TEDGlobal 2005

Richard Dawkins: Why the universe seems so strange

Filmed:

Biologist Richard Dawkins makes a case for "thinking the improbable" by looking at how the human frame of reference limits our understanding of the universe.

- Evolutionary biologist
Oxford professor Richard Dawkins has helped steer evolutionary science into the 21st century, and his concept of the "meme" contextualized the spread of ideas in the information age. In recent years, his devastating critique of religion has made him a leading figure in the New Atheism. Full bio

My title: "Queerer than we can suppose: The strangeness of science."
00:25
"Queerer than we can suppose" comes from J.B.S. Haldane,
00:31
the famous biologist, who said, "Now, my own suspicion is
00:34
that the universe is not only queerer than we suppose,
00:38
but queerer than we can suppose.
00:42
I suspect that there are more things in heaven and earth
00:44
than are dreamed of, or can be dreamed of, in any philosophy."
00:47
Richard Feynman compared the accuracy of quantum theories --
00:53
experimental predictions -- to specifying the width of North America
00:58
to within one hair's breadth of accuracy.
01:03
This means that quantum theory has got to be in some sense true.
01:07
Yet the assumptions that quantum theory needs to make
01:12
in order to deliver those predictions are so mysterious
01:14
that even Feynman himself was moved to remark,
01:18
"If you think you understand quantum theory,
01:21
you don't understand quantum theory."
01:24
It's so queer that physicists resort to one or another
01:27
paradoxical interpretation of it.
01:32
David Deutsch, who's talking here, in "The Fabric of Reality,"
01:34
embraces the "many worlds" interpretation of quantum theory,
01:39
because the worst that you can say about it is
01:45
that it's preposterously wasteful.
01:47
It postulates a vast and rapidly growing number of universes
01:49
existing in parallel -- mutually undetectable except through
01:54
the narrow porthole of quantum mechanical experiments.
01:58
And that's Richard Feynman.
02:04
The biologist Lewis Wolpert
02:07
believes that the queerness of modern physics
02:10
is just an extreme example. Science, as opposed to technology,
02:12
does violence to common sense.
02:16
Every time you drink a glass of water, he points out,
02:19
the odds are that you will imbibe at least one molecule
02:23
that passed through the bladder of Oliver Cromwell. (Laughter)
02:26
It's just elementary probability theory.
02:31
The number of molecules per glassful is hugely greater
02:34
than the number of glassfuls, or bladdersful, in the world --
02:38
and, of course, there's nothing special about Cromwell
02:41
or bladders. You have just breathed in a nitrogen atom
02:44
that passed through the right lung of the third iguanodon
02:47
to the left of the tall cycad tree.
02:51
"Queerer than we can suppose."
02:56
What is it that makes us capable of supposing anything,
03:00
and does this tell us anything about what we can suppose?
03:03
Are there things about the universe that will be
03:07
forever beyond our grasp, but not beyond the grasp of some
03:10
superior intelligence? Are there things about the universe
03:14
that are, in principle, ungraspable by any mind,
03:18
however superior?
03:22
The history of science has been one long series
03:25
of violent brainstorms, as successive generations
03:28
have come to terms with increasing levels of queerness
03:32
in the universe.
03:35
We're now so used to the idea that the Earth spins --
03:37
rather than the Sun moves across the sky -- it's hard for us to realize
03:40
what a shattering mental revolution that must have been.
03:43
After all, it seems obvious that the Earth is large and motionless,
03:47
the Sun small and mobile. But it's worth recalling
03:51
Wittgenstein's remark on the subject.
03:55
"Tell me," he asked a friend, "why do people always say, it was natural
03:57
for man to assume that the sun went round the earth
04:02
rather than that the earth was rotating?"
04:05
His friend replied, "Well, obviously because it just looks as though
04:09
the Sun is going round the Earth."
04:12
Wittgenstein replied, "Well, what would it have looked like
04:15
if it had looked as though the Earth was rotating?" (Laughter)
04:18
Science has taught us, against all intuition,
04:27
that apparently solid things, like crystals and rocks,
04:30
are really almost entirely composed of empty space.
04:33
And the familiar illustration is the nucleus of an atom is a fly
04:37
in the middle of a sports stadium and the next atom
04:43
is in the next sports stadium.
04:46
So it would seem the hardest, solidest, densest rock
04:49
is really almost entirely empty space, broken only by tiny particles
04:52
so widely spaced they shouldn't count.
04:58
Why, then, do rocks look and feel solid and hard and impenetrable?
05:01
As an evolutionary biologist, I'd say this: our brains have evolved
05:06
to help us survive within the orders of magnitude of size and speed
05:11
which our bodies operate at. We never evolved to navigate
05:17
in the world of atoms.
05:21
If we had, our brains probably would perceive rocks
05:22
as full of empty space. Rocks feel hard and impenetrable
05:25
to our hands precisely because objects like rocks and hands
05:29
cannot penetrate each other. It's therefore useful
05:34
