Is "too few people left" a credible explanation for a global knowledge loss of this magnitude?

Question

My setting is what I would call "post-post-apocalyptic", meaning that our civilization doesn't exist anymore, but the collapse has happened in a past distant enough that people aren't really dealing with the direct fallouts of it anymore, or at least those aren't the story's focus. I need this setting to :

• Be technologically medieval, save for a few things like firearms – there are story-specific exceptions, but the general population in most of the world doesn't have even the notion of electricity generation ;
• Have very little to no collective memory of the old world and its history, and a very blurry/distorted memory of the collapse.

My issue is that both of those require a radical, virtually permanent knowledge loss, one that is complicated to make happen in our modern, interconnected world. For this reason, my question isn't about what exact type of collapse I should go for, but whether my focus should be "as few people left as possible without Humanity being doomed to extinction."

The idea is that going below certain figures would lead to a statistical lack of specialized individuals to operate/fix/produce modern technological items and act as teachers ; not enough people to spare from essential survival tasks and educate efficiently, let alone send to collect the knowledge still lying around ; large portions of that knowledge would gradually be lost to time as every electronic storage becomes permanently nonfunctional and books are left on their unprotected shelves to endure whatever comes their way for God knows how long. One can also assume that literacy rates would spiral down to abysmal levels, further hindering future generations' ability to retrieve any knowledge from those books on their own.

Until population recovery happens in any significant way (which I'm able to make as long as it needs to be), all those problems would only worsen until common and even "higher" knowledge stabilize around levels that we left eons ago.

So, to summarize :

• Preservation
• Transmission
• Recovery

Do you consider this a plausible way to reach the outcome that I described, or am I underestimating the resilience of our civilization when it comes to either of those three points?

Answer 1

This is not only possible, it's happened.

The last Mound-Builder culture of the Mississippi River valley collapsed after the introduction of European epidemic diseases, causing the population to decline to the point it could not maintain the chiefdoms it had consisted of. Some tribes managed to maintain legends that connect them to their ancestors, but others even lost the knowledge that the mounds they lived next to were built by human beings.

Likewise, the Bronze Age collapse meant the loss of the knowledge of how to read Linear B and Linear A -- indeed, only Linear B has been deciphered now.

And these were cultures with a lot less specialization and long-distance interdependences. It would certainly be possible for modern society.

Answer 2

Considering our modern society, I'd say it's very plausible.

If production of electricity becomes impossible during an apocalyptic event, what is left of our modern civilization?

First of all, Wikipedia and all online resources are gone forever. But at the same time food production (the raw materials as well as baked / cooked goods) and transportation become incredibly limited. How could anyone produce car fuel without electricity running machines? So very suddenly you have a huge amount of people stuck in cities that rapidly run out of food and too few people in rural areas to farm the available land without machines. Everyone is scrambling to survive and the only education people get in that scenario is what they need to survive.

Who in North America or Europe is currently able to transport large amounts of food without cars or electricity? Who even has a grain mill and oven that works without electricity? Who still knows how to preserve food without electricity? Who is able to weave and sew new clothing when the old one deteriorates? Who can smelter and/or forge metal without electric kilns?

Ironically this would have a much bigger impact on industrial countries relying on automation and global trade than those who have a lower level of industrial development and general education, probably killing off huge numbers of educated people.

Let's assume humanity manages to survive that for 1 - 2 generations and people keep books as memorials stored in their homes. Their level of literacy would probably degrade to a level where most people can comprehend "1 chicken costs 10 breads" but any book about science or engineering would be exceedingly hard to comprehend, especially if vital technical terms haven't been in use for decades and people forgot their meaning. So at that time you would need several books of increasing levels of expertise to first learn about the basic concepts and then the advanced engineering. At the same time the people who did learn all that stuff grow old and eventually die.

