What is necessary for an "Apocalypse" to actually set a civilization (e.g., humankind) back to the stone age?

Question

Premise

The question is relatively simple (I think): How could an advanced, spacefaring civilization slip back into the stone age while also losing most or all of their cultural memory (i.e., people in Europe would mayve vaguely remember that they are "French", but not much beyond that)?
This precludes things like contact with surviving off-planet remnants, etc.
What I would like feedback on is forms of Apocalypse that would be devastating enought to knock humanity globally back, but without causing total extinction or outright destroying the planet.

Answer 1

See Fahrenheit 451.

In order to destroy technology, you can't just attack humans. You have to attack human minds and errode human institutions. You'll need a scalpel, not a hammer.

One option would be a totalitarian regime with a self-destructive agenda. They take over, sculpt the population into a docile herd of illiterates, and then something happens that wipes them out. Libraries and vaults were destroyed by the regime, and a few generations of brainwashing are able to destroy all but the most basic of skills among the population.

Alternatively, perhaps some chemical or disease is released across the biosphere that causes severe paranoia. People begin to form tight-knit communities that refuse to trust the information from any "outside" groups. Libraries are framed as centers of vile propaganda and burned; labratories are slandered and besieged; space colonies are accused of mutiny, cut off from supplies, and starve out. By the time the local population develops a resistance, the world has already torn down civilization and devolved into loose nomadic tribes.

Plenty of other sources could be used. Alien hypnosis against the planet, a secret society dedicated to the apocolypse, planet-wide genetic mutation from a superweapon gone wrong, et cetera. Attack institutions, minds, and knowledge, and you'll have exactly what you want.

Answer 2

Late 1800s is conceivable; anything lower requires a very finely tuned disaster which wipes out almost all humanity but still allows a handful to survive. And such extreme fine tuning is extremely unlikely.

Realistically, in order to reset technological level to anything lower than the late 1800s you need to wipe out almost all humanity, leaving only something like a few thousand breeding pairs, and those surviving breeding pairs have to dispersed, placed in particularly resource poor places, and selected for complete lack of education. And then wait for several thousand years for all the millions of books and billions of ready-made tools to disappear.

Otherwise, nope. There are literally millions of old-fashioned paper books on this Earth, tens of millions of people who know how to reuse metal, billions of ready-made metal tools lying around.

Answer 3

This Cannot Be Done

We've been asked this in many forms many times before. The problems are these:

1. The "stuff" of our lives is all over the place. Roads and cars, houses and buildings, tools and books. Considering we have remains from civilizations thousands of years old still here for us to examine, it would take at a minimum thousands of years to believably erase enough "stuff" that it would no longer stimulate curiosity among survivors.

2. An event so devastating that it solves the problem in #1 also destroyed the entire human race. The world is replete with factories, repair shops, hardware stores.... Even erasing a significant fraction of this would require an extinction-level event. Our world is filled with the history of people who no longer exist... but their stuff remains.

3. People have memories. Unless your event kills everyone over the age of about 14, those memories would drive development. Trained adult memories would directly drive development. Untrained or juvenile memories would drive innovation.

4. I mentioned books. We have a lot of books. I have an entire bookcase full of textbooks. So do millions of others, excluding libraries ranging from your local branch to massive university and government libraries. It's really, really, really, really, really hard to erase knowledge. Curiously, despite our very digital age, most education is still done with fairly permanent paper.

How far back could you drive the world?

It will differ from one branch of science to the next, but as a whole, I doubt any apocalyptic event could drive humanity back much further than the 1820s. Anything more devastating than that would kill the human race.

Having said that... can I contrive a solution?

Yes. We have "stone age" people living in the world today. For example, the Sentinelese people. Are they truly "stone age?" Probably not... but their lack of dependence on technology strongly favors their chances of survival. In other words, it could be believable that an event destroys technology-dependent humanity, leaving the Earth's tribal people behind. Boom, stone age.

