I agree with 1 and 2 to some extent, but still hold to my original opinions about ease of world takeover.
History has a few precedents for this; in particular, the conquistadors were precedents for what can happen when a few people from a more technologically advanced civilization find themselves alone inside a gigantic but technologically less advanced civilization. Some anecdotes: Cortez gave instructions to his native allies for how to make better spears, and they were able to produce lots of them in time for the final battles. Cortez brought with him a shipbuilder named Martin Lopez. Lopez knew enough about shipbuilding that under his direction the natives of Tlaxcala were able to construct a fleet of ships on Lake Texcoco, with which to assault Tenochtitlan. To be fair, he did have a supply of the most important components, cannibalized from the ships they had used to get to Mexico. But still. Ships are much more complicated than bicycles, and manufacturing them isn't as simple as bolting bits of wood together either. They also built a trebuchet during the siege (though embarrassingly they screwed up the first shot, launching the stone straight up into the air and down on themselves!). They also built a mobile fortress thing (a wooden tank?) earlier to escape the city, IIRC. They also made their own gunpowder from local materials. There are probably other things too that I'm forgetting.
Here are some more thoughts:
--I think probably not everyone could do this; having the right skills and preparation would be important. I think the whole "connecticut yankee in king arthur's court" thing is plausible, but only for the right sort of connecticut yankee, who prepared well beforehand!
--Like I said, I think the farther you go back in history, the harder it would be. However, this is not primarily for the reason you mention (that to get up to 21st century tech, you'd need to gradually work your way up through many iterations of gradually more advanced artefacts and production methods.) It's entirely true that you'd need to gradually work your way up like that; however, you don't need to go nearly as far as the 21st century in order to take over the world. All you need to do is go slightly farther than the local tech level, and then you can take over the local region, and then you can use that region's military to take over as much of the world as can be reached using whatever technology is available at the time. (Assuming you have the political and social acumen, of course--like I said, you need to be a particular sort of person with particular skills.) The primary reason it would be harder to take over the world the farther back you go is that, given the lower tech level, it would be harder to reach the whole world in time. (If we loosen the time constraints, and give you say 200 years to take over the whole world, then maybe you could do it even in the Stone Age. But if instead you were sent back to 1700, you'd only need 20 years or so, maybe less. And by you I don't mean you, or me, but rather someone from our time with the right skills.
--I agree that a single person sent back in time would have a lot more difficulty than Cortez did. Having a few hundred men + their equipment is a big deal; it's two order of magnitude better than just yourself. Since you need to scale up to the whole world, you need to cross, like, eight orders of magnitude, and starting with 2 already means you are a quarter of the way there. Less abstractly, a single person would have significantly less knowledge, less equipment, and less credibility/impressiveness, while being much more vulnerable, than a group of a few hundred.
--I agree that lots (most?) knowledge is lost over time, rather than stored somewhere. We still don't know how they made Damascus steel or Greek fire, etc. However, for taking over the world you don't need to know everything, just some things--enough to give you an advantage. Moroever, as Habryka said, it's in general much easier to rediscover something than to discover it. If you already know something is possible, you are 90% of the way there. Then if you remember what it looked like and roughly how it worked, that's 99%. (And again, this doesn't need to be true for everything, only for some things.)
Crossposted from world spirit sock puppet.
When I think of humans being so smart due to ‘cultural accumulation’, I think of lots of tiny innovations in thought and technology being made by different people, and added to the interpersonal currents of culture that wash into each person’s brain, leaving a twenty year old in 2020 much better intellectually equipped than a 90 year old who spent their whole life thinking in 1200 AD.
This morning I was chatting to my boyfriend about whether a person who went back in time (let’s say a thousand years) would be able to gather more social power than they can now in their own time. Some folk we know were discussing the claim that some humans would have a shot at literally take over the world if sent back in time, and we found this implausible.
The most obvious differences between a 2020 person and a 1200 AD person, in 1200 AD, is that they have experience with incredible technological advances that the 1200 AD native doesn’t even know are possible. But a notable thing about a modern person is that they famously don’t know what a bicycle looks like, so the level of technology they might be able to actually rebuild on short notice in 1200 AD is probably not at the level of a nutcracker, and they probably already had those in 1200 AD.
How does 2020 have complicated technology, if most people don’t know how it works? One big part is specialization: across the world, quite a few people do know what bicycles look like. And more to the point, presumably some of them know in great detail what bicycle chains look like, and what they are made of, and what happens if you make them out of slightly different materials or in slightly different shapes, and how such things interact with the functioning of the bicycle.
But suppose the 2020 person who is sent back is a bicycle expert, and regularly builds their own at home. Can they introduce bikes to the world 600 years early? My tentative guess is yes, but not very ridable ones, because they don’t have machines for making bike parts, or any idea what those machines are like or the principles behind them. They can probably demonstrate the idea of a bike with wood and cast iron and leather, supposing others are cooperative with various iron casting, wood shaping, leather-making know-how. But can they make a bike that is worth paying for and riding?
I’m not sure, and bikes were selected here for being so simple that an average person might know what their machinery looks like. Which makes them unusually close among technologies to simple chunks of metal. I don’t think a microwave oven engineer can introduce microwave ovens in 1200, or a silicon chip engineer can make much progress on introducing silicon chips. These require other technologies that require other technologies too many layers back.
But what if the whole of 2020 society was transported to 1200? The metal extruding experts and the electricity experts and the factory construction experts and Elon Musk? Could they just jump back to 2020 levels of technology, since they know everything relevant between them? (Assuming they are somehow as well coordinated in this project as they are in 2020, and are not just putting all of their personal efforts into avoiding being burned at the stake or randomly tortured in the streets.)
A big way this might fail is if 2020 society knows everything between them needed to use 2020 artifacts to get more 2020 artifacts, but don’t know how to use 1200 artifacts to get 2020 artifacts.
On that story, the 1200 people might start out knowing methods for making c. 1200 artifacts using c. 1200 artifacts, but they accumulate between them the ideas to get them to c. 1220 artifacts with the c. 1200 artifacts, which they use to actually create those new artifacts. They pass to their children this collection of c. 1220 artifacts and the ideas needed to use those artifacts to get more c. 1220 artifacts. But the new c. 1220 artifacts and methods replaced some of the old c. 1200 artifacts and methods. So the knowledge passed on doesn’t include how to use those obsoleted artifacts to create the new artifacts, or the knowledge about how to make the obsoleted artifacts. And the artifacts passed on don’t include the obsoleted ones. If this happens every generation for a thousand years, the cultural inheritance received by the 2020 generation includes some highly improved artifacts plus the knowledge about how to use them, but not necessarily any record of the path that got there from prehistory, or of the tools that made the tools that made the tools that made these artifacts.
This differs from my first impression of ‘cultural accumulation’ in that:
Is this is how things are, or is my first impression more true?