“Teaching a Unified Account of the Past”

David Christian

San Diego State University

September, 2008

A Problem for Educators

• Fragmentation of knowledge– We teach different disciplines but not the links

between them

• A sense of meaningless:– For students this creates a sense of a world

without meaning

A problem unique to the modern world

• In all societies we know of, children were taught an account of reality that was– Unified

– Meaningful

– Based on the best available knowledge

– Contained in Creation Stories

• Was Australia 500 years ago (think about it!)– Educationally ahead of the US today?

Francis Firebrace, a storyteller of the Yorta Yorta Nation, N.S.W.

Things are changing!

• Now we are once again within reach of an account of reality that is– More unified– More meaningful– Based on the best of modern scientific knowledge

• I’ve taught such a course for 20 years– I call it “big history”– Others call it “the evolutionary epic”

or “a modern creation story”– A fundamental educational breakthrough?

Why the change? One vital factor:The “Chronometric Revolution”

• Before the mid 20th century all absolute dates based on written records

• As History became more “scientific” it needed rigorous chronologies– These used written evidence– Could only reach back 5,000 years– History came to mean “human history”– History and the Science split into

C.P. Snow’s famous “Two Cultures”

History and Science were no longer talking to each other!

XThere seemed to be no history to Science

There seemed to be little science in History!NO DATES MEANT NO DATES!

Enter the “Chronometric Revolution”Dating the Undateable!

• 1950s, Willard Libby pioneers C14 dating– 1953, Claire Paterson dates the earth– New Radiometric techniques

• Other techniques including dendrochronology

• New techniques in – Biology (genetic dating)– Cosmology

A Unified Chronology for the whole of Time!

• New Paradigms: – In Big Bang Cosmology, Plate Tectonics &

Genetics– Made the sciences more historical

• The Chronometric Revolution:– Provided absolute dates for the whole of time!– Linked cosmology, astronomy,

chemistry, geology, biology, human history

– Within a single timeline

Can History and Science get back together?

Now that dating was possibleWas dating possible?

A unified and meaningful Map of Time and the Universe

• Like traditional creation stories

• The emerging scientific creation story can help students– Map themselves onto reality– Understand their place in reality– See that modern knowledge is unified

• The story is saturated with meaning!

The Story

• You’ll meet it during this course of lectures

• Today: – an introduction and a “taster” to

Big History (aka the Evolutionary Epic)

The whole of time in 11 dates

1. The Universe appeared c. 13.7 bys ago

2. The Earth, c. 4.5 bys ago

3. First living organisms c. 3.8 bys ago

4. First multi-celled organisms c. 600 mys ago

5. Dinosaurs wiped out c. 67 mys ago

6. First “hominines” appeared c. 7 mys ago

7. Our species, Homo sapiens, c. 200,000 ys ago

8. First agricultural societies, c. 10,000 ys ago

9. First civilizations and written documents c. 5,000 ys ago

10. Industrial Revolution (and the USA!) c. 250 ys ago

11. Humans enter space c. 50 ys ago

Another way of seeing time:If the Universe began 13 years ago, then …

– the earth would have existed for about • five years [4.5 billion ys]

– large organisms with many cells for • 7 months [600 million ys]

– the asteroid that killed the dinosaurs would have landed • 3 weeks ago [67 million ys]

– Hominines would have existed for just • 3 days [c. 7 million ys]

– our own species, Homo Sapiens, for • 53 minutes [c. 200,000 ys]

– agricultural societies would have existed for • 5 minutes [c. 10,000 ys]

– the entire recorded history of civilization for • 3 minutes [c. 5,000 ys: that’s when most world history courses start!]

– modern industrial societies (and the USA!) for• 6 seconds [c. 250 ys]

– 1st humans in space and on the moon• 1 second [c. 50 ys] I live here!

Is there unity or meaning in this story?

• Many students feel it belittles them, and deprives them of meaning …

• After all our earth looks small from space …

Apollo 8 photograph of Earth from lunar orbit: Dec 24 1968

Or compared to the Sun?

