

Ask HN: If we woke up tomorrow and... - ftse

If we woke up tomorrow and all technology had gone, assuming we could still make a fire, how long would it take to get back to where we are now?
======
pg
Despite the generally frivolous answers, this is an interesting question and
one I often wonder about. What turns out to take up all the time if we want to
reproduce where we are now? Presumably the optimal plan is to spend
practically all your effort on machine tools.

It would be interesting to be able to figure out what would be the best
benchmark of progress. Would it be the precision with which you could machine
metal? That might do up to about 1900.

It might turn out that most of the time was spent on something nontechnical,
like moving stuff from place to place before you'd developed fast ways of
doing that. So maybe in practice the most important benchmark would be how
fast you could move stuff.

Reproducing where we are now would in some ways be harder than getting here
was. E.g. the most accessible coal and mineral deposits used to be sitting
right on the surface, but now those are gone.

~~~
blackguardx
Minerals are definitely the hardest part.

You wouldn't need coal. If you can make a fire, charcoal is easily produced
from wood.

Making forges and blast furnaces isn't too difficult. To build one, pile up
dirt or clay walls to form a bathtub like structure. Make sure you have holes
at the base so air from your bellows can make it though. Construct a fire in
the tub and pile on alternating layers of charcoal and iron ore. Keep pumping
on the bellows for the next few days until the the charcoal burns up. Your
iron ore should now have turned into pieces of high carbon steel, perfect for
making any tool from ploughs to blades.

You might be able to find iron ore as dark colored sand in stream beds. I
don't know where you would find copper or zinc.

Once you have steel, everything follows. If society knows about existence of a
technology, reproducing it shouldn't be difficult. The hardest part about
progress is inventing brand new things.

If you are interested in learning how to make machine tools from very simple
materials, look up the Gingery series on making a complete metalshop from
scrap:

<http://www.lindsaybks.com/dgjp/djgbk/series/index.html>

~~~
jfoutz
I've built the gingery furnace, an poured aluminum twice. It's hot and scary.
I've made arrowheads out of old glass bottles using a broken antler.

I think you're underestimating how spectacularly hard it is to make anything
without tools. Go into the woods naked, and show me how to make a bellows.

I'm pretty sure i could do it, if i could keep my glasses, and my shoes and a
knife and a bunch of food. I _think_ i could run down a deer, if all the other
people i'd be in competition with didn't kill me after i was 10 miles into the
run.

I don't think steel matters very much. Sanitation, clean water, lots of food.

"If society knows about existence of a technology, reproducing it shouldn't be
difficult. The hardest part about progress is inventing brand new things."

I disagree. Once upon a time, people drove cars on the moon. Should be a n
easy thing to reproduce eh? heck, we've got 40 years of technology on them.
The hardest part about progress is convincing other people to do what you want
them to do.

The gingery books are FANTASTIC. i'd highly recommend them to ... everyone.

~~~
blackguardx
I guess I meant that coming up with new ideas is hard. Invention is hard.

In the hypothetical case that everything is gone tomorrow, the ideas still
exist. All we need to do is implement them.

I'll explain it in CS terms. What would happen if all copies of the quicksort
algorithm were destroyed overnight? Someone would spend a few hours and write
another one because he/she knows about the algorithm. It would take about an
hour.

Consider the further case that no one on earth knew that the quicksort
algorithm even existed. How long would it take to be duplicated? Months?
Years?

How did someone get the idea to smelt metal? It took thousands of years. Now
that we know that smelting exists, all that is left is finding a way to do it.
Many people in modern society will have the knowledge to rebuild technology. I
would argue that expanding technology is much harder than rebuilding
technology.

As to pouring molten metal, sure it is scary at first, just like driving a
car. After much practice, like most things, it ceases being scary.

~~~
mcav
> _I'll explain it in CS terms. What would happen if all copies of the
> quicksort algorithm were destroyed overnight? Someone would spend a few
> hours and write another one because he/she knows about the algorithm. It
> would take about an hour._

That's like saying you just woke up in a Blacksmith's shop, with the anvil and
fire ready. That's the last mile, which isn't the hard part. Compare it to
destroying all traces of CPUs and computer hardware/software. Okay, now go
fabricate a processor.

~~~
blackguardx
I don't think I am explaining myself well.

What I mean to say is that once you know about an invention, reproducing it is
much less difficult than actually inventing it. Do you disagree?

In high school, I was obsessed with metalworking and built several forges. I
played around with melting metal and forging blades. I created charcoal. I
read everything I could get my hands on about blacksmithing. I read a lot of
fiction books about rebuilding post-apocalyptic societies.

I guess I have a different perspective.

