Last week, at the University of Oklahoma, Francisco J. Ayala gave a talk. Ayala, a member of the National Academy of Science, the Presidential Medal of Science, and a pioneer in the molecular study of evolution, made some important points about the creationist “intelligent design” (ID) movement most of us already knew, but said them in a direct and powerful way that most of us had not dared. Ayala is also a former priest, and is one of the few evolutionary scientists with formal training in theology.
Ayala said that, if creationism were true, then God was incompetent. The adaptations of organisms are imperfect and are cobbled together from whatever parts were available. No competent engineer, Ayala said, would use the same design for a car, an airplane, and a boat, yet that is exactly what we see when we compare the designs of, for example, a dog, a bird, and a whale. In particular, he mentioned the process of human birth, in which the birth canal is almost too narrow and the frequent result, before modern medicine, was the death of both mother and child during childbirth. Why would God design something like this? But from an evolutionary viewpoint it makes sense. First, natural selection makes use of whatever parts are available; that is all it can do. That is why dogs, birds, and whales have the same basic design. Second, evolution is constrained by contradictory forces. Natural selection favored, in the human lineage, upright posture (which confers an advantage on a small birth canal) and large brains (which confers an advantage on a large birth canal). These competing forces have resulted in a birth canal that is on the deadly edge of being too small. No competent supernatural designer would have used these imperfect designs.
Ayala also said that, if creationism were true, then God is cruel, even perverted (Ayala’s terms). He made reference to the many extreme examples of extremely prolonged and painful diseases such as river blindness and elephantiasis. What kind of God would design things like this? Certainly not one worthy of worship.
Ayala’s conclusion was that intelligent design was blasphemy, because it makes God out to be incompetent and cruel.
I believe, along with Ayala, that creationists need to be confronted with the consequences of their own beliefs. But I would go even further. The evidence that Ayala cited not only contradict the idea of an Intelligent Designer, but also the concept of an all-powerful God in the universe today. Why does such a God, today, allow us to suffer from the cruelty imposed by the mindless laws of nature and the brainless behavior of parasites? It is not just a matter of asking why God made the world the way it is; it is a matter of asking why God permits it to continue in such a pointlessly cruel state.
In springtime, it is easy to overlook the cruelty of the world. And our brains have an instinct to see much beauty in the world. I plan to focus on the beauty of the world. But I will do so by giving my attention to the beauty itself, rather than digging up the tangled contradictions of attributing the beauty of the world to a creator while making excuses for the world’s cruelty.
Wednesday, April 28, 2010
Saturday, April 24, 2010
Fundamentalist Christianity and terrorism
I have some further thoughts related to the anonymous hate message that I received (see previous post). I now consider creationism to be a terrorist movement, a claim that I will here explain.
Most creationists would not, themselves, commit acts of terrorism or condone them. But the same thing can be said about Islamist terrorist movements around the world. Only a small percentage of Muslims are actually preparing to commit acts of terrorism. A larger, but still small, percent of Muslims would condone those acts, even though they would not personally commit them. However, a large number of Muslims (though still a minority) are sympathetic toward the terrorist movement, even though they do not personally condone the acts of terrorism. Islamist terrorism would not be as common as it is were it not for a widespread base of economic and social support that it receives from sympathizers.
Creationism, in a similar fashion, consists of a small number of people who are willing to break the law and attack others by whatever means is convenient, plus a large number of people who are sympathetic to them though they would never consider committing such acts themselves.
It does not take a large number of violent people to cause a lot of trouble, especially if those people, such as the Taliban, Al Qaeda, or Christian white supremacist cults, have lots of weapons and the sympathy of a large minority of the population.
Most of us would consider it unthinkable to listen to someone who argues that Islamist terrorists are wrong in their actions but have a valid viewpoint—that is, a nonviolent defender of violent people. The same, I believe, is true of fundamentalist Christian creationists. Creationism is a terrorist movement without, thus far, any actual terrorists. I hope it stays that way, but fear that it may not.
