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

by Ryan North

We have several ethicists on staff who have assured us, in no uncertain terms, that this is totally fine. In addition, please keep in mind that these alternate realities are not just for the purpose of entertainment. They have also been used for mining and resource extraction.

Though the idea behind writing is simple—store invisible noises by transforming them into visible shapes—the invention of writing was actually an incredibly difficult thing for humans to do. It’s so difficult, in fact, that across all of human history, it has happened a grand total of two times: in Egypt and Sumer around 3200 BCE. in Mesoamerica between 900 and 600 BCE.

European mathematicians as late as 1759 CE were still arguing that negative numbers were “nonsensical” and “absurd,” which should tell you all you need to know about European mathematicians as late as 1759 CE.

It may surprise you to hear this, but mathematics is actually built on a foundation of things we can’t prove but assume are true. We call them “axioms,” and we think they’re safe assumptions, but at the end of the day, they remain beliefs we cannot prove. Axioms include ideas like “2 + 1 gives the same result as 1 + 2” and “if a equals b, and if b equals c, then a equals c.” These assumptions are useful because they match up with reality—and building math on a foundation that matches up with reality has proven reasonably practical—but there is nothing stopping you from building different mathematical systems.

Scientists are often seen as turbonerds, but the philosophical foundations of science are actually those of pure punk-rock anarchy: never respect authority, never take anyone’s word on anything, and test all the things you think you know to confirm or deny them for yourself.

Well, more food obviously lets you have more people. But it also lets those people stop worrying about where their next meal is coming from, freeing them up to start worrying about different, more productive things: why stars seem to move across the sky or how come things fall down instead of up. Farming also formalizes the idea of an economy in your civilization, since now farmers can regularly trade their food with others. With an economy comes specialization: instead of each human having to do everything necessary to survive (or splitting it among a family group), now someone who’s particularly talented at farming can focus all their efforts on that. A hunter and gatherer simply does not have the time to invent integral calculus, but a professor or philosopher—someone who can both conceive of and devote themselves to such problems—does.

Farming creates the first income inequality, because not everyone can be farmers or share equally in the land required for it. Farmers have the most food and (initially) the most to trade, and everyone who doesn’t want to become a skeleton needs to continue eating food. You have just created rich and poor people, or at the very least the potential for them.

But that can be a lot of very finicky work,

No info on bisecting an angle with a straight edge?

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.

How you too can be out standing in your field.

every avocado you’ve probably ever eaten derives from a seed found under mysterious circumstances in 1926,

Dry the beans, grind them up, and run water through them to produce a black liquid that a lot of people like to drink for some reason. Unrelatedly, coffee is high in caffeine, which is the world’s most-consumed psychoactive drug!

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!

If you’re around when steam travel is beginning between Europe and America, be aware that the unprecedented speed of these ships will allow pale yellow American “phylloxera” insects—all of whom used to perish on the previous, longer oceanic crossings—to survive the voyage. When these insects arrive in Europe, they will become an epidemic, destroying vineyards there for generations. The eventual solution will be to graft European grape plants onto the rootstock of phylloxera-resistant American grape species: the sooner you come up with this, the more you will alter the history of the world (at least the wine-drinking parts of it).

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

All parts of the potato are poisonous until cooked, so don’t eat raw potatoes. Their poison gives you a slight advantage: humans are the only animals that cook their food,* so animals that also find potatoes toxic won’t steal them from your fields.

Pre-domesticated wild wheat had an important feature that was soon bred away: the seed heads would open to scatter their seeds on the ground or in the wind. Humans naturally preferred to collect wheat with closed pods—since then the seeds weren’t lost—and this quickly led to domesticated wheat, which keeps its seed heads closed. These closed seed heads mean that domesticated wheat is now unable to survive without humans to plant it.

Australia—always a special case since it evolved separately from the rest of the world once it separated from Antarctica around 85,000,000 BCE—is a place where marsupials* achieved dominance over other mammals, and horsies never appeared. However, from 2,000,000 BCE until 46,000 BCE there are diprotodons available to you: these giant hippo-sized wombats provide meat, milk, hides, can be ridden, will pull a plow, and have been domesticated by other time travelers.15 They go extinct when humans arrive on the continent, and while kangaroos and emus do survive contact with humanity, neither is well suited for transportation or for pulling a plow. As you require humans for your civilization, your best hope for easily building one in Australia is to be stranded around 46,000 BCE: after humans have begun arriving but before the diprotodon disappears. Protect the diprotodon from the humans and your civilization gets both humans and useful draft animals.