for our brains to construct notions like "solidity" and "impenetrability,"
05:38
because such notions help us to navigate our bodies through
05:44
the middle-sized world in which we have to navigate.
05:48
Moving to the other end of the scale, our ancestors never had to
05:52
navigate through the cosmos at speeds close to
05:56
the speed of light. If they had, our brains would be much better
05:59
at understanding Einstein. I want to give the name "Middle World"
06:03
to the medium-scaled environment in which we've evolved
06:08
the ability to take act -- nothing to do with Middle Earth.
06:11
Middle World. (Laughter)
06:13
We are evolved denizens of Middle World, and that limits
06:17
what we are capable of imagining. We find it intuitively easy
06:21
to grasp ideas like, when a rabbit moves at the sort of
06:25
medium velocity at which rabbits and other Middle World objects move,
06:28
and hits another Middle World object, like a rock, it knocks itself out.
06:32
May I introduce Major General Albert Stubblebine III,
06:38
commander of military intelligence in 1983.
06:44
He stared at his wall in Arlington, Virginia, and decided to do it.
06:49
As frightening as the prospect was, he was going into the next office.
06:54
He stood up, and moved out from behind his desk.
07:00
What is the atom mostly made of? he thought. Space.
07:05
He started walking. What am I mostly made of? Atoms.
07:09
He quickened his pace, almost to a jog now.
07:15
What is the wall mostly made of? Atoms.
07:18
All I have to do is merge the spaces.
07:23
Then, General Stubblebine banged his nose hard on the wall
07:27
of his office. Stubblebine, who commanded 16,000 soldiers,
07:32
was confounded by his continual failure to walk through the wall.
07:38
He has no doubt that this ability will, one day, be a common tool
07:42
in the military arsenal. Who would screw around with an army
07:45
that could do that? That's from an article in Playboy,
07:48
which I was reading the other day. (Laughter)
07:53
I have every reason to think it's true; I was reading Playboy
07:56
because I, myself, had an article in it. (Laughter)
07:59
Unaided human intuition schooled in Middle World
08:07
finds it hard to believe Galileo when he tells us
08:12
a heavy object and a light object, air friction aside,
08:15
would hit the ground at the same instant.
08:19
And that's because in Middle World, air friction is always there.
08:20
If we'd evolved in a vacuum, we would expect them
08:24
to hit the ground simultaneously. If we were bacteria,
08:27
constantly buffeted by thermal movements of molecules,
08:30
it would be different,
08:33
but we Middle Worlders are too big to notice Brownian motion.
08:35
In the same way, our lives are dominated by gravity
08:39
but are almost oblivious to the force of surface tension.
08:42
A small insect would reverse these priorities.
08:46
Steve Grand -- he's the one on the left,
08:50
Douglas Adams is on the right -- Steve Grand, in his book,
08:52
"Creation: Life and How to Make It," is positively scathing
08:55
about our preoccupation with matter itself.
08:59
We have this tendency to think that only solid, material things
09:03
are really things at all. Waves of electromagnetic fluctuation
09:07
in a vacuum seem unreal.
09:12
Victorians thought the waves had to be waves in some material medium:
09:15
the ether. But we find real matter comforting only because
09:20
we've evolved to survive in Middle World,
09:24
where matter is a useful fiction.
09:28
A whirlpool, for Steve Grand, is a thing with just as much reality
09:31
as a rock.
09:35
In a desert plain in Tanzania, in the shadow of the volcano
09:38
Ol Donyo Lengai, there's a dune made of volcanic ash.
09:42
The beautiful thing is that it moves bodily.
09:46
It's what's technically known as a "barchan," and the entire dune
09:50
walks across the desert in a westerly direction
09:53
at a speed of about 17 meters per year.
09:56
It retains its crescent shape and moves in the direction of the horns.
10:00
What happens is that the wind blows the sand
10:04
up the shallow slope on the other side, and then,
10:07
as each sand grain hits the top of the ridge,
10:10
it cascades down on the inside of the crescent,
10:11
and so the whole horn-shaped dune moves.
10:14
Steve Grand points out that you and I are, ourselves,
10:20
more like a wave than a permanent thing.
10:23
He invites us, the reader, to "think of an experience
10:27
from your childhood -- something you remember clearly,
10:30
something you can see, feel, maybe even smell,
10:33
as if you were really there.
10:36
After all, you really were there at the time, weren't you?
10:37
How else would you remember it?
10:41
But here is the bombshell: You weren't there.
10:43
Not a single atom that is in your body today was there
10:46
when that event took place. Matter flows from place to place
10:49
and momentarily comes together to be you.
10:53
Whatever you are, therefore, you are not the stuff
10:56
of which you are made.
10:59
If that doesn't make the hair stand up on the back of your neck,
11:02
read it again until it does, because it is important."
11:04
So "really" isn't a word that we should use with simple confidence.
11:09
If a neutrino had a brain,
11:14
which it evolved in neutrino-sized ancestors,
11:16
it would say that rocks really do consist of empty space.
11:19
