by Richard Dawkins
The following article is from Free Inquiry magazine,
Volume 18, Number 3.
Much of what people do is done in the name of God. Irishmen
blow each other up in his name. Arabs blow themselves up in his name. Imams
and ayatollahs oppress women in his name. Celibate popes and priests mess
up people's sex lives in his name. Jewish shohets cut live animals' throats
in his name. The achievements of religion in past history - bloody crusades,
torturing inquisitions, mass-murdering conquistadors, culture-destroying
missionaries, legally enforced resistance to each new piece of scientific
truth until the last possible moment - are even more impressive. And what
has it all been in aid of? I believe it is becoming increasingly clear that
the answer is absolutely nothing at all. There is no reason for believing
that any sort of gods exist and quite good reason for believing that they
do not exist and never have. It has all been a gigantic waste of time and
a waste of life. It would be a joke of cosmic proportions if it weren't so
tragic.
Why do people believe in God? For most people the answer is still some version
of the ancient Argument from Design. We look about us at the beauty and intricacy
of the world - at the aerodynamic sweep of a swallow's wing, at the delicacy
of flowers and of the butterflies that fertilize them, through a microscope
at the teeming life in every drop of pond water, through a telescope at the
crown of a giant redwood tree. We reflect on the electronic complexity and
optical perfection of our own eyes that do the looking. If we have any imagination,
these things drive us to a sense of awe and reverence. Moreover, we cannot
fail to be struck by the obvious resemblance of living organs to the carefully
planned designs of human engineers. The argument was most famously expressed
in the watchmaker analogy of the eighteenth-century priest William Paley.
Even if you didn't know what a watch was, the obviously designed character
of its cogs and springs and of how they mesh together for a purpose would
force you to conclude "that the watch must have had a maker: that there must
have existed, at some time, and at some place or other, an artificer or artificers,
who formed it for the purpose which we find it actually to answer; who comprehended
its construction, and designed its use." If this is true of a comparatively
simple watch, how much the more so is it true of the eye, ear, kidney, elbow
joint, brain? These beautiful, complex, intricate, and obviously purpose-built
structures must have had their own designer, their own watchmaker - God.
So ran Paley's argument, and it is an argument that nearly all thoughtful
and sensitive people discover for themselves at some stage in their childhood.
Throughout most of history it must have seemed utterly convincing, self-evidently
true. And yet, as the result of one of the most astonishing intellectual
revolutions in history, we now know that it is wrong, or at least superfluous.
We now know that the order and apparent purposefulness of the living world
has come about through an entirely different process, a process that works
without the need for any designer and one that is a consequence of basically
very simple laws of physics. This is the process of evolution by natural
selection, discovered by Charles Darwin and, independently, by Alfred Russel
Wallace.
What do all objects that look as if they must have had a designer have in
common? The answer is statistical improbability. If we find a transparent
pebble washed into the shape of a crude lens by the sea, we do not conclude
that it must have been designed by an optician: the unaided laws of physics
are capable of achieving this result; it is not too improbable to have just
"happened." But if we find an elaborate compound lens, carefully corrected
against spherical and chromatic aberration, coated against glare, and with
"Carl Zeiss" engraved on the rim, we know that it could not have just happened
by chance. If you take all the atoms of such a compound lens and throw them
together at random under the jostling influence of the ordinary laws of physics
in nature, it is theoretically possible that, by sheer luck, the atoms would
just happen to fall into the pattern of a Zeiss compound lens, and even that
the atoms round the rim should happen to fall in such a way that the name
Carl Zeiss is etched out. But the number of other ways in which the atoms
could, with equal likelihood, have fallen, is so hugely, vastly, immeasurably
greater that we can completely discount the chance hypothesis. Chance is
out of the question as an explanation.
This is not a circular argument, by the way. It might seem to be circular
because, it could be said, any particular arrangement of atoms is, with hindsight,
very improbable. As has been said before, when a ball lands on a particular
blade of grass on the golf course, it would be foolish to exclaim: "Out of
all the billions of blades of grass that it could have fallen on, the ball
actually fell on this one. How amazingly, miraculously improbable!" The fallacy
here, of course, is that the ball had to land somewhere. We can only stand
amazed at the improbability of the actual event if we specify it a priori:
for example, if a blindfolded man spins himself round on the tee, hits the
ball at random, and achieves a hole in one. That would be truly amazing,
because the target destination of the ball is specified in advance.
Of all the trillions of different ways of putting together the atoms of a
telescope, only a minority would actually work in some useful way. Only a
tiny minority would have Carl Zeiss engraved on them, or, indeed, any recognizable
words of any human language. The same goes for the parts of a watch: of all
the billions of possible ways of putting them together, only a tiny minority
will tell the time or do anything useful. And of course the same goes, a
fortiori, for the parts of a living body. Of all the trillions of trillions
of ways of putting together the parts of a body, only an infinitesimal minority
would live, seek food, eat, and reproduce. True, there are many different
ways of being alive - at least ten million different ways if we count the
number of distinct species alive today - but, however many ways there may
be of being alive, it is certain that there are vastly more ways of being
dead!
