The Science of Discworld IV Judgement Da

FOUR



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WORLD TURTLES





Before the Large Hadron Collider was turned on, there were attempts to get court injunctions to stop it, in case it created a mini black hole and gobbled up the universe. This was not totally silly, but it ignored a worse problem: according to the cosmological theory of eternal inflation, any part of the universe could blow up at any moment – see chapter 18.

Thanks to the switching on of the Great Big Thing, Marjorie Daw has seeped into Discworld. Since she is a librarian, we suspect the seepage happened through L-space, the interconnected space of all libraries that ever have existed or ever could exist.

This may not be the first time something has seeped from Roundworld into Discworld either. Long ago, when the Omnian religion was founded, its adherents came to believe that Discworld, belying its name, is actually round. Where did that idea come from? For that matter, how did many early Roundworld cultures get the complementary idea that their world is flat?

We can gain some knowledge about early human beliefs from archaeology, the branch of science that examines evidence from our past. The artefacts and records that survive give us clues about how the ancients thought. Those clues can to some extent be clarified by another branch of science, psychology: the study of how people think. The pictures that emerge from the combination of these two sciences are necessarily tentative, because the evidence is indirect. Scholars can, and do, have a field day arguing about the interpretation of a cave painting or a stick with marks on it.

Ancient myths and legends possess a number of common features. They often focus on deep, mysterious questions. And they generally answer those questions from a human-centred viewpoint. The Discworld series takes Roundworld mythology seriously, to humorous effect; nowhere more so than in its basic geography and its magical supports – elephants and turtle. Here we’ll take a look at how various ancient cultures imagined the form, and purpose, of our world, looking for common elements and significant differences. Especially flat worlds and world-bearing animals. Here elephants turn out to be particularly problematic, most likely a case of mistaken identity. In chapter 20 we revisit some of these ancient myths, which will illuminate the science of human belief systems.

In a human-centred view, a flat world makes more sense than a round one. Superficially the world looks flat, ignoring mountains and suchlike and concentrating on the big picture. In the absence of a theory of gravity, people assumed that objects fell down because that was their natural resting-place. To prove it, just lift a rock off the ground and let go. So a round world seems implausible: things would fall off the bottom half. In contrast, there’s no danger of falling off a flat world unless you get too close to the edge.

There is one effective way to counteract this natural tendency to fall downwards: place something underneath as a support. This support may in turn need something underneath to support it, but you can iterate the process many times provided ultimately everything rests on something firm. This process, known as building, was effective enough to erect the Great Pyramid of Khufu at Giza, built in 2560 BC and over 145 metres high. It was the tallest building in the world until 1300, when the architect of Lincoln cathedral cheated by using a lot more up and a lot less sideways.

A common feature of human-centred thinking is that it often works well until you start to ask questions that transcend the human scale. Then it has a habit of falling to pieces. The line of thought just described seems fairly foolproof until you go for the big picture. Applying the kind of logical reasoning that drives so many Discworld stories, it is impossible not to ask: What keeps the world up? Human-centred thinking provides an obvious and compelling answer: something supports it. In Greek mythology, it was Atlas, bearing the world on his sturdy shoulders. Discworld sensibly plumps for a more plausible support cast: the giant world-bearing elephant. As belt and braces, there is not just one of them, but four – or possibly five, if the legend recounted in The Fifth Elephant is to be believed.

All well and good, but both universe-centred science and human-centred myth-making can hardly fail to ask a supplementary question: What keeps the elephants up? If the idea of an ordinary elephant hovering in mid-air is ludicrous, how much more so is that of a vast, extraordinarily heavy elephant doing the same? Discworld’s answer is A’Tuin, a giant space-faring turtle. The turtle’s shell provides a firm place for the elephants to stand. As a cosmology, it all hangs together pretty well … but of course a further question arises: What keeps the turtle up?

It might seem that we could go on like this indefinitely, but at this point observations of nature come into play. The natural world provides a long list of exceptions to the belief that the natural place of any object is on the ground: celestial bodies, clouds, birds, insects and all water-borne creatures – fish, crocodiles, hippos, whales and, crucially, turtles.