~~~
mburns
I understand where you are going. If we lost it all tomorrow, it would be
quite hard to reproduce tools, machinery, high precision equipment, etc. to
get back to where we are. For new inventions, you need both to do all the
building of the machinery that builds that machine that will build the new
invention, but you also need the novel new idea that is the invention to be
made. 2 hard (and quite different) problems to solve, instead of just the
first (which, as mentioned, is ridiculously hard in and of itself).

------
jfoutz
I assume every artifact made by man disappears instantly? No books, no canned
food, no clothes. Everyone i know would die in a week. My grandma grew up very
poor in the dustbowl. She would have a chance, but it's cold at night.

So, you're left with people who can recreate their tools in a few days, and
don't really need what they have. the !Kung in africa? There's probably 20,000
people in the world like that. Expansion around the globe would likely happen
as fast as the first time. 100k years?

I think teching back up would take a lot longer. The easy to get natural
resources are gone. 100k years aren't really enough for plants to turn back
into oil. Maybe really big earthquakes would bring metals to the surface. Once
upon a time there were black puddles of oil on the ground. Now, we have to
pump saltwater into deep reserves to get the oil out. I suppose there's plenty
of easy to reach coal. I don't know much about copper mines, they always look
very deep to me. perhaps there is a lot of easy to get surface copper, just
not in high enough concentrations to make it worthwhile to mine.

~~~
anamax
> Once upon a time there were black puddles of oil on the ground. Now, we have
> to pump saltwater into deep reserves to get the oil out.

Hmm. I know where to find some of said black puddles.

While there are reasons why they're not being exploited today, I guess that
makes me pretty valuable when all the tech goes away, at least until someone
figures out that we need metal to deal with said "puddles".

~~~
seanb
Just out of curiosity, what part of the world are these puddles in? Assuming
that all technology won't be disappearing anytime soon, it's probably safe to
share ;)

~~~
anamax
They're in the US. One is actually well known, but it looks like no one thinks
of it that way, at least for now.

~~~
ibsulon
ANWR? That's a cold place to be without clothes.

~~~
anamax
(1) I doubt that ANWR has ground-level oil because I think that the Inuit
would have exploited it.

(2) The Inuit know, or at least knew, how to survive in that area without
significant tech. If "all the tech disappears" happens in winter and they wake
up naked and outside (with no inside available), they don't wake up. If it's
summer, they can cope.

------
mcav
Long enough that most of humanity would die very quickly. Without tools to
grow food to satisfy our current population, we couldn't make enough. Couple
that with lack of heating for cold regions, general lack of knowledge of
survival skills, and the realization that we must first get _metal_ before we
can even create decent tools... I'd say we'd be goners.

~~~
dctoedt
Don't forget to stir in another factor: Localized conflicts would soon break
out over scarce food and other resources, It's an interesting question whether
the people most likely to prevail in such conflicts (and thus most likely to
avoid near-term starvation) would be those possessing the skills to recreate
even rudimentary technologies.

------
noodle
i think you should clarify more. for example:

do we still have the knowledge but have no material technological items? do we
still have the stuff but no knowledge? are we being impeded by some sort of
magical force? are there dragons?

~~~
TweedHeads
If we have the knowledge, ten years.

If we don't, a thousand.

If there is magic, until the magician decides.

If there are dragons, never.

~~~
bprater
Stop the dragon bashing!

~~~
pistoriusp
Any mention of dragons brings fond memories the Pug, Macros, Thomas and
Arutha.

If you don't know what I'm talking about, then I suggest you pick up a copy of
Feist's "Magician."

~~~
whatusername
I noticed wandering past a bookshop today he has a new title out...
[http://www.amazon.com/Rides-Dread-Legion-Book-
Demonwar/dp/00...](http://www.amazon.com/Rides-Dread-Legion-Book-
Demonwar/dp/0061468363)

Actually - interesting that Amazon don't have it available for the next week -
I saw it on the shelf in Australia.

