The basic premise of this question is, "how long would it take a primitive civilization to catch up with another advanced civilization, given enormous resources?"

Similar questions are generally like "if aliens from star trek gave modern earth x technology, how long would it take to catch up?".

The difference this time is, the benefactor civilization has vanished, and the primitive civilization starts with a low level of initial technology. An example would be, humans from 5000 bc suddenly inherit modern earth as is, sans well, us. They have access to all our infrastructure, and all our equipment. So not only could they find out how to make steel tools right off the bat, they also wouldnt have to go through the painful process of making tools to make slightly better tools, to make slightly better tools...

So given essentially the mantle of modern humanity, with all its infrastructure, equipment, and stored knowledge, how long would it take for the primitives to catch up and surpass us, and how long would they be able to make things that they themselves dont understand?

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    $\begingroup$ Arthur C Clarke wrote several stories where termites were variously super-advanced, equal-to-humans, or starting-up-the-path-to-civilization. The point being that they were alien enough to not anthropomorphize, and their real current-day-behavior gives no clues to us where they really might be...and our infrastructure is irrelevant to them. So the answer to your question seems a matter of opinion. $\endgroup$
    – user535733
    Commented Apr 10, 2018 at 17:07
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    $\begingroup$ The limiting factor is social organization. See first answer to this Q: worldbuilding.stackexchange.com/questions/107028/… $\endgroup$
    – Bald Bear
    Commented Apr 10, 2018 at 17:53
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    $\begingroup$ Your primitive tribes will not be able to read the manuals, they could not figure out who could do which job, or what each job is, and how it relates to others. They will likely end up scavenging consumer-oriented devices, but will never learn to make them. $\endgroup$
    – Bald Bear
    Commented Apr 10, 2018 at 18:00
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    $\begingroup$ On this earth, European tribes have inherited all the knowledge and infrastructure of Roman empire, but it took them almost a thousand years to "fill its shoes" $\endgroup$
    – Bald Bear
    Commented Apr 10, 2018 at 18:13
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    $\begingroup$ Youmay be interested in the uplift series (David Brin)which deal with civilizations that rely on precursor technology, they lack creativity, after all if they precursors could not figure out how to do X what makes you think you can. to the point when they meant humans (who had no precursor) they don't believe them about aircraft (that don't rely on antigravity technology), and think they are tricks. $\endgroup$
    – John
    Commented Apr 10, 2018 at 20:18

7 Answers 7


TL;DR: About 99% of the time it would have taken them to do it on their own. With one possible exception... (see EDIT below)

What is "steel?" Can they find the "start" button before the power plant breaks down or, in the case of nuclear, melts down? Have you ever handed a computer mother board to a child and asked them to find the "on" button (it's there)?

By the time the primitive society figured out how to turn on a hammer-making factory the factory would be falling apart, as would all the vehicles, utilities, and other infrastructure it depends on.

Entropy is your enemy

A friend of mine devoted some of his time to teaching adult prisoners to read. It took them months, and they had a working vocabulary and a tutor that knew what all the letters looked like and what their combinations meant. A person who cannot read can't learn physics by picking up a physics book and staring at it for a really long time. By the time they started working out the basics of the language, all the paper would be moth-eaten dust, all the hard drives would be demagnetized, etc. etc.

A primitive society (let's say stone age) would benefit from the buildings (a great way to stay out of the rain), basic building materials (they don't know how to weld!) and some tools (what's a "torque wrench?"). They'd get a bit of a jump with some of our more useful tools (like spanners/crescent wrenches and channel-lock pliers), but the "advances," while seeming miraculous to them, would be an insignificant advancement.

By the time the more imaginative and creative among them started realizing the world around them was more complex than they could beforehand comprehend, it would would be a proverbial useless pile of dust. Your electricity infrastructure will be gone in mere months at best. And once gone, you can't just "find the start button." Between lack of electricity and rust almost everything would be forever useless.

The technology pyramid is enormous, and the number of people that built it even more so

Knowlege (aka, technology) is a pyramid. What we enjoy today is the tip of an overwhelmingly large body of knowledge that stretches back thousands of years, touching untold billions of people.

And what many people don't realize is that it takes more than scientists to advance technology. It takes more than engineers, and technicians, and even teachers. It literally takes nearly everybody (maybe not the bums1) to provide the food and materials, recreation and education, jobs and duties, organization and structure, to make high technology happen.