The problem is believably destroying technology-dependent humanity. It's easy to destroy the vast majority — technology dependence puts us only a couple of meals away from starvation, and large cities are specifically susceptible — but it's much harder to justify all of the technology-dependent peoples. Every country on Earth has its people who enjoy home gardening, and they'd be more likely to survive.

But, in the end, you can handwave that. Whatever your event (also being handwaved), the only significant populations remaining are tribal populations. So say we all.

Answer 4

Lack of Raw Materials

Easter Island (Rapa Nui) is a real-world example of a civilization that "went back to the stone age" and "lost its memory" and the cause is believed to be deforestation. Whether the people there cut down all their trees, or the trees were killed off by invasive species (rats), they ended up with no wood. The descendants of those who built the huge stone statues could no longer build boats or wagons or make carving tools. After a few generations, they probably even forgot what wood was like and how their ancestors used it. Even if they had a system of writing, they wouldn't have the means to make paper or to carve words into stone, so they lost their history. When Europeans first landed there, they discovered a stone age civilization that could no longer remember or how their ancestors made the famous stone statues.

Your scenario would be similar. Here on earth we have lots of stories about people in a survival civilization building back up to modern technology. We even have famous YouTubers demonstrating "primitive technology". But imagine that they're missing a key ingredient that we are used to taking for granted, such as wood. What if there are no forests? Can they jump directly to stoneworking or metalworking without wood? What if stone is unavailable as well (as it is in some deserts and prairies)? You could see a couple of generations desperately trying to rediscover what was lost, followed by generations that don't remember or know what they're missing.

Answer 5

I have recently had a sci-fi book that has that as part of its plot. Humanity is terraforming and colonizing other planets on faraway stars. But back on Earth there is a world war going on.

At the height of the war a computer virus is created that can disable any technology. It is then broadcast to space. Every human settlement loses all their technology, and being too dependent on tech, everybody outside Earth dies for various reasons. But mostly it boils down to Earth being the only planet able to sustain human life without a lot of technology involved.

Meanwhile on Earth the war leads to global catastrophe. The biosphere is practically destroyed, and humanity is forced to live underground for thousands of years. When the atmosphere finally becomes survivable again people have to restart civilization from a relative stone age - they have few machines underground, no AI (due to the virus) and the engineering knowledge they had during the war was not passed on to the descendents of the war survivors.

The book is called Children of Time, if you are interested. It won a Arthur C. Clarke award and its series got the Hugo last year.

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In a similar tone, the Horizon series of videogames has humanity go through a global war and a virus is involved that keeps people from using technology. Then everybody and everything dies, down to the last bacterium.

The biosphere is restarted centuries later by machines, with the first generations of animals and humans being clones grown in vats from genetic samples. An AI was supposed to educate the new humans and teach them technology, but due to sabotage people only learned how to speak English and were released into the wild - leading to a massive multiplayer version of The Blue Lagoon.

In the 2nd game of the series we learn that some humans had gone to space and survived the initial extinction, but then they destroyed the only planet they were able to colonize and when they come back to Earth you slay all but one of them.

Answer 6

A universal disease that shortens human lifespan to less than 20 years.

It would be best if the average age is somewhere around 15 years before death. That only gives a few years of child-bearing before dying. After the disease spreads initially, the population would drop drastically, and every generation would continue to shrink. Crucially, it shortens the span of time where kids are able to provide skilled labor to feed themselves and their community.

Oral history would continue, although knowledge about complex topics would be lost almost immediately. As they struggle to survive, more and more academic knowledge would be lost in each generation, especially if literacy disappears, which I imagine it would in all but extremely organized communities since nearly every child would be orphaned before they are at an age where they could begin to read. The language itself would change rapidly with such short generations, especially if literacy fades away.