Feist's newer work is still enjoyable - but it's no-where near the level of
his earlier stuff.

------
pavelludiq
At first i would be concerned with not freezing to death and finding food,
I'll leave technological advancement for the better days.

You see, we started to develop technologies only after we had people who could
afford not to have to kill their own food, so they had some free time to make
now tools or have new ideas. cave men weren't stupid, they just didn't have
any spare time to waste.

------
gcheong
Do you have an interview at Google or Microsoft?

------
electromagnetic
Well I suppose the bigger question is, does everything the technology created
go away too?

Technology built everything, but do all our houses disappear or just all the
wiring and plumbing and crap? Because if the house goes, then surely so should
all the people who were brought about by technology.

Realistically there would be approximately (assuming the max for 10,000 years
ago) about 10 million people on the planet. If so, with the distribution
spread throughout the world then I think if humanity were born with our
present knowledge I think we would do rather well, presuming we were swapped
out with the Cro-Magnon. I bet about 50% of the people would probably die off
within the first decade just through lack of knowledge (again presuming even
IQ and knowledge distribution), but if people managed to start bringing back
technology I think we could advance things pretty quick.

I mean one person with the knowledge of how to make steel and devoted their
life to teaching everyone how to make advanced tools, well we'd have skipped
9,800 years in the space of maybe 50.

So I suppose it's all in how it would happen and then a large handful of
random chance and human nature. I mean if the one guy who remembered how to
build a blast forge, also knew how to make gun powder (I know the principle on
how to build both) decided to instead of helping the world decided to build a
machine gun and build his own country then it could all end when someone
usurped him without the knowledge to build tools or weapons.

------
yters
One big problem is that we need working technology to access much of our
technical knowledge.

~~~
jpwagner
HA! I love this thought. I hope we can assume that knowledge is infinitely
accessible. If not, it may turn out more like "idiocracy" in that initially we
build things that suck.

------
dotmatrix
We still have the knowledge, so assuming that knowledge is utilized i guess
you could answer that question by simply reverse engineering the amount of
time it took to obtain the knowledge of achieving a significant process and
then determine from that point how long did it take to implement the solution.
Since you would be implementing the solution only you would then need to know
how many key solutions are you re building and you could figure this question
out quite easily.

------
stavrianos
Seems to me that there are two ways it could go, depending on how you take the
question.

If when all the tech disappears the resources reappear, I'd say it doesn't
take too long at all. Maybe ten years, maybe a hundred, maybe a thousand, but
nothing more than that. This is a sort of "If people with modern knowledge
fall back in time" scenario.

On the other hand, if the resources aren't available, ie all the iron that's
been mined over the last hundred years is simply _gone_ then we'd be pretty
boned, and would probably go extinct. This is more of a post-apocalyptic
scenario, except you can't even mine the I-beams out of old skyscrapers, but
all the cheaply accessible metal's been mined anyways so your civilization
simply can't advance past the bronze age (or wherever you manage to scrape it
up to). We'd be like the australian aborigines, who lived for (if wikipedia is
to be believed) an astronomical 40000 years on the continent without
developing anything more sophisticated than the boomerang.

------
nixme
Are you asking this question in reference to last night's Battlestar Galactica
finale? It was somewhat surprising to see everyone give up technology so
easily and start anew with just clothing, some food, and their own language.
But I guess being cooped up in those ships for that long and seeing how the
abuse of technology led them to such events could have that effect.

To answer your question, it's hard to guess. Without medical or agricultural
technology, I think most of our current population would die out. The rest
would war over the remnants of societal structure. Technical progress, as we
see it, would take a long time to begin -- primarily dependent on stability.
There are too many unpredictable events that would alter the length of time
before returning to stability and our current standards.

~~~
qw
I have not seen that episode. Thank you very much for telling me how it ends.
I guess that will teach me the dangers of not seeing everything the second it
airs. A couple of comments like that, and I can throw away my PVR completely,
and save a lot of money.

To keep on topic, I think that many would die due to lack of food and medical
technology, but it wouldn't take long to reach the technology level of 1900.
The difference between then and now, is that we know it is possible. How much
time was wasted because people didn't think something was possible?

~~~
tlrobinson
Seems like you should have stopped reading after the first sentence.

