DAVID CHRISTIAN
Macquarie University, Sydney, and
WCU Distinguished Professor, Ewha Womans University, Seoul
Understanding
Humans: Like Ants on Elephants: I want to raise one of the most
fundamental questions we can ask about humans and human history. What makes humans different? This is a
deep question and we struggle to find good answers. I think one of the reasons we struggle is not that the
question is impossible to answer but rather that we approach it from multiple,
distinct disciplines. Do you remember the ants on an
elephant. Lots of ants are crawling over an elephant, and eventually they meet
and start discussing their world.
“It’s grey and tough and wrinkly,” says one. “No, its shiny and white and hard,” says another. “The main thing is that it keeps
shaking about so we have to hang on for dear life,” says another. Modern scholarship about humans
is a bit like this. The famous
palaeontologist, Louis Leakey, argued that we were tool-making animals. That idea worked pretty well until a
former student of his, Jane Goodall, showed us that chimps make tools, too, and
so do a lot of other animals.
(Crows are really good at it.
In Tokyo, they sit at traffic lights, wait till the lights go red, place
hard nuts under the tires of cars, then wait till the lights go green then back
to red and go back to collect the cracked nuts.) A famous collection of essays published in 1969 was called
“Man the Hunter”. That idea soon
went the same way, as Jane Goodall and her colleagues showed that chimps
hunt. Humans have a rich emotional
life? Goodall and her colleagues
put paid to that one too. Only
humans can talk? Except that
chimps can clearly communicate to some extent and in captivity they have been
taught basic conversation. We have
exceptionally large brains? Yes,
except that the recently discovered species, Homo floresiensis, had a brain about half the size
of ours but a technology similar to that of our ancestors, Homo erectus, whose brains were
almost as large as ours. And so
on. What we need is an ant
helicopter. I imagine offering to
take an ant on a helicopter trip.
We strap the ant into the seat and then take off and as we rise up it
begins to see not just its own wrinkle but also lots of others. Then it loses sight of its home wrinkle
and begins to panic. “Where’s my
wrinkle?!” I have to say: “Don’t
panic. Just breathe, let your eyes
relax, and tell me what you see.”
So the ant breathes slowly and eventually it says: “You’re not going to
believe this, but I’m seeing the most enormous grey thing with the most gigantic nose thing, with huge
spear-type things on either side and …..”
Finally, it’s seen the elephant.
Now, when I fly it back to its home wrinkle it knows where it is. Something like this happened for
our species when the first humans saw the earth from space. All astronauts and cosmonauts have had
the same experience of suddenly seeing the earth whole. And it is always a powerful experience. My ant helicopter is called big
history. Big history studies the
past at the largest possible scales, beginning, literally, with the origins of
the Universe. Here, to give you a
quick idea of the view from big history, I’ll give a few dates. This two minute course in big history
is a bit like a short trip in an ant helicopter. It includes some of the most important events in 13 billion
years. First I’ll give the dates
straight; then I’ll give a speeded-up version which makes it easier to see the
relationships between different events. What do humans look like from the
cockpit of big history? Our view
is now broad enough to see not just the beginnings of our species but our whole
history. If you look just at one
part of our history you’ll miss what’s important. To see what’s really odd about us you need a perspective that
links what paleontologists, biologists, linguists, archaeologists and
historians see. The View
of Big History: What makes humans different? And what you see when you fly
high enough is something like the familiar computer-generated picture of the
earth at night. If you flew over
an alien planet and saw lights like this you’d surely think you were observing
some geological phenomenon, perhaps vast chains of active volcanoes. What’s really strange is that we know
these lights are the work of a single species. That’s spooky!
