The human race is one of the wonders of the
universe.
We may be unique and of all our remarkable
properties one stands out.
It is that we are restlessly drawn to ask
questions like why are here. What is the purpose of life.
The great civilizations and cultures of the
past came up with various answers, all unsatisfying
because they were made up rather than being
properly investigated.
So, can science come up with something better?
I think so.
It may sound presumptuous, but I believe science
can tell us why we are here. Tell us the purpose
of human existence.
The answer is an optimistic and inspiring
one.
For most of the 500 thousand years of human
existence, we were unable to answer the question of why we are here.
It was only a hundred and fifty years ago
that science first tried to find an answer.
In 1859 Charles Darwin published a book that
changed the world!
When Darwin first got up the courage to publish
the 'Origin Of Species' it shocked the spiritual
foundations of his age.
Victorians had to come to terms with an entirely
new set of unwelcome relations.
We got over it now. Most of us are happy to
teach our children that we descended from
apes. We are apes.
But I believe Darwin has another message for
us. One that could be frightening if we let
ourselves be intimidated but exciting and
uplifting if we have the courage to face it.
Not only did Darwin provide the answer to
the question- how we came to exit, I believe
his theory provides the only answer we are
ever likely to get to the ultimate question-Why
we exist.
What is the purpose of life. There are some
10 million species on earth. The displays
here at the natural history museum in oxford
represent only a tiny fraction of them. But
before Darwin, no one knew how animals came
to be so varied or so complex.
Every last detail of every creature's body and behavior
seems explicitly tailored to its environment.
The Platypus's webbed feet are built for efficient
paddling and its dark bill is a radar, electrically
sensing its pray in the mud. As for the Cheetah,
its sleek and nimble body is a formidable
machine for catching prey. For centuries,
people tried to understand why animals were
so perfectly equipped for their tasks. They
assumed that there was only one explanation.
That the natural world was designed and the
designer was god.
The reverend William Paley, writing half a century before Darwin put the
case with his famous -Watchmaker Argument.
Imagine, Palay said, taking a walk on a heath.
If you came across a rock, you wouldn't be surprised.
The rock might have lain there
forever. It doesn't need explaining. But a
watch on the heath would demand an explanation.
Its existence and complexity would require
a big explanation. The intricate precision
of the cogs, the accuracy with which it keeps
time, these are the evidence that the watch
must have a designer. A watchmaker. Surely,
Paley went on, no less is required to explain
the even greater complexities of nature. There
must be a divine watchmaker. If I had read
Paley in 1802, I would have agreed with him.
But now things are very different. Charles
Darwin has given us a much neater, more self-sufficient
and therefore more satisfying explanation.
Darwin argued that there was no designer.
At the first sight this seems like a ridiculous
idea. Like Paley's watch, plants and animals
appear to be staggeringly improbable combinations
of their component parts, all working towards
one end. Take the nuts, bolts, cogs and springs
of a watch and recombine them at random as
many times as you like. Only one arrangement
tells the time.
As the astronomer Fred Hoyle put it, the possibility that the parts of
a living organism would spontaneously come
together by sheer luck, is about as likely
as a hurricane blowing through a scrapyard
spontaneously assembling a Boeing 747.
So,
how does nature do it? Even a fly is arguably more complex than a 747. If there is no designer,
how did the complexity and variety of life come about?
There's a clue to how the process
works in many people's back gardens.
There aren't many times when the pigeon has played
a starring role in science, but it was this
common place bird, that started Darwin on
his journey of discovery. Darwin noticed that
the pigeon fanciers were able to breed new
varieties. By carefully selecting mates, they
had turned the ordinary pigeon into dozens
of weird looking birds with weird sounding
names. There were fantails, Jacobins, Short-faced
tumblers and a score of other varieties.
Darwin knew these all originated from one bird, the
rock dove. And the pigeon breeder, Pat Pratt,
can demonstrate that Darwin was right.
If fancy pigeons are allowed to breed as they like without any intervention at all from
us, then in no time at all they will revert
to this wild type. Usually the first or second
crosses from our fancy pigeons will show some
return to the drab blue coloring of the rock
dove.