As the resources and memory of times before the apocalypse dwindle, infrastructure falls into disrepair, starting with energy production, then machinery, then eventually structures. Many of the most important tools for farming and daily life will survive for a long time, which abundance will hasten the loss of the ability to manufacture tools. If this continues long enough, even the disappearance of the life-shortening disease will not bring back the memory of how to rebuild their old society. A surviving library would eventually speed up humanity's recovery, but they will need to advance their society enough to support an entire class of scholars to learn from these libraries and direct humanity.

Answer 7

I don't know about stone age - humans would quickly discover ways to make use of leftover things they find around them - but the obvious and probably only plausible way to completely erase cultural memory is to erase everyone old enough for verbal communication with other humans. This could happen, for example, through an infectious disease that somehow kills everyone except infants and toddlers, who then have to fend for themselves, with most ending up dying, but some managing to survive on stored food, then eventually developing their own ways of communicating with one another for mutual survival benefit.

If you're trying to avoid having too many things left over for the "old culture" to re-emerge through, a war, possibly nuclear, coinciding with the disease starting to kill everyone off (maybe one nation blames another claiming it was biological warfare?) could make it so availability of electricity and fuel is spotty even before everyone finishes dying, so that large cities and infrastructure are destroyed, etc.

Answer 8

The Fermi Paradox: Dark Forest Solution

One of the possible explanations as to why humans have not yet discovered intelligent life in the universe is that there is some alien apex civilization out there that wipes out any advanced civilization it finds. Once Humanity reaches its Spacefaring milestone and starts to spread out, this Apex race comes in and wipes out every possible nook and cranny humanity tries to hide in, and they surround our former worlds with satellite networks to make sure we can't rise back up out of the ashes. Since the aliens would want to wipe out human civilization, not all life, thier extermination of humanity would be surgical to the degree that many people could conceivably be missed. So, to solve for this, the Apex race leaves satellites around our worlds that are designed to scan for any remaining signs of civilization that try to come back out of hiding.

Any attempt to produce electricity or radio signals is a dead give away. Even the hot flames required to operate a forge for smelting metal put out unnatural infrared hotspots; so, the only way to hide is to completely blend in with the wildlife. No fires, no architecture, no large swaths of farmland: nothing. At first we will be able to get away with using old metal hand tools for a couple of generations, but as these all fall apart, we will be unable to replace them without calling down an alien kill squad; so, over time we will be forced to resort to stone tools as the only thing we can still make without giving away our positions.

Eventually the Apex Aliens may move on once they are satisfied that their mission was a success, allowing your humans to start making fires and other stone age technologies again, but only after enough time has passed that they can be sure that our collective memory of technology is long gone.

Answer 9

It's completely implausible on any established planet - why? Because the greatest technology that humans have is plants and, to a lesser extent, domesticated animals. So long as you can salvage even a tiny fraction of the incredible improvements in agricultural productivity you can maintain a much higher tech level than stone age.

The only situation in which it could happen then is if you have a small human population stranded somewhere either without access to seeds or with plants that won't grow on the planet that they're stranded. Under these conditions a reversion to mobile hunter-gatherer populations could occur.

Answer 10

Superintelligent AI

Many answers explained why a brute force approach won't work: either everyone is wiped out, or humanity can maintain at least an 1850's level (or late medieval at worst) which is vastly above the stone age. It is very difficult to have an apocalypse at the exact precise level which is not enough to kill everyone but still enough to make an early modern society impossible.

Therefore we need an intelligent force to artificially create the conditions. If we don't want to involve aliens or God to deliberately engineer such a situation, we can have a superintelligent AI which went out of control, or it did exactly what we told it to do but not what we meant to told it to do. "Solve all our pollution and climate related problems without wiping out humanity". Or "without harming humanity", but it interpreted "harming" differently as how we understood it.

Answer 11

Loss of a vital resource.