So, to conclude, it might save the primitive civilization 1% of the time, but I think I'm being generous by saying so.


Raznarok got me thinking (a good thing on this site, right?). In the beginning, the primitive society would benifit by a few, insignificant things (tools, utencils, broken glass...). At the end, it would speed things up considerably (wait, you mean that machine cuts wood? What do the rest do!).

HOWEVER, "considerably" is a relative word. The technology we enjoy today was fundamentally developed ONLY during the last 150 or so years. If you assume Clarkean Magic such that the entire power infrastructure, buildings, tools, etc., did not decay, then you might reduce that 150 year period to 25 (at a guess).

BUT, compared to the thousands of years it took to get to that 125 year savings, my estimate drops from 99% to 98%. It's still pretty insignificant.

1If you think about it, even bums have their uses in terms of social development and the supporting economic and medical infrastructure that "helps" them (that's an argument I'm not going into.) My point is, every problem leads to a solution that contributes in some small way to the pyramid.

  • $\begingroup$ So do you think the difference would be night and day were entropy to be removed or diminished by the infrastructure having been built by much more advanced materials and construction? Say all the equipment only lost 1% condition per 100 years or so. Obviously this would change the scenario a bit by raising the tech level, but you basically see entropy as the primary bottleneck? $\endgroup$
    – Razmode
    Commented Apr 10, 2018 at 20:01
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    $\begingroup$ No. The more advanced the technology, the harder it is to figure it out. I believe that there's a gap (I'd say 1500-2000 years) where no matter when you begin or end, so long as the gap or more time exists between start and end, there's no significant savings to having the infrastructure left behind. $\endgroup$
    – JBH
    Commented Apr 10, 2018 at 20:37
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    $\begingroup$ Let me put that another way. You, the author, can always invent a situation that avoids entropy. You can declare a power system, machinery and building materials, etc. that never decay. In this case, no matter how long it takes to find the proverbial "start" button, it will always work. But, you can't mix tech. Given that level of magic, only the most basic tools and/or shops have an "on" button. The rest have very complex computer-controlled systems. The further into the futre, the less paper, which means manuals are unobtainable and incomprehensible. I can't think of a way for it to work. $\endgroup$
    – JBH
    Commented Apr 10, 2018 at 21:01
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    $\begingroup$ Probably "Oh, god! Please don't smite us!" On the other hand, if you showed us one today, our response would be, "that's so cool! Can I look inside the box?" If you can't imagine the solution, there isn't a solution to be had. $\endgroup$
    – JBH
    Commented Apr 10, 2018 at 21:14
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    $\begingroup$ Oh, and did I say "tank?" I meant "steam engine." Sorry. (Tank... steam engine... basically the same thing... right? :-p ) $\endgroup$
    – JBH
    Commented Apr 10, 2018 at 21:25

Any sufficiently advanced technology is indistinguishable from magic (c)

Catching up with advanced civilization will take millennia, but likely somewhat less than it took humans to advance from 5000 BC to 2000+ AD

5000 BC level civilization has no concept of written language and not accustomed to large scale organization. Leftover buildings and artifacts would be largely misunderstood and, with time, cease to operate and will be dismantled to build more useful projects (like forts or temples), or out of pure curiosity.

If leftover machinery can provide lasting supply of food, that would make things different and prompt population growth, potentially shedding 2000-3000 years. But this machinery has to be very durable and fully automated.

By the time this civilization reaches Renaissance level and may get at least somewhat adequate understanding of the leftovers, including some ability to decipher texts, most of the relics will be destroyed. But after that period, massive efforts to dig out old artifacts and decipher old texts will be under way, and once industrial age is started, development can be very fast - for example, they can jump straight to electricity, bypassing steam.

Overall, the process would be slow, and initial benefit would be minimal.

P.S In a different scenario the benefactors civilization may anticipate that the primitive one has to learn, and organize an automated "school". But I'm not covering this scenario in my answer.