1 million Earths could fit inside the Sun

Alfred Crosby describes the Earth as a “mote of debris” left over from the formation of the Sun [Children of the Sun, p. 2]

Or to the Milky Way?

An Artist’s Reconstruction of Our Galaxy

We are about 2/3 from the Center

How many stars in the Milky Way? About 100 billionHow many galaxies in the Universe? About 200 billion

Cesare Emiliani: There are as many stars in the Universe as there are “sand grains in all the deserts and beaches of the earth”

[Scientific Companion, 2nd ed., p. 9]

Depressed?

Despite this, it turns out there is plenty of meaning in the modern creation story

• One central theme: INCREASING COMPLEXITY

• The Universe began simple– Energy, matter, expanding space

• Over 14 bys more complex things appeared– Most of the Universe remains simple– But new, complex things have emerged:

• New forms of complexity– Galaxies and Stars (in that order!)– More chemical elements– Planets– Living Organisms– Modern Human Society

What is Complexity?A simple definition

1. Multiple Components: diverse, varied

2. Linking mechanisms: components linked together in precise patterns

3. New energy flows: and held together by flows of energy mobilized by the nature of the structure

4. New “Emergent Properties” :new rules, new types of entity appear when components are linked together in particular structures

5. Death: when the energy flows cease, the structure falls apart into its simpler components, ceasing to exist

Complexity exists at many scales

Figure 1 Brain tissue of a cat

Walle J. H. Nauta, Fundamental Neuroanatomy, ed.

Michael Feirtag (New York: Freeman, 1986), 9.

Figure 2 Supercomputer simulation of a clustering of galaxies.

Ron Cowen, “Galaxy Hunters: The search for cosmic dawn,” National Geographic 203, no. 2 (2003): 15.

And at different levels

• “There is a hierarchy, ranging from fundamental particles below the atomic level up through molecules and crystals to the macroscopic chunks which our unaided sense organs are built to appreciate. Living matter introduces a whole new set of rungs to the ladder of complexity: macromolecules folding themselves into their tertiary forms, intracellular membranes and organelles, cells, tissues, organs, organisms, populations, communities and ecosystems. ... At every level the units interact with each other following laws appropriate to that level, laws which are not conveniently reducible to laws at lower levels.”

• Richard Dawkins, The Extended Phenotype: the Long Reach of the Gene, Oxford: OUP, 1982, 1999, p. 112-3

Can we measure levels of complexity? Eric Chaisson’s Idea

• If forming complex things requires work

• And forming more complex things requires more work, then …– We should be able to measure complexity

objectively by measuring energy flows– “Free energy rate density” =

ergs per second flowing through each gram

Some Estimated Free Energy Rate DensitiesBased on: Eric J. Chaisson, Cosmic Evolution: The Rise of Complexity in

Nature, Cambridge, Mass.: Harvard University Press, 2001, p. 139

Generic Structure Free Energy Rate Density(erg s-1 g-1)

Galaxies (e.g. Milky Way) 1

Stars (e.g. Sun) 2

Planets (e.g. Earth) 75

Plants (biosphere) 900

Animals (e.g. Human body) 20,000

Brains (e.g. Human cranium) 150,000

Society (e.g. Modern human culture) 500,000

Stuart Kauffman: “the maintenance of order requires that some form of work be done on the system. In the absence of work, order disappears.” [From Complexity]

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

ergs/sec/gr

In Graph Form:

Estimated Free Energy Rate

Densities

Payoff? Modern Human Society is

a) extraordinarily complex &

b) depends on extraordinarily large energy flows

Interesting! Humans seem back at the center of the picture!

And the picture has meaning!

Humans are different

• “Although we are made up of the same chemicals, with the same physiological reactions, we are very different from other animals. Just as gases can become liquids, which can become solids, phase shifts occur in evolution, shifts so large in their implications that it becomes almost impossible to think of them as having the same components.”