Most creationists would not, themselves, commit acts of terrorism or condone them. But the same thing can be said about Islamist terrorist movements around the world. Only a small percentage of Muslims are actually preparing to commit acts of terrorism. A larger, but still small, percent of Muslims would condone those acts, even though they would not personally commit them. However, a large number of Muslims (though still a minority) are sympathetic toward the terrorist movement, even though they do not personally condone the acts of terrorism. Islamist terrorism would not be as common as it is were it not for a widespread base of economic and social support that it receives from sympathizers.
Creationism, in a similar fashion, consists of a small number of people who are willing to break the law and attack others by whatever means is convenient, plus a large number of people who are sympathetic to them though they would never consider committing such acts themselves.
It does not take a large number of violent people to cause a lot of trouble, especially if those people, such as the Taliban, Al Qaeda, or Christian white supremacist cults, have lots of weapons and the sympathy of a large minority of the population.
Most of us would consider it unthinkable to listen to someone who argues that Islamist terrorists are wrong in their actions but have a valid viewpoint—that is, a nonviolent defender of violent people. The same, I believe, is true of fundamentalist Christian creationists. Creationism is a terrorist movement without, thus far, any actual terrorists. I hope it stays that way, but fear that it may not.
Sunday, April 18, 2010
Why creationism is dangerous
This morning I received an abusive message via Facebook. Facebook allows messages to be sent from anonymous sources, and this source did not identify itself except as male. Its main message was I was offending my creationist students by teaching evolution in an evolution class. The opinions expressed were brutal. The facts it cited were inaccurate. For example, the writer said that evolution was dropped from the core requirements for biology majors because nobody was learning anything from my classes. In fact, the course was dropped from the core before I began teaching it. The message said my colleagues do not respect me, which is not true, according to my colleagues. My student evaluations are mostly positive, with a few negative comments from offended creationists. The message said that my students do not learn anything; test results show that this is not true. The message said nobody accepts my books, which is untrue; they have received good reviews nationwide. The grammar and spelling in this message were bad.
This sort of thing is typical of creationists. They have no hesitation about lying about others; of sending secret abusive messages and threats; about breaking the law. For example, famous creationist Kent Hovind (“Dr. Dino”) went to prison for tax evasion. One of the world’s most famous creationists, who wrote under the name Harun Yahya, went to prison in Turkey for organized crime. In 2007, a creationist send threatening letters to evolutionary science faculty at the University of Colorado, and his messages proclaimed that it was time for Christians to take up arms against those he believed to be his enemies. My experience with creationist students is that they are often the ones who plagiarize papers.
Creationists are fueled by hatred. And since they are associated with the extreme political right wing, many of whom accumulate stockpiles of weapons, their hatred is dangerous. The fact that this message came from an anonymous source was clearly intended to heighten its terrorist effect. The writer used the name “Charles Darwen,” and a photograph of the nineteenth century drawing of Charles Darwin as a chimpanzee.
It should be obvious why “the creationist viewpoint” does not deserve a serious consideration, any more than does the white supremacist viewpoint, which appeals to some of the same people. The creationist viewpoint is a grab for political power by means of intimidation.
This sort of thing is typical of creationists. They have no hesitation about lying about others; of sending secret abusive messages and threats; about breaking the law. For example, famous creationist Kent Hovind (“Dr. Dino”) went to prison for tax evasion. One of the world’s most famous creationists, who wrote under the name Harun Yahya, went to prison in Turkey for organized crime. In 2007, a creationist send threatening letters to evolutionary science faculty at the University of Colorado, and his messages proclaimed that it was time for Christians to take up arms against those he believed to be his enemies. My experience with creationist students is that they are often the ones who plagiarize papers.
Creationists are fueled by hatred. And since they are associated with the extreme political right wing, many of whom accumulate stockpiles of weapons, their hatred is dangerous. The fact that this message came from an anonymous source was clearly intended to heighten its terrorist effect. The writer used the name “Charles Darwen,” and a photograph of the nineteenth century drawing of Charles Darwin as a chimpanzee.