What sort of species can mimic the effects of vast geological forces in
this way? In 2000, and then two years later
in an article in Nature, the
Nobel-prize-winning climate scientist, Paul Crutzen, argued that we recently
entered a new geological epoch, the “Anthropocene”. That is the era in which a single species, our own, has
become the major force for change in the biosphere. During the
past three centuries, the human population has increased tenfold to more than 6
billion and is expected to reach 10 billion in this century. The
methane-producing cattle population has risen to 1.4 billion. About 30–50% of
the planet’s land surface is exploited by humans. … More than half of all
accessible fresh water is used by mankind. Fisheries remove more than 25% of
the primary production in upwelling ocean regions and 35% in the temperate
continental shelf. Energy use has grown 16-fold during the twentieth century,
causing 160 million tonnes of atmospheric sulphur dioxide emissions per year,
more than twice the sum of its natural emissions. More nitrogen fertilizer is
applied in agriculture than is fixed naturally in all terrestrial ecosystems;
nitric oxide production by the burning of fossil fuel and biomass also
overrides natural emissions. Fossil-fuel burning and agriculture have caused
substantial increases in the concentrations of ‘greenhouse’ gases — carbon dioxide
by 30% and methane by more than 100% — reaching their highest levels over the
past 400 millennia, with more to follow.[1]
Let me add to this
already remarkable catalogue. A very rough estimate of human per capita energy
use suggests that each of us may be using, on average, 100 times the energy
needed to survive and reproduce. [2] Not surprisingly, other species are
feeling the pinch. According to a
2010 assessment by the International Union for Conservation of Nature, which
produces a regular “Red List” of endangered species, current rates of
extinction are about 1,000 times more rapid than they have been for most of the
earth’s recent history.[3] These rates are analogous to those
during the 5 episodes of most rapid loss of biodiversity in the last 600
million years, including the Cretaceous event of 65 million years ago, which
wiped out the dinosaurs and cleared the way for an adaptive radiation of our
mammalian ancestors. Our power is now
so great that we can make weapons based on hydrogen fusion, the nuclear
reaction that drives the Sun. With
several thousand nuclear weapons still on “hair-trigger” alert two decades
after the end of the Cold War, we have the ability to wipe out the biosphere in
just a few hours. When J.R.
Oppenheimer witnessed the first detonation of a nuclear weapon (a very weak
version of the weapons available today), he remembered the words of the Hindu
god, Vishnu in the Baghavad Gita:
“Now I am become Death, the destroyer of worlds!” In 2008, a
distinguished group of scientists called on the International Commission on
Stratigraphy, the body that rules on the boundaries between geological epochs,
to adopt Paul Critzen’s idea that the “Anthropocene” had begun in the year
1800.[4] They are right, because we have good
reason to think that our behavior is unique on
geological timescales. Nothing
like this has happened before in the 4 billion year history of our planet. No single species has ever wielded such
power before. If it had, we would notice
it, just as future archaeologists will notice our impact millions of years in
the future. The image of the
earth at night represents the awakening of an entirely new phenomenon in the
earth’s history. What just happened? A New and Terrifying Creativity You may think this is a
modern phenomenon. In its scale,
yes, but its roots go back to the beginnings of our species. Most species evolve with a distinctive
repertoire of ecological tricks that will enable them to survive for perhaps a
few million years. There’s a bit
of variety, and individuals can certainly improvise, but new ideas don’t seem
to accumulate. We know this
because if they did we would notice it.
A species that kept inventing new tricks would begin to control larger
and larger areas, its populations would start growing, and eventually it would
start transforming its environment in ways that archaeologists would notice
millions of years later. We know
of only one species that displays this sort of record: our own. The story goes back at least
100,000 years. Though physical
anthropologists still debate when Homo sapiens first
appeared, we have striking evidence from sites such as Blombos cave in S.
Africa, of humans beginning to experiment with new behaviors, in this case the
use of coastal resources such as shell-fish, as early as 90,000 years ago. The easiest way to see how ecologically
creative our ancestors were is to look at a map of human migrations during the
Paleolithic era. We were the first
large species of mammal to settle all continents on earth (and now we are
settling Antarctica). Each
migration required new technologies, from boat-building and navigation, to
techniques for exploiting unfamiliar plants and animals, to techniques for
keeping warm in ice-age Siberia or N. America. And as we spread we began to re-shape our environments. In regions such as Australia or N.