However, we can prune the list. Birds and insects do not remain aloft indefinitely; wait long enough and they do, in fact, descend to their natural place, typically a tree or a bush. The Sun, Moon and stars do not inhabit the terrestrial realm at all, so there is no reason to expect them to behave in a human-centred way – and they don’t. Assigning them to the realm of the supernatural has so many attractions that it becomes virtually unavoidable. The same arguably goes for clouds, which have a habit of producing awe-inspiring phenomena such as thunder and lightning. Scratch clouds. Crocodiles and hippos are out: they spend a lot of time on land. Fish are not renowned for doing that, but no sensible person would try to fit four elephants on top of a fish.

Which leaves turtles.

Small turtles spend a lot of time on rocks, but no one in their right mind would expect a small turtle to hold up four giant world-bearing elephants. Big turtles come out onto land to lay their eggs, but that’s a mystical event and it doesn’t cast serious doubt on the theory that a turtle’s natural place is in water. Where, please notice, it does not require support. It can swim. So it stands to reason that any self-respecting giant space-faring turtle will swim through space, which implies that it needs no artificial support to avoid falling. Examining the animal more closely, a world-spanning turtle seems ideal as a support for giant elephants. It is hard to imagine what could perform the task better.

In short, Discworld is, as stated earlier, the sensible way to make a world.

By comparison, Roundworld makes no sense. It’s the wrong shape, it’s held up by nothing, and it swims through space unaided despite not being the right shape to swim through anything. Basically, it’s a giant rock, and you all know what rocks do when you throw them in the lake. It is hardly surprising that it took the wizards a long time to come to terms with the way Roundworld organises itself. Accordingly, we should not be surprised to find that pre-scientific humanity had the same problem.

Flat worlds, giant elephants, world-bearing turtles … how did these enter the human psyche? One of the ironies of human-centred thinking is that it is unavoidably attracted to superhuman questions – the big picture. What are we? Why are we here? Where did it all come from? And one of the ironies of universe-centred thinking is that it is far better equipped to answer human-scale questions than cosmic ones.

If you want to find out how the rainbow gets its colours, you can pass light through a glass prism in a darkened room. This is what Isaac Newton did in about 1670, though he had to overcome some practical problems. The worst was his cat, which kept wandering into the attic to find out what Isaac was doing, pushing open the door and letting light in. So the ingenious scientist cut a hole in the door and nailed up a piece of felt, inventing the cat flap. When puss had kittens, he added a smaller hole next to the big one, which probably seemed logical at the time.fn1 Anyway, once the feline disruption was taken care of, Newton discovered that white light from the Sun splits into colours, and optics was born.

This kind of experiment is a cinch for things like light, which can be confined to a laboratory (if the cat complies). If you want to discover the nature of the universe, however, it’s not so easy. You can’t put the universe on a laboratory bench, and you can’t step outside it to observe its form, or go back in time to see how it began. The wizards can do, and have already done, all of these things; however, neither the scientists nor the theologians of Roundworld are likely to accept that the Dean of Unseen University kicked it all off by poking his finger in.

Instead, human-centred thinkers on Roundworld tend to go for human-level explanations like emperors and elephants, scaled up to superhuman levels to become gods and world-bearers. Most human civilisations have a creation myth – often several, not always compatible. Universe-centred thinkers have to fall back on scientific inference, and test the resulting theories indirectly. Their cosmological scenarios have often fared little better than most creation myths. Some look remarkably similar: compare the Big Bang to Genesis. However, scientific cosmologists do try to prove themselves wrong, and keep looking for weaknesses in their theories even when observations seem to confirm that they’re right. Typically, after about twenty years of increasingly good supporting evidence, these theories start to unravel as the observations become more sophisticated: see chapter 18.

Our ancestors needed to rationalise the things they observed in the natural world, and creation myths played a significant role. It can therefore be argued that they helped to bring about today’s science and technology, because they long ago drew humanity’s attention to the big questions, and held out hope of answering them. So it’s worth examining the similarities and differences between the creation stories of different cultures – especially when it comes to world-bearing elephants and space-faring turtles. Along with a third common world-bearing creature, the giant snake.

