Tuesday, November 27, 2012

Religion vs. Science, the Vast Gulf Part Eight: Where Babies Come From

The most widely and deeply held conviction of religious conservatives is that life begins at conception. They believe that the Bible says so. Of course, it does not. The reason is that, back then, and for over a millennium after the Bible was written, nobody knew about sperm and eggs. Everybody thought that babies grew from the man’s “seed,” which is the literal meaning of “sperm,” which he planted in the womb of a “fertile” woman, as a farmer plants seed in a fertile field. When spermatozoa were first observed under a microscope, scientists imagined they contained little humans (homunculi). Since many ancient people had actually seen spontaneously aborted fetuses, they knew that a developmental process occurred, under the direct control of God (“He knit me together in my mother’s womb,” Psalm 139:18). (We will leave aside the question of whether it is literally a process of knitting.)

I tell my biology students that science cannot tell them when life begins. There isn’t even a “moment of conception.” There are three: when the first sperm penetrates the egg membrane; when meiosis is completed; and when the sperm and egg nuclei join. And then everything that we associate with human physiology (brain activity, heartbeat, etc.) begins at a different time during fetal development. If you want to believe human life begins at conception (perhaps the third moment of conception), no scientist can prove you wrong. But if we had only the information in the Bible to go on, we would not even be having the discussion.

It is tragically humorous that religious conservatives seem to have a self-imposed vagueness about where babies come from. It is not exactly a well-taught part of home-school science. Young teenage girls are taught to not sleep with their boyfriends, as part of abstinence-only education. But the Bible belt leads the nation in births to unwed teen mothers. Rick Perry’s protestations aside, abstinence-only education does not work. I heard that one Texas teen said she did not know how she became pregnant because she only had sex with her boyfriend; she did not actually sleep with him. (This story may be apocryphal; but the statistics are not.)

By now everyone has heard about Rep. Todd Akin’s statement that during “legitimate rape.” He said that in certain instances, such as legitimate rape, a woman’s body can shut down a pregnancy. While many people, including myself, ridiculed Akin’s statement, let me stick up for him in just one small way. He was probably remembering, back during a biology class somewhere, the Bruce Effect. This occurs when a pregnant female, exposed to the hormones of a new male, spontaneously aborts the fetus sired by a previous male. Many rodent and primate species do this. According to a recent paper in Science, spontaneous abortion in one monkey species benefits the female as well as the male, assuming that the alternative is that the new male would kill the babies, which is the brutal truth for many species such as lions. So maybe Akin was remembering more of his biology class than most other elected representatives. (A little learning, said Alexander Pope—not to be confused with Pope Alexander—is a dangerous thing.)

Clearly people back in Bible times considered the development of a baby in the womb to be miraculous. Modern physiology is a threat to Biblical literalism because it says otherwise.

Thursday, November 15, 2012

Religion vs. Science, the Vast Gulf Part Seven: Genetics

First, a couple of announcements. First, you don’t want to miss my new Darwin video in which Darwin uses a hookah pipe as an advanced piece of scientific research equipment and for hypothesis testing. Second, my website no longer has original essays, though the previous ones are still archived; I wish to move my essays to my blogs, mostly to this one. The website is now mostly a clearinghouse of links to other things. Now on with the new topic: the Bible and genetics.

The Bible presupposes that characteristics that an organism acquires during its lifetime can be passed on to its offspring. In so doing, the Bible is no different from what everybody, including scientists, thought until a little over a century ago. But to a creationist literalist, the Bible cannot be wrong about something even if every human being was wrong about it until almost two thousand years after the last of the Bible was written.

The most noticeable example of “Biblical Lamarckism” is in the story of Jacob and Laban in the book of Genesis. Jacob was if anything very tricky. He tricked his brother Esau out of his birthright. And he tricked his relative Laban out of some goats too. Jacob was shepherding Laban’s goats, and made a deal: Jacob would get to keep all of the speckled goats, while Laban got to keep the pure white and pure black goats. Sounds like a deal, Laban said. But Jacob had a plan. (He almost always had a plan, except one night when he was terrified of having to face Esau, his defrauded brother, the next day.) Each evening the goats would come to the water trough to drink and to copulate. (Mommy, what does copulate mean? Be quiet and read your creationist book.) Jacob set up a little wall made of alternating dark and light boughs. The goats would see the striped pattern and have striped offspring, which Jacob got to keep. The clear implication is that the goats had striped and speckled offspring because they saw the stripes at the trough. This is a clear Biblical teaching of Lamarckism. Most of us interpret this to mean that Jacob just thought that the goats had striped offspring because they saw the stripes. But the clear implication in the story is that seeing the stripes caused the offspring to be striped. Creationists ought to have trouble with Mendelian genetics.

There is an easy Mendelian explanation for what happened. The genes from the black goats and from the white goats mixed to form striped and speckled goats. That is, the black and white goats were homozy-goats and the striped goats were heterozy-goats. But this is what science, not what Genesis, says.

