DNA, Intelligent Design, and Theodicy, Part One

John C. Avise published a book last year entitled Inside the Human Genome: A Case for Non-Intelligent Design. I would like to share some ideas from this book for your consideration. Avise looks at the age-old question of theodicy (why a good God would permit suffering) in light of the our understanding of human genetics, especially the new revelations that have come from the Human Genome Project just in the last dozen years.

Avise's main point is that if the world were designed by a loving intelligence (which Intelligent Design proponents publicly hesitate to call God), the DNA system shared by all organisms from amoebas to humans would look a lot different from the way it is. And his first set of examples is the sheer number and horror of mutations that fill the human genome.

Many mutations are neutral, or can be easily overcome by technology. And some of them cause a great deal of psychological suffering, such as the mutation that causes trimethylaminuria, which is physically harmless but causes the victims to smell like rotten fish no matter how clean they are. But many other mutations are deadly or, worse yet, can cause a person to have a lifetime of suffering. Perhaps the most disturbing mutation is the one that causes Lesch-Nyhan syndrome. This one mutation, of a single amino acid in a protein, causes the victim to have an uncontrollable compulsion for self-mutilation: they chew their own lips and fingers, and find sharp objects to stab their faces and eyes. The victims are fully able to feel their pain and they know what they are doing, but cannot control it.

But there is more to the story. Most of these genetic syndromes have come into existence many times. Consider glycogen storage disease, in which a defective enzyme causes glycogen (animal starch) to build up in tissues throughout the body. A childhood friend of mine has this disease, which he inherited from his father; by middle age, he was almost constantly incapacitated by this disease. I do not know if he is still alive. Geneticists know of 86 different mutations that can disrupt the enzyme and cause this disease. That is, this genetic disease has mutated into existence 86 separate times. The author directs our attention to several databases, one of which is the Online Mendelian Inheritance in Man (OMIM), which lists over 18,000 genes, three-quarters of which have documented mutations. And these are just the single-gene defects!

The author's first point is that an intelligently-designed genome would not have such a stunning number of mutations. If God designed the DNA to make us adapted to the world we live in, could God not have done a better job? Evolution, in contrast, is dependent upon random mutations, upon which natural selection acts by eliminating the bad ones (that is, disfavoring and perhaps killing the individuals who express them) and favoring the good ones. The existence of a large pool of mutations, which natural selection has not completely gotten rid of, is consistent with evolution but not with Intelligent Design.

One answer that Intelligent Design proponents have to this problem is that the Designer created a mutation-free set of human DNA when our species came into existence, then abandoned the system to take care of itself. But if this is the case, the system was so poorly designed that it could not, in fact, take care of itself.

The connection to the problem of theodicy is obvious, and Avise makes it. Defenders of God (which is the meaning of theodicy) claim that God allows bad things to happen as an inevitable consequence of free will. Their platitude is that if fire did not burn, then it would not be fire. I can understand why God would not automatically give all of us a perfect set of genes; limitations, including genetic ones, are necessary for character development, to show God on judgment day what kind of people we are (from the traditional Christian viewpoint). But Lesch-Nyhan syndrome? Potentially deadly mutations in three-quarters of human genes? Isn't this a bit excessive?

I will summarize some of Avise's other points in the next entry. Please post your comments and/or send the link to this blog to others who might be interested.

Don't miss my new book, Life of Earth: Portrait of a Beautiful, Middle-Aged, Stressed-Out World, just published by Prometheus Books.

The Evolved Capacity for Evil, Part Two

Here are some more thoughts that came to me as a result of reading the book by Barbara Oakley Evil Genes: Why Rome Fell, Hitler Rose, Enron Failed, and My Sister Stole My Mother’s Boyfriend. For part one, see the previous blog entry.

In the previous entry, I established that behavioral differences among individuals are due to genes, which influence brain chemicals and brain structures; to environment; and to habitual reinforcements. By describing the physical basis for behavioral differences, we in no way excuse them. Clinical psychopaths have to be stopped. And subclinical psychopaths, the kind that abuse others, often from positions of business or religious or governmental authority, need to be relocated into some position where their evil will harm as few people as possible. Oakley presents good evidence not just that many evil leaders, such as Slobodan Milosevic and Mao Zedong, had brain problems but just what some of these problems might have been. Failure to stop them has resulted in the gruesome deaths of millions of people.

I mentioned that human populations have plenty of genetic variation for behavior that evolution has clearly produced it. I have written a lot (and I’m not done) about altruism—evolution has given humans an instinct to be good, however imperfectly. But how could evolution favor genetic variation that makes people bad, at the same time? Which is it?

Well, it is both. Most people, through time, have obtained direct personal benefits by cooperation and by even more intense forms of altruism. But some people have obtained direct personal benefits by being evil. In many cases, they pretend to be good, while being evil. A psychopath knows that people have emotions; they just don’t care. They know right from wrong, which is why they can pretend to be good.

Natural selection favors successful reproduction. Good people are successful when their cooperation gains them status and resources and mates. Evil people can be just as successful. After all, according to some figures, about one out of every 200 men in the world have the Genghis Khan Y chromosome.

And there is more to it than this. Human behavior is a spectrum. We all know people who, if their genes were just a little bit more evil, or their amygdalae a little more defective, or under slightly different conditions, would be monsters, but they are able to function in society—we just know to not trust them. (A former colleague from a previous job described a mutual acquaintance who temporarily rose in the field of academic administration, in this way: “And then all the little horns started coming out of his head.” She was tipsy when she told me this but I believe she was correct.) And, in addition, each of us moves around on the good-evil continuum.