Imagine that we, in our time experienced that the silicone that ics are made of just evaporated. We would not be set back to the stone age, as we are still primitive enough to have writing on paper and hand tools. But it would be a serious setback - and the loss of information for us would be significant (although most of the loss would be cat videos).

Now imagine an extremely advanced version of us, where the silicone or any other vital resource has become the core of everything we do. We communicate through neural implants, our history and wisdom is only available digitally. Our memories are enhanced by implants, all tools are replaced by robots and even our buildings are fantastic highrises that are stabilized by computers.

Then suddenly, an event happens that makes this resource defunct. Everything will collapse, many people will probably die from malfunctional implants and collapsing buildings. What is left is a pitiful race which suddenly must stand by itself after losing the crutch that once lifted these feeble beings to a god-like status. They have no way of communicating, of manufacturing of anything substantial.

Depending on their dependence on this resource they might be flung back as far as you like really. In generations, the details of how they lived would fade, they would probably end up with a mythos were they used to be gods, but fell, and their world fell with them.

Answer 12

To have a stable stone age, you need to get away from Earth. We have too much metal lying around. We also have an abundant biosphere compatible with our digestive system, and the tools and knowledge to make it very easy to amass food, giving us time to think, talk, and tinker. A giant catastrophe, while eponymously catastrophic, would leave vastly fewer people with the amounts of metal, shelter, and agricultural equipment from before the catastrophe. We would not have fun, but we would also not need to go stone age.

So your catastrophe needs to happen on another planet, with no compatible biosphere (or very scarce) and just materials and structures that either are worthless post-catastrophe, or get destroyed in it.

Currently OT (operational technology = computers that talk to machines, get stuff done, CNC, agrotech, ...) works. Just does. Stalled? Hit with a hammer and reboot. IT (informational technology = computers that talk to computers for talking's sake) is fickle and convoluted, because hackers. Keys, encryption, access-rights, daily updates, version dependency, ... . After a network goes down hard, an admin will have to physically touch a lot of machines to make it go again. IT and OT are in the process of being united. Cyber Security will reign supreme.

Now let's have a smallish civilisation on an inhospitable planet - breathable atmosphere, but the 'plants' responsible for the oxygen are a completely different biochemistry, only usable after basically breaking them down to trivial molecules. No metals either. The reason we went here was ... a mcguffin. (Near a jumppoint? Plentiful helium? Oceans of heavy water?) We came here with very light baggage, mostly composites and textiles, and the tech we brought was intricate. Spaceworthy, for sure, triple- and quadruple-redundant, photon-based, with plenty of spares. But also ubiquitous. Sure we brought solar panels, but they are smart - every square cm wrapped in networked tech that will make it run at the very peak of it's capabilities. Sure we brought shovels - do we look like complete imbeciles? Well, actually we brought shovelmolds - pour some sand in there (of which we knew there was plenty), add energy, and presto, a shovel. And another one. As many as you'd like. And before you go 'Shovel-molds? That's oddly specific.' - they are basically cornucopias. We brought the build-plan for any imaginable thingy, securely stored on redundant crystals. Weapons you ask? Sure, those too. But those are very dangerous, so we made the access to the cornucopias dependent on reaching a certain quorum of networked participants via a distributed ledger ... it's a whole thing.

So society is coming along just fine, we are third generation now, great fun, cornucopias are doing their thing (we had the old ones build a whole stash of new ones, again, we are not imbeciles), and we occupy ourselves with the important stuff, giving astrogation advice to incoming shuttles, administrating the cornucopias, designing new settlements and leisure parks, gardening (the plants are inedible, but boy are they colorful!), network administration, sewer-inspection, plant-genetics (we even got some of them to be para-edible!), the works.

Then the crash hits. Some will say they saw a ransom notice before the screens went dark, some will report a flicker. The people with the neural implants will report a sense of loss. Some machines will putter on a while, until they reach out to a server for updates and get frozen in shock at the void they discover. Anyone moving faster than 20km/h will die then and there, vehicles crashing left and right.

