"It's kind of fun to do the impossible. " - Walt Disney
Question #65650 posted on 12/08/2011 9:34 a.m.
Q:

Dear 0x64 Hour Board,

I have been wondering about this question for a while, and I just realized that the brilliant people of the 100 Hour Board could probably go a long way in answering this question.

How long would it take to get society to the level where it is today from a dead start? To keep this interesting, I will put a few conditions on it. Let's say a dead start means no infrastructure or starting tools, and a 100 person starting population of healthy 25 year olds evenly split between men and women. Everyone involved is perfectly cooperative and has a single minded determination to rebuild society. In addition, they all have a perfect knowledge of how to set up every intermediate technology at least in theory, but there is no prior knowledge of the land, and everything probabilistic falls on the expected value overall, i.e. luck does not play a crucial role in minimum time. Assume this takes place on an earth-like planet with abundant natural resources, including optimal biomass and ores distributed as if untouched by civilization. For the sake of simplification, also assume God protects this civilization so that all their efforts can go towards growth, and no energy needs to be spent on defense against random animal attacks (unless the people specifically provoked the attack), or on rebuilding after natural disasters.

To sum up, the spirit of this question is what the minimum reasonable length of time it would take a starting group of 100 individuals to to rebuild a completely modern fully functional society of 7 billion individuals with no refined resources but filled brains.

I would really appreciate a well thought-out answer to this puzzle, including details on geography, geology, required infrastructure for any intermediate technologies, and complicating factors that I have not listed, so I don't mind if it takes much longer than 100 hours to get a respectable answer.

-Warped Mastermind

A:

Dear Warped Mastermind,

It seems to me that the most important determinant here is what will take the longest in getting to your seven-billion-person society. Building buildings may take a long time; reinventing modern technology may take a longer time—but that’s not really important, right? We’re only concerned with the last thing to get done: the thing that will take the very longest.

Given the rapid acceleration of technology in the last 250 years or so, I think it’s pretty clear that it won’t be that. Nor the colonization of land—that can happen very quickly as well. No, I think it’ll be the part of making seven billion people. So we really just need some rate of population growth. Let’s settle on one percent—that seems like a reasonable rate of growth averaged over a long time, right? You ruled out war but not disease, which I’m sure would set our people back a few times. So I think one percent is about right.

Starting at 100 and getting to 7,000,000,000 at a rate of growth of one percent per year would take 1,816 years.  

Considering where we were technology-wise 1800 years ago, and ruling out war, I think that’s probably a reasonable estimate.

No Dice