Transcript The Fantasy of First-Person Science

Darwin and the Evolution of
Reasons
Daniel Dennett
Biosphere
February 14, 2009
Philosophers who weren’t
#1 philosopher who wasn’t
Two Evolutionists
Why was Darwin’s idea so great?
It united the world of purposeless causation
with the world of meaning.
From physics to ethics and poetry
in one unified perspective
The trickle-down theory of creation . . .
“Obvious” since Homo habilis?
The trickle-down theory of creation . . .
“Obvious” since Homo habilis?
vs the bubble-up theory of creation
An early critic of Darwin summed it up:
In the theory with which we have to deal, Absolute
Ignorance is the artificer; so that we may enunciate
as the fundamental principle of the whole system,
that, IN ORDER TO MAKE A PERFECT AND
BEAUTIFUL MACHINE, IT IS NOT REQUISITE TO
KNOW HOW TO MAKE IT. This proposition will be
found, on careful examination, to express, in
condensed form, the essential purport of the Theory,
and to express in a few words all Mr. Darwin's
meaning; who, by a strange inversion of reasoning,
seems to think Absolute Ignorance fully qualified to
take the place of Absolute Wisdom in all the
achievements of creative skill.
--Robert Beverley MacKenzie, 1868
In the theory with which we have to deal, Absolute
Ignorance is the artificer; so that we may enunciate
as the fundamental principle of the whole system,
that, IN ORDER TO MAKE A PERFECT AND
BEAUTIFUL MACHINE, IT IS NOT REQUISITE TO
KNOW HOW TO MAKE IT. This proposition will be
found, on careful examination, to express, in
condensed form, the essential purport of the Theory,
and to express in a few words all Mr. Darwin's
meaning; who, by a strange inversion of reasoning,
seems to think Absolute Ignorance fully qualified to
take the place of Absolute Wisdom in all the
achievements of creative skill.
--Robert Beverley MacKenzie, 1868
How could Darwin be right?
Turing’s
strange inversion of reasoning
Darwin
IN ORDER TO MAKE A PERFECT AND
BEAUTIFUL MACHINE, IT IS NOT
REQUISITE TO KNOW HOW TO MAKE
IT.
Turing . . .
IN ORDER TO BE A PERFECT AND
BEAUTIFUL
Turing . . .
IN ORDER TO BE A PERFECT AND
BEAUTIFUL COMPUTING MACHINE,
Turing . . .
IN ORDER TO BE A PERFECT AND
BEAUTIFUL COMPUTING MACHINE, IT
IS NOT REQUISITE TO KNOW WHAT
ARITHMETIC IS.
Pre-Turing computers
Darwin and Turing together:
two strange inversions
IN ORDER TO MAKE A PERFECT AND
BEAUTIFUL MACHINE, IT IS NOT
REQUISITE TO KNOW HOW TO MAKE
IT.
IN ORDER TO BE A PERFECT AND
BEAUTIFUL COMPUTING MACHINE, IT
IS NOT REQUISITE TO KNOW WHAT
ARITHMETIC IS.
We are made of trillions of mindless little
robots
and not one of them knows who we are or
cares!
But we know.
We care.
How come?
The Eukaryotic Revolution
2.5 billion years ago:
Simple prokaryotes (bacteria, blue-green
algae. . . .)
The Eukaryotic Revolution
2.5 billion years ago:
One prokaryote was invaded by another
prokaryote . . . .
The Eukaryotic Revolution
2.5 billion years ago:
One prokaryote was invaded by another
prokaryote . . . .
And the result was a more complicated cell
that was fitter!
Lynn Margulis
Prokaryote invasion →
eukaryotes
Eukaryotes are more talented, more
versatile.
Sand castles
Amoeba, Difflugia coronata
Amoeba, Difflugia coronata
Amoeba, Difflugia coronata
Eukaryotes
This versatility permitted division of labor
making multi-cellular life possible.
Caddis fly larva
Caddis larva food sieve
lobster trap
What’s the difference?
There are reasons for the arrangement of
parts
in the caddis larva’s food sieve
and in the lobster trap.
But the caddis reasons
are not represented anywhere
The free-floating rationales
of evolution:
Cuckoo chick
The free-floating rationales
of evolution:
Cuckoo chick
Natural selection tracks reasons,
creating things that have purposes but
don’t need to know them.
The “Need to Know” principle reigns in the
biosphere.
New Caledonian crow
[alt tab]
“animals that represent
their goals in the same
representational system
in which they represent
their facts.”
Ruth Millikan, 2000,
p170
But they don’t represent the reasons for their
goals!
It’s a long way from
to
We are very different from other animals.
Everything is what it is because it got that
way. —D’Arcy Thompson (1917)
But it isn’t just about genes!
LUCA
Last
Universal
Common
Ancestor
Coprinus
Three closely related genera!
Homo
Zea
David Brooks, NY Times, April 15, 2007:
“The Age of Darwin”
According to this view, human beings, like all
other creatures, are machines for passing
along their genetic code. We are driven
primarily by a desire to perpetuate
ourselves and our species.
David Brooks, NY Times, April 15, 2007:
“The Age of Darwin”
According to this view, human beings, like all
other creatures, are machines for passing
along their genetic code. We are driven
primarily by a desire to perpetuate
ourselves and our species.
The Standard Mistake
David Brooks, NY Times, April 15, 2007:
“The Age of Darwin”
According to this view, human beings, like all
other creatures, are machines for passing
along their genetic code. We are driven
primarily by a desire to perpetuate
ourselves and our species.