The effort to create different types is called artificial selection. Perhaps, Darwin
reasoned, a similar process could occur in
the wild. But how could selection work in
nature without a divine pigeon breeder to do the work.
The work of natural selection
is classically illustrated by the finches
Darwin found on the Galapagos islands. There
are some 13 species all with different beaks.
Yet these varieties all evolved from one ancestral
species which arrived from the main land with
one type of beak. One now behaves like a wood
pecker using a cactus spin to hunt for grubs.
Another now feeds on tics living on giant
tortoises.While the third, the vampire finch
feeds on the blood of sea birds. These are
all activities requiring different types of
beak. Natural selection is about survival.
The beaks changed because the change is hope
the finch is to survive, and there wasn't
a designer insight. When Darwin first explained
evolution by natural selection many people
either wouldn't or couldn't grasp it. I myself
flatly refused to believe it when I first
heard it as a child. For Darwin's theory to
succeed it had to explain both the wonderful
variety of nature and its astonishing complexity.
It does both. With the at most elegance.My
colleague George McGavin has devised an experiment
to show how natural selection works in practice.
It explains how insects acquire their camouflage.
They do it tiny bit by tiny bit. What we got
here is an artificial wooden floor on which
I have placed a variety of insects. Some of
the insects are very easy to see. Some of
the insects are not so easy to see and a few
of them are extremely hard to see. Ok. What
I want you to do is to pretend you are in
a woodland. Ok? And its sort of darkish. OK?
And you are hungry birds and you are hunting
for insects to eat. If you see anything which
you might want to eat you can say- I can see
an insect. Right. Who can see an insect? Me!
How many can you see? 4..er..3..2.. 3? 2?
I cant see any! The children play the role
of predators. They show that even a little
camouflage gives an insect some advantage,
so long its predators don't get too close.
How about that one there? I saw that! Whats
that? Caterpillar. No one spotted that one!
If you are obvious, your chances of being
eaten are very high. And therefore, over time,
small changes which make you not so obvious
will be selected and will be passed on. And
so, at the end of thousands of years of evolution
the end result will be or ought to be an insect
which is extremely well hidden in its background.
The success of those hidden insects show us
how natural selection rewards even tiny changes.
The process of natural selection explains
how simple structures over millions of years
eventually evolved into complex astonishing
creatures, like the dinosaurs or us. But natural
selection is not some kind of award ceremony
where nature applauds interesting new genetic
mutations. Its not nature's fashion show.
Its a competition to the death. Each individual
within every species, competes in the harsh,
even blood thirsty real world, for access
to resources and even opportunities to reproduce.
Natural selection is all about living long
enough to pass on your genes. Darwin realized
that wild animals compete to survive. More
are born than the food supply can sustain.
Inevitably many die young or otherwise fail
to reproduce. Amidst this widespread slaughter,
every animal fights a relentless battle for survival.
In the natural struggle for existence,
some variants were better at surviving than
others. And they, pass their good qualities
on to the future. Natural selection, explains
how we got to where we are now. Does it also
suggest to you a dark and troubling answer to
the question- why we are here. Natural selection
suggests, that we, like all other animals,
are survival machines. We are here only to
compete long enough to pass on our genes.
This seems to be the purpose of our lives.
The reason we are here. But can this really
be the only purpose of human existence? I
don't think so. Darwin's remarkable theory
offers a second meaning of the word 'purpose'.
Its an inspiring one which accords more fully
with our own view of our better selves. It
stems from the curious observation that we
humans appears to be breaking Darwin's rules.
Human behavior in the 21st century seems to have nothing to do with the brutal world of
natural selection. Evolution may explain how
humans came into the world. But it doesn't
shed much light on the way we lead our lives
today. Most of our energy goes into projects
that seem to have nothing to do with the goals
of survival or reproduction. We neither feel
nor act as though we are driven by evolutionary
compulsion. We seem to have freed ourselves
from the need to spend all our time propagating
our selfish genes. We have many other goals
that take our time and energy. We explore
the world around us. Create objects for their
aesthetic beauty. Pursue hobbies for the sake of fun.
And when we have sex, we defy our
genes with contraception. If only they could
think, our genes would be aghast at all these.
I personally am delighted that our big brains
gave us the freedom to defy our selfish genes.
