How quickly would humanity rebuild its scientific and technological knowledge base, if all the accumulated knowledge and technology was wiped out, except for the knowledge that they once possessed it?

63.883 years, ish.

How much was wiped out? Were power plants wiped out? Wires?

The real answer is dependent on how much infrastructure is left

Yes, and how many people are left, or will survive, in what circumstances?

@elbanditoroso
There is no infrastructure left.

Somewhere between lunch & supper, depending on how many courses, naturally.

There wouldn’t be enough time left in Man’s existence. (We’re almost to the end now!)

With no infrastructure, and none of the people with any technical knowledge remaining, the survivors are going to have a bad time… a very bad time.

It seems to me that it means that the smart, educated, and curious people are all gone.

I’m thinking possibly never, or approximately as long as it took the first time.

Welcome back to the Stone Age. Having knowledge of shelter building and fire making would be great progress. Possibly a return to hunter gatherer lifestyle, at best.

I’m guessing 25 years. By that time the gray-beards who have the important base knowledge will have died off or gone senile.
Every electronic device we see today was built on the knowledge of semiconductors that was developed decades ago. The manufacturing processes are likewise built on decades old technologies that have been tweaked as the machine capabilities improved. 50 micron technology, 10 micron, 2 micron, 0.4 micron. 400nm…100 nm… 50nm. It’s all lithography with exotic materials.
99.9% (my crude estimate) of people haven’t clue what is involved in making the little black screen they lovingly stroke with their fingers. Swipe, swipe, swipe., It just works.
The same it true with automobiles, and metallurgy, and fuels, and mining and….
Gray-beards remember what it took to make that magic.
Now get off my lawn, dagnabbit!

It might never happen. If all the roads were wiped out there would be no point in re-inventing the wheel. I think even basic agriculture would be impossibly difficult and without that civilisation can’t get started. You might discover a way to make stone tools and fire but that would be it.

You miss the point that if the technology vanishes along with the knowledge of its application, there isn’t a man made artifact remaining, and billions must die within weeks. No clothing, not so much as a shack to shelter in. The only blessing would be that all of our efficient weapons are none existent, which means the large predatory animals would feast and the scavenging animals banquet for a few weeks while the overpowering world wide stench from the rotting corpses rendered the air unbreathable.

We would have to make the tools to make the special tools, to make more advanced tools. We would learn flint knapping quickly. I would say 25 years to completely partially recover.
It would be like Roberson Crusoe. All over again.

A good part of the reason why it took so long for the world to acquire scientific knowledge is that there was no concept of scientific method. Had Aristotle dropped a pebble and a large rock at the same time, it would have been obvious that things don’t fall at a constant rate proportional to their weight. As long as that concept was around, I think it would not be all that long before science could be reestablished. It has only been about a hundred years since the Wright brothers flew their plane.

My mom was part of the team that invented the wheel! ;-D

Consider if the Dark Ages had never occurred! Mankind would be about 300 years further along than we are now. Which may not have been a good thing…

I’ve read multiple science fiction books and stories over the years that kind of address this, with wildly different numbers. The Postman, Earth Abides, Fahrenheit 451, even Nightfall. Super interesting question.

We have already seen similar things happening in history with various fields of science. Take depression, for example. It was recognized as a disorder of the body and mind by ancient thinkers like Hippocrates. They suggested the imbalance of the four humors as a possible cause, and they suggested treatment to regain the balance that sounded quite reasonable and humane. Then came the Dark Age and depression was considered a sin and people were forced to suppress their feeling or “get over it”. Then the Renaissance and Englightenment came and people started to reconsider mental illness as something wrong in the body instead of a personal failure. But they were confused as how to deal with it, resulting in the horror known as mental asylum. Only in recent history did we start to find a more humane understanding of depression, effectively going back to the day of Hippocrates.

And maybe there are still things out there that people used to discover but have already been forgotten in time, like how the Pyramid was built without any modern equipment.

I believe that if something like the question happened, human would take a long time to reclaim what was lost, but we could potentially discover a much deeper understanding of the established science, like in the case of depression. That is provided that people didn’t die out before that happened.

Or we can all find Brian’s mom and ask her for help :D

This is sort of a variation on a famous Richard Feynman lecture where he asks, “If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generation of creatures, what statement would contain the most information in the fewest words?” It’s come to be known as ‘The Cataclysm Sentence’. So we KNOW there was a table of elements, but just don’t know what they are, so we have to rediscover them. So, then we make steel and materials to build, using what we learn about the elements and metallurgy and chemistry. We know there were internal combustion engines and steam engines and we can produce steel and glass with the metallurgy and chemistry. We know flight was possible and producing things that travel fast through air and water helps us understand air and fluid dynamics. I don’t think it would take as long as it initially did, for sure. People would gather to re-establish the technology they knew existed, but was lost and forward thinking people with resources would help provide the means to make it happen, as they did in the past. It would be interesting to contemplate, that, if we did have a good understanding of our past, would we be more collaborative for well being and peace, or would we squander resources on war and weapons like we did the first time.

@Brian1946 My mother-in-law worked on the Manhattan project. Really!
Sadly, she passed away last year. Other than showing me the location of the lab and telling me about the cockroach races they used to hold, she did not pass down any useful information to me.

Frankly, I don’t know how we all could pull together to work toward a common goal that has so many moving parts. (Heck, just look at the divisiveness about something that should be universally agreed upon as the Covid vaccine.) At the rate things are going and the rapid dumbing down of society, a loss you describe might be unrecoverable if it were to occur even a generation from now.
Already there is an entire generation that thinks meat magically appears in the grocery store.
Also opportunists and criminals will try to take over anything of value as it is produced. There is ample evidence that gangs will take over and exploit the accomplishments of smaller groups.
Here’s an actual example. As part of their training, some groups of Seabees have been given the task of bringing running water to a remote village. The availability of clean water is one of the first steps to good health and prosperity. That is a noble cause and it is good training for the Seabees to learn to use equipment and resources on hand.
However, not long after the wells are built and water is flowing, gangs declare it their property and demand payment from people. They threaten to destroy it if ransom is not paid. The ransom paid strenghtens the gang allowing them to buy more weapons and ammo. And the situation spirals out of control. Eventually some part of the system breaks and no one is interested in fixing it and the people revert back to carrying water on their heads for miles.
I can see that happening with mining, metallurgy, glass making, and virtually every other needed advancement.

With no infrastructure, humans would have no way to communicate or cooperate on technology except in small groups. We wouldn’t even have paper and pens.

And again, if the knowledge is removed, that means you don’t have any of the people who know how anything was made, and since pretty much anyone crafty knows how to make at least some things, and how some things work, that means you probably don’t have any crafty people, and no one knows how to make or has any basic tools.

i.e. Humanity would be screwed, start starving, etc.

The idea that got mentioned and upvoted that humanity would get 21st Century tech back in 25 years is, it seems to me, preposterous. Good luck having more than 1% of your population survive at all. I think if anyone survives, they’ll be trying to work up to stone age technology, and hard-pressed even to record for future generations what humans used to know how to do.

In fact, without the knowledge about how technology works in any detail, the knowledge that we had various technology is nearly useless. About as useful as fairy tale technology. And even less useful for a population that’s starving and acting out The Lord of the Flies.

We’ve only just begun to learn.
If we can master cold fusion then in wind power, solar and nuclear power and monkeying around on Mars would be like banging rocks together.