The world turtle (cosmic turtle, divine turtle, world-bearing turtle) can be found in the myths of the Chinese, Hindus and various tribes of native North Americans, in particular the Lenape (or Delaware Indians) and the Iroquois.

Around 1680 Jasper Danckaerts, a member of a Protestant sect known as Labadists, travelled to America to found a community, and he recorded a Lenape myth of a world turtle in Journal Of A Voyage To New York In 1679-80. We paraphrase the story from a 1974 article by Jay Miller.fn2 At first, all was water. Then the Great Turtle emerged, mud on its back became the Earth, and a great tree grew. As it rose skywards, one twig became a man; then it bent to touch the Earth and another twig became a woman. All humans descended from these two. Miller adds: ‘my … conversations with the Delaware indicate that life and the Earth would have been impossible without the turtle supporting the world.’

According to the Iroquois creation story, immortal Sky People lived on a floating island before the Earth existed. When one of the women discovered that she was going to have twins, her husband lost his temper and pulled up a tree at the island’s centre, the tree being their source of light at a time when the Sun did not exist. The woman looked into the hole thus created, and far below she saw the ocean that covered the Earth. Her husband pushed her into the hole, and she fell. Two birds caught her, and tried to get mud from the ocean floor to make land for her to live on. Finally Little Toad brought up mud, which was spread on the back of Big Turtle. The mud grew until it turned into North America. Then the woman gave birth. One son, Sapling, was kind, and filled the world with all good things; the other, Flint, ruined much of his brother’s work and created everything evil. The two fought, and eventually Flint was banished to live as a volcano on Big Turtle’s back. His anger can still sometimes be felt when the Earth shakes.

In these myths, there are partial parallels with ancient Egyptian mythology, in which the primal mound or benben rose from a sea of chaos. The god Seth wanted to kill his brother Osiris. He constructed a coffin, lured Osiris inside, shut the lid, sealed it with lead and threw it in the Nile. Their sister Isis set out to find Osiris, but Seth got there first and cut him into 14 pieces. Isis located 13 of them, but a fish had eaten Osiris’s penis. So she made an artificial one for him from gold, and sang until he came back to life.

The world-bearing turtle never made it into the Egyptian pantheon, but it was common in ancient central America, among cultures such as the Olmecs. To many of these cultures, the world was both square and round, and it was also a caiman or turtle floating on a primordial sea, which represented the Earth and might or might not carry it. The world had four corners, one for each cardinal direction, and a fifth symbolic point at its centre. The cosmos was divided into three horizontal layers: the underworld below, the heavens above, and the everyday world in between.

In another central American culture, the Maya civilisation, thirteen creator gods constructed humanity from maize dough. The world was carried at its four cardinal points by four bacabs, elderly deities of the earth’s interior and waters, shown carrying a sky-dragon in early depictions but later believed to be drowned ancestors. Their names were Cantzicnal, Hobnil, Hosanek and Saccimi, and each ruled one of the four directions.fn3 They were closely associated with four rain gods and four wind gods. They can appear as a conch, a snail, a spider web, a bee-like suit of armour, or a turtle. In the Dresden Codex the turtle is also associated with the rain-god Chaac, which similarly has four aspects, one for each cardinal direction.

At the Puuc Maya site at Uxmal there is a building called the House of the Turtles, whose cornice is decorated with hundreds of the animals. Its function is unknown, but the Maya associated turtles with water and earth. Their shells were used in making drums, and seem to have been associated with thunder. The god Pauahutun, who like Atlas carried the world on his shoulders, is sometimes shown wearing a turtle-shell hat. The Maize God is occasionally shown emerging from a turtle’s shell. The Mayan name for the constellation Orion is Ak’Ek’ or Turtle Star.