Ca. 3.5 billion years for the whole Tree of
Life.
ca. 6 million years to evolve away from our
common ancestor with the chimpanzees
and bonobos.
All the differences observable today must be
due to R and D occurring in that interval.
10,000 years ago: human population plus livestock
and pets was approximately 0.1% of terrestrial
vertebrate biomass.
Today: 98%!
Over billions of years, on a unique sphere, chance
has painted a thin covering of life–complex,
improbable, wonderful and fragile. Suddenly we
humans (a recently arrived species no longer
subject to the checks and balances inherent in
nature), have grown in population, technology,
and intelligence to a position of terrible power:
we now wield the paintbrush. –Paul MacCready
10,000 years ago: human population plus livestock
and pets was approximately 0.1% of terrestrial
vertebrate biomass.
Today: 98%!
Over billions of years, on a unique sphere, chance
has painted a thin covering of life–complex,
improbable, wonderful and fragile. Suddenly we
humans (a recently arrived species no longer
subject to the checks and balances inherent in
nature), have grown in population, technology,
and intelligence to a position of terrible power:
we now wield the paintbrush. –Paul MacCready
Cf. the “Cambrian explosion”
occurred over millions of years
ca 530 million years ago
Wonderful Life, Stephen Jay Gould
The MacCready explosion
occurred over 10,000 years
≈ 500 generations
It’s not just genes!
A second information highway from parents
to offspring
Richerson and Boyd
Not by Genes Alone
Culture is transmitted more generally.
oblique transmission
“rogue cultural variants” (Boyd and
Richerson)
memes
memes
are analogous to genes
Or to viruses (which are “naked” genes)
A virus is a string of nucleic acid with
attitude.
A meme is a data structure (made of
information) with attitude.
We are apes with infected brains.
infected with virtual machines
designed by natural selection.
These virtual machines give us powers,
which give us the versatility to take
organization up a level.
Our power
depends on the culture that permits us to
divide labor
and share expertise.
“You can’t do much carpentry with your bare
hands, and you can’t do much thinking
with your bare brain.”
--Bo Dahlbom
“You can’t do much carpentry with your bare
hands, and you can’t do much thinking
with your bare brain.”
--Bo Dahlbom
You need thinking tools.
“You can’t do much carpentry with your bare
hands, and you can’t do much thinking
with your bare brain.”
--Bo Dahlbom
You need thinking tools.
Fortunately, there are lots of them lying
around. . .
Dogs are a kind of
mammal
pet
Words are a kind of ________?
meme
Words are memes that can be pronounced.
(Millikan: “members of first-order
reproductively established families.” 1984 )
The diversity of words
Where did they all come from?
thousands of languages
Could they have a common ancestor?
15,000 years of natural selection
Proto-Indo-European languages
Finno-Ugric languages
Languages of China
Proto-Mayan languages
Since anastomosis (branch-joining,
horizontal transmission) is rife in
languages. . . .
words are more trackable items than whole
languages.
Words as tools.
Words are not always elements of
grammatical constructions:
passwords
labels
tools made of
“technique”
recipes for action
what is long division made of?
what is cost benefit analysis made of?
virtual machines
made of information
technology
that remade the brain
and make our minds
Doug Hofstadter’s toolkit
includes
‘wild goose chases’
‘tackiness’
‘dirty tricks’
‘sour grapes’
‘elbow grease’
‘feet of clay’
‘loose cannons’
‘crackpots’
‘lip service’
‘slam dunks’
’feedback’
Who designed the treasures we share?
Pythagoras, Plato, Descartes, Newton,
Shakespeare, Austen, Curie, . . . . .
But nobody designed
language
tonal music
Did anybody invent the decimal number
system?
Did anybody invent the map?
Did anybody invent money?
Darwin’s trio
Methodical selection
Unconscious selection
Natural selection
(we add: genetic engineering)
Darwin’s trio
Of memes: Natural selection of synanthropic
memes.
Unconscious selection
(differential replication of tunes,
earworms, etc.)
Methodical selection of domesticated
memes.
e.g., calculus!
(we add: memetic engineering)
Bootstrapping
has worked in the past
and can work again
How do you draw a straight line?
Use a straightedge.
How do you make a straightedge?
making a straight-edge
making a straight-edge
The ideal of a perfectly straight line
(The Form of the Straight—as Plato might
say)
Was arrived at by approximation—both the
artifacts and the idea itself.
The Form of the True has a similar history.
Memes have been selected for veridicality.
What makes us human
Our brainchildren,
not our ‘biological’ children!
We (alone)
represent our reasons.
We can think about our values, our reasons.
That is the source of our creativity.
“Why” makes us human
We represent our reasons.
“Why did you do that?”
This is what enables us to devise moralities,
Compare them, persuade each other. . .
“Responsibility” wears its meaning on its
sleeve.
Caddis larva food sieve
lobster trap
We, the reason representers,
can now look back and discover the reasons
everywhere in the tree of life.
It took Darwin
to discover that a mindless process created
all those reasons.
We “intelligent designers” are among the
effects, not the cause, of all those
purposes.
IO1KG
IZF@Ll
Jesus
OD4FJ@H Christ
1,@L
God
K4@H
Son
GTJ0D
Savior
DARUUIN
Delere
Auctorem
Rerum
Ut Universum
Infinitum
Noscas
DARUUIN
Delere
Auctorem
Rerum
Ut Universum
Infinitum
Noscas
Destroy
the Author
of Things
in order to
Understand the
Infinite Universe
Thanks for your attention.