It should be obvious why “the creationist viewpoint” does not deserve a serious consideration, any more than does the white supremacist viewpoint, which appeals to some of the same people. The creationist viewpoint is a grab for political power by means of intimidation.
Tuesday, April 13, 2010
Thomas Jefferson's birthday
Thomas Jefferson may well have been the president that most strongly supported scholarship in general and science in particular. He was just as proud of being the founder of the University of Virginia as of being the third president. The Lewis and Clark expedition, which Jefferson organized and funded as president, was primarily a scientific expedition to explore, rather than a military expedition to conquer, the Louisiana Purchase. He kept copious notes of a scientific nature (though science in its modern form did not yet exist), and his reputation as an inventor is or should be well known to everyone.
When President Kennedy hosted Nobel laureates at the White House, he said that event was the greatest concentration of brain power that there had ever been in the White House, except when Jefferson dined there alone. But it is not just that Jefferson was smart. There were lots of other smart people involved in the founding of our nation. But he had a zeal for getting new and reliable information upon which to base human activities, especially farming, which was and is the basis of the world economy. He had trouble letting go of precious theories—he probably never quite believed that mammoths really had become extinct, and was hoping the Lewis and Clark expedition would find some—but was more open to new information than nearly anyone else then or now. It was this attitude of openness that led scholars, decades after Jefferson’s death, to finally accept evolutionary science. Jefferson did not accept evolution, because during his lifetime the evidence for it was not very good.
Conservatives do not like Jefferson. I believe that this is partly due to the fact that, to conservatives, it is not important what you know, but just what you believe. Conservatives generally think that you should impose your beliefs on the facts, rather than letting the facts lead you to your beliefs. They fear new information and, in many cases, attempt to suppress it. They also strongly resent the fact that Jefferson did not believe in conventional Christian theology, although he was by no means what we would today call an agnostic or atheist. This is the principal reason that the Texas Board of Education attempted to expunge much of the information about Jefferson from the educational standards in high schools. Conservatives are threatened by Thomas Jefferson and people like him.
When President Kennedy hosted Nobel laureates at the White House, he said that event was the greatest concentration of brain power that there had ever been in the White House, except when Jefferson dined there alone. But it is not just that Jefferson was smart. There were lots of other smart people involved in the founding of our nation. But he had a zeal for getting new and reliable information upon which to base human activities, especially farming, which was and is the basis of the world economy. He had trouble letting go of precious theories—he probably never quite believed that mammoths really had become extinct, and was hoping the Lewis and Clark expedition would find some—but was more open to new information than nearly anyone else then or now. It was this attitude of openness that led scholars, decades after Jefferson’s death, to finally accept evolutionary science. Jefferson did not accept evolution, because during his lifetime the evidence for it was not very good.
Conservatives do not like Jefferson. I believe that this is partly due to the fact that, to conservatives, it is not important what you know, but just what you believe. Conservatives generally think that you should impose your beliefs on the facts, rather than letting the facts lead you to your beliefs. They fear new information and, in many cases, attempt to suppress it. They also strongly resent the fact that Jefferson did not believe in conventional Christian theology, although he was by no means what we would today call an agnostic or atheist. This is the principal reason that the Texas Board of Education attempted to expunge much of the information about Jefferson from the educational standards in high schools. Conservatives are threatened by Thomas Jefferson and people like him.
Wednesday, April 7, 2010
Populations, evolution, and the census
In order to understand how evolution works in populations (of plants, animals, or humans), scientists need accurate population information. This includes not only the size of the population but also information about the animals or plants within the population. They need to know how many individuals in the population are young, middle-aged, or old; how many male, how many female; and genetic characteristics. This information lets scientists know not only whether the population (for example, of an endangered species) is in decline, but also the possible directions that evolution may take in the future.
Population information is also important as a basis for human societies. Governments need to know how many people live in each area, and their ages, so that they can plan revenues and expenditures. An aging population means lower revenues and higher expenditures, while a young population may mean just the opposite. This is exactly the kind of information that the Census, due this month, obtains.
