How to Invent Everything: A Survival Guide for the Stranded Time Traveler

by Ryan North

A rock tied to a string that can swing freely is called a pendulum, and it turns out that one second is the time it takes any pendulum on Earth—regardless of weight—to swing from one end to the other, as long as the pendulum is 99.4cm long.

Wouldn’t it be nice if you had machines that ran on water and light and turned gross dirt into delicious food and fun chemicals? Also, wouldn’t it be nice if the machines were self-duplicating, self-improving, and—most exciting of all—not all of them wanted to kill you? Good news: these machines exist! They’re called “plants,”

To save yourself from wasting time eating poisons, remember that bright colors are usually (but not always) used in nature to mean “I’m easily seen, which means I’m not worried about predators, which means if you eat me you’re probably going to have a bad time.”*

Domesticated corn (available after around 7000 BCE) does not naturally reproduce: to produce more corn, you must conserve kernels until next spring, then bury them in the ground. It’s been so thoroughly domesticated that it can no longer survive without human aid and interference. Thanks for the trust, corn!

Oak trees can live for more than 1,500 years, and it takes about 150 years for an oak tree to grow to the point where it can be harvested for wood, so oak farming is a situation in which you’ll want to plan ahead.

Potatoes are one of the few plants that contain almost all the nutrition humans need! You can live entirely off potatoes (but shouldn’t, because then you’re extremely vulnerable to crop failure, and to vitamin A, B12, and E deficiencies).

All parts of the potato are slightly poisonous until cooked, so don’t eat raw potatoes.

Potatoes can be grown almost anywhere except in the tropics, and they produce more calories per square kilometer than any cereal crop!

Soybean plants produce two times as much protein per square kilometer as other vegetables, five to ten times more than land used for grazing animals to make milk, and fifteen times more than land set aside for meat production.

Soybeans are also a great source of many essential nutrients.

Like yams, soybeans are toxic to humans (and all other animals with just one stomach) when raw, and need to be cooked before being eaten.

Plenty of foods have toxins that get destroyed by cooking, and no foods become toxic when cooked.

Avoid introducing tobacco to your civilization, and you will save yourself billions of dollars and millions of lives and prevent the invention of vaping.

While you can find food with hunting and gathering, you won’t find any beer: it requires reliable agriculture to produce and is therefore one of the perks available only with civilization.

Congratulations! You have used the labor of microscope beasties to produce a more pleasant bread, then killed them the instant they were no longer useful. Millions of their corpses are baked into every slice of bread you eat.

Fermentation doesn’t just produce alcohol: yeasts can actually add nutrients to your beer when fermenting, particularly those in the B-vitamin family.

While you can’t survive on beer alone (at least, not for more than a few months, before the symptoms of scurvy and protein deficiency set in),

there’s always the option of making chicha instead: here instead of malting you chew the food in your mouth for a while before spitting it out, relying on the enzymes in your saliva to break starches down into sugars.

Being with you and not being with you is the only way I have to measure time. —You (also, Jorge Luis Borges)

but at this point it’s probably worthwhile to tell you that you don’t actually need to know exactly what time it really is anyway, and that the fifteen minutes of error we’re going to such lengths to correct honestly don’t matter.

No act of kindness, no matter how small, is ever wasted.

The solutions all are simple—after you have arrived at them. But they’re simple only when you know already what they are.

a guide to reinventing civilization also functions pretty well as a guide to having a really delightful picnic? Picnics are objectively one of the crowning achievements of humanity,

The coming of the wireless era will make war impossible, because it will make war ridiculous.

A skilled sailor with a proper boat can achieve a travel speed of 1.5 times the wind. Something to shoot for!

With these instructions, you’ll be able to paint with any color you can produce. Colors you can’t yet produce, however, will remain pigments of your imagination.

Re-creating medicine in the past will require you have some . . . patients.

the Hippocratic Oath, which is still used today by many doctors, who for some reason feel compelled to publicly promise they won’t intentionally kill their patients.

In the modern era, the international standard A note—the foundational note of the musical scale—is called “A440,” and it’s at, you guessed it, precisely 440Hz.

We don’t need to tell you this, because you’ve seen computers. You know how useful, productive, entertaining, and completely awesome they are. Here’s how you build them from scratch.

x × y = x added to itself y times

x – y = x + (–y)

x/y = x added to itself until it reaches y, counting the number of additions it took