The conclusion from this blog entry is that human populations have heritability of behavioral characteristics, and evolution has worked upon human behavior. This is why we have always had and will always have good and bad individuals. Natural selection maintains genetic variability. But there is more. In the next essay I explore the question of whether natural selection can result in good vs. bad populations.

The Evolved Capacity for Evil, Part One

My blog entries have been sporadic recently, because we have had recurring storms that have closed down educational institutions. (I do not have internet connections at my house.) I was expecting that I would get back to my series of essays based on my new book, Life of Earth. But during the most recent snow days, I happened to start reading a book by my fellow Prometheus Books author, Barbara Oakley. The book is Evil Genes: Why Rome Fell, Hitler Rose, Enron Failed, and My Sister Stole My Mother’s Boyfriend. How could you not want to read a book with that title?

I found myself frequently lost in the mass of information, but that is, I think, the nature of the subject. Maybe nobody could make it fully comprehensible. And the author’s stories, of historical figures and personal experiences, drew me in anyway.

At first, one would think the book was intended as an argument against the Skinnerian blank-slate theory. (Last year I read Skinner’s Walden Two as one of my rare ventures into fantasy.) But very few people take that theory seriously anymore, and Oakley’s purpose is not to tell us that but to tell us how genes affect human behavior.

First, there are no genes for behavior patterns, but there are genes for inclinations such as impulsivity and anxiety. There are many examples interspersed through the book, but I will mention just one. Serotonin is a chemical that carries messages in the brain. After it has delivered its message, it has to be re-absorbed by the neuron that released it. This reuptake is the business of the SERT (serotonin transporter) protein. If serotonin lingers in the spaces between the brain cells, anxiety can result. A word about genes: they contain stretches of non-coding DNA, such as tandem repeats, which are not transcribed into the protein. Just junk, you say? Read on. The SERT gene has two forms (alleles), the short form (with 14 tandem repeats) and the long form (with 16 tandem repeats). Aside from these seemingly meaningless insertions, the alleles are identical. The short allele results in the production of less SERT, and therefore contributes to anxiety. I hope I got that right.

Second, differences in brain structures influence behavior patterns as well. Psychopaths, for example, often have a defective corpus callosum, the part of the brain that connects the left and right sides. They also have a smaller amygdala, an almond-shaped structure in the middle of the brain. Perhaps these people need more excitement in order to feel normal, and have less fear, both of which contribute to a dampening of conscience. A dysfunction of the right orbital cortex (just behind the eye) also makes it difficult for a person to form a conscience. The brain structure differences between one person and another are influenced by which alleles the person inherits.

Third, brain chemicals and structures both influence brain circuitry. This circuitry is what determines behavior. One example is that the amygdala sends fear signals to dampen the cingulate cortex, but this communication is inhibited if the person has one or two copies of the short version of the SERT gene. Indeed, people with the short allele have smaller amygdalae and cingulate cortices. Again, I hope I got that right.

It gets even more complicated. The behavioral abnormalities recognized by psychologists often overlap: each disorder has some characteristics of the others. This may be because each behavior pattern is influenced by many parts of the brain and many brain chemicals. This is one reason why people who have the “same” disorder differ from one another so much. But, based on the three points above, it is clear that differences in genes result in differences in behavior, all other things being equal.

Of course, all other things are never equal. Environment is important too. Nearly every trait, and perhaps every behavioral trait, is both genetic and environmental, never one or the other. Part of this is the prenatal and childhood environment. Time and again, researchers have found that people with the same physical brain problem may develop more or less normally if they had good childhoods, but develop behavioral problems if they had abusive childhoods. I say more or less, because the normal people with brain problems still have to struggle a little—but they are generally successful. Environment is why some people with brain problems become clinically dysfunctional and some do not.

Of course, there is even more, something that is largely absent from Oakley’s book. We can influence our own habits of thought, to a certain degree. New brain cells develop in our brains, but too few to be of much use. However, the old cells keep destroying and rebuilding connections. Frequently-used connections, therefore frequently-used behavior patterns, are reinforced. This is not enough to wholly compensate for chemical or large-scale structural problems, but it helps.

Genes create our brains; environments create our brains; and we create our own brains.

Genes make us capable of evil behavior, but also good behavior. Sometimes pathologically good behavior. Everyone’s favorite mutants are the people with Williams syndrome, traced to defects on chromosome 7. These people are completely trusting of strangers; they are super-altruists. I’ve never knowingly met one, but my impression is that they are the sweetest people you could know, sort of like straight out of the pre-pome Garden of Eden. It turns out that they stress out about everything except strangers, but hey, nobody’s perfect.

The point for this evolution blog is that there is a lot here for evolution to work on, in both trusting and evil directions. Scientists would say there is a lot of heritability for good and evil behavior patterns. Evolution can, of course, work on the alleles, for which every human population has plenty of variation. Evolution can also work on the culture. The only thing it cannot work on is you as an individual. But you as an individual can work on evolution—that is, at least you can contribute to cultural evolution.

More on this next time. Meanwhile, I just note that differences in behavior patterns appear to be due to genes, brains, environment, and habits, not to spirits, human or Holy.