Participation in the Census is required by the Constitution of the United States. Despite this, many people refuse to participate in the census, for reasons that are clearly incorrect and sometimes incoherent. Numerous conservative activists refuse to participate because (according to Republican representative Michele Bachmann) they think the government will use this information to locate conservatives and send them to internment camps. They think the Census is a Democratic plot to destroy them. Many of them also think that the government is specifically targeting illegal immigrants so as to increase expenditures in and congressional representatives from areas in which many illegal immigrants live.
But the opposite may be true. Hispanics, in particular, are being scared away from Census participation. The reason is that they fear that, by submitting their names and the names of family members and guests to the government, they are endangering arrest by immigration authorities. Even if the Hispanic householder that receives the form is a U.S. citizen, some of the residents of the household may not be, therefore the householder may not submit information to the Census even if he or she is a citizen and pays taxes. If you have received your census form, you may notice that the return address on the envelope is to the “Data Capture Center” in Phoenix. Now what is a Hispanic to think when asked to submit personal information to a “capture center”?
The conservatives, with typical fearmongering, claim that the Census is a trick to over-represent Democratic areas by counting illegal immigrants. However, the opposite is just as likely to be true. This is also part of the general conservative dislike of data. They want people to believe their broad and incorrect generalization, rather than to base opinions upon scientifically-collected data.
Population information is also important as a basis for human societies. Governments need to know how many people live in each area, and their ages, so that they can plan revenues and expenditures. An aging population means lower revenues and higher expenditures, while a young population may mean just the opposite. This is exactly the kind of information that the Census, due this month, obtains.
Participation in the Census is required by the Constitution of the United States. Despite this, many people refuse to participate in the census, for reasons that are clearly incorrect and sometimes incoherent. Numerous conservative activists refuse to participate because (according to Republican representative Michele Bachmann) they think the government will use this information to locate conservatives and send them to internment camps. They think the Census is a Democratic plot to destroy them. Many of them also think that the government is specifically targeting illegal immigrants so as to increase expenditures in and congressional representatives from areas in which many illegal immigrants live.
But the opposite may be true. Hispanics, in particular, are being scared away from Census participation. The reason is that they fear that, by submitting their names and the names of family members and guests to the government, they are endangering arrest by immigration authorities. Even if the Hispanic householder that receives the form is a U.S. citizen, some of the residents of the household may not be, therefore the householder may not submit information to the Census even if he or she is a citizen and pays taxes. If you have received your census form, you may notice that the return address on the envelope is to the “Data Capture Center” in Phoenix. Now what is a Hispanic to think when asked to submit personal information to a “capture center”?
The conservatives, with typical fearmongering, claim that the Census is a trick to over-represent Democratic areas by counting illegal immigrants. However, the opposite is just as likely to be true. This is also part of the general conservative dislike of data. They want people to believe their broad and incorrect generalization, rather than to base opinions upon scientifically-collected data.
Wednesday, March 31, 2010
There are adaptations and there are adaptations
Natural and sexual selection produce adaptations. It seems so obvious to us now that Darwin has explained it to us.
But it turns out to not be so simple. Natural and sexual selection may act directly upon certain traits, and indirectly upon others; the trait may have been a side-effect of the real story of natural selection. Stephen Jay Gould and Richard Lewontin realized this as they looked at the spaces between the arches of a cathedral, and the artwork contained therein. The artwork was constrained by the spaces. The design of the cathedral was focused on the arches; the spaces between them, or spandrels, were a side effect. Later, Gould and Elizabeth Vrba expanded this concept. Some evolutionary changes occurred, like artwork in spandrels, within necessary constraints. Other evolutionary changes in traits resulted from natural selection acting on other traits; they called these changes exaptations rather than adaptations.