  • $\begingroup$ One of the things that I wondered about as an aside to this topic is how automated equipment would be treated, and if it would realistically have much of an effect. One could set up an automated school or autonomous tractors that automatically plant and bring in a harvest, but could be easily undone by a single war. A Khan/King/Chief could easily roll through and break them all to deny access to them. $\endgroup$
    – Razmode
    Commented Apr 10, 2018 at 19:04
  • $\begingroup$ Also to note, Kardashev III artifacts would be as magical to us as they are to Neolithic people. I have a bit of a doubt they will use robotic tractors, for example. $\endgroup$
    – Alexander
    Commented Apr 10, 2018 at 19:08
  • $\begingroup$ The K-III civilization definitely wouldn't but for this particular experiment they are using more contemporary technology. $\endgroup$
    – Razmode
    Commented Apr 10, 2018 at 19:09
  • $\begingroup$ Being a bit pedantic here, but modern infrastructure is built on steam power. The difference is, instead of having steam power things directly, we turn it into electricity. It's how coal powerplants work, how nuclear powerplants work, how many ships work... Steam all the way down. You'll still need steam power. $\endgroup$
    – Andon
    Commented Apr 10, 2018 at 19:33
  • $\begingroup$ @Andon but they don't have to go to pitfalls of modern civilization either. Solar appears to be the new king of energy, and we may only guess what can come after solar. $\endgroup$
    – Alexander
    Commented Apr 10, 2018 at 19:44

While some of the answers have rightfully pointed out the difficulties of a Bronze Age civilization to use this “gift” properly to their advantage, I have a slightly more optimistic outlook and like to focus on the best possible course of action the civilization can take. Note that I will assume some additional information missing in your question. It will make a huge difference whether or not the Bronze Age people stumbling over the remnant of a modern city is a small clan living in a nearby village or one of the early civilizations with a large population and infrastructure of their own.

Picking up the knowledge

As other answers pointed out, reading and understanding the manuals, school books and scientific monographs will be more or less impossible for your “primitives”. But there is one source of knowledge which will be understandable: Children’ picture books! And there are quite a lot of them purely focusing on explaining how the world works for children. Moreover, any pictures in books will grant additional help here to understand how this advanced world worked. Even better might be children history books and otherwise illustrated history books, which will provide much easier to follow “instructions” for the primitives. This will not allow the “primitives” to start up the steel factory, but it will allow them to understand the usefulness of many modern tools and techniques. They will also gain an idea of what is possible, if they finally understand how these things work. It is the difference between wanting to have something better, but not knowing what will be better and the clear knowledge of what is better, but not knowing how to produce this. This will significantly cut the trial and error period down.

Better agriculture

Jump starting the agriculture is the first thing your “primitives” will be interested in. If they find one or more of the aforementioned children’ books on farming, they will get some interesting ideas how to advance their farming techniques. Finding pictures of modern plows drawn by a tractor will give them a massive head start. The plough was first used in Egypt around 5,000 BC (give or take). Having access to much better plows will greatly help farming, increasing yield and taking less time. While tractors will likely not be used by the primitives, they can use oxen to draw the plough. They will also find hints to modern irrigation techniques. Even better for them are the modern domesticated species. While around 5,000 BC the Neolithic Revolution already had happened, the much better “optimized” farm animals of our modern age will provide an immense multiplier to food yields be it milk, eggs, crops or meat. This requires of course, that seeds and animal herds have also been left for the primitives. Another very important domesticated plant is cotton, which would also come with a significant advancement in the timeline.

Better tools

Your primitives would have easy access to lots of high grade tools. The most interesting here are those which are easily understood and used and do not need to be powered by electricity. Axes are already known, they will get excellent steel versions. Hammers are easily understandable. Saws will be a new tool, but easy to figure out. Again, children’ picture books come in handy. The problem with these is that they will degrade over time. It will depend on how much is stored in advance. Further interesting tools are shovels, pick axes, cooking ware, high end ceramics, steel needles of all variants, surgical tools … oh and foam filled rubber wheels (great for much better transportation). Replacing these tools will not be easy. But the people will have experienced a basic understanding of these advanced tools and will want to reproduce them. Most likely they will first use bronze, but they will look out for the metal, these tools were made from and work from there.


Considering all this I think that you could easily shave off between 1,000 and 4,000 years of development. That would still mean a pretty long time to advance to the point where we are today, but it could skip a pretty long time of very slow developments, between around 5,000 BC and 1,000 BC. It should be noted though that this requires no huge losses of knowledge through other interferences besides natural degradation. War between the “primitives” or further advanced tribes or natural disasters could lead to the same destruction of knowledge and stalled development we experienced for example after the fall of Rome or the Bronze Age collapse.