And let's not forget that modern bleached paper degrades much quicker than vellum, papyrus and other old types of paper you might find in a museum. After 100 years in a not ideal environment the books might be molded, eaten by bugs, or simply crumbling between the fingers of a reader.

And during all that time, the machinery still surviving the apocalypse slowly breaks down, either by disuse or overuse. If possible, people will try reverse-engineering vital machines like water pumps and cranes and rebuild them with readily available materials like wood and stone. Others like clocks will slowly rot and eventually people won't believe that this hunk of rust could once tell the time. That is a direct equivalent of "medieval technology".

However, it's hard to make people completely forget the time before the apocalypse. We know from religious texts and oral traditions like that of the Australian Aborigines that memories of certain events can survive an incredibly long time if the people deem them important enough. It's not very plausible that an event eradicates all religious elites and their knowledge and literacy from all of humanity. However, even written accounts of events long past lose more and more information. The many contemporary discussions about biblical topics like Noah's Arc or Solomon's Temple and what they actually looked like should be proof enough.

Imagine what a person in 1920 would think about our current life. People back then did theorize what the future would look like, but they imagined flying cars and life on Venus. They had no comprehension of what a "Computer" is and that you could carry a device in your pocket that lets you speak to a remote person, record moving pictures, view moving picture from all over the planet, calculate complex math formulas, translate spoken or written words and read more knowledge than a single person can possibly read in their lifetime. Accurate descriptions of our current life may still exist 100 years after the apocalypse, but they would seem just as real as aliens or high magic in novels, or maybe as real as Jesus parting the sea.

Answer 3

"Can my modern society be reduced to medieval technology?" has been asked before, and the answer is always "no."

The examples given by other authors are not from the perspective of modern society. They describe ancient peoples having had complex interdependencies — but compared to today, that simply isn't true. It's only easy to lose knowledge when:

1. Almost no one knows it, and...

2. There's almost no record of it.

What most people don't realize is that 99% of all human technology was invented over the last 150 years

And that's a groundswell of what I'll call "knowledge inertia" that's whomping hard to overcome if your goal is to justify a substantial reduction (pre-industrial-revolution) of general knowledge. While some of the most specialized knowledge might (might) be lost (like how to make nuclear reactors) due to lack of people to maintain the study, the vast majority of knowledge (e.g. electricity) would be very, very quickly re-established.

And then you're on a f(150_years)(population_growth_to_1.5B) or less clock to re-establish all of it.

Remember, knowledge (even advanced knowledge) is located in...

• Universities, colleges, and high school libraries
• Business and industrial centers
• Government repositories and scientific centers
• Even individual homes

And even today, a ton of it is in printed books. Rationalizing the loss of all those books for such a long time is very hard. People live in deserts. Worse, your idea about loss of specialized knowledge isn't practical. You'd be surprised how many PhDs there are in the world (some of whom are working as janitors because there aren't enough jobs for that many PhDs). Knowledge is everywhere.

There isn't a realistic reason for the loss you're looking for, but that doesn't mean you can't reasonably rationalize why it doesn't exist

And this is important. Many authors get caught up in trying to be "realistic." Realism in the central aspects of your story is important. Realism (or too much realism) in the back story is actually counter-productive. What you need is the proverbial one-sentence "reason" to set the story in the circumstances that you want. That "reason" should be based on some basic assumptions:

• Whatever the apocalypse, it drove people away from population centers 5,000 and above. The higher the population, the greater the taboo. This causes the vast majority of knowledge repositories to become unavailable.

• Whatever the apocalypse, it didn't result in a dry climate (perfect for preserving paper!) but a wet climate (paper rots, gets eaten by pestiferous critters). You also want a warm climate, not a cold climate. The colder it is, the easier it is to preserve the paper. This is also useful for rationalizing the destruction of vast amounts of machinery and technology. Rust is your friend when it comes to loss of knowledge. What you want if for things to not work.

