The GOD Delusion (55 page)

The
evolution of complex life, indeed its very existence in a universe
obeying physical laws, is wonderfully surprising - or would be but for
the fact that surprise is an emotion that can exist only in a brain
which is the product of that very surprising process. There is an
anthropic sense, then, in which our existence should not be surprising.
I'd like to think that I speak for my fellow humans in insisting,
nevertheless, that it is desperately surprising.

Think
about it. On one planet, and possibly only one planet in the entire
universe, molecules that would normally make nothing more
complicated than a chunk of rock, gather themselves together into
chunks of rock-sized matter of such staggering complexity that they are
capable of running, jumping, swimming, flying, seeing, hearing,
capturing and eating other such animated chunks of complexity; capable
in some cases of thinking and feeling, and falling in love with yet
other chunks of complex matter. We now understand essentially how the
trick is done, but only since 1859. Before 1859 it would have seemed
very very odd indeed. Now, thanks to Darwin, it is merely very odd.
Darwin seized the window of the burka and wrenched it open, letting in
a flood of understanding whose dazzling novelty, and power to uplift
the human spirit, perhaps had no precedent - unless it was the
Copernican realization that the Earth was not the centre of the
universe.

'Tell
me,' the great twentieth-century philosopher Ludwig Wittgenstein once
asked a friend, 'why do people always say it was natural for man to
assume that the sun went round the Earth rather than that the Earth was
rotating?' His friend replied, 'Well, obviously because it just
looks
as though the Sun is going round the Earth.' Wittgenstein
responded, 'Well, what would it have looked like if it had looked as
though the Earth was rotating?' I sometimes quote this remark of
Wittgenstein in lectures, expecting the audience to laugh. Instead,
they seem stunned into silence.

In
the limited world in which our brains evolved, small objects are more
likely to move than large ones, which are seen as the background to
movement. As the world rotates, objects that seem large because they
are near - mountains, trees and buildings, the ground itself - all move
in exact synchrony with each other and with the observer, relative to
heavenly bodies such as the sun and stars. Our evolved brains project
an illusion of movement onto them rather than the mountains and trees
in the foreground.

I
now want to pursue the point mentioned above, that the way we see the
world, and the reason why we find some things intuitively easy to grasp
and others hard, is that
our brains are themselves evolved
organs:
on-board computers, evolved to help us survive in a
world - I shall use the name Middle World - where the objects that
mattered to our survival were neither very large nor very small; a
world where things either stood still or moved slowly compared with the
speed of light; and where the very improbable could
safely be treated as impossible. Our mental burka window is narrow
because it didn't
need
to be any wider in order to
assist our ancestors to survive.

Science
has taught us, against all evolved intuition, that apparently solid
things like crystals and rocks are really composed almost entirely of
empty space. The familiar illustration represents the nucleus of an
atom as a fly in the middle of a sports stadium. The next atom is right
outside the stadium. The hardest, solidest, densest rock, then, is
'really' almost entirely empty space, broken only by tiny particles so
far apart that they shouldn't count. So why do rocks look and feel
solid and hard and impenetrable?

I
won't try to imagine how Wittgenstein might have answered that
question. But, as an evolutionary biologist, I would answer it like
this. Our brains have evolved to help our bodies find their way around
the world on the scale at which those bodies operate. We never evolved
to navigate the world of atoms. If we had, our brains probably
would
perceive rocks as full of empty space. Rocks feel hard and
impenetrable to our hands because our hands can't penetrate them. The
reason they can't penetrate them is unconnected with the sizes and
separations of the particles that constitute matter. Instead, it has to
do with the force fields that are associated with those widely spaced
particles in 'solid' matter. It is useful for our brains to
construct
notions like solidity and impenetrability, because such
notions help us to navigate our bodies through a world in which objects
- which we call solid - cannot occupy the same space as each other.

