Comment by hs586

Almost certainly. I can go out into the woods behind my house and get into the iron age in a few days (most of that time would be waiting for clay to dry and charcoal pits to cool). That cuts out ~300k years of anatomically modern human history. Whether or not it would be possible to bootstrap the industrial revolution without easily accessible coal and petroleum is a bigger question.

We might lose electricity for a while. There's not a lot of utility for electricity in pre-industrial society. Like, given enough copper, I could make a wind turbine, but I can't casually make a useful lightbulb. Maybe a ceiling fan, but it would almost certainly be easier to run that off of mechanical power directly via a series of gears and belts. Electrochemistry would be a neat party trick, but I don't think my shoddily built wind turbine would generate enough juice to process aluminum.

Firearms would probably continue to exist. I could make a musket, and its utility for hunting and defense would make it immediately worth it. Black powder's not terribly difficult to manufacture from base ingredients.

Are we including domesticated crops as "man-made"? Because that would complicate matters. A lot of knowledge could be lost in the time it takes to rebreed the kinds of grains that allow for stable settlement.

We wouldn't need to re-invent writing, since that's just knowledge, and that would give a pretty big leg up in not losing a bunch of knowledge every time someone dies.

On the whole, if we keep selectively bred crops, I'd say we'd be bumped back to about the Middle Ages at the most. If we're losing the crops, then it would come down to whether we could preserve our more advanced knowledge long enough for agriculture to redevelop.

John Plant has been working to get to the Iron Age for eleven years, but he's doing it for the lulz.

https://www.youtube.com/@primitivetechnology9550/videos

I've always wanted to write a "How to make a peanut butter and jelly" cookbook that starts with "okay, first you're going to need to find a stalk of wheat that's ready to seed, but don't worry about germinating it because we'll do that in the next chapter.

It's hard to say if we ever would. We used up a lot of the very easy to access sources of many resources - minerals, oil, etc.

Without having access to the advanced techniques, I think it's unlikely we'd even reach the industrial revolution again.

You probably need to change the thought experiment to get at what you're really trying to get at. If all man-made things disappeared tomorrow, you're talking pipes, wires, streets, houses, antibiotics, the immediate effect is very close to 8 billion people die within a few weeks. The hundred thousandor so survivors may know what they already knew, but now they need to find a way to find each other, write it all down, without pens or paper, make more people, and teach those new people so the knowledge isn't lost within a generation or two, all while also building enough infrastructure to at least keep the tiny communities still around from also starving.

All of the post-apocalypse LARP scenarios other responses are describing tend to assume at least books and some small number of durable structures survive. If nothing at all makes it, the first thing that happens is most everyone not living on a ground floor dies instantly from falling. Everyone living where it freezes dies in a few hours from exposure. Most people living anywhere experiencing a heat wave die from heat exhaustion in the next day or two. Most everyone else everywhere else dies from starvation or disease in the next few weeks. Even if you're living on a farm, you've got no fences or tools, so you better hope it's a farm with lots of edible plants and it's near harvest season. If you live in a city, you have no hope at all. Even existing food stores will spoil quickly with no containers or refrigeration. The people who do the best will be Hadza and uncontacted tribes and what not that lose their spears and tents, but all they have to do to get back to their prior situation is make more spears and tents, which thankfully doesn't require a global transportation network or modern manufacturing techniques. They're not the ones who know how to build iPhones, though. I'm not sure anyone knows how to build an iPhone, really. The knowledge is probably largely digital. The chief engineer at Apple knows where to look and who to ask, but no single person has all of the knowledge in their own head.

In such a situation, I'd really hope that I have my handy copy of https://www.howtoinventeverything.com/ available!

It's surprising how relatively recent shirt buttons are. 1000s of years no one thought (or couldn't?) sew a hole and put button through it.