The Magic of Reality (3 page)

Given enough generations, ancestors that look like newts can change into descendants that look like frogs. Given even more generations, ancestors that look like fish can change into descendants that look like monkeys. Given yet more generations, ancestors that look like bacteria can change into descendants that look like humans. And this is exactly what happened. This is the kind of thing that happened in the history of every animal and plant that has ever lived. The number of generations required is larger than you or I can possibly imagine, but the world is thousands of millions of years old, and we know from fossils that life got started more than three and a half billion years ago, so there has been plenty of time for evolution to happen.

This is Darwin’s great idea, and it is called Evolution by Natural Selection. It is one of the most important ideas ever to occur to a human mind. It explains everything we know about life on Earth. Because it is so important, I’ll come back to it in later chapters. For now, it is enough to understand that
evolution
is very slow and gradual. In fact, it is the gradualness of evolution that allows it to make complicated things like frogs and princes. The magical changing of a frog into a prince would be not gradual but sudden, and this is what rules such things out of the world of reality. Evolution is a real explanation, which really works, and has real evidence to demonstrate the truth of it; anything that suggests that complicated life forms appeared suddenly, in one go (rather than evolving gradually step by step), is just a lazy story – no better than the fictional magic of a fairy godmother’s wand.

As for pumpkins turning into coaches, magic spells are just as certainly ruled out for them as they are for frogs and princes. Coaches don’t evolve – or at least, not naturally, in the same way that frogs and princes do. But coaches – along with airliners and pickaxes, computers and flint arrowheads – are made by humans who
did
evolve. Human brains and human hands evolved by natural selection, just as surely as newts’ tails and frogs’ legs did. And human brains, once they had evolved, were able to design and create coaches and cars, scissors and symphonies, washing machines and watches. Once again, no magic. Once again, no trickery. Once again, everything beautifully and simply explained.

In the rest of this book I want to show you that the real world, as understood scientifically, has magic of its own – the kind I call poetic magic: an inspiring beauty which is all the more magical because it is real and because we can understand how it works. Next to the true beauty and magic of the real world, supernatural spells and stage tricks seem cheap
and
tawdry by comparison. The magic of reality is neither supernatural nor a trick, but – quite simply – wonderful. Wonderful, and real. Wonderful
because
real.

MOST CHAPTERS IN
this book are headed by a question. My purpose is to answer the question, or at least give the best possible answer, which is the answer of science. But I shall usually begin with some mythical answers because they are colourful and interesting, and real people have believed them. Some people still do.

All peoples around the world have origin myths, to account for where they came from. Many tribal origin myths talk only about that one particular tribe – as though other tribes don’t count! In the same way, many tribes have a rule that they mustn’t kill people – but ‘people’ turns out to mean only others of your own tribe. Killing members of other tribes is just fine!

Here’s a typical origin myth, from a group of Tasmanian aborigines. A god called Moinee was defeated by a rival god called Dromerdeener in a terrible battle up in the stars. Moinee fell out of the stars down to Tasmania to die. Before he died, he wanted to give a last blessing to his final resting place, so he decided to create humans. But he was in such a hurry, knowing he was dying, that he forgot to give them knees; and (no doubt distracted by his plight) he
absent-mindedly
gave them big tails like kangaroos, which meant they couldn’t sit down. Then he died. The people hated having kangaroo tails and no knees, and they cried out to the heavens for help.

The mighty Dromerdeener, who was still roaring around the sky on his victory parade, heard their cry and came down to Tasmania to see what the matter was. He took pity on the people, gave them bendable knees and cut off their inconvenient kangaroo tails so they could all sit down at last; and they lived happily ever after.

Quite often we meet different versions of the same myth. That’s not surprising, because people often change details while telling tales around the camp fire, so local versions of the stories drift apart. In a different telling of this Tasmanian myth, Moinee created the first man, called Parlevar, up in the sky. Parlevar couldn’t sit down because he had a tail like a kangaroo and unbendable knees. As before, the rival star god Dromerdeener came to the rescue. He gave Parlevar proper knees and cut off his tail, healing the wound with grease. Parlevar then came down to Tasmania, walking along the sky road (the Milky Way).

The Hebrew tribes of the Middle East had only a single god, whom they regarded as superior to the gods of rival tribes. He had various names, none of which they were allowed to say. He made the first man out of dust and called him Adam (which just means ‘man’). He deliberately made Adam like himself. Indeed, most of the gods of history were portrayed as men (or sometimes women), often of giant size and always with supernatural powers.

The god placed Adam in a beautiful garden called Eden, filled with trees whose fruit Adam was encouraged to eat – with one exception. This forbidden tree was the ‘tree of knowledge of good and evil’, and the god left Adam in no doubt that he must never eat its fruit.