The Popol Vuh of the Quiché Maya provides more detail. It tells of three generations of deities, beginning with the creator grandparents of the sea and the lightning gods of the sky. The Mayans were corn farmers, so their human-centred worldview naturally related to the cycle of wet and dry seasons: their creator gods brought rain and the corn cycle into being. Their gods came as a standard package. Each god was associated with an aspect of the Mayan calendar, so one function of the calendar was to specify which god was in the ascendant at any given time. Often gods possessed several different aspects, and some of the major deities had four aspects, one for each cardinal direction, each with slightly different responsibilities.

The Popol Vuh tells that before the Earth appeared, the universe was a huge freshwater sea, above which was a blank sky with no stars or Sun. In the sea dwelt the creator grandparents Xpiyacoc and Xmucane. Below was Xibalba, the place of fright, domain of the gods One Death and Seven Death. The gods of sea and sky decided that they would create people to worship them. Since such creatures would need somewhere to live, the gods created the Earth, raising it from the primordial sea and covering it in vegetation.

That was Mayan cosmogony: the origin of the universe. In their cosmology (the shape and structure of the universe) the Earth was a flat disc, but it also had aspects of a square, whose corners were determined by the rising and setting of the solstice Sun, and whose sides were four great mythical mountains. It has been suggested that the notion of a square world reflects the shape of a cornfield. A rope formed a protective perimeter, reminiscent of Discworld’s ‘circumfence’fn4 but this one was intended to keep out malevolent supernatural beings. Each of the mountains was the home of one aspect of a grandfather deity, Mayan name unknown or uncertain, referred to by anthropologists as God N. The gods’ homes could be reached through caves, but these created gaps in the protective perimeter so that evil could enter.

The Earth was next made ready for growing corn. So the children and grandchildren of the creator grandparents, now living on the Earth, set up the Sun and the yearly cycle of the seasons and synchronised them with the movements of the Moon and Venus. There were two children, Hun Hunahpu and Vucub Hunahpu. The first married Bone Woman – the book does not say how she came into being (just as Genesis tells us that Cain’s wife ‘dwelt in the land of Nod’, but is silent about the creation of both Nod and the wife). When Bone Woman died, Hun Hunahpu and Vucub Hunahpu went to the underworld, suffering defeat at the hands of the two lords of death. Blood Woman, the daughter of an underworld being, was made pregnant by spittle from Hun Hunahpu’s dead head, and gave birth to Hunahpu and Xbalanque, the hero twins. Much of the tale deals with the twins’ eventual defeat of the lords of death, which required assistance from their grandparents. Xmucane made a mixture of corn and ground bone into dough, from which the creator grandparents formed the first people. Job done, the hero twins became the Sun and the full Moon.

God N is often shown wearing a net bag on his head. One of his manifestations was as a possum; another was as a turtle. An inscribed stone at Copán bears his name ‘yellow turtle’, in the form of his image together with phonetic signs for ak – meaning turtle. In his turtle aspect, God N represented the Earth, because the creation of the Earth, rising from the primordial sea, was like a turtle coming to the surface of a pool. God N also manifested himself as the four bacabs, whom the sixteenth-century Bishop of Yucatán Diego de Landa described as ‘four brothers whom [the creator] god placed, when he created the world, at the four points of it, holding up the sky so that it should not fall’.

Benford’s distinction is very visible here. The Mayan view, like that of many ancient cultures, was human-centred. They tried to understand the universe in terms of their own everyday experiences. Their stories rationalised nature, by portraying it in human terms – only bigger. But within that framework, they did their best to tackle the big questions of life, the universe, and everything.

To westerners, a turtle/elephant world is most commonly associated with Hinduism. Turtles are often confused with tortoises, as they generally are in American English. Philosopher John Locke’s Essay Concerning Human Understanding in 1690 mentions an ‘Indian who said the world was on an elephant which was on a tortoise’. In his 1927 Why I Am Not A Christian Bertrand Russell writes of ‘the Hindu’s view, that the world rested upon an elephant and the elephant rested upon a tortoise’, adding, ‘When they said, “How about the tortoise?” the Indian said, “Suppose we change the subject.”’ The elephant-turtle story remains in common circulation, but it is a misrepresentation of Hindu beliefs, conflating two separate mythical beings: the world-turtle and the world-elephant. In fact, Hindu mythology features three distinct species of world-bearing creature: tortoise, elephant and snake, with the snake being arguably the most important.