We can safely conclude that living bodies are billions of times too complicated
- too statistically improbable - to have come into being by sheer chance.
How, then, did they come into being? The answer is that chance enters into
the story, but not a single, monolithic act of chance. Instead, a whole series
of tiny chance steps, each one small enough to be a believable product of
its predecessor, occurred one after the other in sequence. These small steps
of chance are caused by genetic mutations, random changes - mistakes really
- in the genetic material. They give rise to changes in the existing bodily
structure. Most of these changes are deleterious and lead to death. A minority
of them turn out to be slight improvements, leading to increased survival
and reproduction. By this process of natural selection, those random changes
that turn out to be beneficial eventually spread through the species and
become the norm. The stage is now set for the next small change in the evolutionary
process. After, say, a thousand of these small changes in series, each change
providing the basis for the next, the end result has become, by a process
of accumulation, far too complex to have come about in a single act of chance.
For instance, it is theoretically possible for an eye to spring into being,
in a single lucky step, from nothing: from bare skin, let's say. It is theoretically
possible in the sense that a recipe could be written out in the form of a
large number of mutations. If all these mutations happened simultaneously,
a complete eye could, indeed, spring from nothing. But although it is theoretically
possible, it is in practice inconceivable. The quantity of luck involved
is much too large. The "correct" recipe involves changes in a huge number
of genes simultaneously. The correct recipe is one particular combination
of changes out of trillions of equally probable combinations of chances.
We can certainly rule out such a miraculous coincidence. But it is perfectly
plausible that the modern eye could have sprung from something almost the
same as the modern eye but not quite: a very slightly less elaborate eye.
By the same argument, this slightly less elaborate eye sprang from a slightly
less elaborate eye still, and so on. If you assume a sufficiently large number
of sufficiently small differences between each evolutionary stage and its
predecessor, you are bound to be able to derive a full, complex, working
eye from bare skin. How many intermediate stages are we allowed to postulate?
That depends on how much time we have to play with. Has there been enough
time for eyes to evolve by little steps from nothing?
The fossils tell us that life has been evolving on Earth for more than 3,000
million years. It is almost impossible for the human mind to grasp such an
immensity of time. We, naturally and mercifully, tend to see our own expected
lifetime as a fairly long time, but we can't expect to live even one century.
It is 2,000 years since Jesus lived, a time span long enough to blur the
distinction between history and myth. Can you imagine a million such periods
laid end to end? Suppose we wanted to write the whole history on a single
long scroll. If we crammed all of Common Era history into one metre of scroll,
how long would the pre-Common Era part of the scroll, back to the start of
evolution, be? The answer is that the pre-Common Era part of the scroll would
stretch from Milan to Moscow. Think of the implications of this for the quantity
of evolutionary change that can be accommodated. All the domestic breeds
of dogs - Pekingeses, poodles, spaniels, Saint Bernards, and Chihuahuas -
have come from wolves in a time span measured in hundreds or at the most
thousands of years: no more than two meters along the road from Milan to
Moscow. Think of the quantity of change involved in going from a wolf to
a Pekingese; now multiply that quantity of change by a million. When you
look at it like that, it becomes easy to believe that an eye could have evolved
from no eye by small degrees.
It remains necessary to satisfy ourselves that every one of the intermediates
on the evolutionary route, say from bare skin to a modern eye, would have
been favored by natural selection; would have been an improvement over its
predecessor in the sequence or at least would have survived. It is no good
proving to ourselves that there is theoretically a chain of almost perceptibly
different intermediates leading to an eye if many of those intermediates
would have died. It is sometimes argued that the parts of an eye have to
be all there together or the eye won't work at all. Half an eye, the argument
runs, is no better than no eye at all. You can't fly with half a wing; you
can't hear with half an ear. Therefore there can't have been a series of
step-by-step intermediates leading up to a modern eye, wing, or ear.
This type of argument is so naive that one can only wonder at the subconscious
motives for wanting to believe it. It is obviously not true that half an
eye is useless. Cataract sufferers who have had their lenses surgically removed
cannot see very well without glasses, but they are still much better off
than people with no eyes at all. Without a lens you can't focus a detailed
image, but you can avoid bumping into obstacles and you could detect the
looming shadow of a predator.
As for the argument that you can't fly with only half a wing, it is disproved
by large numbers of very successful gliding animals, including mammals of
many different kinds, lizards, frogs, snakes, and squids. Many different
kinds of tree-dwelling animals have flaps of skin between their joints that
really are fractional wings. If you fall out of a tree, any skin flap or
flattening of the body that increases your surface area can save your life.