The god then realized that Adam might be lonely all by himself, and wanted to do something about it. At this point – as with the story of Dromerdeener and Moinee – there are two versions of the myth, both found in the biblical book of Genesis. In the more colourful version, the god made all the animals as Adam’s helpers, then decided that there was still something missing: a woman! So he gave Adam a general anaesthetic, cut him open, removed one rib and stitched him up again. Then he grew a woman from the rib, rather as you grow a flower from a cutting. He named her Eve and presented her to Adam as his wife.

Unfortunately, there was a wicked snake in the garden, who approached Eve and persuaded her to give Adam the forbidden fruit from the tree of knowledge of good and evil. Adam and Eve ate the fruit and promptly acquired the knowledge that they were naked. This embarrassed them, and they made themselves aprons out of fig leaves. When the god noticed this he was furious with them for eating the fruit and acquiring knowledge – losing their innocence, I suppose. He threw them out of the garden, and condemned them and all their descendants to a life of hardship and pain. To this day, the story of Adam’s and Eve’s terrible disobedience is still taken seriously by many people under the name of ‘original sin’. Some people even believe we have all
inherited
this ‘original sin’ from Adam (although many of them admit that Adam never actually existed!), and share in his guilt.

The Norse peoples of Scandinavia, famous as Viking seafarers, had lots of gods, as the Greeks and Romans did. The name of their chief god was Odin, sometimes called Wotan or Woden, from which we get our ‘Wednesday’. (‘Thursday’ comes from another Norse god, Thor, the god of thunder, which he made with his mighty hammer.)

One day Odin was walking along the seashore with his brothers, who were also gods, and they came upon two tree trunks.

One of these tree trunks they turned into the first man, whom they called ‘Ask’, and the other they turned into the first woman, naming her ‘Embla’. Having created the bodies of the first man and first woman, the brother gods then gave them the breath of life, followed by consciousness, faces and the gift of speech.

Why tree trunks, I wonder? Why not icicles or sand dunes? Isn’t it fascinating to wonder who made such stories up, and why? Presumably the original inventors of all these myths knew they were fiction at the moment when they made them up. Or do you think many different people came up with different parts of the stories, at different times and in different places, and other people later put them together, perhaps changing some of them, without realizing that the various bits were originally just made up?

Stories are fun, and we all love repeating them. But when we hear a colourful story, whether it is an ancient myth or a
modern
‘urban legend’ whizzing around the internet, it is also worth stopping to ask whether it – or any part of it – is true.

So let’s ask ourselves that question – Who was the first person? – and take a look at the true, scientific answer.

Who was the first person
really
?

This may surprise you, but there never was a first person – because every person had to have parents, and those parents had to be people too! Same with rabbits. There never was a first rabbit, never was a first crocodile, never a first dragonfly. Every creature ever born belonged to the same species as its parents (with perhaps a very small number of exceptions, which I shall ignore here). So that must mean that every creature ever born belonged to the same species as its grandparents. And its great-grandparents. And its great-great-grandparents. And so on for ever.

For ever?
Well, no, it’s not as simple as that. This is going to need a bit of explaining, and I’ll begin with a thought experiment. A thought experiment is an experiment in your imagination. What we are going to imagine is not literally possible because it takes us way, way back in time, long before we were born. But
imagining
it teaches us something important.

So, here is our thought experiment. All you have to do is imagine yourself following these instructions.

Find a picture of yourself. Now take a picture of your father and place it on top. Then find a picture of his father, your grandfather. Then place on top of that a picture of your grandfather’s father, your great-grandfather. You may not
have
ever met any of your great-grandfathers. I never met any of mine, but I know that one was a country schoolmaster, one a country doctor, one a forester in British India, and one a lawyer, greedy for cream, who died rock-climbing in old age. Still, even if you don’t know what your father’s father’s father looked like, you can imagine him as a sort of shadowy figure, perhaps a fading brown photograph in a leather frame. Now do the same thing with his father, your great-great-grandfather. And just carry on piling the pictures on top of each other, going back through more and more and more great-great-greats. You can go on doing this even before photography was invented: this is a
thought
experiment, after all.

How many greats do we need for our thought experiment? Oh, a mere 185 million or so will do nicely!

Mere?

MERE?

It isn’t easy to imagine a pile of 185 million pictures. How high would it be? Well, if each picture was printed as a normal picture postcard, 185 million pictures would form a tower about 220,000 feet high: that’s more than 180 New York skyscrapers standing on top of each other. Too tall to climb, even if it didn’t fall over (which it would). So let’s tip it safely on its side, and pack the pictures along the length of a single bookshelf.

