Has human technological levels ever regressed? When/how much?

I have to say that’s a topic that intrigues me greatly. It’s a staple of narrative, sci-fi or not, but how much is it actually “possible” (historical “proofs”?)?

On the OP question: Has anything like this happened before in human history WITHOUT the civilization/culture in question dying out? If so, how much was the regression?
Mayans maybe? It was a writing and city-buiding civilization (and not small cities, even if a little different from “normal ones”), and it had a great downfall, but from what I understand you can speak of a mayan society even after that.

Of course NASA has all the Apollo blueprints. The problem is that it’s all 1960’s technology, and many of the parts just aren’t made anymore. There are far better alternatives, which aren’t likely to fit in with the old plans.

That means that a new Moon mission program has to be designed mostly from scratch. General principles of “what works and what doesn’t” still can be passed down from Apollo engineers, and IIRC there has been an effort by NASA to gather that knowledge for the benefit of Constellation engineers.

National Geographic had a wonderful article about the colonization of the Pacific quite recently. It is available for free on-line.

An engineer of the future might find some interest and amusement in how supersonic flight was done 200 years in the past. There might even be a few aerodynamic lessons to learn. But the basic approach (engines, materials, control system, tires, etc.) used for the new aircraft would almost certainly be wildly different from Concorde.

Minor nitpick. I don’t believe the Romans had windmills. As best we can tell, those were invented in Persia in the 9th century. OK, Wikipedia says that Hero of Alexandria had invented one, but it doesn’t look like it lead to anything.

The Romans (and Greeks) did have waterwheels, but I’m not sure if that technology was lost when the Empire fell. Likely it wasn’t.

I know this is a zombie, but no. Practice Steam engines required much more advanced metallurgy than the Romans had at the time. It needed several centuries of advances and knowledge gleaned from making cannon and firearms to progress to the point.

Ten years late to the party, but just got to reply.

Fletching arrows by hand & using feathers, the fletching automatically imparts a spin to the arrow. It would take special effort to put the naturally-curved feathers onto the arrow shaft straight. And even the slightest curve or offset is enough to make the arrow spin in flight. This is easy to observe, shooting arrows with a very short draw.

Completely complete ancient arrows are rare (though some survive), but hundreds of ancient arrows bear traces of being fletched with feathers. Add to this the global aboriginal arrow material with naturally curved, spin-inducing fletchings, and the claim made earlier that the stabilizing spin is an example of lost technology is patently bogus.

In the introduction to one of her books, Jane Jacobs described a trip she took as a teen-ager with her church group to an isolated mountain valley in, IIRC, WVa. Before they were “discovered”, the inhabitants were totally isolated and had essentially lost all their technology. They spoke recognizable English so they were descended from Europeans. It was a day’s hike to leave their valley and they had stopped doing so. They had basically devolved to a hunting and gathering economy. I forget if they had retained any agriculture, but the thing that struck me most was that they had totally lost the art of weaving and their clothes were animal skins. There was evidence to show that they had known how to weave, but at some point their last weaver died and the skill disappeared.

The Easter Islanders cut down their last trees and thereby had noting to build boats from.

I don’t think the boat-building technology was lost in Tasmania: sea levels were much lower and you needed little or no boat technology to cross back then.

It’s possible you needed sophisticated-for-the-time boats to travel to Australia from SE Asia, depending on when it was colonized, but it took thousands of years for Tasmania to be colonized after that, and human culture can change so much in that time period that I don’t think it would be fair to call them part of the same “culture” that they were when their ancestors first reached Australia.

As long as this zombie is up and shambling, I’ll add in that the OP’s premise seems misguided. Peak oil theory isn’t about people forgetting technology. It’s about resources getting scarce.

People may still be capable of building internal combustion engines. But if gasoline costs the equivalent of fifty dollars a gallon, they won’t be building very many of them.

The Easter Island example, which some people have brought up, is a good equivalent. The Easter Islanders didn’t stop using wood because they forget how to cut down trees. They just used up the supply of trees.

Yes, I was going to say the same thing - I think the first Europeans found a few Easter Island caoes made out of chunks of bark sewn together - there were no longer the massive trees to make dugouts like the ones that brought the original colonists.

I think too an important point is that civilizations rarely completely “died”. What happens is the tech moves or is adopted elsewhere. As an example - Western Europe fell to pieces after the barbarian invasions, then the Hun invasions, and the collapse of central authority - resulting in a decentralized society too busy engaging in warfare to provide any educational continuity - so no scholars or engineers, no money for great work (or to repair the old aqueducts, etc.) But that tech moved on with the surviving civilizations, to Constantinople, then to Arabia; so a lot of the scientific advances of the renaissance were built upon what Arabs did (numbers, anyone? Astronomy?)

The gear device was an old Greek invention, not a Roman one. gears were not that important until someone wanted to tell time beyond the accuracy of a sundial - appropriate technology is probably the applicable phrase. Gearing as in driving millwheels from wind or water with peg-and-post type giant gears had been around for centuries; anything fancier just needed a reason - like a steam engine.

I do recall reading that not only did the Viking settlements die out in Greenland, but apparently one branch of the Inuit along the shore of Greenland had regressed so badly they had forgotten how to make fire; they eventually died out, and then the area was resettled by another group over the centuries.

IMHO with peak oil - fortunately or not, depending on viewpoint, the USA has developed fracking to extend the available resource to a new level. What will happen when oil runs out? It won’t. Like any other resource, it will start to become scarce and so expensive. As a result, some activities that require it will scale back, become rarer, or find alternate methods. The regulatory hurdles to building hydroelectric dams have for example become forbidding over the decades. When that is needed for air conditioning, expect more cooperative regulations. But we make a decent amount of electricity already with water - it’s not going away without oil. Batteries are becoming more feasible to use with cars, trucks, and home power every year. Meanwhile - suburbs, big houses spread apart are a feature or easy transportation. Make autos expensive, and living downtown in row houses or apartments will be more desirable - meaning public transport will be simpler… etc.

It’s worth bearing in mind that Hero’s ‘engine’ was almost inherently useless. To get any sort of reasonable power output and efficiency it would have to spin at an enormous rate.

De Laval turbines were invented in 1882, and while much more advanced than Hero’s machine, had to spin at 30,000 rpm, and so were hugely geared down. Suitable gearing for for Hero’s machine was a complete impossibility at the time.

I know people have already mentioned the Greek Dark Age, but to add to this: IIRC, Donald Kagan compared it to hitting the “reset” button on the entirety of Greek civilization. What’s most interesting in relation to the OP is that the Classical Greeks were well aware that there was an earlier era of superior art and learning. Around 900-800 BC they were comparable (with small hyperbole) to a post-apocalyptic society that re-emerged after a “Dark Age” which lasted somewhere between two or three hundred years. One thing I find most interesting is that the Greek oral tradition retained knowledge of certain Mycenaean cities and locations which were not rediscovered until the era of modern archeology.

Not sure if its been mentioned, this sort of complaint but: We’ve regressed right now! At Thanksgiving my aunt had some sort of stupid electronic trash can. There was no place to manually open it, I waved my hand over it and then said fuck it and put the plates on the counter. I could have had the trash taken to the curb in the time it would have taken to get the thing open.

I’m sure there are tons of regressive 'build a better mousetrap examples" like that.