The Complete Guide to Absolutely Everything

Book Preface

Close your eyes.
Admittedly, reading generally requires your eyes to be open. If you are holding a copy of this book, in a few seconds you will certainly need them open, because you can’t read the rest of what we’re about to say with them shut, obviously.
But for now, close your eyes.
During that brief moment of darkness, not much changed. The words stayed on the page; the book, thankfully, was still in your hands. When you opened your eyes, indeed when you opened them this morning after some restful sleep, the light flooded in, and you recognized everything as pretty much the same as when you’d closed them. Reality persists whether you are paying attention to it or not. All of this might seem very obvious. Silly, even. But this is a fact that, once upon a time, you had to learn.
Next time you’re playing with a baby, try taking a toy and hiding it under a blanket in front of them. If they’re less than about six months old, they won’t pull the blanket away to get the toy back, however much they were enjoying playing with it beforehand. That’s not because they lack the skill to grab and move the cloth – it’s because, unlike you, they simply don’t realize the toy still exists. To their tiny mind, it simply poufed out of existence the moment it vanished. This is why babies find the game of peekaboo such fun. It’s why peekaboo is played by every culture, by all humans all around the world. When you place your hands in front of your face, a very young and immature mind assumes that you have literally disappeared, and possibly ceased to exist. The joy in discovering that your existence hasn’t been erased from the universe shines out in the baby’s giggles when you take your hands away.
Peekaboo exemplifies quite how badly equipped humans are for comprehending the universe, and everything in it. We’re not born with an innate understanding of the world around us. We have to learn that stuff –including people – doesn’t just vanish when we are not looking at it. In babies, it’s an important milestone in development known as ‘object permanence’ – something that many other animals never quite manage to grasp. A crocodile can be subdued by covering its eyes. Some birds can be calmed by placing a cover over their cage. It’s not just that they find the darkness soothing – they don’t realize the pesky human bothering them is still there, on the other side of the cloth.
Why should their brains care about object permanence? The primary motivation of almost every organism that has ever existed has been not to die – at least, not until it has had a chance to reproduce. Most life on Earth is altogether unconcerned with the question of why things are the way they are. Dung beetles navigate at night using the Milky Way as their guide, with limited interest in the structures of galaxies, or the fact that almost all of the mass of the universe is (so far) unaccounted for.fn1 The tiny mites that live in your eyebrows are oblivious to the concept of symbiotic commensalism whereby they innocuously feed off us. Until now, you were probably entirely unaware of them too, but they are definitely there. A peahen has no interest in processing the complex equations that explain why she finds that ridiculous tail on a peacock so irresistibly sexy; she just kinda likes it.
Only one animal has ever asked these questions – us. At some time in the past hundred thousand years or thereabouts, some mostly bald apes started to get curious about pretty much everything. The brains of these apes had been growing bigger over the previous million years or so, and they began doing things that no other animal before them had done. They started drawing, and painting, and making music, and playing peekaboo.
It’s important to not get too mushy about this. Prehistoric life was still pretty wretched compared to today, and survival was still everyone’s primary concern. But our ancestors had taken a step away from the rest of nature by considering not just the immediate concerns of survival, but the whole universe, and their place in it. However, we are still apes – and much of our brains and bodies is still fundamentally concerned with just living and reproducing. Physically, and genetically, we haven’t changed much in the last quarter of a million years. Take a woman or man from Africa 300,000 years ago, transport them forwards in time, tidy them up, give them a haircut and stick them in a nice dress or sports casual, and you wouldn’t be able to pick them out of a crowd today. Much of our biological hardware is largely unchanged from a time when none of these highfalutin ideas about how the universe works were of much concern to anyone.
What all this means is that our senses routinely let us down. We jump at quick, unexpected movements, despite no longer having to worry about predators trying to eat us every day. We crave sweet, salty and fatty foods –a perfectly sensible hunter-gatherer strategy, helping us prioritize high-calorie inputs when food was scarce, but much less useful when there’s the option of ice cream after every cheeseburger.
These evolutionary hangovers go beyond our instincts; they affect our intuition too. If you’d asked our uneducated ancestors about the shape of the Earth, they might well have told you it was flat. It makes sense that it’s flat. It looks pretty flat – and surely, if it wasn’t flat we’d fall off. But it’s not even remotely flat. In Chapter 3, we’ll intimately explore our lumpy rock and determine that not only is it not flat, but it’s not even a sphere: owing to its rotation, the Earth is an oblate spheroid – essentially, a slightly deflated ball that is a bit flat at the poles and a bit fat around the middle.
