[ethbr0]

One thing not to discount is that if we needed to rebuild civilization suddenly... a lot of us are going to be dead.

And consequently, those surviving and rebuilding are going to have the residue of a civilization that supported many more people to work with.

Cast iron might be relatively rare, but would it be relatively rare for 1/1000th as many of us?

[notahacker]

And to a large extent, you skip the searching for raw materials to smelt cast iron to make a stove and go straight to searching collapsed buildings for cast iron stoves, or collecting railings to make a ladder etc...

[nostrademons]

Knowing how to repair and re-cast is still a useful skill, though. At some point the scavengeable items will have been scavenged and worn out, and if you want civilization to continue, you need to reboot it at a drastically lower level of complexity. That means building new production that can still be operated at the lower population levels of a post-apocalyptic world.

[ethbr0]

"Civilization" is really two things though: intangible facts & physical artifacts

If you preserve facts, you can reboot pretty quickly, relative to the initial time they took to discover.

Imagine how quickly you could make high quality steel if you could skip all the fumbling and straight to the proper carbon mix! https://acoup.blog/tag/iron/

[nostrademons]

Certainly you can probably do it faster than the 10,000 years or so it took the first time.

But it's not a panacea. A "cold start" of a complex system isn't just about replicating the system itself, it's about replicating the conditions that gave rise to it. (Witness how many ex-Googlers have founded search startups and failed to get traction, or how many people have replicated Facebook and Reddit clones and failed to get traction.) A lot of our industrial processes (like building microchips, photovoltaics, plastics, modern manufacturing) require a large base of tooling that itself requires prerequisites which may not be available. In some cases the raw materials (eg. crude oil, rare earths) are no longer accessible.

The knowledge is useful, but it'll be useful in the sense that then people can look at their current situation and bring portions of the past into it. That's probably going to involve a lot of scavenging and looting, because why dig iron ore out of the ground and fire it with coal dug out of the ground when there are large supplies of abandoned scrap steel in the world?

[ethbr0]

The analogies are apples and oranges, as all of them face existent incumbents with massive resources.

Which is where the point about population comes into play. Refining low-density elements (e.g. rare earth) into purified form is most of the difficulty and industrial base.

The available recyclable material from a civilization with a couple+ orders of magnitude larger population would be more than sufficient, even if chemical reprocessing is required.

Consequently, you run into an either/or. Either (1) there wasn't substantial loss of life (and industrial base), in which case no need to reboot, or (2) there was substantial loss of life, in which case there are more than sufficient recyclables.

And it's also hard to imagine a scenario by which we lack essential inputs. We've got more than enough crude oil or rare earths for the future. The only arguable example I can think of is helium...

[bsder]

> A "cold start" of a complex system isn't just about replicating the system itself, it's about replicating the conditions that gave rise to it.

True, but we also know the usefulness of what is beyond certain points so we don't have to do the stochastic walk through the economics to get there.

We know we want the printing press. We know we want glass. We know we want antibiotics. We know we want steam engines. We know we want electricity. We know we would want steel. etc.

Since we know that steam engines are useful, we don't have to wait for knowledge to get good enough and materials to get good enough to make them economically viable so we can gain the knowledge that putting them to general use is valuable. see: The Cotton Gin--anybody could have made it, but until the demand for cotton was sufficient there was no reason to take the risk.

Avoiding the technologic stochastic walk would be a big deal.

[lancesells]

This comment reminds me of the book "Earth Abides" and where the main character is internally debating these sorts of things. Highly recommend.

[NegativeLatency]

Casting aluminum is pretty easy and readily available