~~~
qw
The first sentence said it all really. The article was about giving up
technology. The only remaining fact would be if they had a choice or not.

------
brianobush
funny thing was just the other day I was showing my children how to make fire
with two sticks. Didn't work. Father failure, though they did understand the
idea of friction and the result: heat. Now, my second attempt is using a boot
lace with bow (from curved stick) to turn a wood axle with a top brace. Makes
smoke, but no fire yet. Somehow, this was much easier when I was younger.
However, my point is the basic skills are just as important as the knowledge.

------
cool-RR
I think it's a very interesting question.

I would say three to five years. In my opinion, technological tools are
overrated. Most things can be built by hand using common materials.

Actually, it would be a very cool project! Take a bunch of hackers. Set up an
isolated camp for them in a remote area. There will be no technology there,
but there will be plenty of edible plants, fresh water, and some medical
supplies. The hackers will be supplied with a sample of every raw material
that Earth has to offer. And when I say raw, I mean, for example, iron ore.
Have video cameras all around the place to make sure they are not bringing
technology from anywhere. Measure how long it takes them to build, say a
computer. I think it will be less than a year. (The reason I answered 3-5
years to the main question is because in the situation you described most
humans will be busy fighting each other, and hackers will have less time to
devote to rebuilding technology.)

------
kellishaver
I think you would see a large drop in population before we were able to
rebuild. Population growth only occurs when the technology can support it.

If we were starting over without any of the knowledge we have now, then it
seems reasonable to assume that it would take roughly the same amount of time.

If we had history to look back on, then maybe we would be looking at a few
hundred years instead of a few thousand.

I think the more interesting question is, if we had the knowledge of our past
history to look back on, what would we do differently? Would we be more green
from the start, for instance? A lot of the problems with adapting to green
tech today isn't that the technology is necessarily so knew and unknown, it's
that well-established infrastructures and systems are in place that are
implemented on vastly different technologies and the cost/logistics of
replacing them is prohibitive.

------
baddox
If every piece of human technology disappeared, I would probably die in a few
seconds, since I sleep on the 7th hour.

------
cmos
Now that we have all witnessed the greatness that is online porn, probably not
that long.

------
kenver
If we woke up and all the technology was gone, would we want to get back to
where we are now...a second time around would be a good chance to fix/improve
stuff.

------
tesseract
You'd hopefully get pretty far while current experts are still alive.
Otherwise, you'd better at least have a plan for getting printing and
libraries up and running pretty darn quickly so they can leave instructions
for the next generation...

------
geuis
Was this somehow inspired by the BSG finale?

However, I find this kind of question fascinating. This question is posited in
the book Marrow, and it takes a very advanced society about 5000 years to get
back to where they were.

I think the situation right away would work more or less like this. Within the
first few weeks to months, nasty. We're literally talking about BILLIONS of
people that will starve to death within a matter of several months.

Based on your scenario, we're not looking at instantly restored nature. Vast
areas of the world would suddenly be large, vacant, barren land where the
cities were. Places that were verdant farm land before being paved over by
roads, cities, and suburbs are likely to be nutrient starved and unfarmable
for many years.

You would immediately have millions of people moving out into surviving
"wilderness" areas. Trees burning, wild animals being hunted for food. I'm
mainly thinking of the U.S., but the ideas apply to most other industrialized
countries. "Third world" and agrarian societies might actually fair better.
We're talking about the utter decimation of many remaining "protected"
species. Suddenly removing everything humans have built, at this point in
history, would seriously fuck what's left of nature on the land. On the other
hand, humans would no longer have immediate access to the deep ocean. Given
the results of ocean recovery in protected areas in recent years, its
encouraging to think that many threatened and endangered species and
ecosystems would immediately start recovering.

The next important thing to take into account is culture and religion. There
will likely be surviving populations worldwide that represent the varieties of
cultures and religions that we already have. In small pockets, you might find
members of the intelligentsia trying to recreate primitive paper as soon as
possible, to re-record as much general knowledge as they can. In other parts
of the world, particularly the Muslim populations, there will be a religious
fervor and general destruction of any remaining advanced knowledge. This will
also happen in much of America, due to our retarded Evangelican populations.
We might actually find more preservation efforts in Europe and Japan, due to
their longer-term cultural histories mixed with being extremely modern. I
can't say about China, but they have a long history and might also work to
preserve knowledge.