America, regular firing of the land transformed the forests. When Captain Cook sailed up the east
coast of Australia in 1770, he saw lots of fires and lots of eucalypts. He was not seeing a natural landscape,
but the results of perhaps 40,000 years of “fire-stick farming”; eucalypts love
fire. He also saw a landscape
largely devoid of giant animals or “megafauna”. Yet we know that huge wombats and kangaroos lived in
Australia before humans arrived, so it seems that our ancestors also
transformed the animal life of Australia. Each new technology meant a
new way of extracting energy and resources from the environment and it is this
sustained ecological creativity, this capacity to keep generating new ways of
relating to our environment, that explains the astonishing technological,
cultural and artistic variety of our species (each community accumulated ideas
in its own way) and the fact that we have a History of long-term change. Agriculture was particularly
powerful. Humans began to remove
the plants and animals they didn’t want, and alter the land so that those
plants and animals they could use flourished. They even altered the plants and animals to make them
tastier and more useful.
Agriculture diverts energy flows just as irrigation diverts rivers. It was a way of diverting more and more
of the energy generated in the center of the Sun, then captured by plants
through photosynthesis, to the needs of one species, our own. Not surprisingly,
human populations began to grow until today there are almost 7 billion of
us. Meanwhile, our closest
relatives, the Neanderthals and Homo erectus, are extinct and our
closest living relatives, the chimps and gorillas, are nearly there. Our unique ecological power
has roots that go back to the origin of our species, even if the pace of change
has accelerated in recent centuries.
In embryonic form, the Anthropocene was already present in whispered
conversations in Blombos cave. What’s the source of our creativity? What is the source of this
astonishing ecological creativity?
Answers from several disciplines seem to be converging on an answer. Language seems to be the
key, but not just language in general.
Rather, it seems that our ancestors crossed a critical threshold in
linguistic efficiency. In all
systems of communication, information gets garbled or blurred or lost. Chimps, like many other intelligent
species, can communicate. But
evidence from primatologists suggests that there are limits to the precision
and volume with which they can communicate. Do you remember the days of stand-alone computers? Each computer depended more or less on
what was in its own memory.
Sometimes, the easiest way of moving information from one computer to
the other was to print it out, then type it in to the second computer, making
new mistakes as you did so.
The process was slow and cumbersome and inefficient, and severely
limited the power of each individual computer and of computers in general. Chimps are a bit like this.
As individuals they are almost as clever as us. But they cannot communicate as well. For many
years, the primatologist, Shirley Strum, observed a troop of baboons in Kenya
that she named the ‘Pumphouse Gang’.
Compared to other troops, they were virtuoso hunters; they often ate
meat as much as once a day. But
they hunted most eagerly and successfully when led by one particular male. So
when their virtuoso hunter died, the troop’s tradition of hunting died too.[5]
The pumphouse gang lacked the cultural ratchet that allows
technological innovations to accumulate from generation to generation. That is why chimps don’t have a
“History” in the sense that we do.
(Can you imagine a University department of chimp history?) In contrast,
humans are like networked computers.
They can share information with such ease and precision and in such
volume that each individual has easy access to vast stores of information in
the brains of other humans.
Somehow or other, our ancestors acquired new forms of language that
enabled us to communicate so effortlessly that information began to accumulate
in the collective memory. The
result was that each individual faced the world not just with their own brain
power, but also with the accumulated results of the experience and creativity
of millions of other humans, many of whom had lived in the distant past. If you doubt the importance of shared
ideas, try a simple thought experiment. Look inside
your own mind and imagine what would be there if you had never acquired a human
language and never had a conversation with another human. Not much! The words we think with would be absent; so would most of
the information we take for granted, knowledge of how to do things, technical,
ethical and social. But our
emotional world would also be impoverished because we would lose all the
stories told us by family, friends and lovers. We would lose the rich inner world of thought and feeling
that we share with other humans. We do not
yet know exactly how we crossed this threshold. Was it a single genetic mutation? Or a slow process of evolution over hundreds of thousands of
years? We don’t really know, but
we do know that crossing this linguistic threshold was a momentous event in the
history of the planet. Remarkably,
this was not the first time something like this had happened. Early in the planet’s history, there
evolved complex bags of chemicals that exchanged energy with their environments