Water buffalo were domesticated in 3000 BCE (India) and 2000 BCE (China), but American buffalo have never been domesticated.

Domestication didn’t work out too well for the silkworms though: those that emerge from their cocoons do so without the ability for sustained flight, and will not eat unless fed by humans. They live for only a few days—during which they mate and lay eggs—before dying.

The mosquito is one of the few animals that, if removed, would have no lasting negative impact on the world: the activities they perform in the ecosystem (feeding birds, some light pollination) are already performed by other insects. The only legacy would be fewer human deaths from malaria.

Until 1910 CE, all humans knew about vitamins was that certain foods gave you different perks: around 1500 BCE Egyptians knew that eating liver helped you see in the dark without knowing what vitamin A was, and as early as 1400 CE Europeans with no knowledge of vitamin C picked up on how fresh food and citrus kept you from getting scurvy. But sadly, in what can fairly be described as “a comedy of errors, only not funny,” Europeans—who generally like to think of themselves as being a pretty savvy lot—managed to forget and then rediscover this fact about vitamin C at least seven more times over the next five hundred years, including rediscoveries in 1593 CE, 1614 CE, 1707 CE, 1734 CE, 1747 CE, and 1794 CE, until the idea finally stuck in 1907.*

Fire is a reaction requiring three ingredients: fuel, heat, and oxygen.* Put any fuel (wood, say) in an area with an abundance of heat and oxygen, and you’ll get fire. But if you put your wood somewhere where there’s plenty of heat but minimal oxygen, then instead of fire, a different reaction takes place. It’s called “dry distillation,” and while less entertaining than watching the world burn, it’s arguably more useful! In dry distillation, the moisture and impurities in the wood get evaporated away without the wood burning, leaving behind a purer version of your fuel: purified lumps of carbon.* That’s your charcoal! You might find some charcoal produced accidentally in the remains of a fire (which is where it was harvested from back in 30,000 BCE when it was used for drawing on walls), but if you read how useful it is at the start of this section, you’ll probably want to produce it deliberately.

A collar harness is simply a padded piece of wood or metal that fits around the base of the horse’s neck, with points to attach the load near the bottom, on either side of the horse. This distributes the force of the load away from the neck and onto the shoulders. Instead of just pulling the load with its front, the horse can fully engage its rear end to also push against it. This (finally!) allows the horse to exert its full strength against a load, and your horses will go from being (accidentally) artificially constrained to operating at full efficiency, simply by changing the way they’re harnessed.

A second, more ignominious, fun fact about pasteurization: it’s a technology that both saves millions of lives and requires only fire to work, and as our protohuman ancestors were using fire before we ever showed up, it actually could’ve been invented by us at any point in human history! But we didn’t figure it out until 1117 CE, and for hundreds of years after that it was used only to preserve wine.

First, blend together a mixture of your flour and water, with about twice as much flour as water. Cover it, put it someplace warm, and check it every twelve hours. You’ll be looking for bubbles, which are signs of fermentation: in other words, signs some wild yeast colonized your flour mixture and is now feeding on it. Once you’ve found fermentation, throw away half of your culture and replace what you removed with some fresh 2:1 flour/water mixture. This gives your remaining yeast new food, and provides evolutionary pressure on yeast that can feed off your flour quickly. You, my friend, are selectively breeding yeast that go crazy for whatever type of flour you’ve got on hand.

By adding some yeast to your flour/water mixture and letting it sit for a few hours before cooking, you will produce leavened bread. This works because the yeast you’ve selected for are bred to feed on the sugars in your flour and water, and if there’s oxygen around, they’ll produce carbon dioxide as waste. This carbon dioxide is trapped by the gluten in your flour, where it causes your bread to rise. When you cook your dough, the yeast will happily keep gorging themselves in the food utopia you’ve given them, right up to the point where things become so hot that they all die as their entire colony is cooked to death. Congratulations! You have used the labor of microscopic animals to produce a more pleasant bread, then killed them the instant they were no longer useful. Millions of these microscopic animal corpses are baked into every slice of bread you eat.

After the grains have germinated you’ll want to stop them from growing, or else all your grain’s sugars will get used up growing a stupid plant you don’t even want. You can either pull the sprouts off each grain manually, or you can save time by roasting your seeds over a fire and then shaking the sprouts off. Roasting also adds flavor to your beer through the Maillard reaction,* so it’s worth a try! The entire process is called “malting.”