These creatures occur in several guises. The commonest name for the world-tortoise is Kurma or Kumaraja. According to the Shatpatha Brahmana its upper shell is the heavens, its lower shell the Earth, and its body is the atmosphere. The Bhagavata Purana calls it Akupara – unbounded. In 1838 Leveson Vernon-Harcourt published The Doctrine of the Deluge, whose purpose is clearly indicated by its subtitle: vindicating the scriptural account from the doubts which have recently been cast upon it by geological speculations. In it, he wrote of a tortoise called Chukwa that supported Mount Meru. This mountain is sacred in both Hindu and Buddhist cosmology, the centre of the universe – physical, spiritual and metaphysical – where Brahma and the demigods reside. Vernon-Harcourt attributes the story to an astronomer who described it to Bishop Heber ‘in the Vidayala school in Benares’. Since the word ‘vidyayala’ (note slight difference in spelling) means ‘school’ in Sanskrit, it is hard to give the report much credit. Brewer’s Dictionary of Phrase and Fable includes the entry ‘Chukwa. The tortoise at the South Pole on which the Earth is said to rest’, but there is little evidence to support this statement. However, Chukwa appears in the Ramayana as the name of a world-elephant, also known as Maha-padma or -pudma. Most likely various mythological entities were being confused and their stories combined.

Some sources say that Chukwa is the first and oldest turtle, who swims in the primordial ocean of milk and supports the Earth. Some also say that the elephant Maha-Pudma is interposed. This story apparently occurs in the Puranas, dating from the Gupta period (320-500). Whether the Hindus believed this myth, other than in a ritual sense, is debatable. Hindu astronomers of the Gupta period knew the Earth was round, and they may even have known that the Earth goes round the Sun. Perhaps there were ‘priests’ and ‘scientists’ – human- and universe-centred thinkers – then too.

The ocean of milk appears in one of the most famous reliefs at one of the great world heritage sites, the Khmer temple complex of Angkor Wat in Cambodia. In one version of Hindu cosmology, the ocean of milk was one of seven seas, surrounding seven worlds in concentric rings. Horace Hayman Wilson’s 1840 translation of the Vishnu Purana relates that the creator god Hari (aka Vishnu and Krishna) instructed all the other gods to throw medicinal herbs into the sea of milk, and to churn the ocean to make amrit – the food of the gods. Assorted gods were told to use the mountain Mandara as a churning-stick, winding the serpent Vásuki round it like a rope. Hari himself, in the form of a tortoise, served as a pivot for the mountain as it was whirled around.

Around 1870 Ralph Griffith translated the Rámáyan of Válmíki into verse. Canto 45 of Book 1 relates that it didn’t go as well as had been hoped. When the gods and demons continued to churn the Ocean of Milk, a fundamental engineering blunder became apparent:

Mandar’s mountain, whirling round.

Pierced to the depths below the ground.

They implored Vishnu to help them ‘bear up Mandar’s threatening weight’. Obligingly, he came up with the perfect solution:

Then Vishnu, as their need was sore,

The semblance of a tortoise wore,

And in the bed of Ocean lay

The mountain on his back to stay.

Despite its neglect in Discworld cosmology, we must now introduce another species of world-bearing animal: the snake.

You’ll see why in a moment.

In many Hindu and Buddhist temples, the handrails of staircases are long stone snakes, which terminate at the lower end as a many-headed king cobra, each head having an extended hood. This creature is called a naga. The nagas of Angkor generally have seven heads in a symmetric arrangement: one in the centre, three either side. A Cambodian legend tells of the naga as a race of supernatural reptiles whose kingdom was somewhere in the Pacific Ocean; their seven heads correspond to seven distinct races, mythically associated with the seven colours of the rainbow.

