“Fearfully and Wonderfully Made:
A Christian Perspective on the Molecular Foundation of Life”
By Michael J. Behe, Ph.D.
Professor of Biochemistry, Lehigh University
Edited transcript
from a lecture given
Saturday,
April 30, 2005, 10:00 a.m.
Grace Valley Christian Center, Davis, California
As part of the
Faith and Reason series
sponsored by
Grace Alive! and Grace Valley Christian Center
King David
Psalm 139:14
says, “I will praise thee; for I am fearfully and wonderfully made: marvellous
are thy works; and that my soul knoweth right well” (KJV). The psalmist was
saying that we are wonderful creations, put together in a marvelous fashion.
But who wrote this? The author of Psalm 139 was King David, who lived about one
thousand years before Jesus Christ. The Jewish people of that time were not
renowned for science; their medical knowledge was rather meager and obscure. As
a matter of fact, the medical knowledge of much of the world was obscure at that
time.
In this
lecture I want to go through our knowledge of what the human body is like, and
how that knowledge has developed, and show that the psalmist clearly had much
more insight than existed generally when he wrote. I first want to clarify that
I am not a pastor and nor a theologian; I am just a biochemist. But, strangely
enough, at this time science and theology seem to have some points of
intersection; we want to talk about those points today.
Hippocrates
Knowledge of how
the human body is put together really did not get started until long after
David’s time. The first person credited with making a small amount of progress
in this area is Hippocrates, often called “the father of medicine,” who lived
about 500 years or more after King David, around 460-370 B.C.
When
Hippocrates was alive, the prominent scientific theory was that four
elements—earth, air, fire, and water—made up all matter. Associated with those
were the four humors: with earth there was black bile; with air there was yellow
bile; with water there was phlegm; with fire there was blood. These ancient
scientists hypothesized that different combinations of the elements gave rise to
“qualities”: for example, fire and earth was dry, earth and water was
cold, water and air was wet, and air and fire was hot.
Clearly, the
“father of medicine” lived in a time that we would consider as exceedingly
primitive scientifically. But Hippocrates took the first steps towards trying to
figure out how the body works and how medicine should be used. He came up with
a number of good ideas. For example, in Hippocrates’ Aphorisms he wrote,
“Art is long and life is short”; “Desperate diseases need desperate remedies”;
“Sleeping too much is as bad as waking too much”; and “One man’s meat is another
man’s poison.” Many of these sayings have the ring of truth about them. But
they are not really science, as we would define it.
Nonetheless,
Hippocrates is considered to be the father of medicine. Why is that? One of the
main reasons is that he wanted to understand how nature worked. Even if he
could not figure out too much, he at least wanted to understand how natural
things worked. For example, in some of his writings, he talked about an illness
called the “sacred disease,” because people who had it were considered to have
run afoul of the gods of ancient Greece and been struck down by them. But
Hippocrates did not think this illness was due to Zeus or Poseidon. He wrote,
“It appears to me nowise more divine nor more sacred than other diseases, but
has a natural cause that originates like other affections. Men regard its
nature and cause as divine from ignorance and wonder, because it is not at all
like to other diseases.” Hippocrates did not think this disease was due to
direct supernatural intervention, and that people should try to understand this
illness as a problem of the workings of the human body.
He went on
to say, “They who first referred this malady to the gods appear to me to have
been just such persons as the conjurers, purificators, mountebanks, and
charlatans now are, who give themselves out for being excessively religious, and
as knowing more than other people. Such persons, then, using the divinity as a
pretext and screen of their own inability to afford any assistance. . . .” In
other words, people who pretended to know the cause of this disease ascribed it
to the pantheon, and then tried to profit from their knowledge. Hippocrates was
saying, “No, we have to understand the disease as it is.”
He went on
to say that these people who purported to be able to cure the disease through
special knowledge were, in fact, relying on physical cures: “But if these
things, when administered in food, aggravate the disease, and if it be cured by
abstinence from them, godhead is not the cause at all; nor will purifications be
of any avail, but it is the food which is beneficial and prejudicial, and the
influence of divinity vanishes.” Again, his point was that some people were
trying to profit from this, but we really should be studying nature as it is. So
although Hippocrates did not make much progress, he was considered the father of
medicine.