A
little comic relief at this point - from
The Men who Stare at
Goats
by Jon Ronson:

This
is a true story. It is the summer of 1983. Major General Albert
Stubblebine III is sitting behind his desk in Arlington, Virginia, and
he is staring at his wall, upon which hang his numerous military
awards. They detail a long and distinguished career. He is the United
States Army's chief of intelligence, with sixteen thousand soldiers
under his command ... He looks past his awards to the wall itself.
There is something he feels he must do even though the thought of it
frightens him. He thinks about the choice he has to make. He can stay
in his office or he can
go into the next office. That is his choice. And he has made it. He is
going into the next office . . . He stands up, moves out from behind
his desk, and begins to walk. I mean, he thinks, what is the atom
mostly made up of anyway? Space! He quickens his pace. What am I mostly
made of? He thinks. Atoms! He is almost at a jog now. What is the wall
mostly made up of? He thinks. Atoms! All I have to do is merge the
spaces. . . . Then General Stubblebine bangs his nose hard on the wall
of his office. Damn, he thinks. General Stubblebine is confounded by
his continual failure to walk through his wall. What's wrong with him
that he can't do it? Maybe there is simply too much in his in-tray for
him to give it the requisite level of concentration. There is no doubt
in his mind that the ability to pass through objects will one day be a
common tool in the intelligence-gathering arsenal. And when that
happens, well, is it too naive to believe it would herald the dawning
of a world without war? Who would want to screw around with an army
that could do
that?

General
Stubblebine is appropriately described as an 'out of the box thinker'
on the website of the organization which, in retirement, he now runs
with his wife.

Having
evolved in Middle World, we find it intuitively easy to grasp ideas
like: 'When a major general moves, at the sort of medium velocity at
which major generals and other Middle World objects do move, and hits
another solid Middle World object like a wall, his progress is
painfully arrested.' Our brains are not equipped to imagine what it
would be like to be a neutrino passing through a wall, in the vast
interstices of which that wall 'really' consists. Nor can our
understanding cope with what happens when things move at close to the
speed of light.

Unaided
human intuition, evolved and schooled in Middle World, even finds it
hard to believe Galileo when he tells us that a cannon ball and a
feather, given no air friction, would hit the ground at the same
instant when dropped from a leaning tower. That is because, in Middle
World, air friction is always there. If we had evolved in a vacuum, we
would
expect
a feather and a cannonball to hit the
ground simultaneously. We are evolved denizens of Middle World, and
that limits what we are capable of imagining. The narrow window of our
burka permits us, unless we are especially gifted or peculiarly well
educated, to see only Middle World.

There
is a sense in which we animals have to survive not just in Middle World
but in the micro-world of atoms and electrons too. The very nerve
impulses with which we do our thinking and our imagining depend upon
activities in Micro World. But no action that our wild ancestors ever
had to perform, no decision that they ever had to take, would have been
assisted by an understanding of Micro World. If we were bacteria,
constantly buffeted by thermal movements of molecules, it would be
different. But we Middle Worlders are too cumbersomely massive to
notice Brownian motion. Similarly, our lives are dominated by gravity
but are almost oblivious to the delicate force of surface tension. A
small insect would reverse that priority and would find surface tension
anything but delicate.

Steve
Grand, in
Creation: Life and How to Make It,
is
almost scathing about our preoccupation with matter itself. We have
this tendency to think that only solid, material 'things' are 'really'
things at all. 'Waves' of electromagnetic fluctuation in a vacuum seem
'unreal'. Victorians thought that waves had to be waves 'in' some
material medium. No such medium was known, so they invented one and
named it the luminiferous ether. But we find 'real' matter comfortable
to our understanding only because our ancestors evolved to survive in
Middle World, where matter is a useful construct.