• Whatever the apocalypse, the survivors are young. This isn't hard to rationalize. Children and young adults are remarkably resilient. As we age, we become more susceptible to disease, damage, etc. But it's us old folks that have the greater amount of practical knowledge in our heads. Don't get me wrong, I've spoken with 13-year-olds who have a breathtaking amount of data in their heads. But what good is it? Answer: not much. That's because they've yet to learn how to use the data (through education or life experience, doesn't matter which). They're also the most likely to forget that data because it hasn't been deeply associated with practical uses.¹

• Whatever the apocalypse, the next 2-5 generations need to work like dogs to survive. Maybe this is toxic soil or toxic rain or prolific super-hyenas or whatever the reason that people have a constant and long-term struggle just to survive. The goal here is to rationalize a lack of time to pass knowledge along.

Keep in mind that none of this would definitively explain a shift from modern tech to medieval tech. That's simply impossible. What it does is allow the reader to suspend their disbelief so they can move on to the story you're actually trying to tell.

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_{¹ While we can always find that one child who is remarkably capable, that isn't a reflection of all children. Children are amazing, but they're not small adults. That's why they can be used to rationalize loss of knowledge.}

Answer 4

Yes, if you just have a few hundred people left globally you wouldn't be surprised they lost a lot of knowledge.

An apocalypse bad enough to wipe out humanity to the last few hundred is bad enough that most sources of knowledge could be destroyed, and is enough that there wouldn't be many experts left. You wouldn't necessarily have many books left- if you have as few people as possible, whoever is surviving is probably at somewhere remote without any books. Those in cities probably all died, along with their books.

Answer 5

The answer is undoubtedly yes, because you didn't specify how small the population could be. Obviously, if you had a population of 2, then it's simply not possible for 2 people to know 99%+ of all modern knowledge.

But I'm guessing that what you really want is a self-sustaining civilization. In other words, you don't want the population to be so small that it goes extinct. If that's the case, then you want to learn about the concept of Minimum Viable Population: the smallest a population can be without a species going extinct over time.

One of the major factors is that you have to have enough DNA in the gene pool to not have inbreeding factors, over time, cause the population to become infertile. That bumps the number up to at least around 100, give or take.

But there are many other factors. The population has to be resilient to a disease or famine or natural disaster (etc) wiping out a chunk of them. There's debate as to what homo sapiens' true MVP is, but a good guess is that it's in the single-digit thousands.

So: could you have only a few thousand humans left and have mass knowledge loss?

Well, yes, depending on how you define "mass," but certainly a lot of knowledge would be lost, just from a statistical perspective alone this has to be the case:

• The population of earth right now is 7.9 billion. If 7,900 was your population size, that would mean you've lost 99.9999% of the population.
• Of any given profession, how many people would have to survive for knowledge of that profession to be passed down? Remember, it's not enough that some textbooks survived. Even assuming that your civilization is able to create printing presses, learning from unorganized, random books, without the aid of a teacher, is extremely time-consuming, and in general is not going to be a scalable way of people learning lost knowledge. Remember, your people are going to have to be spending the vast majority of their time just foraging for food, water, and protecting themselves and their food from the elements and animals, so people don't have all day to be reading books and trying to learn the hard way with no guidance (not to mention, most people don't have the proclivity for that anyway; remember only a small percentage of the population is nerds who enjoy that kind of thing).
• Of all the professions on earth, how many people have to survive in order for knowledge of their profession to get passed down? It will vary by profession. Carpentry? The answer may be as low as 5 (disclaimer: am not a carpenter). But for building computers? We're talking thousands, at a minimum. You would not believe how much specialized knowledge there is for manufacturing CPUs, let alone everything else involved. But suffice it to say, for some professions this number will be single digits, for others in the dozens, for others in the hundreds or thousands.
• And bear in mind that that many people need to be located together to share their combined knowledge. If it takes the knowledge of 2,000 people to build a CPU, it's not enough that 2,000 people survived...they have to be able to find each other and actually organize to do it.
• Ok so, given that number, what is the likelihood that that many people of that profession survived? For example, if it took 20 people who understand how to make an engine in order for that knowledge to be passed down, what are the odds that, when only .0000001% of the population survived the apocalypse, that that 7,900 people happened to include 20 people who knew how to build an engine? And those people all find each other and work together and have time for that?