From our perspective, the Sun looks very much like it revolves around the Earth: every day for the past 4.54 billion years, it has come up in the morning over here, scooted across the sky and gone down over there. But in reality, the Earth orbits the Sun – and it doesn’t do that in a perfect circle, either. As far as we are concerned, the Sun is static in space while we whizz round it. But in reality the Sun and our whole solar system are charging round a point at the centre of the Milky Way at a bracing 514,000 miles per hour, completing a full orbit once every galactic year (that’s 250 million Earth years). None of us have the slightest experience of that while we’re sitting reading in a deckchair.
Curiosity might have marked humans as different from other creatures, but curiosity alone is not enough. When humans ask curious questions about the mysteries of reality, we don’t necessarily come up with the right answers instantaneously; there’s no end to the myths that we concocted to explain the inexplicable nature of nature. Vikings decided that the deafening sound of thunder was Thor charging across the sky in his goat-powered chariot, and his fearsome hammer Mjölnir was the source of lightning.fn2 The Gunai, indigenous to Australia, thought that the Southern Lights, what we call the Aurora Australis, were bush fires in the spirit world.
Stories of gods, goats and ghosts are still widely believed by billions of folk on every continent. Some of those stories might be easy to mock, but intuitively they make sense, and intuition is an incredibly powerful thing. We cannot help but see the universe through human-tinted glasses. In fact, though, much is not as it seems. As you’ll discover in this book, a day is not 24 hours. A year is not 365 (and a quarter) days. When we admire our star sitting just above the horizon in a beautiful sunset, it’s actually already beneath the horizon: the atmosphere of the Earth bends the light so we can see it even after it has set. Eating sugary sweets and cake doesn’t make kids go nuts at parties.fn3 More people die by drowning in the bath than are killed by terrorists and sharks combined every year, but no government has introduced laws on bath-time policy (yet).
Whatever way you look at it, intuition is a terrible guide.
And at some point, we curious apes realized this. We created science and mathematics in an attempt to step out of our limited human perspective and see the world as it objectively is, not merely as we experience it. We recognized the limits of our senses, and came up with ways to expand them so we could see beyond the narrow spectrum of our vision, hear beyond the range of our ears, and measure beyond distances we could see, to the unimaginably large and infinitesimally small.
Since then, we’ve been striving to learn how reality truly is. That is what science is. We have been doing this for hundreds, if not thousands of years, but not always successfully. Earlier attempts are often easy to poke fun at, and not always far from the gods and goats. Plato believed that we could see thanks to invisible ray beams shooting from our eyeballs, probing and investigating everything they touched; but then again, he didn’t have theories of the electromagnetic spectrum or neuronal phototransduction. Early biologists thought that sperm contained a homunculus, a teeny tiny version of a person, and that the woman’s job was merely to act as a vessel to incubate this mini-person until it was a full-size baby. Isaac Newton was an alchemist who put much more effort into trying to turn lead into gold than into his work on the mechanics of the cosmos. Galileo was an astrologer as well as an astronomer, and did horoscopes for paying customers when he was short of cash. Van Helmont, the father of gaseous chemistry, believed that mice would ping into existence if you just stuffed a vase with some wheat seeds and a sweaty shirt and left it in a dank basement for 21 days.
Science has got an awful lot wrong over the years. One could argue that it is, in fact, science’s job to get things wrong, as that is the place from which you can start to be less wrong, and after a few rounds get things right. On the whole, the arc of history curves in a progressive direction. We’ve built huge civilizations that lasted for centuries. We’ve changed nature, and bred animals and crops that feed billions. We’ve used maths and engineering to put up buildings that last for millennia, and to construct ships that allowed us to traverse the globe (and in doing so, affirm that it is a globe). We’ve created spaceships that can master the dynamics of the solar system and visit alien worlds billions of miles away. We’ve even populated an entire planet with robots. Some day soon, one of us will embrace all the brilliance of the people who came before them, and will set foot on that planet and become the first ape on Mars.
All of that is worth celebrating. Science and maths are a toolkit, the ultimate shed, crammed full of the most wonderful instruments and ideas, devices and gizmos to augment our abilities and expand our senses so that we can observe more and more of reality.