Aristotle
Hippocrates
was succeeded by Aristotle (384-322 B.C.); their lives overlapped a few years.
Although he is best known for being one of the great philosophers of Western
thought, Aristotle was also considered the father of biology. He was interested
in a great many things, including the study of life, and took science beyond
what Hippocrates discovered. Aristotle realized that to understand the way the
world worked, one had to study it closely. For example, he wrote the following
observations on the octopus: “The octopus breeds in spring, lying hid for about
two months. The female, after laying her eggs, broods over them. She thus gets
out of condition since she does not go in quest of food during this time. The
eggs are discharged into a hole and are so numerous that they would fill a
vessel much larger than the animal’s body. After about fifty days the eggs
burst. The little creatures creep out and are like little spiders, in great
numbers. The characteristic form of their limbs is not yet visible in detail,
but their general outline is clear. They are so small and helpless that the
greater number perish. They have been so extremely minute as to be completely
without organization, but nevertheless when touched they move.”
Aristotle’s
innovation of closely observing nature and writing down what he saw had not been
done before. That is the first step in explanation. We must observe what is
going on before we can try to understand and explain it. But also notice that,
as closely as he watched, he got some things wrong. He said that the eggs are
“so numerous they would fill a vessel much larger than the animal’s body.” That
would imply that the volume of the eggs was greater than that of the octopus,
which is not possible. Also, he noted that the little octopi are so small that
they are “completely without organization.” To Aristotle, they looked like
little dots or small spiders, so he thought they must be simple little things.
He could not see closely enough to understand how in fact they were organized.
So the first
point I want to make is that one of the important steps in learning about nature
is observation. We have to look at it, and then we have to write down what is
going on. The other point is that sometimes we cannot see what is going on. And
if we can’t see what is going on, we have no hope of making much progress.
Pliny the Elder
A few hundred years
after Aristotle, another scientist named Pliny the Elder observed blood in
animal bodies. He wrote: “The arteries have no sensation, for they even are
without blood, nor do they all contain the breath of life; and when they are cut
only the part of the body concerned is paralyzed. . . . the veins spread
underneath the whole skin, finally ending in very thin threads, and they narrow
down into such an extremely minute size that the blood cannot pass through them,
nor can anything else but the moisture passing out from the blood in innumerable
small drops which is called sweat.”
Pliny was
intelligent, and he tried his best to describe what was going on, but he just
could not see what was going on. Veins go into capillaries, and we cannot see
them with the naked eye because they are too small. Pliny had to more or less
guess at some observations and tried to put together a coherent expression of
what was going on. But because he could not see what was going on, he failed.
Galen
Another person who
tried to describe what was going on with the blood was the physician Galen, a
Greek who lived in Rome. He believed that there were two distinct types of
blood—nutritive blood, thought to be made by the liver and carried through the
veins to the organs, where it was consumed; and vital blood, thought to be made
by the heart. Galen essentially believed that the heart pumped out blood to the
tissues, and the blood “irrigated” the tissues and was consumed. Since the blood
was continually pumped out to irrigate the tissues and was consumed, he thought
blood was continuously produced.
Galen was a
very influential figure, so his ideas on blood and other things were taught to
medical students for a thousand years. So for a thousand years this mistaken
idea about what blood does was held, mostly because Galen had taught it and
Galen could not be wrong.
In the early
Middle Ages, attitudes started to change. The History of Biology by
Charles Singer contains a drawing of the basil plant from a textbook on herbs
written in 1200A.D. In this very stylized drawing, the plant is depicted with
several wolves’ heads coming from the leaves. For quite some time, people imbued
mythical qualities into plants and animals, and drew them, not as they were, but
as idealized types. But then, somewhere around the 1200s, things began to
change. People became more and more interested in drawing plants and animals
exactly as they were. Thus, when we look at a stone carving from a church (circa
1260 A.D.), we see a number of species of plants carved in close representation
to what they look like in nature. For a thousand years, science had lost
Aristotle’s insight that we have to look closely at nature in order to
understand it. But eventually this understanding was recovered, and it was the
precursor of modern science.