We have brains that evolved in medium-sized ancestors
11:24
which couldn't walk through rocks.
11:26
"Really," for an animal, is whatever its brain needs it to be
11:29
in order to assist its survival,
11:33
and because different species live in different worlds,
11:36
there will be a discomforting variety of "really"s.
11:39
What we see of the real world is not the unvarnished world
11:45
but a model of the world, regulated and adjusted by sense data,
11:49
but constructed so it's useful for dealing with the real world.
11:54
The nature of the model depends on the kind of animal we are.
11:58
A flying animal needs a different kind of model
12:02
from a walking, climbing or swimming animal.
12:05
A monkey's brain must have software capable of simulating
12:08
a three-dimensional world of branches and trunks.
12:13
A mole's software for constructing models of its world
12:16
will be customized for underground use.
12:19
A water strider's brain doesn't need 3D software at all,
12:22
since it lives on the surface of the pond
12:26
in an Edwin Abbott flatland.
12:28
I've speculated that bats may see color with their ears.
12:32
The world model that a bat needs in order to navigate
12:37
through three dimensions catching insects
12:40
must be pretty similar to the world model that any flying bird,
12:42
a day-flying bird like a swallow, needs to perform
12:45
the same kind of tasks.
12:48
The fact that the bat uses echoes in pitch darkness
12:50
to input the current variables to its model,
12:53
while the swallow uses light, is incidental.
12:56
Bats, I've even suggested, use perceived hues, such as red and blue,
12:59
as labels, internal labels, for some useful aspect of echoes --
13:04
perhaps the acoustic texture of surfaces, furry or smooth and so on,
13:11
in the same way as swallows or, indeed, we, use those
13:15
perceived hues -- redness and blueness etc. --
13:19
to label long and short wavelengths of light.
13:22
There's nothing inherent about red that makes it long wavelength.
13:24
And the point is that the nature of the model is governed by
13:29
how it is to be used, rather than by the sensory modality involved.
13:31
J. B .S. Haldane himself had something to say about animals
13:38
whose world is dominated by smell.
13:41
Dogs can distinguish two very similar fatty acids, extremely diluted:
13:44
caprylic acid and caproic acid.
13:49
The only difference, you see, is that one has an extra pair of
13:52
carbon atoms in the chain.
13:55
Haldane guesses that a dog would probably be able to place the acids
13:57
in the order of their molecular weights by their smells,
14:01
just as a man could place a number of piano wires
14:05
in the order of their lengths by means of their notes.
14:08
Now, there's another fatty acid, capric acid,
14:12
which is just like the other two,
14:16
except that it has two more carbon atoms.
14:17
A dog that had never met capric acid would, perhaps,
14:20
have no more trouble imagining its smell than we would have trouble
14:23
imagining a trumpet, say, playing one note higher
14:28
than we've heard a trumpet play before.
14:31
Perhaps dogs and rhinos and other smell-oriented animals
14:36
smell in color. And the argument would be
14:41
exactly the same as for the bats.
14:44
Middle World -- the range of sizes and speeds
14:48
which we have evolved to feel intuitively comfortable with --
14:52
is a bit like the narrow range of the electromagnetic spectrum
14:55
that we see as light of various colors.
14:59
We're blind to all frequencies outside that,
15:02
unless we use instruments to help us.
15:04
Middle World is the narrow range of reality
15:09
which we judge to be normal, as opposed to the queerness
15:12
of the very small, the very large and the very fast.
15:15
We could make a similar scale of improbabilities;
15:20
nothing is totally impossible.
15:23
Miracles are just events that are extremely improbable.
15:25
A marble statue could wave its hand at us; the atoms that make up
15:29
its crystalline structure are all vibrating back and forth anyway.
15:33
Because there are so many of them,
15:37
and because there's no agreement among them
15:39
in their preferred direction of movement, the marble,
15:41
as we see it in Middle World, stays rock steady.
15:44
But the atoms in the hand could all just happen to move
15:47
the same way at the same time, and again and again.
15:49
In this case, the hand would move and we'd see it waving at us
15:52
in Middle World. The odds against it, of course, are so great
15:56
that if you set out writing zeros at the time of
16:00
the origin of the universe, you still would not have
16:03
written enough zeros to this day.
16:06
Evolution in Middle World has not equipped us to handle
16:12
very improbable events; we don't live long enough.
16:13
In the vastness of astronomical space and geological time,
16:16
that which seems impossible in Middle World
16:21
might turn out to be inevitable.
16:24
One way to think about that is by counting planets.
16:28
We don't know how many planets there are in the universe,
16:32
but a good estimate is about 10 to the 20, or 100 billion billion.
16:34
And that gives us a nice way to express our estimate
16:38
of life's improbability.
16:41
Could make some sort of landmark points
16:44
along a spectrum of improbability, which might look like
16:46
the electromagnetic spectrum we just looked at.