The Mahabharata takes a fairly negative view of nagas, portraying them as treacherous and venomous creatures, the rightful prey of the eagle-king Garuda. But according to the Puranas the king of the nagas, Shesha (aka Sheshanag, Devanagari, Adishesha), was a creator deity. Brahma first saw him in the form of a devoted human ascetic, and was so impressed that he gave him the task of carrying the world on his head. Only then did Shesha take on the aspect of a snake, slithering down a hole in the Earth to reach the base of the world, so that instead of placing the planet on his head, he placed his head beneath the planet. As you would.

Why are we talking about world-bearing snakes, not exactly prominent in the Discworld canon?

World-bearing elephants are probably snakes that got lost in translation.

The Sanskrit word naga has several other meanings. One is ‘king cobra’. Another is ‘elephant’ – probably a reference to the animal’s snake-like trunk. Although world-bearing elephants appear in later Sanskrit literature, they are conspicuously absent from the early epics. Wilhelm von Humboldt has suggested that the myths of world elephants may have arisen from confusion between different meanings of ‘naga’, so that stories about the world-bearing serpent became corrupted into myths about world-bearing elephants. This is, in any case, an attractive idea for a culture that routinely used elephants for heavy lifting.

Classical Sanskrit writings include many references to the role of world elephants in Hindu cosmology. They guard and support the Earth at its four cardinal points, and the Earth shakes when they adjust their positions – an imaginative explanation for earthquakes. They variously occur as a set of four, eight, or sixteen. The Amarakosha, a dictionary in verse written by the scholar Amarasinha around AD 380, states that eight male and eight female elephants hold up the world. It names the males as Airavata, Anjana, Kumunda, Pundarika, Pushpa-danta, Sarva-bhauma, Supratika and Vamana. It is silent about the names of the females. The Ramayana lists just four male world elephants: Bhadra, Mahápadma, Saumanas and Virúpáksha.

It may or may not be significant that the name Mahápadma is mentioned in Harivamsa and Vishnu Purana as a supernatural snake. Like dragons in the mythology of other cultures, it guards a hoard of treasure. Brewer’s Dictionary describes a ‘popular rendition of a Hindu myth in which the tortoise Chukwa supports the elephant Maha-pudma, which in turn supports the world’. This variant spelling seems to come from a misprint in a 1921 edition of one of the stories of the Mahabharata by the Indian freedom fighter and poet Sri Aurobindo:

On the wondrous dais rose a throne,

And he its pedestal whose lotus hood

With ominous beauty crowns his horrible

Sleek folds, great Mahapudma; high displayed

He bears the throne of Death.

However, this creature is clearly a giant cobra – unless you think the lotus hood is the elephant’s ears.

Our main interest in these stories, in the present context, is comparative mythology. The creation myths of many ancient cultures contain very similar elements. It is tempting to explain these similarities in terms of cross-cultural contact. It is becoming increasingly clear that the ancient world, at various times and in various places, was more advanced than we have previously imagined, and there is good archaeological evidence for trade over much longer distances than used to be assumed. However, temptation should probably be resisted, even so, because other explanations are more plausible. One is cultural convergence driven by human psychology and common environments.

Images such as the Earth rising from a primal ocean seem to be the sort of thing that naturally occurs to intelligent but uninformed human beings who try to explain where their world came from using human-centred thinking. Seas rise and fall with the tides, rocks appear and disappear. Floods drown low mounds, and then reveal them again as the waters recede. We take inspiration from nature, make it larger than life, and use our own invention to explain what we can’t understand. Creation myths open up windows into the human psyche. Ubiquitous natural phenomena, such as seas, mountains, volcanoes and earthquakes, suggest similar supernatural explanations. All ancient cultures were greatly influenced by the animals and plants that existed in their vicinity. If you live in a land full of possums and jaguars, it is no surprise if you develop possum gods and jaguar gods.

In many ways the differences between mythologies in disparate cultures are their most significant features. They suggest that the similarities may often result from some kind of convergent evolution, in which the same general supernatural explanation turns up independently because it has a certain logic – often of the Discworld kind – that appeals to the human mind. Explaining thunder as the gods throwing things, for example.