and occasionally split in two. But
they didn’t really evolve in a Darwinian sense, because to evolve you need to
preserve the information that works best, and without DNA the earliest
proto-organisms were as likely to lose useful innovations as to preserve
them. The evolution of DNA provided
a mechanism for the accurate preservation and reproduction of genetic
information, just as human language provides a mechanism for the accurate
preservation and reproduction of cultural information. In both cases, improved fidelity in the
exchange of information created a sort of technological ratchet that allowed
for long-term change, in one case by accumulating genetic information, in the
other case by accumulating cultural information. I call our
remarkable capacity for sharing information “collective learning”. While other intelligent species, such
as chimps, learn for the most part as individuals, so that most of what they
learn dies with them, we learn collectively, so that what we learn is preserved
in the community and can accumulate from generation to generation. Collective Learning, Growth and Human Happiness: Collective learning is what
makes us different. It is an
entirely new and much more rapid way of “adapting” to our environment. While other species adapt through the
slow, patient, sharing of genes, we adapt by sharing ideas. Collective learning is the source of
our creativity as a species and the reason why we, alone, have a History. But collective learning,
like fire, is a dangerous gift. We
are not just highly “adaptive”; we are “hyper-adaptive”, so good at adapting
that it is no longer clear that we can control our own creativity. We adapt at warp speed; but the
biosphere adapts at the agonizingly slow pace of genetic change. It cannot keep up with our growing
demands. The Irish elk, one of the
largest deer ever to exist, had vast antlers. It was once thought that, through sexual selection, the
antlers grew so large and unwieldy that the species was driven to extinction.[6] Is this a parable for humans? Are we getting too good at collective
learning? Collective learning may also
turn out to be our get-out-of-jail card.
The synergy of exchanges between almost 7 billion people, building on
earlier exchanges between the 80 billion humans who lived before us, is a very
powerful force for creative change.
But we may have to start using that synergy in new ways because we
cannot just keep using it to increase our consumption of the resources of the
biosphere. As our brief discussion of the “Anthropocene” suggests, the biosphere
is creaking under the strain as more and more of its energy and resources are
diverted to the use of one species. Besides, do we really need this
sort of sustained growth? Relevant to this discussion is a simple but profound
discovery made by psychologists who study human contentment. Research over many decades suggests
that the experience of contentment and well-being is closely linked to income
levels, and therefore to economic growth, but only at very low income
levels. Above a certain, not very
high, threshold, the correlation between income and contentment breaks down.
Some wealthy people are happy; some are miserable. Friendship, community, health—above a basic level these seem
to be much more accurate predictors of contentment than income. Do we really need 100 times
the amount of energy and resources necessary to survive and reproduce? Wouldn’t twenty times that amount be
enough to live well? If so, in coming
decades we may have to re-think our ideas about the purpose of economic
activity. We can imagine a world
in which growth does not continue to take the form of increasing appropriation
by a single species of the resources of the biosphere. Instead, it might take the form of new
creative, artistic, social and even philosophical activities that do not
require more resources but nevertheless can sustain our sense of well-being and
also sustain our biosphere so that future generations will also be able to
share in the precious gift of a good life on this good earth. The Challenge: So here’s a three-part
challenge. Can we: a) use
our remarkable capacity for collective learning to b)
drastically reduce our ecological footprint; while c)
maintaining the well-being, contentment and sense of fulfillment of the maximum
number of people on earth?
[1] “The Anthropocene”, in Nature,
Vol. 415, 3 January, 2002: www.nature.com
[2] Based on the very rough calculations of I.G. Simmons, Changing the Face of the Earth, 1st ed., p. 27, who estimates that, instead of the 2-3,000 calories we need each day to survive, we now consume on average about 230,000 calories
[3] Data accessed from the IUCN website, http://www.iucn.org/what/tpas/biodiversity/about/, on May 30 2010
[4] See Jan Zalasiewicz et. al., “Are we now living in the Anthropocene?”, Geological Society of America, Vol. 18, No. 2 (Feb 2009), pp. 4-8, from p. 7; for a good introduction to the idea, see Will Steffen, Paul J. Crutzen & John R. McNeill, “The Anthropocene: Are Humans Now Overwhelming the Great Forces of Nature?”, in Ambio, Vol. 36, No. 8, Royal Swedish Academy of Sciences, Dec 2007
[5]. Craig Stanford, The Hunting Apes: Meat Eating and the Origins of Human Behaviour, Princeton: Princeton University Press, 1999, pp. 28-9
[6] The Irish elk vanished about 7,700 years ago, so that human over-hunting may be a more likely explanation
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