There are alternatives to malting to increase the sugar content of your grains. If you get lucky you might isolate a mold called “koji,” first discovered in China around 300 BCE. This mold—which looks like a dark-gray spot on rice—miraculously converts starches to sugars while also imparting a nice flavor, no malting required. It led to the invention of several fermented foods in Asia, including soy sauce (which is fermented soy) and sake (which is beer produced from rice infected, and therefore sweetened, by koji). If you don’t find koji mold and still don’t want to malt, 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. If you’re willing to get a dry mouth and don’t mind other people chewing things before you brew them, this is an ancient and viable option.

To invent butter, just fill up a jar one-third of the way with milk, seal it, and start shaking. This churning will cause your milk to separate into milk solids and buttermilk. Rinse off those milk solids, press and knead them together, add some salt to preserve it, and you’ve got a delicious water-in-oil emulsion of spreadable fat.

Hops—the green, fragrant, pinecone-shaped flowers of the vinelike hops plant that naturally grows in northern Europe and the Middle East—can be added to your beer to act as a preservative and flavoring. Many people will grow to like the taste of hoppy beers! Their opinion is incorrect, but popular!

The ratio of 2A to A is 2:1, and we’ll be defining any two notes whose frequencies are in that 2:1 ratio as being one octave apart. And while those notes one octave apart are a pretty safe bet for composing, there’s only a handful of them in human hearing range, and they get boring pretty quick. Other generally-accepted-as-pleasant-across-cultures ratios for notes include 3:2, 4:3, 5:4, and (somewhat more contentiously) 5:3, 6:5, and 8:5. But you don’t want to only have consonance in your songs: introducing, building up, and resolving dissonance can help give a song surprising beauty and grace.*

The invention itself is beautifully simple: you just press a card against a spiked wheel.* Turn the wheel slowly and you’ll hear distinct clicks as the card hits each tooth, but turn it faster and those clicks blur into a tone. The faster the wheel turns, the higher the tone gets. You’ve already invented a Hooke’s wheel if you ever stuck a card into the spokes of your bicycle (Section 10.12.1), and by spinning your Hooke’s wheel such that the card gets hit 440 times per second, the sound you produce will be A440.

The red grapefruit eaten today is a product of a 1950s program in the United States called Atoms for Peace, whose goal was to promote practical uses for nuclear power outside of a wartime context. One of the things Atoms for Peace came up with was the gamma garden, which is exactly as amazing as it sounds. Radioactive material was put in the middle of a garden, around which concentric rings of plants were planted. The plants closest died of radiation poisoning, the plants farthest away were largely unaffected, but the plants in the middle mutated. Some of those mutations were useful, and among them was the modern red grapefruit: a sweeter, atomically induced mutation of the existing red grapefruit, whose flesh often faded to a less-desirable pink. Most red grapefruit today comes from the descendants of those atomically mutated plants.

Incidentally, tons of dishes were first invented as a way to preserve other foods, but are now enjoyed for their own merits as delicacies. Besides bacon (and all the other delicious salt-cured meats like ham, pastrami, sausages, jerky, and corned beef), you have preservation to thank for raisins (dried grapes), prunes (dried plums), jam, marmalade, sauerkraut, kimchi, smoked meats, pickles, cheese, beer, preserved fish like sardines and anchovies, and more.

* While glass was being created in kilns as a glaze in this era, it took until 1500 CE for hollow drinking vessels—now so synonymous with glass that if you’re thirsty you’ll ask for “a glass of water”—to be produced. This 5,000-year delay between having the technology required to produce glass and actually making a glass is so embarrassing that we felt compelled to hide it in this footnote.

Drums are far from the only percussion instruments you can make! Arrange solid beams of wood of different lengths on a stick and hit them and you’re the proud inventor of the xylophone! Put some pebbles in a sealed wooden container and shake it and you’ve invented the maraca. Hit two tiny shells together for castanets, which you can also mount on a curved piece of wood to get tambourines! And if you’ve got metalworking, curved metal sheets make a great noise when struck, which gives you cymbals, and if you go larger, gongs. And you can even add metal to the heel and toe of your shoes, which makes you the proud inventor of performative choreographic percussion instrumentation, aka “tap dancing.”

There was actually an upward trend in music, called “pitch inflation,” caused by the perception that higher notes sounded better. In competition to make their music sound best, musicians would adjust their “A” note higher and higher. In some areas pitch inflation became so severe that not only did strings begin snapping more frequently (from the higher tensions they were put under), but singers began to complain that songs were rising out of their ranges. This led to governments actually passing laws that defined a fixed value for “A,” the earliest being the French government in 1859 CE.