Some characteristics of organisms are, like spandrels, structurally inevitable. Consider the patterns of allometry. Large trees must have relatively thick trunks, and large animals must have relatively thick legs. An animal that is twice as large as another in all linear dimensions would weigh eight times as much but have legs only four times as strong; to make up for this, the legs must be more than twice as thick. They have to be the square root of eight times as thick. There is no choice in the matter. Natural selection may have made the animal larger, an adaptation; but the thicker legs are an exaptation.
One humorous example of an exaptation (three exaptations walked into a bar…) is the human chin. Why do we have chins, and chimps do not? Some scientists have really used their imagination on this one. They imagined that the chin served as a way of expressing threat gestures. No kidding; I read that. (Post a comment to tell us your favorite story about why humans have chins.) But it turns out that the human chin is not an adaptation at all; it is an exaptation. One of the major characteristics of human evolution has been neoteny, the retention of juvenile characteristics into adulthood. Neoteny affected the growth patterns of the bones of the skull; in addition, natural selection favored jaws and teeth suitable for an omnivorous diet in human ancestors. The chin was a side-effect of these different facial bone and jaw growth patterns. The chin was probably not, itself, selected for anything; natural selection acted upon neoteny, not directly upon the chin.
Sometimes a feature can evolve for one reason and then turn out to be useful for another. Here are a couple of examples. Today, birds use feathers primarily for flight. But the earliest birds (according to fossils discovered in 2009) did not use feathers for flight; they had down feathers, which held in body heat. Once they had feathers, natural selection could act upon the feathers to make them into flight feathers. Another example is one of the most famous evolution just-so stories, the neck of the giraffe. What a weird adaptation. Giraffes have to spread their legs awkwardly just to drink from a pond. (Three giraffes walk into a bar…) To most observers, it would appear obvious that long necks are an adaptation that allows giraffes to feed at the tops of trees. But if this is so, why do female giraffes have shorter necks than male giraffes, and why are giraffes so frequently observed actually bending down to eat leaves? Careful observations have shown that males with longer necks prevail in battles with one another, and that females choose the males with longer necks. Long necks apparently evolved by competition for mates. Now that giraffes have long necks, they can use them for eating leaves from treetops, but that is not the original reason that long necks evolved in these animals.
Creationists could come up with their own version of exaptation. They could say that God created sex so that humans could make babies. But once sex existed, it could be used just for fun. Sexual fun is an exaptation, or sexaptation, or ecstatic-taptation. But I am not aware that any creationists have made this argument.
Adapted from the entry “Adaptation” in Encyclopedia of Evolution (Facts on File, 2006).
But it turns out to not be so simple. Natural and sexual selection may act directly upon certain traits, and indirectly upon others; the trait may have been a side-effect of the real story of natural selection. Stephen Jay Gould and Richard Lewontin realized this as they looked at the spaces between the arches of a cathedral, and the artwork contained therein. The artwork was constrained by the spaces. The design of the cathedral was focused on the arches; the spaces between them, or spandrels, were a side effect. Later, Gould and Elizabeth Vrba expanded this concept. Some evolutionary changes occurred, like artwork in spandrels, within necessary constraints. Other evolutionary changes in traits resulted from natural selection acting on other traits; they called these changes exaptations rather than adaptations.
Some characteristics of organisms are, like spandrels, structurally inevitable. Consider the patterns of allometry. Large trees must have relatively thick trunks, and large animals must have relatively thick legs. An animal that is twice as large as another in all linear dimensions would weigh eight times as much but have legs only four times as strong; to make up for this, the legs must be more than twice as thick. They have to be the square root of eight times as thick. There is no choice in the matter. Natural selection may have made the animal larger, an adaptation; but the thicker legs are an exaptation.
One humorous example of an exaptation (three exaptations walked into a bar…) is the human chin. Why do we have chins, and chimps do not? Some scientists have really used their imagination on this one. They imagined that the chin served as a way of expressing threat gestures. No kidding; I read that. (Post a comment to tell us your favorite story about why humans have chins.) But it turns out that the human chin is not an adaptation at all; it is an exaptation. One of the major characteristics of human evolution has been neoteny, the retention of juvenile characteristics into adulthood. Neoteny affected the growth patterns of the bones of the skull; in addition, natural selection favored jaws and teeth suitable for an omnivorous diet in human ancestors. The chin was a side-effect of these different facial bone and jaw growth patterns. The chin was probably not, itself, selected for anything; natural selection acted upon neoteny, not directly upon the chin.