The unrefined world of natural selection is
not the sort of world I want to live in. The
beauty and purposeful elegance of living creatures
like Cheetahs and Ghazals is bought at huge
cost in the blood and suffering of countless
ancestors on both sides. But if the ultimate
purpose of our existence is the narrowly Darwinian
one of propagating our genes, how can we defy
them? Ironically enough the things that freed
us from our genes are also the result of natural
selection and it all began millions of years ago in Africa...
At the time, humans were
still prey. Surrounded by predators, we evolved survival tools
. And the most important of
these was the brain. Natural selection drove
the development of the human brain. It did
so with no more purpose than it drove the
development of the tail of a peacock or the
speed of a cheetah. A genetic advantage was
rewarded and our brains got bigger. They dint
just get bigger, they became different. We
evolved the ability to do something no other
animal could do. Set goals. Find a new water hole.
Plan a hunt. Set aside food for the
winter. And we learned to adapt, change our goals.
What natural selection built into us
in Africa was the capacity to seek. To strive.
To setup short term goals, in the service
of long term goals, eventually a capacity
for foresight. Bigger brains allowed individual
ancestors to compete more effectively and
then something unprecedented happened. A brain
arose which was able to look around the world
and ask perhaps for the very first time the
question- 'Why?' Why are we here.
We were no longer content to do what nature told us.
We had begun to think about other goals that
suited us. And we had a tool to express those
goals- Language. Speech lets us share goals.
And the creature able to communicate its goals
begins to think purposefully. Act Purposefully.
Create purposefully. And even more amazing,
through language our goals can take on a life beyond any one individual.
One inventor introduced
the wheel. Using language, generations of
inventors sharing the goal of fast travel
had produced the modern car. Technology is
human goal seeking writ large. And once human
beings set themselves to a goal, they force
the pace of evolution themselves. This is
an entirely new kind of evolution. Non genetic
evolution. Advancing at a speed that maybe
a million times faster than the genetic evolution which it resemble.
We see its products everywhere-
In the technology of the modern world. We
have created a technological world that enables
us to move far beyond the dictates of nature.
And it allows us to do astonishing things.
we alleviate hunger with new strains of crops.
Predict the weather with high speed computers
and cure diseases with pharmaceuticals. Through
technology we have filled the world with purposeful
creations. But technology does something else-
it breeds an odd habit of thought. An animal
who invents will look at the world in a different
way from any other animal. We see the world
through purpose colored spectacles.
Because we create things for a purpose, in the past,
we assumed there was purposeful design in
nature too. There wasn't. As it happens, it
took Darwin to realize this. He looked deep
into the heart of nature and discovered a
beautiful mechanism which blindly simulates
the illusion of purpose. For the first time,
an evolved creature had seen beneath nature's
veil, and worked out what nature was really
up to. And its this spirit of inquiry that
drove Darwin that gives our life meaning and
still drives us today, powered by our technical
capacity, our flexible behavior and our rapid
communication of new ideas, we have burst
out beyond the confines of our atmosphere
to explore new worlds.
And our minds have voyaged even further. We have looked across
the deserted vacuum of space to distant galaxies.
Which means we have looked backwards in time
to the very birth of the universe and of time itself.
At the other extreme, we have looked
deep into the atom at the strangeness of sub
atomic particles. And most amazing of all,
we have dissected the living cell, finally
unraveling the digital codes of the genes
themselves and still we are not satisfied.
We reach out in our search for meaning until
we suddenly realize it is we who actually
provide the purpose in a universe which otherwise
would have none. Nothing else can do it. At
least nothing we know of! In a small, or otherwise
unimportant corner of the universe, a birth
is celebrated. The birth of deliberate purpose,
planning,design, foresight. For all we know,
it maybe an unprecedented event. We have no
evidence that it has ever occurred anywhere
else, and after we are gone, it may never
happen again.
We can can leave behind the ruthlessness, the waste, the callousness of
natural selection. Our brains, our language,
our technology make us capable of forward
planning. We can setup new purposes of our
own and among these new goals, can be the
complete understanding of the universe in
which we live. A new kind of purpose is evolved
in the universe. It resides in us.