Around 3000-4000 years is a good safe estimate, as that is how long it took us. ~3400 ago is the bronze age collapse when what you described basically happened, technology was reset to that similar to that of 5000 years ago or even farther back.

the bronze age collapse involved the loss of writing and infrastructure, drastic regression in technology an end to long distance trade, and a collapse of centralized government, with people basically starting over as hunter gatherers or herders. even stone construction all but ceased. It is probably the single biggest kick in the teeth technology and civilization experienced and survived. Reading up on the bronze age collapse is well worth your time. Afterward people basically reinvented technology instead of recovering it.

Your humans may be set back a little further but not much and they will be starting with more useful raw material not rubble, war, and famine. People are decent at figuring out how to use tools so they will be able to exploit a decent number of tools, especially hand tools, engineered crops, and solid infrastructure like roads (don't underestimate roads well built roads last a long time). The biggest question is do they contained herd animals to exploit and plentiful self perpetuating food sources. Without that they will be regressing far further, if they have to reinvent domestication they may never succeed, because they will likely wipe out the domesticated species with their better tools. As it is worded they should be starting with some knowledge of agriculture so they should be fine.

Keep in mind a lot of the technology and knowledge will break down before it can be useful. SO if technology is sufficiently preserved you can probably speed this up drastically (likely half as much time with magical perfect in caches or vaults so they don't get broken down for material) but a lot of advancement will be social as much as technological, You need international trade before many kinds of technology become feasible.

You can subtly introduce the concept of writing bt labeling all tools, buildings, and artifacts you can. it won't teach them a language but will give drastically encourage them to develop one and plant the seeds of the idea.

this all hinges on basic culture already existing, becasue if they don't have this they are not socialized and you don't have a people you have a mass of sociopaths and children in adult bodies. this means you aliens will have to let them develop stone age agriculture on their own (teaching would require a shared language) before the experiment.

  • $\begingroup$ Actually, domestication is a really good point, since modern animals and plants are very efficient and useful, and they would be leapfrogging straight to those. You would also have the primitives having early access to what is essentially ALL the seeds that the planet has. It would be skipping the Triangle Trade step entirely. $\endgroup$
    – Razmode
    Commented Apr 10, 2018 at 20:02
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    $\begingroup$ Assuming they don't wipe them out, modern wheat for instance can't really reproduce without humans (they don't drop their seeds they stay on the stalk till they rot), and modern cattle would be really really easy to hunt to extinction. $\endgroup$
    – John
    Commented Apr 10, 2018 at 20:05
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    $\begingroup$ I can definitely see some of the more 'temperamental' modern crops and animals dying out, for sure. Although I would think cattle would probably end up being extremely useful since the primitives would have a tech level comparable to humans of that time period, and probably have a basic understanding of domestication (5000bc). $\endgroup$
    – Razmode
    Commented Apr 10, 2018 at 20:12
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    $\begingroup$ @Alexander your right I mixed up the numbers for the bronze age collapse with bronze age. $\endgroup$
    – John
    Commented Apr 10, 2018 at 20:53

TL;DR: Likely never, it would take very special setup to happen.

Why never?

  • RL examples: Roman empire, and other empires that fell into decay and lost most of their knowledge even though the advanced people have never left. In modern times: failure of many near-primitive societies to develop even though they have the technology and training provided by international agencies.

  • It is easier to scavenge for tools and supplies than to create new ones. 5000 BC had a lot fewer people than we do now, so there will be plenty of resources for everybody.

    • And by the time they run out of leftover resources, technology to make new ones will decay. 99% of our technology will not be operational in 50 years, plenty of things will be out after a few years.
  • Dependence of everything on electricity or fuel. Power plants and grid will be gone in days. Gasoline will go bad in a few months. Solar+battery setups are rare and fragile.

    • Resources for bronze/iron age are exhausted. All easily available coal deposits are used up. Forests are gone from anywhere near industrial centers. They can salvage metals, but fuels will run out.
  • No language, no instruction, no basic education. Most modern technology requires a least a bit a bit of explanation and demonstration to use, and a lot of baseline knowledge. You can figure a new kind of machine because you know buttons tell it to do stuff, "(X)" means stop, red light means problem, etc. A primitive man will think a machine is a weird rock until it does something, and then he will think it is an animal that needs to be (at best) fed , or (at worst) killed.

  • Religious mindset rather than our engineering approach. If a machine does not work, you will try something else. A primitive man might decide that this pet of the Gods talks only to Gods, or requires a chant and a sacrifice.

