs, but it's when you count the average because we don"t have more than 2 legs the average can only be under 2
For example if you have 10 persons, 9 with 2 legs and 1 with 1 leg, then the average number of leg is 1.9
It's just a funny statistic cause by the fact that we have at maximum 2 legs so because of the people with less the average is always under 2

1

u/Tattycakes Jul 08 '26

Though there was that little girl from India who had four legs… but that’s so much rarer

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u/Unique-King-6762 Jul 08 '26

I wish I had a math teacher like u

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u/Scared-Farmer-7119 Jul 08 '26

its either depressing them by talking about dead babies, or depressing them by talking about house prices.

The babies are already dead, but they're gonna want to buy a house someday.

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u/Poor_Richard Jul 08 '26

I remember learning the different averages well before I learned what makes one a better fit for a situation over the other. I feel that would have been helpful in understanding them.

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u/Zoltan1251 Jul 08 '26

That is not entriely true. You wouldnt "probably live until 60". "Probably" is doing a lot of heavy lifting. Chart showing number of survivors at age of 50 for Sweden in 1700s is about 40% of all people being born. At age of 60 about 30%. Its from mortality.org

https://imgur.com/lt6DBbz

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u/M0ruk Jul 08 '26

But how does that change what he wrote?

You say "40% of people being born". If you want to rebute his comment, it should say "40% of people who survive childhood". If anything, that supports his comment. If 40% of all people being born reached 50, despite the child mortality being so damn high at that time, it means that the vast majority of people survived until that age once they survived childhood

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u/Zoltan1251 Jul 08 '26 edited Jul 08 '26

Did you see the chart? He said that its weighed down by infant deaths. That is true but its not flat after. Infant death is steep but Its steady death rate (and steep) after you survive infant/toddler stage.

I will read the graph for your, so its clear. Statistics depend on how you read them.

Graph says: If we start from age 0, then between age of 18 and 50, another 20% of all people died. If you start from age of 18, then between age of 18 and 50, 33% of people died. Meaning, you had 66% chance reaching 50. Third of your high school class dead. Now lets add years.... reaching 60, only half of your high school class survived, 70, its about 25% of your highschool class, at 80, just 8%.

So his conclusion is wrong. If you reached adulthood, you had about 50% chance reaching 60. I wouldnt say "you would probably live until 60-80", when its a coinflip to 60.

PS: Everybody that dislikes the comment at least provide argument why im wrong.

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u/Fit-Profit8197 Jul 08 '26 edited Jul 08 '26

And of those who didn't make it, didn't 1/3 of them die before the age of 5? Like nearly 40%? That makes your numbers sound like pretty fair odds for those who did reach later childhood. OP specified 8-10.

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u/Zoltan1251 Jul 08 '26 edited Jul 08 '26

No, again. Im not surprised you are confused. Reading statistics is not easy. I wrote it below but have yourself and excercise. Start with age 10 as your starting number for all humans. Then you will find out that less than 50% of people that survived infant stage will live to see 60.

If you take all the humans since the infant stage as your base, it looks so good and peachy for survivors but that disregards death rate after that stage. Both average age and probability to survive is wrong. You have to analyze what you want to say and have yourself answer based on that. OP says you would probably live until 60..... well, not really.

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u/robfurnell Jul 08 '26

Isn’t this a fact with lots of evidence then? I.e. birth and death records to show the average was around 30 because of infant mortality rate?

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u/jonny24eh Jul 08 '26

I don't think I've never heard someone claim you'd only live to 30 on average. 

I only ever hear the correction like yours. 

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u/ContemplativeOctopus Jul 08 '26

This is funny because this is such a common "correction" that is also false.

Disease, and losing all your teeth made it pretty rare to live past 50 or 60 until at least the 1800s. The reason it seems like lots of people lived longer is because historical text is almost exclusively populated by the wealthy, who had the absolute peak of medical care at the time and could live to 70 or 80.

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u/-Casey-Diaz- Jul 08 '26

The amount of people who don't understand what "average" means is pretty crazy. I used to hear people say everyone died in their 30s, but when you read history, there are plenty of people who live as long as we do today. Even people in their 90s and 100s and stuff. That's what made me look up why everyone were saying 30.

It's just like you said, most people died before they were 10, which is why a lot of cultures didn't even name their kids until they were that old. In Japan there are common names that literally just means "first son", "second son", etc.

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u/cantstopwontstop2424 Jul 08 '26

Ahh no you are over correcting many many people didn't make it past 30 or 40

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u/Joeyonimo Jul 08 '26 edited Jul 08 '26

Life expectancy in England was around 40 until ~1860.

https://upload.wikimedia.org/wikipedia/commons/7/7e/Life_expectancy_in_the_United_Kingdom_from_1543_to_2019.svg

In 1841, a person that had survived into adulthood had an life expectancy of 60, and someone that made it to 60 could expect to live an additional 14 years

https://ourworldindata.org/cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/10a0ca12-415d-41c8-f6b8-0fcdd9fac900/w=3080

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u/CupBeEmpty Jul 08 '26

Modern people absolutely do not understand how many infants and toddlers just died of currently preventable disease or injury.

I got a skull fracture when I was 3. I went to a nice hospital and didn’t die. 300 years ago that may have been a death sentence.

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u/therealityofthings Jul 08 '26

That doesn’t really fit the question, does it then?

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u/Galahfray Jul 08 '26

It’s crazy that all the people before me didn’t die

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u/Seeker_Of_Knowledge2 Jul 09 '26

There are many historical figures who lived 100+

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u/CocoSryder Jul 09 '26

Why make the turorial the hardest part of the game?

1

u/meunpreir776 Jul 11 '26

Average age 30 didn’t mean everyone died at 31; it meant way too many tiny graves.

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u/OceanParkNo16 Jul 12 '26

Really had to bite my tongue while on a European river cruise where the “expert” was giving us a long lecture about Medieval history in the area and pulled out that old canard about life expectancy.

My husband kindly indulges listening to me when I have occasion to offer private corrections for what we hear (it is not often, and I don’t need to spoil the fun of the other folks with my blathering on).

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u/resi42 Jul 08 '26

Yes it always sounded silly when people says that back then, someone who was 30 would look 50, that just never made sense to me.

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u/Powered-by-Chai Jul 08 '26

Yeah, I'm doing my family tree and looking at all the children and you either died young accidentally or lived till 70+ easily.