And, however small or large your flaps may be, there must always be a critical
height such that, if you fall from a tree of that height, your life would
have been saved by just a little bit more surface area. Then, when your descendants
have evolved that extra surface area, their lives would be saved by just
a bit more still if they fell from trees of a slightly greater height. And
so on by insensibly graded steps until, hundreds of generations later, we
arrive at full wings.
Eyes and wings cannot spring into existence in a single step. That would
be like having the almost infinite luck to hit upon the combination number
that opens a large bank vault. But if you spun the dials of the lock at random,
and every time you got a little bit closer to the lucky number the vault
door creaked open another chink, you would soon have the door open! Essentially,
that is the secret of how evolution by natural selection achieves what once
seemed impossible. Things that cannot plausibly be derived from very different
predecessors can plausibly be derived from only slightly different predecessors.
Provided only that there is a sufficiently long series of such slightly different
predecessors, you can derive anything from anything else.
Evolution, then, is theoretically capable of doing the job that, once upon
a time, seemed to be the prerogative of God. But is there any evidence that
evolution actually has happened? The answer is yes; the evidence is overwhelming.
Millions of fossils are found in exactly the places and at exactly the depths
that we should expect if evolution had happened. Not a single fossil has
ever been found in any place where the evolution theory would not have expected
it, although this could very easily have happened: a fossil mammal in rocks
so old that fishes have not yet arrived, for instance, would be enough to
disprove the evolution theory.
The patterns of distribution of living animals and plants on the continents
and islands of the world is exactly what would be expected if they had evolved
from common ancestors by slow, gradual degrees. The patterns of resemblance
among animals and plants is exactly what we should expect if some were close
cousins, and others more distant cousins to each other. The fact that the
genetic code is the same in all living creatures overwhelmingly suggests
that all are descended from one single ancestor. The evidence for evolution
is so compelling that the only way to save the creation theory is to assume
that God deliberately planted enormous quantities of evidence to make it
look as if evolution had happened. In other words, the fossils, the geographical
distribution of animals, and so on, are all one gigantic confidence trick.
Does anybody want to worship a God capable of such trickery? It is surely
far more reverent, as well as more scientifically sensible, to take the evidence
at face value. All living creatures are cousins of one another, descended
from one remote ancestor that lived more than 3,000 million years ago.
The Argument from Design, then, has been destroyed as a reason for believing
in a God. Are there any other arguments? Some people believe in God because
of what appears to them to be an inner revelation. Such revelations are not
always edifying but they undoubtedly feel real to the individual concerned.
Many inhabitants of lunatic asylums have an unshakable inner faith that they
are Napoleon or, indeed, God himself. There is no doubting the power of such
convictions for those that have them, but this is no reason for the rest
of us to believe them. Indeed, since such beliefs are mutually contradictory,
we can't believe them all.
There is a little more that needs to be said. Evolution by natural selection
explains a lot, but it couldn't start from nothing. It couldn't have started
until there was some kind of rudimentary reproduction and heredity. Modern
heredity is based on the DNA code, which is itself too complicated to have
sprung spontaneously into being by a single act of chance. This seems to
mean that there must have been some earlier hereditary system, now disappeared,
which was simple enough to have arisen by chance and the laws of chemistry
and which provided the medium in which a primitive form of cumulative natural
selection could get started. DNA was a later product of this earlier cumulative
selection. Before this original kind of natural selection, there was a period
when complex chemical compounds were built up from simpler ones and before
that a period when the chemical elements were built up from simpler elements,
following the well-understood laws of physics. Before that, everything was
ultimately built up from pure hydrogen in the immediate aftermath of the
big bang, which initiated the universe.
There is a temptation to argue that, although God may not be needed to explain
the evolution of complex order once the universe, with its fundamental laws
of physics, had begun, we do need a God to explain the origin of all things.
This idea doesn't leave God with very much to do: just set off the big bang,
then sit back and wait for everything to happen. The physical chemist Peter
Atkins, in his beautifully written book The Creation, postulates a lazy God
who strove to do as little as possible in order to initiate everything. Atkins
explains how each step in the history of the universe followed, by simple
physical law, from its predecessor. He thus pares down the amount of work
that the lazy creator would need to do and eventually concludes that he would
in fact have needed to do nothing at all!
The details of the early phase of the universe belong to the realm of physics,
whereas I am a biologist, more concerned with the later phases of the evolution
of complexity. For me, the important point is that, even if the physicist
needs to postulate an irreducible minimum that had to be present in the beginning,
in order for the universe to get started, that irreducible minimum is certainly
extremely simple. By definition, explanations that build on simple premises
are more plausible and more satisfying than explanations that have to postulate
complex and statistically improbable beginnings. And you can't get much more
complex than an Almighty God!
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Richard Dawkins is Oxford's Professor of Public Understanding of Science.
He is the author of The Blind Watchmaker (on which this article is partly
based) and Climbing Mount Improbable. He is a Senior Editor of Free Inquiry.
Christine
DeBlase-Ballstadt
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