It is also interesting to see how myths evolve, like Chinese whispers, when they are passed on by oral tradition. Snakes become elephants. When the myths were preserved in written form, they still underwent dramatic changes before the invention of printing made it easy to mass-produce books. Even today, many of us can remember the general outline of a joke, or a story, but not the names of the characters. In mathematical circles, there are some standard stories about famous mathematicians, and the stories never change, but the famous mathematicians often do; the important point is that they should be famous. After that, it doesn’t greatly matter who they were – the story is just as funny, whoever you choose. The turtle joke in the next section is an example.

The logic of mythology can also sometimes shed a little light on scientific issues, by reminding us of the principal reason for adopting the scientific method: the human tendency towards self-deception. We all too easily accept some kinds of evidence, or some types of argument, when they confirm what we want to believe; we tend to reject them if they conflict with our beliefs.

In 2012 a Gallup poll found that 46% of American adults agreed that ‘God created human beings pretty much in their present form at one time within the last 10,000 years or so’. It was agreed by 32% that ‘Human beings developed over millions of years from less advanced forms of life, but God guided this process’. And 15% believed that ‘Human beings have developed over millions of years from less advanced forms of life, but God had no part in this process’. The scientific figures, based on a variety of evidence, place the first members of genus Homo at about 2.5 million years ago, and Homo sapiens – anatomically modern humans – at about 200,000 years ago, with archaic forms dating back perhaps twice as far.

We’ve mentioned Young Earth creationists in chapter 2. They argue that since Biblical scholarship dates the creation of humans to at most 10,000 years ago, and both the planet and humanity were created a few days apart, the Earth itself must also be less than 10,000 years old. As we saw, the scientific evidence that the planet is far older – homing in on about 4.5 billion years – is extensive, consistent, and comes from a variety of independent lines of thought, all supported by observations. If you insist on denying all of that, however, there is a straightforward way to do so: the scientific view rests on logical inference, not just direct personal experience.

It would seem strange, however, that a creator god should have gone to such extreme lengths, less than 10,000 years ago, to give his creation every appearance of being billions of years old, with humans existing for hundreds of thousands of years. It could be a test of faith, the universal get-out clause, but that’s a peculiar reason for deceiving your own creations.fn5

The turtle-and-elephant universe features early on in Stephen Hawking’s rampant bestseller A Brief History of Time. He tells us that a famous scientist, possibly Bertrand Russell,fn6 was giving a public lecture, explaining how the Earth goes round the Sun and the Sun shares the rotation of the Galaxy. When he asked for questions, a proverbial little old lady complained that his theories were nonsense: the world was flat and rode on the back of a giant tortoise. ‘What does the tortoise stand on?’ the lecturer enquired. ‘You’re very clever, young man,’ said the old lady, ‘but it’s turtles all the way down!’fn7

Before the Big Bang theory became the orthodoxy, cosmologists espoused the steady-state theory: the universe has always existed and is essentially static. Although they have now abandoned the steady-state theory, many people still find it more congenial than any theory with an origin. In particular, an origin seems to require a precursor, so it seems natural to ask ‘What happened before the Big Bang?’

Until recently most cosmologists would have answered that since time began with the Big Bang, there was no before: it’s like asking what lies north of the North Pole. In the last few years, however, many cosmologists have started to wonder if something more interesting might be going on, and whether there is a sensible series of events that led up to the Big Bang – in effect happening ‘before’ it in a causal sense, even if not a strictly temporal one. In Figments of Reality, Ian and Jack wrote:

Most people seem perfectly happy with ‘it’s always been like that’, finding no difficulty in conceiving of a universe that goes back for ever. Yet nearly everybody finds an infinite pile of turtles highly incongruous … So why are we so happy with an infinite pile of causality: today’s universe riding on the back of yesterday’s, which rides in turn on the day before’s? It’s universes all the way back.

Mathematical calculations show that an infinite pile of stationary turtles can support itself in a universe in which gravity is a constant force in a fixed direction (call this ‘down’). This rather improbable structure works because the force of gravity acting on each turtle is exactly balanced by the reaction force where it stands on the turtle below, so Newton’s third law of motion – action equals reaction – is obeyed. Similarly, there is no problem with causality in the infinite temporal pile of universes: each is caused by the previous one, so every universe has a cause. But psychologically, human beings are entirely happy with infinite piles of causality, yet find an infinite pile of turtles ridiculous.