Michael Gazzaniga, Human, Prologue

The Story of increasing complexity:Eight Thresholds

1. The Universe [Cosmology]

2. The first Galaxies & Stars [Astronomy]

3. New chemical elements [Chemistry]

4. Planets and our earth [Geology]

5. Life [Biology]

6. Human beings [History]

7. Agriculture [History]

8. Modern Society [History]

I’ll focus on the last three steps

Increasing human control of energy began deep in the Paleolithic

Chimp range: no change Range of

early humans250,000 BP?

c. 60,000 BP

50,000 BP?

15-13,000 BP?

4,000 BP?

1,000 BP?

New Sea-going

technologies

New hunting techniquesAdaptations to cold

Many new

technologies required

New ocean-going

technologies

Arctic technologies

Each migration = new ways of extracting energy

Paleolithic migrations based on comparisons of mitochondrial DNA

[see http://www.mitomap.org/WorldMigrations.pdf ]

Populations of Homo sapiens sapiens 100,000 BP - Now

100,000 90,000 80,000 70,000 60,000 50,000 40,000 30,000 20,000 10,000 00

1,000

2,000

3,000

4,000

5,000

6,000

7,000

Years Before Pesent

Mill

ions

10,000 BP-Now

Slowly at first, human numbers grew as they entered new

environments

10,000 humans? 5,000,000 humans?

6,300,000,000humans?

Per Capita Energy Consumption increased

[Smils, Energy in World History, p. 236]

Paleolithic Era

Modern Era

Today each individual

consumes c. 60 times as much as 10,000 years agoPopulations have grown by 1,000 times, so total

energy consumption has

increased by almost 60,000

times

Our control of energy has increased rapidly in the last

centuryJohn McNeill, Something New under the Sun,

p. 15:

“We have probably deployed more energy since 1900 than in all of human history

before 1900. My very rough calculation suggests that the world in the twentieth

century used 10 times as much energy as in the thousand years before 1900 A.D.”

On land, humans now control 25-40% of all energy from photosynthesis![Vaclav Smil, The Earth’s Biosphere: Evolution, Dynamics, and Change, Cambridge, Mass.: M.I.T., 2002, p. 240]

From Alfred Crosby, Children of the Sun, p. 162

Biomass of mammals as a measure of energy control

[from Vaclav Smil, The Earth’s Biosphere, pp. 186]

0

20

40

60

80

100

120

Million tons carbon

Non-domesticated("Wild")

Mammals (5)

Humans (40) DomesticatedMammals (120)

Anthro

poge

nic

Mam

mal bio

mass

How complex is modern human society?Brains: 100,000,000,000 neurons (as many as stars in the Milky Way), each connected to hundreds of others, computing in parallelModern Human Society: 6 billion human brains, multiply connected through language, phones, and the internet, computing in parallel

Some Estimated Free Energy Rate DensitiesBased on: Eric J. Chaisson, Cosmic Evolution: The Rise of

Complexity in Nature, Cambridge, Mass.: Harvard UniversityPress, 2001, p. 139

Generic Structure Approximatelife span(Years)

Free EnergyRate Density(erg s-1 g-1)

Galaxies (e.g. Milky Way) billions 1

Stars (e.g. Sun) billions 2

Planets (e.g. Earth) billions 75

Plant species (biosphere) millions 900

Animal species (e.g. human body) millions 20,000

Large Brains (e.g. human brain) millions 150,000

Society (e.g. Modern humanculture)

centuries? 500,000

Complexity is not necessarily good!Perhaps complexity = fragility

More complexity more energy/resources for

humans less for other species

“Over the past few hundred years, humans have increased the species extinction rate by as much as 1,000 times over background rates typical over the planet’s history (medium certainty). Some 10–30% of mammal, bird, and amphibian species are currently threatened with extinction (medium to high certainty).”

“Baiji”, or Yangtse Dolphin: Now thought to be extinct

[From the Millennium Ecosystem Assessment, March 2005]

Human energy use now affects the biosphere

“Within a few centuries we are returning to the atmosphere and oceans the concentrated organic carbon stored in sedimentary rocks over hundreds of millions of years.”