And remember, it's not just the knowledge that you need, but also the whole supply chain and all of the resources and capabilities to extract those resources, everything that goes into making the thing, not just knowledge of how to make the thing if you were given all the materials on a silver platter.

And you have to pull off the organization of the whole thing.

Another way to look at it: you're one of the 7,900 people who survived the apocalypse. Let's say all 7,900 of you are located within a few hundred miles of each other. You're really outgoing, so you personally know 300 people. You have some knowledge of how to build an engine. You couldn't do it alone, but if you were able to get together with 20 other people who know about building engines, and you were able to convince the population to support you for many years, you could eventually start producing engines.

I say years because remember, you have to manufacture parts to make it, and that involves getting steel, and that involves forges...it wouldn't be enough for the 20 of you to be involved with trying to build engines, you would need hundreds of people at a minimum to be doing other tasks to provide you with the materials you need to build an engine.

Ok, let's say you get all of that buy-in. What are the odds that you even know 20 people, out of those 300 that you know, who have this kind of knowledge? Are 7% of your acquaintances experts in building engines? Not just that they know about it in theory, but they actually know actionable, specific details?

I think it's a good assumption that, given a population this small, the knowledge of how to build engines, as well as how to do a great many other things, would eventually die. Generating electricity is going to be hard, but possible in limited amounts. No one's going to make a full-blown power plant, but maybe some of the simpler ways of generating energy might happen in isolated areas. But without manufacturing happening, there's going to be a lot of difficulty using even that paucity of energy to make most items we're familiar with.

I think it's very plausible for you to get the end-state that you want.

Answer 6

Modern records are incredibly flimsy by historical standards

Paper is terrible for long-term storage; even in an arid environment, it starts to break down after hardly any millennia at all.

However, since the invention of the printing press, there has been loads of it. The most limited-release textbook will have a print run of a few thousand, and there must be tens of millions of copies of any given work of Shakesphere, Newton or Einstien. Further, they are scattered worldwide in public and private libraries.

It only takes one of these to survive to prevent the knowledge from being lost. It doesn't even have to survive all in one place - parts of texts from around the world can be recombined into the original. It also doesn't matter if no one can speak the language - we can reconstruct dead languages given enough material.

But without the right hardware, we can't read data from only a few years ago

Even if we have the hardware, digital storage degrades alarmingly fast. Remove the power from your flash drive; you will have no data in three to five years.

When society collapses, future historians will date it to the turn of the 2nd millennia

It doesn't matter if it happens now or 500 years from now; the start of the 21st century will be where history stops. Up until then, there will be a wealth of paper records - fragmentary, yes; difficult to understand, yes; full of gaps and inconsistencies, yes - but there. After that, there will just be void of information: archiologists can play in the debris of the computer age but for historians there will be nothing.

Answer 7

After the fall of the Roman Empire, no pottery was made in Britain for a substantial period; losing knowledge of historical details or electricity is easy by comparison!

Answer 8

"Too few people left" is indeed a credible explanation. Small groups of surviving people struggling every day cannot pertain knowledge. A reduction in numbers alone is not the point, 1 million people maintaining a city state can save a lot of knowledge, the same number of people scattered in small tribal groups all around the world can't.

There may be additional factors like deliberate destruction of knowledge and technology: After the catastrophic events, some prophets arise and found a new religion and demand to destroy the evil writings of the past that led to the current desaster. Such events have taken place in history in the late Roman Empire after the transition to Christianity, or at the introduction of Islam in the Near East region.

