Glenn Branch is deputy director of the National Center for Science Education in Oakland, Calif.
Is it going to be a happy 200th birthday for Charles Darwin? Yes and no. Born on Feb. 12, 1809, the British naturalist wasn't the first to think of evolution, but he deserves credit for amassing the evidence to convince the scientific community of his day that living things have descended with modification from common ancestors, as well as for positing natural selection as the main engine of evolution.
Darwin would be happy to discover that 150 years after the publication of his 1859 tour de force, On the Origin of Species, the scientific community remains convinced about evolution—on the basis not only of evidence he cited but also of evidence from sources he could not have dreamed of. Today, as the National Academy of Sciences puts it, "the scientific consensus around evolution is overwhelming."
But he would not be happy to learn that almost half of Americans don't accept evolution. And he would be downright dismayed that teaching evolution is a routine source of controversy in public schools, even though organizations such as the National Science Teachers Association regard understanding evolution as essential to scientific literacy.
The news gets grimmer. Last year, Louisiana enacted a law that encourages teachers and students to debate the "strengths and weaknesses" of evolution, with the clear implication that evolution is shaky science. Oklahoma is considering a similar bill. A bill introduced in Mississippi would require disclaimers about evolution to be affixed to biology textbooks.
What is behind such efforts? Creationism, usually. Although it comes in different flavors—differing on the age of the Earth, whether living things share a common ancestry, and the power of natural selection—at its core is the rejection of the scientific explanation of the history of life in favor of a supernatural account involving a personal creator: God.
In the United States, creationists are typically fundamentalist Christians. But certainly not all Christians reject evolution. Francis Collins, the geneticist who led the effort to sequence the human genome, describes himself as a "serious Christian" who believes that "God, in his wisdom, used evolution as his creative scheme." And more than 11,000 members of the Christian clergy have recently expressed their support for teaching evolution.
Still, driven by their religious discomfort, creationists have long assailed the teaching of evolution. At first they tried to ban it. In the 1920s, antievolution laws were filed in 20 states and enacted in five. When, in 1968, the Supreme Court ruled that such laws were unconstitutional, creationists regrouped and rebranded their view as "creation science."
Scientists evaluated the claims of creation science, rejecting them as scientifically unfounded. Yet law after law was proposed to require equal time for teaching creation science as a credible alternative to evolution. Finally, in the 1987 case of Edwards v. Aguillard, the Supreme Court ruled such laws unconstitutional, too.
Undaunted, a group of creationists devised a minimalist form of their view—dubbed "intelligent design"—in the hope of evading the constitutional barrier to teaching creationism in the public schools. Their hopes were dashed in 2005, when a federal judge found intelligent design was a variant of creationism and not a scientifically credible alternative to evolution.
These attempts have foundered because of the First Amendment's establishment clause, which forbids government actions that have no secular purpose or have the primary effect of promoting (or inhibiting) religion. Creationists have failed to convince the courts that teaching creationism passes the test.
Creationism is not just a legal failure. It is a scientific failure as well. Scan the scientific research literature: There are no signs that anyone is using creationism, whether as creation science or its newfangled form of intelligent design, to explain the natural world. In contrast, not a year passes without the appearance of thousands of scientific publications that apply, refine, and extend evolution.
Defeated in court and unable to make their mark in science, creationists have increasingly turned to the fallback strategy of attacking evolution without mentioning any specific creationist alternative. The bills in Louisiana, Oklahoma, and Mississippi are examples, as are struggles over the treatment of evolution in state science standards in Kansas, Ohio, and Texas.