William Harvey
Many people
attribute the beginning of modern science to William Harvey, an Englishman who
lived in the early seventeenth century. Harvey revisited the question, thought
to be resolved by Galen, of what happens to blood. He did something very
special, something that had not been done before: he reasoned about the
situation. His reasoning was as follows: Suppose the heart pumps two ounces
per beat. There are seventy-two beats every minute in the average pulse, and
sixty minutes in an hour. Harvey multiplied those all together, and then
reasoned that, since there is one pound per sixteen ounces, the body would be
producing 540 pounds per hour! Clearly, that is not what happens. That would
be triple the weight of a large man. No one can make that much blood; we cannot
eat that much in a day.
This seems
simple to us. Why, then, were people stumped on this question for a thousand
years? Were they not as smart as Harvey was? Think about this: Suppose instead
that William Harvey had been forced to reason this way: There are II
ounces per heart beat, and LXXII beats per minute, and LX minutes
per hour, and I pound per XVI ounces. How many is that? That is a
much tougher question to answer.
The European
world did not have Arabic numerals until the sixteenth century. Up until then,
Roman numerals were used throughout the region, and it is very difficult to
calculate with Roman numerals. In the sixteenth century, modern math notation
came to Europe from the Hindus by way of the Mesopotamian Arabs. Only then did
they get such things as plus (+) and minus (-) signs; only then did they begin
to use positional notation and fractions (3/4 = 0.75) and so on. Before this,
their ability to calculate numerical problems had been severely limited, and
this in turn limited their understanding of what was going on in biology.
After
William Harvey made his calculations and showed how reasonable it was to think
that the blood circulated—deducing that it had to circulate because the blood
simply could not be made at a sufficient rate to keep up with what would be
needed if it was consumed—many others opened their eyes and said, “If we reason
about these other questions, maybe we can make more progress.” So people got
back to observing things, doing so in greater and greater detail than had ever
been done in the past. For example, vivisectionists began to take out veins from
animals and started looking closely at human veins. They noticed little bumps,
which turned out to be valves in the veins. These valves are exactly what one
would expect if the circulatory system were designed to pump blood in only one
direction.
Biologists
started looking in greater detail at all living systems, dissecting animals and
illustrating the lymphatic and circulatory systems. Yet the actual connection
between capillaries and arteries was still not seen. People knew it must be
there, due to Harvey’s calculations, but they could not observe it directly.
Robert Hooke
At this
point, scientific progress had advanced greatly, but scientists were still
stymied, because much of what goes on in biology occurs at a level too small to
be seen with the naked eye. In order to make more progress, a technical advance
needed to be made. That technical advance was the invention of the microscope.
Robert Hooke used the first microscope in 1665. It was extremely crude,
compared with our best microscopes these days, but it was an astounding advance
in Hooke’s day, for it allowed people to see things that they had not been able
to see before. For example, one of the first things that Hooke used the
microscope to look at were feathers. To the naked eye, feathers look like fluffy
little things, but when observed closely, one notices intricate structures of
branches with little barbs sticking out from them. The barbs are wrapped around
the branches sticking out from another part of the feather on the opposite side
and give feathers the strength that they need to fly.
Scientists
also examined insects using microscopes. At the time, insects were thought to be
so simple that they could arise spontaneously from decaying matter. They were
thought to be so simple as to have no internal organs. But when insects were
examined by microscope, incredible details became visible. Details of the
anatomy of bees and wasps and other insects were also studied. Hooke himself,
upon examining a small mite, was astonished to see that the mite had tiny mites
on top of it! Such activities had never before been imagined, and led others to
imagine that there was a progression of infinitely smaller and smaller life
forms who preyed on each other.
This new
knowledge had a profound effect on those who observed it for the first time.