Answer 9

In my opinion, no, not completely. At this stage it's not possible to lose the knowledge so completely so that humanity globally slides back to some less advanced level. Barring Extinction Level Event I can't imagine such situation.

Now, please do not mistake that with complete collapse of our modern society, or even whole civilization. The fact is it is so close to collapse that it's not even funny. More specifically, we are at a stage of transitioning to a global model of technological society based on (and almost completely dependent upon) cheap and abound energy. While disrupting that transition may be catastrophic, and may well end, rather easy, any developed country in mere weeks, it will not be total.

Our globe's regions are still developed - and progress in that development - at different stages, which means somewhere there will be a strong resilience to problems that will be disastrous elsewhere.

And, to be honest, at this stage we're extremely susceptible to cascade failure, leading to collapse. There will be no access to technology, thus leading to mass die-off due to famine, disease and - of course - violence, especially in urban and suburban regions, but it will be quick enough so that some areas will be left relatively intact, and those will be the ones that can easily become self-reliant.

The only way I can imagine it happen is conjunction of several global events, impacting all regions similarly (though at different intensity). As of right now this would be, in my opinion, simultaneous: extremely powerful Solar flare, shift of the magnetosphere (flipping of the magnetic poles) and a global pandemic at the same time.

Explanation is simple: we are spread enough that pocket-sized societies will survive, and enough of them have still access to print-based knowledge that, after some initial adaptation period, people will bounce back up. Admittedly it will be locally only, but it will be enough.

Not to mention that some of those societies - i.e. small towns or large villages - are now being created with the explicit purpose of sheltering their dwellers from outside turbulences and preserving the culture. Of course, they may fail, there may be not enough of them to restore civilization, but again - barring real cosmic disaster - enough of them will survive.

Answer 10

Limited numbers is not enough

Limiting numbers can be very effective in restricting knowledge. If only a few thousand around the world are left, too few are available to maintain the technologies and knowledge. However, there is a big flaw. The time after which it takes place.

Imagine that for whatever reason all people died, except children without even having seen electricity. No knowledge remains! The problem is that the technology does. There is plenty of simple electronics surviving that people are bound to come across it and start to use it. As simple as dynamo lamps or certain batteries. With enough time to forget the history of why the apocalypse happened, it seems doubtful that any remaining technology or (written) knowledge isn't found and eventually used. Unless you're able to destroy or otherwise make unavailable any piece of technology or knowledge of electricity or similar it is highly unlikely.

Lastly, even if everything is gone, it can be found again. We discovered electricity early on and used it in time.

Does that mean it is impossible? Not at all! There are many factors that can contribute to an electricity free society that has guns. Cultural, genetic or physical are all candidates!

Cultural

The post apocalyptic society could have an aversion for electricity, blaming it for the collapse of society. It can be as simple as that social media is to blame, but as social media doesn't survive they can blame any electronic device. The problem is that such things are difficult to last for generations. We vowed we would never let it come to war after WW2. A generation or two later and it seems forgotten, ignored or even celebrated in the children.

Electricity can also not be understood because of culture and it's knowledge. Electricity was known about thousands of years in varying degrees, but it took very long before it was implemented as more than a curiosity. It is unlikely in your case with their technological progress, it can simply be overlooked.

Genetics

Intelligence is a complex thing. Even between humans we see huge differences in their cognitive abilities with little differences in the brain structures. From hardly able to speak to flawless twelve languages, from understanding complex math to not being able to count.

The apocalypse could've affected the genetics, hampering certain understanding. The technology can be present and guns understood, but electricity or it's potential is lost on them.

Physics

The apocalypse can also have different reasons than humans. If for whatever reason the magnetosphere of the Earth is changed, or the activity and strength of the solar winds, it can cause world wide destruction of any electrical apparatus. Electricity isn't impossible, but many electronics are difficult to use on long term. If every week or year most electronics are subject to a strong EMP of the solar storms it is hard to develop them.

