Darwin‘s Dangerous Idea

Daniel Dennett

Revolución Darwin

Santiago, Chile

September 6, 2009

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 Pre-Darwinian worldview

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

Darwin‘s greatest idea

If during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organization, and I think this cannot be disputed; if there be, owing to the high geometric powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each being's own welfare, in the same way as so many variations have occurred useful to man. But if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterized. This principle of preservation, I have called, for the sake of brevity, Natural Selection.

Origin of Species, end of chapter 4

Darwin‘s greatest idea

If during the long course of ages and under varying conditions of life, organic beings vary at all in the several parts of their organization, and I think this cannot be disputed; if there be, owing to the high geometric powers of increase of each species, at some age, season, or year, a severe struggle for life, and this certainly cannot be disputed; then, considering the infinite complexity of the relations of all organic beings to each other and to their conditions of existence, causing an infinite diversity in structure, constitution, and habits, to be advantageous to them, I think it would be a most extraordinary fact if no variation ever had occurred useful to each being's own welfare, in the same way as so many variations have occurred useful to man. But if variations useful to any organic being do occur, assuredly individuals thus characterized will have the best chance of being preserved in the struggle for life; and from the strong principle of inheritance they will tend to produce offspring similarly characterized. This principle of preservation, I have called, for the sake of brevity, Natural Selection.

Origin of Species, end of chapter 4

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

AlanTuring

Turing‘s

strange inversion of reasoning

Pre-Turing computers

In the old days, computers had to

understand arithmetic,

had to appreciate the reasons.

Turing recognized that this was not

necessary.

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.

Darwin and Turing

Competence without comprehension!

Understanding (mind, consciousness,

intention) is the effect, not the cause!

von Kempelen‘s Turk

1770- 1854

von Kempelen‘s Turk

Unmasked in the USA

by Edgar Allan Poe

In 1836

von Kempelen‘s Turk

Poe thought it was impossible for a

mindless machine to play chess.

It isn‘t.

There may be a little man inside Deep Blue,

but if so, he may well be sound asleep.

Some people think today that it is impossible

for a mindless process to produce

evolution.

It isn‘t.

There may be an intelligent God hidden in

the evolution process, but if so, he might

as well be asleep, since there is no work

for him to do!

Compare

Amoeba, Difflugia coronata

Sand castles

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.

Natural selection itself doesn‘t need to know

what it is doing!

A common error:

We attribute more understanding to the

agent than Need Be.

We lack a familiar concept of semi-

understood quasi-representations

(or hemi-semi-demi-understood pseudo-

representations)

Turing gives us all of these.

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 . . . 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 . . . have grown in population, technology, and intelligence to a position of terrible power: we now wield the paintbrush. –Paul MacCready

John Maynard Smith and Eors Szathmary,

The Major Transitions in Evolution, 1995

Major transitions

1. Eukaryotic revolution

2. Sex

3. Multicellularity (and cell differentiation)

4. Language

5. Human Culture (art, religion, politics,

science, engineering. . . )

Major transitions

1. Eukaryotic revolution

2. Sex

3. Multicellularity (and cell differentiation)

4. Language

5. Human Culture (art, religion, politics,

science, engineering. . . )

Where did culture come from?

A divine gift?

Human genius?

Over the centuries, intelligent (human)

designers created cultural treasures. . . . ?

The inherited treasures model

of cultural evolution

(prevailing wisdom)

Culture is

composed of ―good‖ things

invented by innovators with insight,

recognized and valued as such by

adopters,

Who transmit and tinker. . . .

(an economic model of possessions)

The inherited treasures model

of cultural evolution

A problem:

Who invented

words,

arithmetic,

music,

maps,

money?

Nobody.

The inherited treasures model

of cultural evolution

Then how did they get to be such perfect

tools for the jobs they do?

They evolved.

Just the way animals and plants

and viruses did.

By natural selection.

Words

—the most important cultural items.

The diversity of words

Where did they all come from?

thousands of languages

Could they have a common ancestor?

Phylogenetic trees . . .

Glossogenetic trees . . . .

Proto-Indo-European languages

Finno-Ugric languages

Languages of China

Proto-Mayan languages

Horizontal word transfer

is rife in languages. . . .

So words are more trackable items than

whole languages.

memes

as cultural items analogous

to genes

or to viruses.

They evolve by natural

selection.

For evolution to occur, copying must be high

fidelity (but not perfect).

Are there any memes?

Words are memes that can be pronounced.

Repeat after me. . . .

norms of correction

Information about kayaks is stored in Inuit

brains

AND in kayaks!

But only on the (default) presumption that

the design is good.

Even if it isn‘t understood.

A kind of digitization.

Correction to the norm

Polynesian canoes

"every boat is copied from another boat... it

is the sea herself who fashions the boats,

choosing those which function and

destroying the others" (Alain, 1908)

Memes are like software viruses.

Memes are software viruses.

To understand this, you need to adjust your

imagination re computation and software.

The inherited treasures model

of cultural evolution

(prevailing wisdom)

Culture is

composed of ―good‖ things

invented by innovators with insight,

recognized and valued as such by

adopters,

Who transmit and tinker. . . .

(an economic model of possessions)

The Darwinian (memetic) model

Culture is composed of

Good, bad and indifferent things

Created by processes with variable insight

(ranging from 0 to genius)

Adopted with variable recognition of value

(ranging from -100 to +100!)

Having an economic model as a limiting

case. . . .

Compare

Traditional Darwinian

good things good, bad, soso

invented with insight insight 0-100

valued value -100 - +100

passed on passed on

w/improvements with mutations

economic model as a limiting case.

Once we have cultural software ‗installed‘

it creates ‗top down‘ patterns of causation.

Our minds can be

dominated, or driven,

by an idea—or ideas.

This is the fulcrum for

intelligent design.

Compare

Top-down design

Turing‘s computer!

We are the first

Intelligent designers in the Tree of Life.

Our natural tendency to interpret all design

as top-down.

as representation-driven,

is both anachronistic and

anthropocentric.

―In the beginning was the word . . . .‖

NO.

Words are a very recent invention,

one of the most recent products of blind,

purposeless natural selection.

We, the reason representers,

can now look back and discover the reasons everywhere in the tree of life.

It took Darwin

to figure out that a mindless process discovered all those reasons.

We intelligent designers are among the effects, not the cause, of all those purposes.

DARUUIN

Delere

Auctorem

Rerum

Ut Universum

Infinitum

Noscas

DARUUIN

Delere Destroy

Auctorem the Author

Rerum of Things

Ut Universum in order to

Infinitum Understand the

Noscas Infinite Universe

Thanks for your attention.