Evolution is a scientific fact – except, perhaps, in Texas, where the school board is trying to cast doubt on it
Imagine that your state legislature has decided to revamp the way that health and medicine are taught in public schools. To do this, they must tackle the "germ theory of disease", the idea that infectious disease is caused by microorganisms such as viruses and bacteria. The legislature, noting that this idea has many vocal opponents, declares that it is "only a theory". Many people, for instance, think that Aids has nothing to do with viruses, but is the byproduct of a dissipated life. Christian Scientists believe that disease results from sin and ignorance, spiritual healers implicate disturbed auras and shamans cite demonic possession.
In light of this "controversy", the legislature sets up a school board that includes not only doctors, but also shamans, faith healers and, for good measure a few "psychic surgeons" who pretend to extract veal cutlets from patients' intact bodies. Taking account of these diverse views, the board recommends that from now on all teaching of modern medicine must be accompanied by a discussion of its weaknesses, including the "evidence" that Aids results from drug use and malnutrition, as well as from impure thoughts and evil spirits. And our failure to understand the complexities of chronic fatigue syndrome might be seen as reflecting its causation by an inscrutable and supernatural designer.
You would rightly be furious if all this happened. After all, the "germ theory" of disease is more than just a theory – it's a fact. Like all scientific theories, it might be wrong, but in this case that chance is roughly zero. That is because the germ theory works. Antibiotic and antiviral drugs really do cure diseases, while spiritual healing does not. Only an idiot, you'd say, would try to tamper with medical education in this way.
But this is precisely what is happening in Texas with respect to another well-established theory of biology: evolution.
Like the "germ theory" of disease, the "theory" of evolution is also a fact, as firmly established as the proposition that bacteria cause tuberculosis, or viruses cause Aids. And the fact of evolution is supported by mountains of evidence from many areas of biology. Every one of the thousands of sequences of DNA that have been studied support the theory of evolution.
What's more, evolution explains many puzzling observations about biology, like the existence of transitional fossils, vestigial organs and nonfunctional genes, that are incomprehensible under any creationist view. No serious biologist doubts the major tenets of the modern theory of evolution, which are these: life began around 3.5 billion years ago, all living species have common ancestors, descent involves evolution (genetic change over time), lineages divide, forming new species that lead to the branching tree of life, this change took immense spans of time, and that, in the vast majority of cases the diversification and change was due to natural selection and other well-understood evolutionary processes.
So what do creationism and its new incarnation of "intelligent design" explain? Nothing.
Despite all this, the Texas school board will vote this week on a bill that requires educators and textbooks to play up the "problems" with evolution, emphasising both its "strengths and weaknesses". The weaknesses supposedly involve "the insufficiency of common ancestry to explain the sudden appearance, stasis and sequential nature of groups in the fossil record." This is nonsense, of course. There is a mountain of evidence for common ancestry – ancestry that clearly explains the "sequential nature of groups in the fossil record".
The bill also requires schools to teach "the insufficiency of natural selection to explain the complexity of cells." More nonsense, straight out of the playbook of intelligent design. Of course we don't understand everything about the evolution of cells – if evolution had all the answers it would be a dead field – but there is plenty of evidence that natural selection was involved in cell evolution, and not a shred of evidence that it wasn't.
The mention of "sudden appearance" of species leaves no doubt about the bill's motivation, which is to promote Biblically-based creationism in public schools. Tellingly, the Texas bill is not aimed at discussing the "strengths and weaknesses" of chemistry, physics or astronomy. It singles out evolution for one reason alone: it is the only branch of science that some Christians perceive as endangering their theology.
It's no surprise, then, that seven of the 15 members of the Texas state board of education have a socially conservative agenda, several of them explicitly endorsing creationism. And the head of the school board, one Don McElroy, is a creationist dentist whose pedagogical experience is limited to teaching Sunday school. McElroy also holds the Biblically-based view that the world is only 6,000-10,000 years old. How can it be that someone with such preposterous views is given any say in the education of our children?
What happens in Texas doesn't stay in Texas. That state is a sizeable consumer of public school textbooks, and it's likely that if it waters down its science standards, textbook publishers all over the country will follow suit. This makes every American school hostage to the caprices of a few benighted Texas legislators.
What's next? Since there are many who deny the Holocaust, can we expect legislation requiring history classes to discuss the "strengths and weaknesses" of the idea that Nazis persecuted Jews? Should we teach our children astrology in their psychology classes as an alternative theory of human behaviour? And, given the number of shamans in the world, shouldn't their views be represented in medical schools?
Our children will face enormous challenges when they grow up: global warming, depletion of fossil fuels, overpopulation, epidemic disease. There is no better way to prepare their generation than to teach them how to distinguish fact from mythology, and to encourage them to have good reasons for what they believe.
How sad that in the 21st century the Texas legislature proposes the exact opposite, indoctrinating our children with false ideas based squarely on religious dogma. Can't we just let our kids learn real science?
Monday, 6 April 2009
A View From the Pulpit - Jerry Coyne
From the Guardian;