The ancient Hebrews also had a very limited idea of what we today call genetic variation. They did not know about many species of animals, or different races of people. They knew about “Ethiopians,” but did they have any idea about the blonds and redheads up north? For aught they knew to the contrary, all genetic variability within each animal species could be contained within a pair of animals on Noah’s Ark, and all human diversity could be contained within Noah’s family. But we know that each species of animals (and everything else) has more genetic variation than could possibly be contained within two individuals, even if God chose the two most diverse and different individuals (for example, two animals of genotypes A1A2 and A3A4 for gene A). No more than four alleles for each gene could be so preserved to account for the whole world of diversity within each species. Modern creationists get around the human problem by claiming that Noah’s daughters-in-law were black, oriental, and white. The Bible mentions nothing of the sort (although it sounds like a good premise for a sitcom), but creationists have never been hesitant to make stuff up about God.

If I may stray a moment from the topic of genetics, I might mention that Biblical biogeography is also wonderfully strange. All the animals debarked from Mt. Ararat in what is now Turkey, and somehow most of the marsupials went to Australia, except for Pogo the Possum, who always had to be different from the others and went to North America. This is just one example. There are hundreds of examples of animals—and plants too—whose geographical distribution looks as if the taxonomic orders and families of which they are a part evolved in the locations where they now reside, rather than migrating there from Ararat. In his book The World That Perished, the father of flood theology John C. Whitcomb answered the question of why the marsupials all went to Australia. He said, in effect, they hopped.

The ancient Hebrews did as good a job as anyone else at figuring out how traits passed from one generation to another. They did as good a job as Darwin, whose pangenesis theory is almost painful to read—such a wrong theory from a man who got almost everything right. But you cannot base the science of genetics on what the Bible says. Darwin did do one thing much better than the ancient Hebrews, however. He extensively studied the genetic (“heritable”) variation in plant and animal species, and knew that there was a lot more of it than met the eye. This was the basis of natural selection.

Wednesday, November 7, 2012

Religion vs. Science, the Vast Gulf Part Six: Continents

It is with considerable relief when I say, Congratulations to Barack Obama for winning a second term. I was afraid that Mitt Romney would make devastating cuts to science and education, cuts that would actually not reduce the deficit very much. At the same time, almost exactly half of the voters voted against Barack Obama. His next four years may be even harder than his previous four years.

Now back to our series about the many ways in which science differs from traditional religion.

The Biblical view of the Earth is that orderly dry land is surrounded by chaotic oceans; in fact, one of God’s earliest acts of creation was to set a boundary between land and sea. The landlubber Israelites were frankly afraid of being out on the ocean (so am I). The God of orderliness had created dry land as the place for people to live.

But the Israelites had no idea that the continents moved around. Of course, neither did anybody else. The idea of continental drift was proposed by Alfred Wegener in the early twentieth century, and accepted only decades later by geologists. You cannot fault the Bible for omitting continental drift, unless you believe the Bible to be the outline of all scientific truth, in which case you have to reject continental drift.

But it is a little more complicated than this. Creationists believe that God sent a Flood upon the Earth, saving only Noah and his family (which, they imagine, contained black, white, and oriental daughters-in-law) from which all the people of the Earth are descended. This was such a severe disruption to the stable continents that all sedimentary rocks (of which continents largely consist) and all volcanic and metamorphic layers between them were produced at that time. Where did all the land come from? Not from day three of Genesis 1, but from the big piles of mud left over after the Flood of Noah. The problems with this theory could fill a book, and have filled many books.

But it gets even more complicated than this. Genesis 10:25 said that in the days of Peleg (a mysterious patriarch about whom little is known) the Earth was divided. This was after the Flood. Let us consider the tremendous scientific implications of this verse, if we take it literally. This verse literally says the Earth was divided. The word for “earth” is the same Hebrew word that is used for the entire planet (see here for concordance references). The word for “divided” refers to cutting entirely in half (see here for concordance references). To really take this verse literally, we have to say what one creationist (Walter Brown) once said in a public forum at the University of Illinois: this was when God created the Atlantic Ocean, causing the Eurasian and North American plates to diverge. But the word literally means to split into pieces, thus we must go way beyond continental drift and believe that the entire planet was split in two. One of the halves must be the one we are on, and presumably the other half has been lost. This would mean that, even right after the Flood, Earth was a much bigger planet, which would give it stronger gravitation, which would make birds unable to fly and large animals (as they are currently designed) unable to walk… This quickly leads to absurdity. Therefore, creationists such as the people at Answers in Genesis claim that “earth” in this verse refers to the people of the Earth. They refuse to allow this interpretation for the very same word in reference to the whole Earth being covered by the Flood, or to God creating the whole Earth in Genesis 1. Apparently, creationists have appointed themselves as the official “deciders” of which passages are to be taken as scientifically literal statements and which are more figurative.

It gets even stranger. Something interesting happened during King Solomon’s coronation parade. “And all the people went up after him [King Solomon], playing on pipes, and rejoicing with great joy, so that the earth was split by their noise.” Some translations say that the earth rumbled with their noise, but the actual Hebrew words refer to the Earth itself actually splitting. Most of us would assume this is the figurative equivalent of “ear-splitting,” and some Bible translations take the liberty of translating it, “The earth rumbled with their noise.” But if you base your science on a literal interpretation of the Bible, you have a problem here. Creationists quietly accept the figurative meaning of this verse.

There are whole continents of difference between the ancient religious view of the earth and the modern scientific one.