16:49
If life has arisen only once on any --
16:54
if -- if life could -- I mean, life could originate once per planet,
16:58
could be extremely common, or it could originate once per star,
17:01
or once per galaxy or maybe only once in the entire universe,
17:06
in which case it would have to be here. And somewhere up there
17:11
would be the chance that a frog would turn into a prince
17:14
and similar magical things like that.
17:16
If life has arisen on only one planet in the entire universe,
17:20
that planet has to be our planet, because here we are talking about it.
17:24
And that means that if we want to avail ourselves of it,
17:28
we're allowed to postulate chemical events in the origin of life
17:31
which have a probability as low as one in 100 billion billion.
17:35
I don't think we shall have to avail ourselves of that,
17:39
because I suspect that life is quite common in the universe.
17:42
And when I say quite common, it could still be so rare
17:45
that no one island of life ever encounters another,
17:48
which is a sad thought.
17:52
How shall we interpret "queerer than we can suppose?"
17:55
Queerer than can in principle be supposed,
17:58
or just queerer than we can suppose, given the limitations
18:01
of our brain's evolutionary apprenticeship in Middle World?
18:04
Could we, by training and practice, emancipate ourselves
18:09
from Middle World and achieve some sort of intuitive,
18:12
as well as mathematical, understanding of the very small
18:15
and the very large? I genuinely don't know the answer.
18:18
I wonder whether we might help ourselves to understand, say,
18:22
quantum theory, if we brought up children to play computer games,
18:25
beginning in early childhood, which had a sort of
18:29
make-believe world of balls going through two slits on a screen,
18:32
a world in which the strange goings on of quantum mechanics
18:34
were enlarged by the computer's make-believe,
18:37
so that they became familiar on the Middle-World scale of the stream.
18:40
And, similarly, a relativistic computer game in which
18:44
objects on the screen manifest the Lorenz Contraction, and so on,
18:47
to try to get ourselves into the way of thinking --
18:52
get children into the way of thinking about it.
18:54
I want to end by applying the idea of Middle World
18:57
to our perceptions of each other.
19:01
Most scientists today subscribe to a mechanistic view of the mind:
19:04
we're the way we are because our brains are wired up as they are;
19:08
our hormones are the way they are.
19:12
We'd be different, our characters would be different,
19:13
if our neuro-anatomy and our physiological chemistry were different.
19:15
But we scientists are inconsistent. If we were consistent,
19:20
our response to a misbehaving person, like a child-murderer,
19:24
should be something like, this unit has a faulty component;
19:27
it needs repairing. That's not what we say.
19:30
What we say -- and I include the most austerely mechanistic among us,
19:33
which is probably me --
19:37
what we say is, "Vile monster, prison is too good for you."
19:38
Or worse, we seek revenge, in all probability thereby triggering
19:42
the next phase in an escalating cycle of counter-revenge,
19:46
which we see, of course, all over the world today.
19:49
In short, when we're thinking like academics,
19:52
we regard people as elaborate and complicated machines,
19:55
like computers or cars, but when we revert to being human
19:58
we behave more like Basil Fawlty, who, we remember,
20:03
thrashed his car to teach it a lesson when it wouldn't start
20:06
on gourmet night. (Laughter)
20:09
The reason we personify things like cars and computers
20:13
is that just as monkeys live in an arboreal world
20:16
and moles live in an underground world
20:19
and water striders live in a surface tension-dominated flatland,
20:22
we live in a social world. We swim through a sea of people --
20:26
a social version of Middle World.
20:30
We are evolved to second-guess the behavior of others
20:34
by becoming brilliant, intuitive psychologists.
20:37
Treating people as machines
20:41
may be scientifically and philosophically accurate,
20:43
but it's a cumbersome waste of time
20:47
if you want to guess what this person is going to do next.
20:48
The economically useful way to model a person
20:52
is to treat him as a purposeful, goal-seeking agent
20:55
with pleasures and pains, desires and intentions,
20:58
guilt, blame-worthiness.
21:01
Personification and the imputing of intentional purpose
21:03
is such a brilliantly successful way to model humans,
21:08
it's hardly surprising the same modeling software
21:11
often seizes control when we're trying to think about entities
21:14
for which it's not appropriate, like Basil Fawlty with his car
21:18
or like millions of deluded people with the universe as a whole. (Laughter)
21:21
If the universe is queerer than we can suppose,
21:29
is it just because we've been naturally selected to suppose
21:32
only what we needed to suppose in order to survive
21:35
in the Pleistocene of Africa?
21:38
Or are our brains so versatile and expandable that we can
21:41
train ourselves to break out of the box of our evolution?
21:45
Or, finally, are there some things in the universe so queer
21:50
that no philosophy of beings, however godlike, could dream them?
21:54
Thank you very much.
22:01