Charles Singer, a historian of science, wrote, “The infinite complexity of
living things thus revealed was as philosophically disturbing as the ordered
majesty of the astronomical world which Galileo had unveiled to the previous
generation, though it took far longer for its implications to sink into men’s
minds.” People did not expect this complexity. They did not know how fearfully
and wonderfully made nature was. They thought that things were simple enough
that what they saw was all there was. It turns out there was much, much more to
life than was commonly thought.
Discovery of the Cell
When
Nehemiah Grew looked at beans with a microscope in the seventeenth century, he
saw many tiny compartments. He did not know what they were, but they reminded
him of the cells where monks lived. So he named these things cells, even
though he did not have the slightest idea what a cell was. As science advanced
and microscopes got better, scientists found these little compartments
everywhere, even though they were not always as regular as Grew observed in the
bean plant.
In the early
nineteenth century, Theodore Schwann and Matthias Schleiden proposed the “cell
theory of life,” claiming that somehow cells are the basis of life. Schleiden
wrote, “The question as to the fundamental power of organized bodies resolves
itself into that of individual cells. Thus the primary question is, what is the
origin of this peculiar little organism, the cell?” Thus, people were beginning
to realize that, as they tunneled down into life, there was a unit called the
cell that somehow had much to do with life.
Further
observations with microscopes showed that the cell was capable of doing many
things, including mitosis and cell division. People started realizing that the
cell was not just a simple glob of jello, as some scientists had though, but
that it had active substructures within it.
Later,
scientists noticed that prokaryotic cells, bacterial cells, had many different
features, such as cell walls and membranes; hair-like things called flagella
sticking out from them; a dense nucleoid; and more little hairs sticking out
from the sides. Animal cells were even more interesting. Each one had a
nucleus, as well as centrioles, endoplasmic reticulum, and all sorts of other
substructures.
Thus, as we
were able to see more and more, studies in biology went further and further down
into life. As scientists could see more, they discovered that life, rather than
the simple thing it looked like on the surface, was very complex.
Friedrich Wöhler
As
biologists were going further and further down into life, chemists were starting
at the bottom and working their way up. A major event linking chemistry with
life occurred in 1828 when a German chemist, Friedrich Wöhler, went into his
laboratory, mixed ammonium and cyanate together, heated it up and produced urea.
When he did this, he was astounded; when he published his results, the
scientific world was astounded.
Why was this
so astonishing? Because ammonium and cyanate are inorganic chemicals not found
in living systems. Yet even then urea was known as a biological waste product.
This was the first demonstration that nonliving chemicals could give rise to a
substance found in life. Until then, scientists thought that living things were
made of some different materials than nonliving things, and that living things
were entirely different from rocks and gases and so on, because they felt and
acted differently. It was a reasonable conclusion. Wöhler’s work showed that we
are made up of the same materials as everything else in the world. This may be
the only chemical reaction with such philosophical implications.
Amino Acids and Proteins
So now
chemists were getting into the act, and in the nineteenth century they
discovered other chemicals called amino acids. All amino acids have a
common structure with N, C, and COO. They just differ in the R1 and R2 side
chains. Some examples are glycine, with an H in the side chain; alanine has CH3;
valine has another side chain, and tryptophan has another. But amino acids have
an interesting chemical property—when we take two of them, heat them up, and
eliminate water from them, they join together into a bigger molecule that is two
amino acids in length.
Chemists
found out that in life there are just twenty different types of amino acids, and
the things they called proteins were actually made from stringing these
amino acids together. It turns out that the proteins of life generally consisted
of one to two hundred or so amino acids strung together in a row in very
specific sequences. So each protein has a specific sequence, just like words
have specific sequences of letters and different sequences spell different
words.
Later,
biochemists discovered that these sequences of amino acids could fold themselves
up into very specific shapes. They do so not by magic, but because some of the
side chains have positive charges, and others have negative ones, and they
attract each other. Other side chains are somewhat oily and band together to
stay out of water. And when they are precisely positioned, the whole chain folds
up into a special shape that gives the protein special powers. Just like the
shape of a wrench or a hammer allows it to do its job, the shapes of proteins
allow them to do their jobs. Some sequences of amino acids fold up into helical
shapes, and the helices then fold over upon themselves to make bow-like
structures. Sometimes a couple of these chains then associate to form larger
aggregates of proteins.