How long is the bookshelf?

About forty miles.

The near end of the bookshelf has the picture of you. The far end has a picture of your 185-million-greats-grandfather.
What
did he look like? An old man with wispy hair and white sidewhiskers? A caveman in a leopard skin? Forget any such thought. We don’t know exactly what he looked like, but fossils give us a pretty good idea. Believe it or not, your 185-million-greats-grandfather was – a fish. So was your 185-million-greats-grandmother, which is just as well or they couldn’t have mated with each other and you wouldn’t be here.

Let’s now walk along our forty-mile bookshelf, pulling pictures off it one by one to have a look at them. Every picture shows a creature belonging to the same species as the picture on either side of it. Every one looks just like its neighbours in the line – or at least as much alike as any man looks like his father and his son. Yet if you walk steadily from one end of the bookshelf to the other, you’ll see a human at one end and a fish at the other. And lots of other interesting great- … great-grandparents in between, which, as we shall soon see, include some animals that look like apes, others that look like monkeys, others that look like shrews, and so on. Each one is like its neighbours in the line, yet if you pick any two pictures far apart in the line they are very different – and if you follow the line from humans back far enough you come to a fish. How can this be?

Actually, it isn’t all that difficult to understand. We are quite used to gradual changes that, step by tiny step, one after the other, make up a big change. You were once a baby. Now you are not. When you are a lot older you’ll look quite different again. Yet every day of your life, when you wake up, you are the same person as when you went to
bed
the previous night. A baby changes into a toddler, then into a child, then into an adolescent; then a young adult, then a middle-aged adult, then an old person. And the change happens so gradually that there never is a day when you can say, ‘This person has suddenly stopped being a baby and become a toddler.’ And later on there never comes a day when you can say, ‘This person has stopped being a child and become an adolescent.’ There’s never a day when you can say, ‘Yesterday this man was middle-aged: today he is old.’

That helps us to understand our thought experiment, which takes us back through 185 million generations of parents and grandparents and great-grandparents until we come face to face with a fish. And, turning round to go forwards in time, it’s what happened when your fish ancestor had a fishy child, who had a fishy child, who had a child … who, 185 million (gradually less fishy) generations later, turned out to be you.

So it was all very gradual – so gradual that you wouldn’t notice any change as you walked back a thousand years; or even ten thousand years, which would bring you to somewhere around your 400-greats-grandfather. Or rather, you would notice lots of little changes all the way along, because nobody looks exactly like their father. But you wouldn’t notice any general
trend
. Ten thousand years back from modern humans is not long enough to show a trend. The portrait of your ancestor of ten thousand years ago would be no different from modern people, if we set aside superficial differences in dress and hair and whisker style. He would be no more
different
from us than modern people are different from other modern people.

How about a hundred thousand years, where we might find your 4,000-greats-grandfather? Well, now, maybe there would be a just noticeable change. Perhaps a slight thickening of the skull, especially under the eyebrows. But it would still only be slight. Now let’s push a bit further back in time. If you walked the first million years along the shelf, the picture of your 50,000-greats-grandfather would be different enough to count as a different species, the one we call
Homo erectus
. We today, as you know, are
Homo sapiens. Homo erectus
and
Homo sapiens
probably wouldn’t have wanted to mate with each other; or, even if they did, the baby would probably not have been able to have babies of its own – in the same way that a mule, which has a donkey father and a horse mother, is almost always unable to have offspring. (We’ll see why in the next chapter.)

Once again, though, everything is gradual. You are
Homo sapiens
and your 50,000-greats-grandfather was
Homo erectus
. But there never was a
Homo erectus
who suddenly gave birth to a
Homo sapiens
baby.

So, the question of who was the first person, and when they lived, doesn’t have a precise answer. It’s kind of fuzzy, like the answer to the question: When did you stop being a baby and become a toddler? At some point, probably less than a million years ago but more than a hundred thousand years ago, our ancestors were sufficiently different from us that a modern person wouldn’t have been able to breed with them if they had met.

Whether we should call
Homo erectus
a person, a human, is a different question. That’s a question about how you choose to use words – what’s called a semantic question. Some people might want to call a zebra a stripy horse, but others might like to keep the word ‘horse’ for the species that we ride. That’s another semantic question. You might prefer to keep the words ‘person’, ‘man’ and ‘woman’ for
Homo sapiens
. That’s up to you. Nobody, however, would want to call your fishy 185-million-greats-grandfather a man. That would just be silly, even though there is a continuous chain linking him to you, every link in the chain being a member of exactly the same species as its neighbours in the chain.