The rest will scramble for shelter, their habitats frozen in whatever is their unpowered state. Drinking water is still in the pipes, but you'll have to do some plumbing to have it trickle out into a pan. Stoves will never work again, fridges are now only cupboards for soon-to-be moldy things. Everyone is waiting for the inevitable reboot, but it's just not coming. The planetary admin has an air gapped system with the recovery process written out in painstaking detail, again, we are not imbeciles, but the powerswitch of the USV was part of the core system, a detail once admonished in a long-past era - and it's air-gapping still an item in the ticket system, but be as it may, it's gone too.

Prescient people begin planting the para-edibles on as much area as they can cover, others suspiciously stock up on kitchen knives. Population crashes (no fingerpointing!) Kids get their education with stick-drawings in the mud, and hey-presto! third-generation post-apocalyptic children do not even know anybody that knew the Before. Food is too scarce to have any measurable part of the population just sit around and think, talk, tinker, you know, progress. Metal is basically nonexistant, with some bigger parts too cumbersome to rework, some smaller parts too dang specialized to be any help, and some just-right parts being the centre of much (unwanted?) attention. Stone age. till the end of time, or until we evolve to be compatible to the biosphere (though at that point: do we get it, or are we got?)

Answer 13

The only feasible way I can see, if someone deliberately keeps a population in a stone age scenario.

As many here pointed out natural disasters would throw humanity back to pre-industrial revolution - and it would be a fickle game of having no long lasting effect or simply extinct mankind completely.

So for a stone age world to perpetuate after a certain event - there needs to be some deliberate force to keep it that way. It would be a little like the movie 'The Village' or maybe 'Reign of Fire' (yes both movies are a bit corny - but it's just to highlight the concept. There needs to be some ongoing threat - most likely controlled by a mind.

On one hand it would add an interesting layer of conflict for, say an rpg-campaign or a book. There is some evil force behind this, that needs to be stopped - maybe. But I feel this could go into corny territory pretty fast.

Answer 14

At the time of writing this, you only have 19 replies, so clearly not enough :-)

I offer yet another angle, though. One thing is, we think of 'back to the stone age' as a metaphor for losing all civilisation and returning to completely basic skills, but I think that is completely wrong. The people in the stone ages (paleaolithic, mesolithic and neolithic) were not 'primitive savages' - they were highly skilled, but had simpler resources and technologies (many of which we still haven't rediscovered, actually). Modern humans simply don't have the knowledge to match a stone age hunter-gatherer; by using modern technology, most of us have given up the skills we no longer need.

So, getting back to living in a stone age - any of them - is not straight forward, and the disaster that can take us there is not necessarily physical cataclysm, but rather something that makes a lot of people reject modern knowledge - some kind of religion, perhaps, or survivalism. Once a sufficiently large group have established a sustainable culture, feel free to eradicate the rest.

This could possibly be achieved by a slow decline of modern society: everybody begin to realise that consumerist capitalism is destroying the world, and it becomes modern to learn old skills, things like foraging, flint knapping, building shelter, making fire etc. The wars over resources, migration and disease kills off the vast majority.

Answer 15

Solar flare

The world becones increasingly digital. This brings two major problems, should this suddenly be destroyed. One is that we rely more and more on this digital world for everything. How to create a TV or chip, to the (partial) automation of farming telling us when, how and where to do what things, to the simplest acts of transportation and buying something. Taken on a long enough scale we grow so dependent on it that losing it can mean the whole society is thrown back in technology.

A solar flare is a natural phenomenon that in general is harmless to Earth and it's satellites. We're also well protected on Earth thanks to it's composition. However, there are solar flares that can fry nearly all electronics in it's path. This depends on size and a lot of other things, so your phone might survive while your house catches fire from the electrical wires. However, we depend more and more on the digital world to arrange things for us. As an example, a Dutch bicycle company recently had some problens with it's servers (and later bankruptcy). The moment the servers were unreachable, people couldn't unlock or use their bikes any more. The system was so dependent on some authorisation and other services, that it ceased to function with a disruption. This vould be your world. Fried by a particularly strong solar flare, with everything surviving basically locked out. The surviving tech too advanced to use without the digital book to learn it again. The surviving people knowing too little to even create their own food.