On
the other hand, even we Middle Worlders can see that a whirlpool is a
'thing' with something like the reality of a rock, even though the
matter in the whirlpool is constantly changing. In a desert plain in
Tanzania, in the shadow of 01 Donyo Lengai, sacred volcano of the
Masai, there is a large dune made of ash from an eruption in 1969. It
is carved into shape by the wind. But the beautiful thing is that it
moves
bodily. It is what is technically known as a barchan
(pronounced bahkahn). The entire dune walks across the desert in a
westerly direction at a speed of about 17 metres per year. It retains
its crescent shape and creeps along in the direction of the horns. The
wind blows sand up the shallower slope. Then, as each sand grain hits
the top of the ridge, it cascades down the steeper slope on the inside
of the crescent.

Actually,
even a barchan is more of a 'thing' than a wave. A wave
seems
to move horizontally across the open sea, but the molecules
of water move vertically. Similarly, sound waves may travel from
speaker to listener, but molecules of air don't: that would be a wind,
not a sound. Steve Grand points out that you and I are more like waves
than permanent 'things'. He invites his reader to think . . .

...
of an experience from your childhood. Something you remember clearly,
something you can see, feel, maybe even smell, as if you were really
there. After all, you really were there at the time, weren't you? How
else would you remember it? But here is the bombshell: you
weren't
there. Not a single atom that is in your body today was there
when that event took place . . . Matter flows from place to place and
momentarily comes together to be you. Whatever you are, therefore, you
are not the stuff of which you are made. If that doesn't make the hair
stand up on the back of your neck, read it again until it does, because
it is important.

'Really'
isn't a word we should use with simple confidence. If a neutrino had a
brain which had evolved in neutrino-sized ancestors, it would say that
rocks 'really' do consist mostly of empty space. We have brains that
evolved in medium-sized ancestors, who couldn't walk through rocks, so
our 'really' is a 'really' in which rocks are solid. 'Really', for an
animal, is whatever its brain needs it to be, in order to assist its
survival. And because different species live in such different worlds,
there will be a troubling variety of 'reallys'.

What
we see of the real world is not the unvarnished real world but a
model
of the real world, regulated and adjusted by sense data - a
model that is constructed so that it is useful for dealing with the
real world. The nature of that model depends on the kind of animal we
are. A flying animal needs a different kind of world model from a
walking, a climbing or a swimming animal. Predators need a different
kind of model from prey, even though their worlds necessarily overlap.
A monkey's brain must have software capable of
simulating a three-dimensional maze of branches and trunks. A water
boatman's brain doesn't need 3D software, since it lives on the surface
of the pond in an Edwin Abbott Flatland. A mole's software for
constructing models of the world will be customized for underground
use. A naked mole rat probably has world-representing software similar
to a mole's. But a squirrel, although it is a rodent like the mole rat,
probably has world-rendering software much more like a monkey's.

I've
speculated, in
The Blind Watchmaker
and elsewhere,
that bats may 'see' colour with their ears. The world-model that a bat
needs, in order to navigate through three dimensions catching insects,
must surely be similar to the model that a swallow needs in order to
perform much the same task. The fact that the bat uses echoes to update
the variables in its model, while the swallow uses light, is
incidental. Bats, I suggest, use perceived hues such as 'red' and
'blue' as internal labels for some useful aspect of echoes, perhaps the
acoustic texture of surfaces; just as swallows use the same perceived
hues to label long and short wavelengths of light. The point is that
the nature of the model is governed by how it is to be
used
rather
than by the sensory modality involved. The lesson of the bats is this.
The general form of the mind model - as opposed to the variables that
are constantly being inputted by sensory nerves - is an adaptation to
the animal's way of life, no less than its wings, legs and tail are.

J.
B. S. Haldane, in the article on 'possible worlds' that I quoted above,
had something relevant to say about animals whose world is dominated by
smell. He noted that dogs can distinguish two very similar volatile
fatty acids - caprylic acid and caproic acid - each diluted to one part
in a million. The only difference is that caprylic acid's main
molecular chain is two carbon atoms longer than the main chain of
caproic acid. A dog, Haldane guesses, would probably be able to place
the acids 'in the order of their molecular weights by their smells,
just as a man could place a number of piano wires in the order of their
lengths by means of their notes'.