[Revelle & Suess, 1957, cited from Smils, The Earth’s Biosphere, p. 15]

HOW COMPLEX ARE WE ON COSMOLOGICAL SCALES?

Fermi’s question• If creatures similar to my governor are common• There should be millions in our galaxy• Some civilizations should be millions of years

more advanced than ours• Some must have left signals or objects for us to

detect• After 30 years of searching we have detected none• WHERE ARE THEY?

The Meaning of this Story:Human history may be one of the most complex phenomena in the Universe!

• “History” tells a story of one planet

• And one species’– Accelerating control of resources and energy– Leading to levels of complexity that may be

significant at cosmological scales– And may lead to our early retirement!

• A conclusion full of meaning!

Why so complex? a new adaptive mechanism?

• Adaptive mechanisms:– How living organisms acquire and pass on new and

more complex structures– How they mobilize more energy and become more

complex

• All other living organisms adapt genetically

• Humans find new ways of mobilizing energy without waiting for genetic change– How? Why are we so good at continually adapting?

New Adaptive mechanisms imply new “linking mechanisms”

• Linking mechanisms: – join once independent entities into new,

precisely structured and more complex, entities

• The Sun: – formed when gravity bound clouds of atoms

into a larger structure fuelled by fusion

The Structure of our Sun

Fusion takes place in the core

New supplies of hydrogen come from the outer layers

Heat from the centre travels outwards (taking about 1 mys!)

Energy from the core sustains its structure

Complexity in Human History: A Hypothesis

Humans “adapt” faster than other organismsbecause they use a new, more powerful, adaptive mechanism that links them within the complex structures of human societies:

Compare three adaptive mechanisms:1. Natural Selection: Slow, but recorded in DNA2. Learning: Fast change, but little communication so

non-cumulative3. Collective Learning: Fast change + linked through

language cumulative change HISTORY!

The Synergy of Collective Learning

0

200

400

600

800

1000

1200

10 20 30 40 50

Edges and VerticesModelling Synergy of Info-networks

No. of possibleEdges

No. ofVertices

As populations increase, possible exchanges between individuals increase even faster, and at an accelerating

rate

Basic “Graph Theory”: No. of “Nodes” compared to No. of possible links between “Nodes”

No. of Possible Links

No. of “Nodes”

The equation: if the no. of nodes is n, the number of possible links between them is (n x (n-1))/2.

Setting up a feedback loop

Collective Learning more energy more people more complexity

more collective learning …

Compare the history of Chimp energy use over 10,000 years

(1,000 Cals. Per person per day)

0

50

100

150

200

250

1,000 Calories perindividual per day

NOT MUCH SYNERGY HERE IN 100,000 YEARS!

With average human energy use(1,000 Cals. Per person per day)

0

50

100

150

200

250

1,000 Calories perperson per day

THIS IS SYNERGY!

A SIMPLE 3-PART PERIODIZATION1. The Paleolithic Era: feedback but limited

– Collective learning migrations to new environments– Energy control increases more humans, but …– Communities remain small little increase in complexity

collective learning slow2. The Agrarian Era: increasing positive feedback

– Collective learning domestication intensification– More energy from a given area: agriculture– Average community size increases population growth

social complexity more collective learning feedback!3. The Modern Era: positive feedback accelerates

– Collective learning global in scale + new technologies increase number of exchanges

– Energy control increases sharply; exploitation of fossil fuels– Average community size increases social complexity

RESULT?SOMETHING NEW APPEARS

IN THE COSMOS

• All the remarkable “emergent properties” of human society and human history are products of these processes

• Human Society counts as– A new phenomenon– A new level of complexity

A unified and meaningful account of the past

• Based on the best of modern science

• Coherent

• Full of meaning– Particularly if you happen to be

human!

• Highly teachable!

Thank You!

Eric Idle’s big history courseEric Idle’s big history course