Answer 16

How about a repeat of the Carrington Event?

Modern agriculture depends on a web of information: the farmer needs agricultural chemicals, people need food shipped (yesterday, at my supermarket in New Zealand, much of the fruit came from America, except for the Kiwifruit from Italy). Wipe out the Internet, the phones, and communications to ships (ships depend on oil and stuff, hence they depend on communications); we'd quickly find we couldn't feed more than a fraction of our present 8 billion.

What are the starving majority going to do? Take whatever food they can get. If a state has enough weapons and thugs to stop that, we might slip back to a dark ages society of robber barons. (Humanity survived the Carrington Event, and most of them didn't notice. Maybe we would be lucky enough to drop back to an 1859 lifestyle, but I doubt it.).

Answer 17

You need a reason for people to prefer the "stone age" over the technology based society. People who give up participation in the economy consider themselves better off, while a majority of those who leave the "outside" society for the technological one find themselves wanting to come back after a few years. It's more likely a structural failure that unfolds over a few hundred years than a sudden shock.

Perhaps leadership is "off-world" and doesn't care much, and the officials below them paint a false rose-tinted picture, while fighting amongst themselves for control over still functioning / wealthy areas? A tipping point is reached where many industrial processes are loss making and someone in charge decides to cut their losses by not maintaining stuff?

A background factor that tips society toward collapse is peak metals. Certain minerals become uneconomic to mine and refine on earth. All hope is pinned on space mining, but that turns out more expensive / difficult / low yielding than expected, with great improvements just around the corner (we promise).

Answer 18

The show "See" solves it in a clever way: a global pandemic wipes out most of humanity, leaving the survivors (and descendants of survivors) BLIND.

Blindness precludes the possibility of moving past the most primitive technologies. herding animals is next to impossible. Farming, extremely difficult. Blacksmithing, forging, smelting, any kind of heat-based technology is extremely difficult to do, and dangerous. Large populations cannot feed themselves, and since everyone relies on touch, diseases spread quickly.

Blind survivors of such an event could possibly hover for a while on a strange mix of modern, 1800s and medieval level, but a few centuries in there would be no way to repair or scavenge the remains of modern technologies, until all erodes to about the early Neolithic level at best.

OTOH, blindness does not make a person totally helpless. One can still forage by touch, trap animals, tan hides, weave cloth, build shelter, carefully cook by fire, and maintain simplified oral culture to spread useful primitive skills.

Could the same be done with an attack on other senses? Probably not. But we can make the case for a plausible virus that could attack intelligence or memory. We know Covid can lead to long term memory loss or brain fog. What if it was 10x worse? what if EVERY person infected with some unstoppable form of COVID either died or was reduced to a half-amnesiac with the intelligence of a 5 year old? Brute force approach would be just that the virus shrivels the brain, like some kind of infection Alzheimer's, but we can try something more subtle. What if the virus attacked the parts of the brain most necessary for abstract thought? Or just the ones needed for mental focus, giving everyone an extreme version of ADHD? Viral brain damage could easily reduce us to the level of the Australopithecus, without the need to kill us, or change our bodies. The effect can be even made so slow and gradual that the whole human population is doomed to idiocy before we even notice the problem.

Answer 19

You Can't because:

There is domino effect whit stone age thing:

• back then we have been hunter-gatherers which leads to (WLT)
• no farming WLT
• no big population WLT
• more then 7 billions of us had to die - which is total extinction

But you may try:

In other answers people mainly focus on going back - I would revers it and look into the future.