Max Perutz
But what are these proteins, and how do we know
their shape? In the 1950s a new breakthrough in technology allowed us to see the
shapes of these single protein molecules. The first breakthrough was made by
Max Perutz, who solved what is called the x-ray crystal structure of the protein
myoglobin. He made a schematic model of the protein myoglobin showing the
position of all the amino acids. It folds up, forming what is called a heme-group,
something which allows myoglobin to bind oxygen. Myoglobin is a protein that is
in our muscles. It binds oxygen and stores it in muscles so that when we
exercise, oxygen is there to power the burning of food molecules in our muscle
cells to give us energy.
When Max
Perutz solved the structure of myoglobin and beheld it for the very first
time—he was the first person in history to see the shape of one of the basic
constituents of life—he was really disappointed. He later wrote, “Could the
search for ultimate truth really have revealed so hideous and visceral-looking
an object?” Scientists of the time, at each stage, kept thinking that the bottom
must be simple, yet pretty, like a salt crystal or some pleasing shape. When
they saw the ugly structure of myoglobin, they were really disappointed.
It is
interesting that in his quotation he called it “the search for ultimate truth.”
Perutz was looking for ultimate truth about how life worked, and he was
disappointed. Nonetheless, in the past fifty years or so, scientists have grown
accustomed to the way proteins look.
Myoglobin and Hemoglobin
The
structure of myoglobin is similar in many respects to another protein,
hemoglobin. Hemoglobin is found in red blood cells, where it binds oxygen in the
lungs, circulates through the blood to the cells and delivers the oxygen to the
cells, where it can be bound by myoglobin to be available to the muscles when
needed.
The
requirements for picking up oxygen in the lungs and then dropping it off in
peripheral tissues are different than the requirements for a molecule like
myoglobin, which just stores oxygen in the tissue. In other words, the ability
of hemoglobin to bind oxygen is different from the ability of myoglobin to do
the same. At a certain pressure of oxygen, myoglobin is almost totally
oxygenated, meaning all the myoglobins in a solution have oxygen molecules bound
to them. (GVCC) But at low oxygen pressures, hemoglobin does not have much
oxygen bound to it. It is only when the pressure of oxygen gets pretty high that
hemoglobin gets saturated with oxygen. Why is that?
It turns out
that this little trick is crucial to hemoglobin’s ability to do its job. In the
lungs, where we breathe in and where the hemoglobin comes around in the red
blood cells, the pressure of oxygen is very high. Hemoglobin becomes saturated
with oxygen in the lungs. Then the circulation of the blood takes it out to our
fingers and toes, where the pressure of oxygen is pretty low. At low pressures,
hemoglobin cannot bind much oxygen, so it drops off the oxygen.
The point is
that in order to deliver something, we have to not only grasp it, but we also
have to let it go where it is needed. It is no good to have a hunting dog
retrieve the duck if the dog won’t let go when it brings it to you. Even so,
hemoglobin not only has to bind the oxygen, but it also has to let it go. How
does it do that? The key is the shape of the hemoglobin molecule. It has four
units that are roughly the same shape as myoglobin, but the four units are all
joined together. When hemoglobin does not have any oxygen bound to it, there is
a certain distance from one side to the other. But when it binds oxygen, that
distance is decreased. In other words, the shape of the molecule changes when it
binds to oxygen. This happens because two of the subunits rotate with respect to
the other two subunits.
How does
this happen? We find the answer in the heme, which is the business end of the
hemoglobin molecule, the site that actually binds the oxygen. In
deoxyhemoglobin, oxygen comes in and binds to one side of the iron atom and
forms a chemical bond to the iron. Now it is called oxyhemoglobin. But
when it binds, it pulls the iron down to one side. When it pulls the iron down
into the plane of the porphyrin, that tugs on the histidine side chain to which
the iron is attached. The histidine side chain is attached to a helical segment
of the molecule, and that pulls the whole helical segment along with it. When
that happens, the whole segment moves up one notch from where it was before.
