Fun Thought Experiment

Tim Urban (Wait but Why)is one of my favorite content filters and in his recent apearance on Lex Fridman’s podcast, he mentioned this excellent thought exercise. I immediately paused the show to go find it on his blog. He writes:

A powerfully magical, but very dickish witch decides to cast a spell on all of humanity. With a single swoop of her wand, she makes all man-made objects vanish and restores the Earth to its pre-human, 200,000 BC state. What’s left is 7.3 billion naked humans, standing on grassy plains, in forests, in swamps, on tundra, and in deserts in the exact spots where their cities and villages were just a second ago.

The humans themselves are unchanged—each person knows everything they know right now.

The only other thing is that in each of their hands is a piece of paper with a note in their language that says, “I’ve cast a spell on all of humanity because why not. Here’s how it works: everything will remain as is until humanity manages to create a fully-featured and perfectly functional iPhone 6S. As soon as that happens, the spell will be reversed and all man-made objects will instantly reappear.”

In the Podcast it’s an iPhone 13 but that’s kind of irrelevant – the point here is to determine how long it would take humans to produce something state-of-the-art from whole cloth with nothing but their memories.

Immediately I thought something like 1-10 years; a large amount of variance there. But as I unwound the prospect I realized I’m probably way off. Humans are pretty incredible but we’re also quite dependent on the technology we’ve created. I haven’t listened to the rest of the episode nor read the entirety of the post above so here it goes unprompted.

First, I think we need to figure out what our bounds are. On the low end, let’s say an iPhone design cycle is 18mo from concept to shipping product. Maybe it’s less or maybe it’s more but it’s fair to say that Apple takes about a year and half to do the task the experiment challenges us with, given all their advantages. On the high end, we have the entire information era starting back with analog communications. So maybe 80-100 years. Let’s say 100. So our range of possible values is 1.5-100 years. OK.

In order to make an iPhone, you need the chips so you have to invent semiconductor design and fabrication. Apple’s chips are among the highest density in the world so you can’t bootstrap 70’s IBM, you need the real deal. You also need battery tech and material science and manufacturing. The humans are naked but they aren’t stupid so let’s just ask the smart people how to make this stuff. No problem right?

Well, where are they? They’re not all sitting togehter on a beach – they’re strewn across the world and they don’t have their notes. Furthermore it’s unlikely any one person could even name 1/100th the people needed to do just those things. So let’s call them up! Well, we have no communications so we need to invent at least regional communications if not national. That’ll take a few years. International communications are gonna be tough without satellites so let’s just lay some undersea cable – first we need boats and machinery to build all that. And communication equipment for all the end points.

Once we can talk to each other, we’ll need a way to collaborate and share progress so we’ll need travel. Let’s invent cars and maybe some airplanes. Cars need roads so figure a few years to get asphalt and rudimentary urban planning.

All of this is adding up and pushing us pretty far away from that 1.5 year lower bound but remember folks are naked and hungry. Better start feeding and housing people so throw in some yurts with enough drainage to handle waste.

I’m not even anywhere near done yet and I’m realizing 10 years is extremely optimistic. So I’d give this 20 years minimum if we manage not to kill ourselves in the process. Of cousre, if we can prevent the advent of social media maybe we could knock it out in five…