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About the Speaker:

Richard Dawkins - Evolutionary biologist
Oxford professor Richard Dawkins has helped steer evolutionary science into the 21st century, and his concept of the "meme" contextualized the spread of ideas in the information age. In recent years, his devastating critique of religion has made him a leading figure in the New Atheism.

Why you should listen

As an evolutionary biologist, Richard Dawkins has broadened our understanding of the genetic origin of our species; as a popular author, he has helped lay readers understand complex scientific concepts. He's best-known for the ideas laid out in his landmark book The Selfish Gene and fleshed out in The Extended Phenotype: the rather radical notion that Darwinian selection happens not at the level of the individual, but at the level of our DNA. The implication: We evolved for only one purpose — to serve our genes.

Of perhaps equal importance is Dawkins' concept of the meme, which he defines as a self-replicating unit of culture -- an idea, a chain letter, a catchy tune, an urban legend -- which is passed person-to-person, its longevity based on its ability to lodge in the brain and inspire transmission to others. Introduced in The Selfish Gene in 1976, the concept of memes has itself proven highly contagious, inspiring countless accounts and explanations of idea propagation in the information age.

In recent years, Dawkins has become outspoken in his atheism, coining the word "bright" (as an alternate to atheist), and encouraging fellow non-believers to stand up and be identified. His controversial, confrontational 2002 TED talk was a seminal moment for the New Atheism, as was the publication of his 2006 book, The God Delusion, a bestselling critique of religion that championed atheism and promoted scientific principles over creationism and intelligent design.

More profile about the speaker
Richard Dawkins | Speaker | TED.com