When it moves up like that, it has to break some other electrostatic bonds that
other subunits made. But it turns out that that is very difficult to do unless
there are a couple of oxygens binding simultaneously. So that means it can only
happen in high oxygen environments. In a low oxygen environment, all these
oxygens just spring off.
To state it
more directly, the hemoglobin molecule is a machine that carries oxygen from our
lungs to our tissues. It is so designed to be exactly what we need to pick up
the oxygen where it is readily available, and to dump it off where it is needed.
Molecular Machines
Hemoglobin
was one of the first molecules studied by biochemists because it is readily
available in blood and easy to detect because it is red. So the study of
hemoglobin became one of the first places where scientists appreciated that the
molecular foundation of life is literally based on machinery. Since then, many
more systems in the cell have been elucidated, and this machinery-based view of
molecular life has been reinforced.
In 1998, the
journal Cell published a special issue on molecular machines. Down in the
corner of the cover was an illustration of something resembling a watch. It was
a take-off on an argument that William Paley, an Anglican clergyman, made in the
1800s. Paley said that if we walked through a meadow and stumbled across a
watch, which is a machine, we would realize that it was designed. The artist of
the Cell journal cover was inferring that we have found such machines in
the cell. So the table of contents shows these titles: “The Cell As a
Collection of Protein Machines,” “Polymerases and the Replisome: Machines within
Machines,” “Mechanical Devices of the Spliceosome: Motors, Clocks, Springs, and
Things.”
This edition
of Cell had a special editor, Bruce Alberts, president of the National
Academy of the Sciences and a prominent biochemist. He wrote: “We have always
underestimated cells. Undoubtedly we still do today. But at least we are no
longer as naïve as we were when I was a graduate student in the 1960s. . . . The
chemistry that makes life possible is much more elaborate and sophisticated than
anything we students had ever considered. . . . Indeed, the entire cell can be
viewed as a factory that contains an elaborate network of interlocking assembly
lines, each of which is composed of a set of large protein machines” (B.A.
Alberts, The Cell as a Collection of Protein Machines. Cell, Vol. 93,
291-294).
Alberts
wrote further: “Why do we call the large protein assemblies that underlie cell
function protein machines? Precisely because, like the machines invented
by humans to deal efficiently with the macroscopic world, these protein
assemblies contain highly coordinated moving parts” (Alberts, pp. 291-294). So
he is emphasizing that the word machine is not just a fuzzy analogy; it
is meant quite literally.
The Appearance of Design
When we look
at proteins and hemoglobin molecules, they look like they were designed. Every
scientist who studies these things has admitted as much. In fact, they have been
overwhelmed by the sense of intricacy and design that they see. For example,
Francis Crick, an atheist and famous scientist who discovered the shape of DNA
along with James Watson, wrote, “Biologists must constantly keep in mind that
what they see was not designed, but rather evolved” (Francis Crick, What Mad
Pursuit: A Personal View of Scientific Discovery [New York: Basic Books,
1988] 138). They have to close their eyes and scrunch up their teeth and say,
“It was not designed; it was not designed; it was not designed”! Of course, the
reason they have to try so hard is because the appearance of design is so
overwhelming.
In fact, a
man who is perhaps the foremost popularizer of Darwinian evolution in the world
today is Richard Dawkins, professor of biology at the University of Oxford in
England. His book, The Blind Watchmaker (New York: Norton, 1986), is a
vigorous defense of Darwinian evolution. In it he tries to counter William
Paley’s idea that if we stumbled across a watch we would know it was designed.
Dawkins argues that natural selection, or evolution, is actually the blind
watchmaker.
On the first
page of the first chapter of that book, Dawkins writes: “Biology is the study of
complicated things that give the appearance of having been designed for a
purpose” (Dawkins, p. 1, italics added). That is what biology is—the study
of these purposeful things. Dawkins agrees that life overwhelms us with a sense
of design. Nevertheless, he also writes, “Natural selection is the blind
watchmaker, blind because it does not see ahead, does not plan consequences, has
no purpose in view. Yet the living results of natural selection
overwhelmingly impress us with the appearance of design as if by a master
watchmaker, impress us with the illusion of design and planning” (Dawkins, p.