1. We digitalize stuff (knowledge) - and move from training trainers (teachers) to creating training materials - longer period of energy shortage/computer virus/lack of materials to build new data storage - would lead to periods of anarchy/fights/etc.
2. We globalize - 1000 year ago Occitan have been wildly used language - now barely anyone knows it - Italy 100 years ago was divided into few kingdoms - EU etc. - we communicate in English etc. - so in few centuries who knows how this world will look like
3. There isn't many people which know how to made a whole product - product line are here for more then 100years and we use it in every aspect of life - craftsman's are read and usually expensive so during fight from point 1 they may be targeted by restless mob.

So i would advise to move forward about 100-200 years to time when books are mostly antiques in posh people collections - and as such most of them may be stolen/destroyed during episode from 1. Now you have to figure out how don't let your population stay alive (don't starve and get sick).

Answer 20

The volcanoes went off all at once. If there was a geologist around, they could tell you it was due to that asteroid, which underwent extreme pressure far in our galaxy, basically turning it into a massive magnet; when it flew by our planet it disturbed its molten core, leading to dramatic changes in the Earth geology. But no one around you could explain it, all they know is that this was the start of several years of massive volcanic activity.

An immediate consequence is the death of a large part of the population, and the destruction of most of the infrastructure. The second consequence is a "nuclear Winter", a heavy cloud of particles covering the entire planet, decreasing the amounts of light and leading to the decay of most plant life (and animal life). But not all! An unsuspecting fern, that no one cared about until now, happens to thrive in these conditions, and spreads across the continent. And, lucky us, it turns out to be edible. So, rapidly after the fall of civilization, humans switch to it as their main food source. Unfortunately, fern salad is not very nutritive, basically an adult will have to spend 10 hours a day foraging to simply survive, even more if they have children to take care of. Another consequence of this volcanic activity and cloud blanket is that the temperature of the Earth has increased, by several degrees. So the person who has spent a few hours foraging wishes only for one thing: a nap.

Of course, people know what used to be, they can still see remnants of the old civilization all around them. Some particularly enterprising tribes do attempt to build new things, some military facilities did survive with stockpiles of food. At first, everyone talks about how it used to be. But, you know, the ferns aren't going to harvest themselves. If you do any kind of hard work, you start sweating after five minutes. Those ferns do grow fast, but still, after you've eaten all of those in a given area, you have to give them a few months to regrow. So a sedentary lifestyle becomes impossible, you have to constantly move to have a fresh supply. At first, you might be moving pushing your cart full of your old life. But do you really need all of it? The ferns are tender, there is no need for strong metal tools. And moving all that around on roads in disrepair makes you want to nap even more. After a few years of that life, most people only keep the basic necessities with them.

For some, this basic necessity includes books. And they make it a point to teach their children how to read. And these children do grow up with their head full of words like "America", "melting iron", "wizard", or "computer". Of course they never see any of those in their life. Their own children aren't as motivated to learn to read, and to cary books around (that are all starting to fall apart in that warm and humid climate). As new superstitions and religious beliefs develop, this old writing is seen with mistrust.

Military bases and other well-stocked bunkers do hold out longer, there is still a semblance of State for a while. But they don't get any new supplies, they can't easily refill their food stocks, and they get regularly attacked by the neighboring tribes who accuse them of trampling their ferns. 100 years after the cataclysm, the last sedentary group turns nomad when their water supply dries out. Another 100 years, and the dust begins to settle, the old plant life (those species that haven't died out) starts to outcompete the ferns again. But humans have lost the capacity to read and write, their memory of the old civilization is confused and unrealistic, and the cities and their metal artefacts are mostly under the lava. People do find occasional bits of steel that aren't rusted away, and do put them to good use in their new hunter-gatherer lifestyle, but they never think of heating it to temperatures higher than a campfire, it will take them thousands of years to re-discover bronze. They assume it's a type of stone that happens to be a bit more elastic.