We seem to accept or reject infinite piles of causality in a rather haphazard way, however. The philosopher David Hume rejected one example of what he called ‘infinite progression’ in his 1779 Dialogues Concerning Natural Religion. The context was a discussion of a creator God as an explanation of the material world. The obvious question ‘what created God?’ leads all too naturally to ‘creators all the way back’, a line of thinking that Hume wanted to close off. He says:

Have we not the same reason to trace that ideal world into another ideal world, or new intelligent principle? But if we stop, and go no further; why go so far? Why not stop at the material world? … after all, what satisfaction is there in that infinite progression? … If the material world rests upon a similar ideal world, this ideal world must rest upon some other; and so on, without end. It were better, therefore, never to look beyond the present material world. By supposing it to contain the principle of its order within itself, we really assert it to be God; and the sooner we arrive at that Divine Being, so much the better. When you go one step beyond the mundane system, you only excite an inquisitive humour which it is impossible ever to satisfy.

In short, if we identify God with the material universe, we need go no further, and that’s great because it stops us asking awkward questions. However, this does seem to imply that the universe created itself. And that seems to leave open exactly the line of thinking that Hume was trying to close (but Spinoza, two hundred years earlier, had already espoused that idea…).

Other scientific issues can be similarly swayed by human psychology. It is difficult to imagine Einstein’s curved space (though not impossible for a trained mathematician or physicist), because we foolishly ask ‘curved round what?’ The answer is that it’s not curved round anything – it’s just curved. Its natural metric – its mathematical measure of distance – is not flat. Space seems to bunch up or spread out compared to a naive model based on Euclid’s geometry. On the other hand, we are very happy with an infinite flat Euclidean plane or its three-dimensional analogue, space. It never occurs to us to ask ‘flat along what?’ But it’s an equally sensible (or equally senseless) question.

These cognitive biases probably stem from the model of space that our brains have evolved to contain, which seems to be Euclidean. This may perhaps be the simplest model that fits our experiences of the nearby world, extrapolated in the simplest way to avoid space having a boundary. Which would be appealing because we don’t see any boundary. Our minds are very parochial. Our model of causality presumably evolved to match sequences of events that are common in our immediate vicinity, the human-scale world.

When it comes to the crunch, looking at both the theory that time had a specific origin, a finite period into the past, and the theory that it did not, but has always been in existence, then both have inherent flaws. This suggests that we are not thinking about the right question. Our view of the universe may be just as parochial and unreasonable as the world-bearing animals of ancient cultures were. Future scientists may view both the Big Bang, and four elephants riding on a turtle, as conceptual errors of a very similar kind.

fn1 Like all really nice stories this tale, told by a ‘country parson’, may be false. Other versions say that Newton kept losing time from his research by letting the cat out. Selig Brodetsky’s Sir Isaac Newton and Louis Trenchard More’s Isaac Newton: a Biography both state that the great mathematician did not allow either a cat or a dog to enter his chamber. But in 1827 J.M.F. Wright, who lived in Newton’s former rooms at Trinity College, Cambridge, wrote that the door once had two holes – by then filled in – of the right size for a cat and a kitten.

fn2 Jay Miller, Why the world is on the back of a turtle, Man 9 (1974) 306–308.

fn3 It’s fascinating how priests always know the names of the gods.

fn4 A 10,000-mile long drift net built to catch items falling over the edge.

fn5 In 1857 Philip Gosse wrote a book called Omphalos: An Attempt to Untie the Geological Knot that argued for this approach – see The Science of Discworld II: The Globe.

fn6 In his 1967 Constraints on Variables in Syntax the linguist John R. Ross states that it was the psychologist/philosopher William James. In other sources the scientist is variously identified as Arthur Stanley Eddington, Thomas Huxley, Linus Pauling, Carl Sagan, and many others. Insert scientist here.

fn7 Notice how ‘tortoise’ morphs into ‘turtle’. Perhaps the lady was American.