21, italics added).
Here again
Dawkins is echoing the words of William Paley, the Anglican clergyman from the
1800s, who said about mechanical objects: “When we come to inspect the watch, we
perceive . . . that its several parts are framed and put together for a purpose,
e.g. that they are so formed and adjusted so as to produce motion, and that
motion so regulated as to point out the hour of the day; . . . The inference we
think is inevitable, that the watch must have had a maker” (William Paley,
Natural Theology, 1802, Ch. 1). So whenever we see something so fearfully
and wonderfully made, we realize that it must have been designed.
The Molecular Basis of Life
This, then,
is the progress of science in the past several thousand years. Hippocrates and
Aristotle could only see the external, visible parts of biology. But as science
and technology progressed, we have been able to go lower and lower, to the
fundamental molecular basis of life. As we have done that, we have seen more and
more intricacy and sophistication. It is not an exaggeration to say that the
view of the cell which modern science has discovered is like the engine control
room in a ship. That is a fairly good analogy for what we find in the cell. Such
machinery is the foundation of life.
Every step
along the way, science was expecting to find that life would resolve into
simplicity the further down we got. But we have reached the basement of life,
and we find that that is not the case.
In 1996 I
wrote Darwin’s Black Box: The Biochemical Challenge to Evolution (New
York: The Free Press), in which I argued that Richard Dawkins and others are
wrong because Darwinian evolution cannot explain what we have found in the cell,
and that those who believe in it are essentially making an assumption that does
not agree with the facts.
Briefly, I
said that the reason that Darwinian evolution can’t explain these things is
because much of the machinery that we find in the cell is what we call
“irreducibly complex,” which means that it needs a number of different parts in
order to work. An example of irreducible complexity that we are all familiar
with is a mousetrap. A mousetrap has a number of different parts—a spring, a
hammer, a holding bar—and it turns out it needs all these things to work. If you
take away any of the components, the mousetrap is broken.
Darwinian
evolution works by having something that is functional, and very slowly
improving it by natural selection and random mutation. But if we wanted to build
something like a mousetrap by many small steps, each of which was functional,
how would we do it? It turns out to be very difficult to figure out. In fact,
many people have tried, but so far have been unable to even say how we could
gradually build something as simple as a mousetrap by a process akin to natural
selection.
The Bacterial Flagellum
Yet consider
the incredible complexity of the cell, even when viewed in a cartoon-like
diagram of a basic biology textbook. It has little hair-like things called
flagella. Would they be a problem to make? After all, they are just simple
little things flowing off the cell. But if we look very closely at the business
end of the bacterial flagella, we find an entirely different story.
The
structure of the bacterial flagellum has been pieced together by biochemistry,
looking at the molecular level of life rather than the level of life we can see
through a microscope. The flagellum is literally an outboard motor that bacteria
use to swim, just like an outboard motor on a boat. It is a rotary engine with
a propeller that spins around and pushes against water and propels the bacterium
forward. The propeller is attached to the drive shaft by the hook region, which
acts as a universal joint. The drive shaft is attached to the motor, which uses
a flow of acid from the outside to the inside to power the turning. The drive
shaft has to poke up through the bacterial membrane, so there are proteins that
act as bushing material to allow that to happen. There is a wonderful schematic
drawing of the bacterial flagellum in a popular biochemistry textbook that is
used in many colleges around the nation (Biochemistry, Voet & Voet,
1995). When we see it, we very quickly apprehend that, yes, this is indeed a
machine, a real molecular machine. That might give us an intuition about how we
need to go about explaining it.
Recognizing Design
I wrote in
Darwin’s Black Box that, if we look at such molecular machines, there is
a much better explanation for where they came from than Darwinian evolution. We
could say that they were purposely designed by an intelligent agent. Critics of
mine have said, “That is a religious conclusion, not a scientific one.” But I
disagree. I think the conclusion of design is completely empirical; it is a
scientific conclusion based solely on the physical structure of the object. In
other words, we are deducing design from the physical structure.