Sometimes a feature can evolve for one reason and then turn out to be useful for another. Here are a couple of examples. Today, birds use feathers primarily for flight. But the earliest birds (according to fossils discovered in 2009) did not use feathers for flight; they had down feathers, which held in body heat. Once they had feathers, natural selection could act upon the feathers to make them into flight feathers. Another example is one of the most famous evolution just-so stories, the neck of the giraffe. What a weird adaptation. Giraffes have to spread their legs awkwardly just to drink from a pond. (Three giraffes walk into a bar…) To most observers, it would appear obvious that long necks are an adaptation that allows giraffes to feed at the tops of trees. But if this is so, why do female giraffes have shorter necks than male giraffes, and why are giraffes so frequently observed actually bending down to eat leaves? Careful observations have shown that males with longer necks prevail in battles with one another, and that females choose the males with longer necks. Long necks apparently evolved by competition for mates. Now that giraffes have long necks, they can use them for eating leaves from treetops, but that is not the original reason that long necks evolved in these animals.
Creationists could come up with their own version of exaptation. They could say that God created sex so that humans could make babies. But once sex existed, it could be used just for fun. Sexual fun is an exaptation, or sexaptation, or ecstatic-taptation. But I am not aware that any creationists have made this argument.
Adapted from the entry “Adaptation” in Encyclopedia of Evolution (Facts on File, 2006).
Thursday, March 25, 2010
Imperfection
The previous entry, about death, brings up an important point about evolution: imperfection. Imperfection is one of the most important ways in which an evolutionary view of the world differs from a creationist one.
An all-powerful God ought to have created a perfect world. This God is supposed to have given humans free will and the ability to choose evil; therefore one might not expect any human utopias. But the natural world is also pervaded by imperfection. The only explanation creationists have for this is that God cursed the whole natural world during Adam’s fall—something that is simply not found in the Bible; it is something creationists just made up. I guess they think God gives them permission to just make stuff up and then proclaim it in God’s name. Stephen Jay Gould was particularly active in pointing out that imperfections are much better evidence for evolution than perfections.
The idea that organisms are perfectly adapted to their environments predates evolutionary theory. This idea was central to natural theology, in which the perfect fit of organism and environment was considered evidence of divine creation. English theologian William Paley, in his famous 1802 book Natural Theology, used perfect adaptation of organisms as evidence that a Supreme Being had created them. At the time Paley wrote his book there was no credible evolutionary theory that could challenge this view.
Natural theology is wrong in one particularly important way. Scientific investigation has found numerous examples of adaptation that are far from being a perfect fit between organism and environment. One example (Gould’s favorite) is the digestive system of the panda. The immediate ancestors of pandas were carnivores, but pandas are herbivores, living exclusively on leaves. Pandas have intestines that are better suited to a carnivore. In well-adapted herbivores, such as sheep, the intestines are up to 35 times as long as the body, while in well-adapted carnivores, the intestines are much shorter, only four to seven times as long as the body. With the help of bacteria, longer intestines allow herbivores more time to digest coarse plant materials, such as cellulose. Meat, in contrast, requires less digestive breakdown. Pandas have intestines that are in the carnivore, not the herbivore, range. The panda’s digestive system is, therefore, not well adapted to its function. Modern evolutionary scientists would attribute this to the recent evolutionary shift from meat to leaves in the diet of the panda’s ancestors: there has not been time for better adaptation in this case. A natural theologian, in contrast, would have a difficult time explaining this example of imperfection. Stephen Jay Gould used the sixth digit, or thumb, of the panda as another example of the imperfection of adaptation produced by the ongoing process of evolution rather than by the Supreme Being invoked by natural theology.