Answer 11

I do not agree with your premise that our "modern, interconnected" world is robust against radical loss of knowledge. We have plenty of single points of failure; remove only one of electricity, water, (easily available) gasoline, network access, etc. from a region, and that region will - unless being rescued from outside - fall into a scenario like you're describing very quickly. We're talking about days here, not years. Take away the internet, and within days there will be no food, no fuels, nothing at all left, with the exception of rural areas. Large cities will be like we know it from any of the Zombie movies of your choice. Cold, hunger and thirst make short work of civilization very quickly.

Even without massive population loss, knowledge is lost all the time, rapidly. There have been videos of younger people puzzling over an old-fashioned dial phone, and taking quite some time to figure out how to use it. In modern western countries, there are virtually no people who could, say, build up a factory or even workshop from the industrial age from first principles. Not to speak of a modern factory or workshop. Take our file servers away, and who will be able to read archaic microfiche archives of all our old knowledge?

If you wish to have some inspiration which is agnostic of the exact scientific/technological level of the world at the point in time everything went horribly wrong, one of my absolute favorites is the relatively thin book "A Canticle for Leibowitz". While my crystal ball is broken and I won't speculate what will hit our particular world, I could very well imagine that it'd turn out somewhat like in this story.

Answer 12

Wow, lots of conflicting responses here. I'm not going to weigh in on whether or not you could break humanity this badly though. Let's ignore the naysayers and (as the slogan goes) just do it.

If only there were global stockpiles of explosives powerful enough to not only depopulate large parts of the globe but to smash basically every building, every port, every major infrastructure node into poisonous rubble in a matter of hours. Some sort of weaponry that assures destruction of all of the technologically advanced countries on the planet in a brief but very bright ware. (But who would be MAD enough for that?)

If we took all of those weapons and threw them at all of the tech-rich targets on the planet then all that would be left are a few million people living in wilderness areas, most of whom would die pretty darned quickly. Oh a few might ride out the aftermath for a few years in fallout shelters and such, and the resultant nuclear winter would eradicate a large chunk of the rest. The last few remaining viable populations would be people living near thermal sources and caves, and most of them would starve to death before a sustainable food crop could be located. (Probably mushrooms. I hate mushrooms.)

The first few decades would be pretty harsh. The surviving populations would be entirely focused on survival, with no remaining energy budget for anything as wateful as talking about the lost past. The survivors wouldn't have much of a past to talk about as far as your problem is concerned, since they'd almost exclusively be tribal populations who were living low-tech lives before the End. What little technology they do know about wouldn't be as important knowledge to pass on, except perhaps in cautionary tales.

When the endless winter eventually breaks and the world starts to heal, in a couple of hundred years or so, the descendants of those survivors may eventually spread out to take over the world again, with only garbled retellings of half-remembered stories about what happened. Half of the world will be closed to them due to radiation and toxicity. The parts that weren't smashed flat has fallen to corrosion and the march of time.

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While not specifically intended for this scenario, it's on the list of considerations for the 1,700 seed vaults and data archives scattered around the world. The most famous is probably the Svalbard Global Seed Vault. A little less famous is the Arctic World Archive next door (relatively speaking) which claims to have a data storage medium designed to last for at least 1,000 years. If your survivors eventually dig this all up then they'll find all sorts of interesting things in there, including some of my code on GitHub. (Oh joy, future survivors are going to be shaking their head at my code too.)

At that point the whole "lost past" thing bursts back into public knowledge. Whatever society has been created, whatever technology they've built for themselves, it's all going to change radically once they unearth one of the archives. It might take them decades to understand it all, but they'll have videos and audiobooks and cat pictures! They'll have a full dump of Wikipedia, so they can be just as misinformed as we are! Frabjous day!

(Unless someone nukes Svalbard. At least then my code follies will be safely lost to the mists of time.)