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:

  1. physical artifacts are central to the process: a lot of the accumulation is happening inside them, rather than in memetic space.
  2. humanity is not accumulating all of the ideas it has come up with so far, even the important ones. It is accumulating something more like a best set of instructions for the current situation, and throwing a lot out as it goes.

Is this is how things are, or is my first impression more true?