“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!
X
There 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 possible
Was 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]
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?
Alfred Crosby describes the Earth as a “mote of debris” left over from
the formation of the Sun [Children of the Sun, p. 2]
1 million Earths
could fit inside
the Sun
Or to the Milky Way?
How many stars in the Milky Way? About 100 billion
How 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]
We are about 2/3 from
the Center
An Artist’s Reconstruction of Our Galaxy
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
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]
Some Estimated Free Energy Rate Densities
Based 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
500,000
In Graph
Form:
Estimated Free
Energy Rate
Densities
450,000
400,000
350,000
300,000
250,000
200,000
ergs/sec/gr
150,000
100,000
50,000
0
la
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a
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A
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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.
2.
3.
4.
5.
6.
7.
8.
The Universe [Cosmology]
The first Galaxies & Stars [Astronomy]
New chemical elements [Chemistry]
Planets and our earth [Geology]
Life [Biology]
Human beings [History]
Agriculture [History]
Modern Society [History]
I’ll focus on the last three steps
Increasing human control of energy began
deep in the Paleolithic
Each migration = new ways of extracting energy
New hunting techniques
Adaptations to cold
Arctic
technologies
15-13,000 BP?
c. 60,000 BP
Chimp
range:
no
change
4,000 BP?
New Seagoing
technologies
Range of
50,000 BP?
early humans
250,000 BP?
1,000 BP?
New oceangoing
technologies
Paleolithic migrations based on
comparisons of mitochondrial DNA
[see http://www.mitomap.org/WorldMigrations.pdf ]
Slowly at first, human numbers
grew as they entered new
environments
Populations of Homo sapiens sapiens
100,000 BP - Now
7,000
6,000
5,000
Millions
10,000 BP-Now
6,300,000,000
humans?
4,000
3,000
2,000
1,000
0
100,000
90,000
80,000
70,000
60,000
50,000
40,000
30,000
20,000
10,000
0
Years Before Pesent
10,000 humans?
5,000,000 humans?
Per Capita Energy
Consumption increased
[Smils, Energy in World History, p. 236]
Modern Era
Paleolithic Era
Today each
individual
consumes c. 60
times as much as
10,000 years ago
Populations 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 century
John 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]
120
100
80
Million tons
60
carbon
40
20
0
Non-domesticated
("Wild")
Mammals (5)
Humans (40)
Domesticated
Mammals (120)
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 parallel
Modern Human Society: 6 billion human brains, multiply connected
through language, phones, and the internet, computing in parallel
Complexity is not necessarily good!
Perhaps complexity = fragility
Some Estimated Free Energy Rate Densities
Based on: Eric J. Chaisson, Cosmic Evolution: The Rise of
Complexity in Nature, Cambridge, Mass.: Harvard University
Press, 2001, p. 139
Generic Structure
Approximate
life span
(Years)
Free Energy
Rate 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
centuries?
500,000
Society (e.g. Modern human
culture)
More complexity 
more energy/resources for
humans 
less for other species
“Baiji”, or Yangtse Dolphin:
Now thought to be extinct
“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).”
[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
Heat from the centre
travels outwards
(taking about 1 mys!)
Fusion takes place in
the core
New supplies of
hydrogen come from
the outer layers
Energy from
the core
sustains its
structure
Complexity in Human History:
A Hypothesis
Humans “adapt” faster than other organisms
because 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 DNA
2. Learning: Fast change, but little communication so
non-cumulative
3. Collective Learning: Fast change + linked through
language  cumulative change  HISTORY!
The Synergy of Collective Learning
As populations increase, possible exchanges between
individuals increase even faster, and at an accelerating rate
The equation: if the no. of nodes is n, the number of
possible links between them is (n x (n-1))/2.
Basic Edges
“Graph Theory”:
No. of
“Nodes”
and
Vertices
compared
to No. Synergy
of possibleoflinks
between “Nodes”
Modelling
Info-networks
1200
No.
No. of
of possible
Edges
Possible
Links
1000
800
600
400
No. of
No. of
Vertices
“Nodes”
200
0
10
20
30
40
50
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)
250
200
150
100
50
0
o
o
y
o
o
g
g
a
g
g
A
A
A
A
od
s
s
s
s
T
Y
Y
Y
Y
0
0
0
0
10
00
00
00
,
,
,
0
1
0
1
0
1
1,000 Calories per
individual per day
NOT MUCH SYNERGY HERE IN 100,000 YEARS!
With average human energy use
(1,000 Cals. Per person per day)
250
200
150
100
50
0
y
ic
t
rs
r s i e ty
e
e
e
h
ci
c
m
m
lit
o
o
r
r
o
le
.S
Fa r Fa d. S
a
d
P
In
In
rly ate
.
a
ly
E
L
r
od
a
M
E
1,000 Calories per
person per day
THIS IS SYNERGY!
A SIMPLE 3-PART PERIODIZATION
1. 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 slow
2. 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 course