    • Inevitable accidents will reinforce the idea that God's palaces and God's pets are not for mere mortals to tamper with. In particular industrial accidents, which happen even with modern workers, and totally look like wrath of Gods.
  • Manpower. In primitive societies, 90% of man-hours are dedicated to food production, and 10% to maintenance of tools. Our tools and developed agriculture will free up some time, but there is no guarantee that this free time will be devoted to studying the technology, rather than getting better food, fancier clothes, or bigger dwelling. "Professional development" is a very recent concept, for much of human history people were perfectly happy to do same thing as their parents, and even actively resisted innovation.

Best case: special setup to overcome the challenges above.

Ancient Egyptian society. The one that built the irrigation systems and pyramids (not sure if they were there by 5000 BC, though).

First, their society has found a way to put substantial manpower into well coordinated projects. Even if it was a God-Emperor's noble slave-drivers. Now, the project will be preserving and reviving advanced technology.

Second, both irrigation and pyramids show the engineering mindset. So they try to figure out technology, and not appease Gods' pets.

Third, they are located in middle east & North Africa, so they benefit from both some natural resources, less corrosion, and technology that is less dependent on modern interconnectivity and supply chains.

Finally, they get pick the right technologies to revive:

  • Schools. Starting with elementary, to learn the language. Then up to middle school and professional/trade schools (universities can wait)

  • Coal mines, of open-pit variety (to avoid methane in underground mines). Mainly to fuel medieval-level metalworking (using scrap metal)

  • Small scale oil fields, refineries, powered by generators (courtesy of third-world power grids).

  • Vehicles, powered by gasoline and maintained using salvaged parts.

  • Maybe batteries (lead acid type), to store energy from renewable sources.

  • Modern metallurgy and metalworking (powered by electricity), to make new generators.

That seems like a fully self-sufficient set of technology.

Things not to revive, (or to revive later): - Large power plants and electric grid. Ton of work, capacity for large accidents, and requires good communication.

  • Electronics beyond the transistor radios. Again, hard and not critical.

  • Modern electronics. Requires too much chemistry and engineering.

PS best RL examples of successful and rapid technology transfer are small East Asian nations. Typically under dictatorship government.


Let's start by looking at jump-start technologies that the 5,000 BC population will inherit and be able to figure out, despite the ravages of time on physical things:

  • The wheel.
  • Bearings.
  • Springs.
  • Carts.
  • An amazing road network, even if all the bridges have rusted out.
  • The road network provides a 1:1 map of good farmland and mines.
  • Pre-dug irrigation canals, even if the reservoirs are silted up.
  • Examples of how to build arches, cantilever bridges, suspension bridges, and dams -- on a wide variety of scales.
  • Readily domesticated pets, guard dogs, and livestock, available in much of the world.
  • By ancient standards, a wide variety of amazingly high-yielding crop plants.
  • Legumes as weeds.
  • A huge number of sample tools.

Without us to guide them, a long time. Consider the example of Modernization of Japan during the Meiji Restoration. From time Admiral Perry arrived at Japan in 1853 to the Japanese victory over Russia in 1908, Japan transformed itself from an feudal agricultural nation to a modern nation in less than a century. It did so quickly because the leaders of Japan wanted to modernize and willing to change their society based on what they saw other nations do. Japan stopped paying its samurai and created a conscription army. They instituted compulsory education for Japanese children. They sent missions to other countries for best practices and sent many of their children overseas to complete their education. Those who returned described what saw and motivated others to change based on their accounts.

Your primitives will take longer because there is no one there to guide them. Trial and error, and experimentation takes time and manpower. Without an entrepreneurial class to organize the resources of time, money and manpower and group of learned men and women to use the knowledge and to spread it to others.

Let us assume a king of half million people sees the picture books of the modern world and has the vision and drive to create a world like ours. He will need to implement agriculture reform right away to free up resource. He will need to create institutions of learning and education so there will be a sufficient workforce with the expertise to create the infrastructure.

The book "The Knowledge: How to Rebuild our World from Scratch" deals with what technologies must be revived to get to our modern world. Even with a glide path described to them they could stop somewhere and not continue. Your primitives could take the improvements in agriculture and medicine and stop there. They could learn to extract ammonia for fertilizer and develop vaccines but have no need to build cars or to mass produce steel.

Japan during the Meiji Restoration was able to learn quickly because it was a very literate society and was able to build quickly because it already had merchants who were capable of becoming industrialists. The king would need to build these human resources and institutions.


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