People are adaptable, and anything short of a global disaster that fucks the
basic life processes of the world, people will survive. It would likely take
several hundred years at a minimum, and at most several thousand, before we
saw some resemblance of modern technology re-emerging.

However, the only cultural artifacts that people would have is what was
created from the morning after, onward. There would be no Pyramids,
Stonehenge, Jerusalem, Aztec ruins, or anything. No cave paintings, primitive
burials, etc. By saying "all technology", this means that all physical remains
of our progress would need to disappear too. We would only be left with our
memories. In every graveyard around the world, all caskets would disappear.
All pacemakers and artificial joints would be gone from the skeletons. They
would also be gone from the living.

After a couple of generations without any physical remnants of our
civilization's evolution, with no pre-history, our descendants would be
completely cut off from their past. They would of course be able to re-learn
about evolution over the billions of years of life because fossils won't go
anywhere. They could relearn about our own evolution, but only from the
biology side of things.

I would imagine that future historians would eventually realize their legends
of an ancient global civilization might have some credence, even though there
is no physical evidence. There would be the tell-tale signs, the footprint,
that our technology had even though the tech itself is gone. There would be
the atmospheric carbon levels, the concentrations of uranium where reactors
and weapons were, and hundreds of other alterations to the physical world that
we've made.

------
raquo
So the question is whether the humanity will be able to stabilize before
current generation (with the knowledge of technology) will die (including
because of age)

------
known
<http://en.wikipedia.org/wiki/Cast_Away>

~~~
Zev
I prefer <http://en.wikipedia.org/wiki/Robinson_Crusoe> \- Crusoe built all
sorts of things to make his life easier from wood. Tom Hanks just spoke to a
volleyball the entire time.

------
nazgulnarsil
I think people speculating in this thread would greatly enjoy Earth Abides by
George Stewart.

------
jodrellblank
All technology? I guess we're back at the bottom of the Civilization advances
tree, eh? Do you want triremes, maths, militia or granaries?

England has ~65 millions of people. Take away all manmade technology
(including buildings, tarmac, concrete) and any city would be many square
miles of bare earth collapsing into holes where sewers and tunnels and
underground trains once were.

Within a day or two it would be many square miles of human waste, corpses, mud
if it rained, and people making their way to the nearest rivers.

Within a couple of weeks, significant fractions of people have starved or died
of lack of medical treatment, fighting, illness from river water contaminated
with sewage and corpses, etc.

OK, you can drink from the river you may not get ill for a while. What can you
eat but other people? City areas -> wastelands.

Out in the country, farmers with easily harvested crops in season are the best
off, until they get looted. With no food stores or shops, animals and current
crops will be eaten quickly and that's pretty much that. Good luck surviving
on hedgerow food and hunting with no experience and everyone else trying to as
well.

Some strong willed resourceful people in remote niches will survive (nobody
could travel to them very quickly). After a few years we'll see who. Small
farms, maybe some farm animals, fast growing trees coming into usable sizes.
Levers, (wooden) wheels, barrows, hammers hoes, heaters, cookers, flint/stone
axes, they'll be around.

Maybe in short order some beach sand melting -> glass jars, glasses. The
people who survive are the people who currently live with reduced technology
and will be busy staying alive.

What then? I don't know. A few decades to a population big enough and
connected enough for mass trade, I suppose. By then a similar sort of grind up
through metalwork, blacksmithing, banking, debt, economic collapse...

What technology could we skip to that would hasten us through such
developments? I say at least two hundred years.

------
jodrellblank
On reading the replies, I suddenly remembered this:
<http://www.overcomingbias.com/2007/09/planning-fallac.html>

My revised estimate for the time it would take to recreate all of history is
approximately as long as it took the last time, plus a bit.

------
jodrellblank
The last time a similar topic came up at HN, it was the "what if you time
travelled back to the past" question.

I didn't think of it in time for that thread, but I wanted to turn the
question around: Looking back through history, if we wanted to spot a
technologically advanced person appearing in the past and trying to create
'future' technology, what markers should we look for? (and ... has this
happened?).