Another example of an imperfect adaptation is pain. The function of pain is to alert an animal to danger or possible damage. Victims of some kinds of strokes, and of leprosy, lose much of their ability to feel pain, and cannot feel the damage that they may do to their extremities. Healthy individuals feel pain and avoid movements that would damage their extremities. Excessive and prolonged pain, however, serves no useful purpose, and much of modern medicine is devoted to the control of excessive pain. Pain is therefore an adaptation, but an imperfect one—a fact to which all of us can attest. Those of us who experience little pain empathize with those who experience much, and if we were in charge the way God supposedly is, we would alleviate some of this pain.
The world is only as good as it has to be for organisms to win in the game of natural selection. It is not perfect, nor is there any evolutionary way for it to be. But at least evolutionists do not have to come up with an excuse for how a God of Infinite Love could allow pervasive and painful imperfections to mar the Creation.
Adapted from the entry “Adaptation” in Encyclopedia of Evolution (Facts on File, 2006, 2007).
An all-powerful God ought to have created a perfect world. This God is supposed to have given humans free will and the ability to choose evil; therefore one might not expect any human utopias. But the natural world is also pervaded by imperfection. The only explanation creationists have for this is that God cursed the whole natural world during Adam’s fall—something that is simply not found in the Bible; it is something creationists just made up. I guess they think God gives them permission to just make stuff up and then proclaim it in God’s name. Stephen Jay Gould was particularly active in pointing out that imperfections are much better evidence for evolution than perfections.
The idea that organisms are perfectly adapted to their environments predates evolutionary theory. This idea was central to natural theology, in which the perfect fit of organism and environment was considered evidence of divine creation. English theologian William Paley, in his famous 1802 book Natural Theology, used perfect adaptation of organisms as evidence that a Supreme Being had created them. At the time Paley wrote his book there was no credible evolutionary theory that could challenge this view.
Natural theology is wrong in one particularly important way. Scientific investigation has found numerous examples of adaptation that are far from being a perfect fit between organism and environment. One example (Gould’s favorite) is the digestive system of the panda. The immediate ancestors of pandas were carnivores, but pandas are herbivores, living exclusively on leaves. Pandas have intestines that are better suited to a carnivore. In well-adapted herbivores, such as sheep, the intestines are up to 35 times as long as the body, while in well-adapted carnivores, the intestines are much shorter, only four to seven times as long as the body. With the help of bacteria, longer intestines allow herbivores more time to digest coarse plant materials, such as cellulose. Meat, in contrast, requires less digestive breakdown. Pandas have intestines that are in the carnivore, not the herbivore, range. The panda’s digestive system is, therefore, not well adapted to its function. Modern evolutionary scientists would attribute this to the recent evolutionary shift from meat to leaves in the diet of the panda’s ancestors: there has not been time for better adaptation in this case. A natural theologian, in contrast, would have a difficult time explaining this example of imperfection. Stephen Jay Gould used the sixth digit, or thumb, of the panda as another example of the imperfection of adaptation produced by the ongoing process of evolution rather than by the Supreme Being invoked by natural theology.
Another example of an imperfect adaptation is pain. The function of pain is to alert an animal to danger or possible damage. Victims of some kinds of strokes, and of leprosy, lose much of their ability to feel pain, and cannot feel the damage that they may do to their extremities. Healthy individuals feel pain and avoid movements that would damage their extremities. Excessive and prolonged pain, however, serves no useful purpose, and much of modern medicine is devoted to the control of excessive pain. Pain is therefore an adaptation, but an imperfect one—a fact to which all of us can attest. Those of us who experience little pain empathize with those who experience much, and if we were in charge the way God supposedly is, we would alleviate some of this pain.
The world is only as good as it has to be for organisms to win in the game of natural selection. It is not perfect, nor is there any evolutionary way for it to be. But at least evolutionists do not have to come up with an excuse for how a God of Infinite Love could allow pervasive and painful imperfections to mar the Creation.
Adapted from the entry “Adaptation” in Encyclopedia of Evolution (Facts on File, 2006, 2007).
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