But how do
we conclude something is designed? What reasoning do we use? We can say many
things, but I think a good example of how we conclude design is captured in one
of Gary Larson’s The Far Side cartoons in which there is a troupe of
jungle explorers in a line. The lead explorer has been strung up by a vine and
skewered by two apposing three-pronged bamboo forks. And the third fellow in
line turns to the fellow behind him and says, “That’s why I never walk in
front.”
Now,
everyone who looks at this cartoon will immediately realize that this event was
not accidental but intended. In fact, the humor of the cartoon depends on us
recognizing the design. Are we making a religious conclusion? Probably not. We
can say this is designed because we see a number of different parts interacting
with each other to produce a function that the parts by themselves could not
produce. This is essentially what we mean by the term “irreducible
complexity.” Like the mousetrap, the jungle trap needs all of its components in
order to work. When we see how the parts of a trap fit together to perform its
intended function of killing someone, we can conclude that it was designed. That
is how we conclude design—when we see a system with a number of parts that are
fitted to each other to perform a function.
Reacting to Complexity
This, then,
is where science has taken us. As Charles Singer said, “The infinite complexity
of living things thus revealed was as philosophically disturbing as the ordered
majesty of the astronomical world which Galileo had unveiled to the previous
generation, though it took far longer for its implications to sink into men’s
minds” (Charles Singer, History of Biology).
Science has
uncovered this unexpected and enormous complexity. What are we to think of all
this? People have reacted in various ways. Richard Dawkins wrote, “The universe
we observe has precisely the properties we should expect if there is at bottom
no design, no purpose, no evil and no good, nothing but pointless indifference”
(Dawkins, as quoted in Easterbrook, G. Science and God: A Warming Trend?
Science, 1997, vol. 277, p. 890-893).
But there is
another, and I think much more reasonable, point of view. I am going to
illustrate it with quotations from a small book written by Cardinal Joseph
Ratzinger (now Pope Benedict XVI) in the 1980s. In this book, Cardinal Ratzinger
addresses the question of evolution, writing, “Let us go directly to the
question of evolution and its mechanisms. Microbiology and biochemistry have
brought revolutionary insights here. . . . They have brought us to the awareness
that an organism and a machine have many points in common. . . . Their
functioning presupposes a precisely thought-through and therefore reasonable
design” (J. Ratzinger, In the Beginning: A Catholic Understanding of the
Story of Creation and the Fall [Grand Rapids: Eerdmans, 1986] 54). He goes
on to say, “It is the affair of the natural sciences to explain how the tree of
life in particular continues to grow and how new branches shoot out from it.
This is not a matter for faith. But we must have the audacity to say that the
great projects of the living creation are not the products of chance and error.
. . .[They] point to a creating Reason and show us a creating Intelligence, and
they do so more luminously and radiantly today than ever before” (Ratzinger,
p.56-57).
Cardinal
Ratzinger makes the following three points in that excerpt: First, contrary to
Richard Dawkins’ conclusion, life shows signs of design and purpose. What is
more, to support his argument, Ratzinger points to physical evidence, that is,
to the great projects of the living creation, which point to a creating Reason.
He does not point to philosophical or theological or Scriptural arguments, as
important as those might be, but to physical evidence. There is physical
evidence to support the contention that life is designed. His third point is
that biochemistry, which studies the molecular foundation of life, gives us the
most insight into life’s design. For my money, I would say that Ratzinger has
much the better point than Dawkins.
Conclusion
In the end,
let us go back to Psalm 139:14: “I will praise thee; for I am fearfully and
wonderfully made: marvellous are thy works; and that my soul knoweth right well”
(KJV). When the psalmist was writing this, he had none of the knowledge that we
have now. Yet, perhaps through the grace of special insight, he realized that
life is indeed fearfully and wonderfully made, extraordinarily intricate, and
indicative of the wisdom and power of the Master Designer.
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