Almost 150 years after Charles Darwin published his groundbreaking work On the Origin of Species by Means of Natural Selection, Americans are still fighting over evolution. If anything, the controversy has recently grown in both size and intensity. In the last five years alone, for example, debates over how evolution should be taught in public schools have been heard in school boards, town councils and legislatures in more than half the states.
Throughout much of the 20th century, opponents of evolution (many of them theologically conservative Christians) either tried to eliminate the teaching of Darwin's theory from public school science curricula or urged science instructors also to teach a version of the creation story found in the biblical book of Genesis. The famous 1925 Scopes "monkey" trial, for instance, involved a Tennessee law prohibiting the teaching of evolution in the state's schools. (See The Social and Legal Dimensions of the Evolution Debate in the U.S.)
But beginning in the 1960s, the U.S. Supreme Court issued a number of decisions that imposed severe restrictions on those state governments that opposed the teaching of evolution. As a result of these rulings, school boards, legislatures and government bodies are now barred from prohibiting the teaching of evolution. Teaching creation science, either along with evolutionary theory or in place of it, is also banned.
Partly in response to these court decisions, opposition to teaching evolution has itself evolved, with opponents changing their goals and tactics. In the last decade, some local and state school boards in Kansas, Pennsylvania and elsewhere have considered teaching what they contend are scientific alternatives to evolution - notably the concept of intelligent design, which posits that life is too complex to have developed without the intervention of an outside, possibly divine force. Other education officials have tried to require schools to teach critiques of evolution or to mandate that students listen to or read evolution disclaimers, such as one proposed a number of years ago in Cobb County, Ga. It read, in part, that evolution is "a theory, not a fact [and] ... should be approached with an open mind, studied carefully and critically considered." The Cobb County disclaimer and a number of other efforts have been withdrawn following successful court challenges by proponents of teaching evolution.(See Fighting Over Darwin, State by State.)
Recent public opinion polls indicate that challenges to Darwinian evolution have substantial support among the American people. According to an August 2006 survey by the Pew Research Center's Forum on Religion & Public Life and the Pew Research Center for the People & the Press, 63 percent of Americans believe that humans and other living things have either always existed in their present form or have evolved over time under the guidance of a supreme being. Only 26 percent say that life evolved solely through processes such as natural selection. A similar Pew Research Center poll, released in August 2005, found that 64 percent of Americans support teaching creationism alongside evolution in the classroom.
This view is not shared by the nation's scientists, most of whom contend that evolution is a well-established scientific theory that convincingly explains the origins and development of life on earth. Moreover, they say, a scientific theory is not a hunch or a guess but is instead an established explanation for a natural phenomenon, like gravity, that has repeatedly been tested through observation and experimentation. Indeed, most scientists argue that, for all practical purposes, evolution through natural selection is a fact. (See Darwin and His Theory of Evolution.) These scientists and others dismiss creation science as religion, not science, and describe intelligent design as little more than creationism dressed up in scientific jargon.
So if evolution is as established as the theory of gravity, why are people still arguing about it a century and a half after it was first proposed? (See Evolution: A Timeline.) The answer lies, in part, in the possible theological implications of evolutionary thinking. For many, the Darwinian view of life - a panorama of brutal struggle and constant change - goes beyond contradicting the biblical creation story and conflicts with the Judeo-Christian concept of an active and loving God who cares for his creation. (See Religious Groups' Views on Evolution.) In addition, some evolution opponents argue that Darwin's ideas have proven socially and politically dangerous. In particular, they say, the notion that more resilient animals survive and thrive ("survival of the fittest") has been used by social thinkers, dictators and others to justify heinous crimes, from forced sterilization to mass genocide.
But while theologians, historians and others argue over evolution's broader social impact, the larger and more intense debate still centers on what children in public schools learn about life's origins and development. Indeed, the teaching of evolution has become a part of the nation's culture wars, manifest most recently in the 2008 presidential campaign, particularly in the attention paid to Republican vice presidential nominee Sarah Palin's statements in favor of public schools teaching creation science or intelligent design along with evolution. And while evolution may not attain the same importance as such culture war issues as abortion or same-sex marriage, the topic is likely to have a place in national debates on values for many years to come.
Evolution: A Glossary of Terms
Creationism - The belief that the creation story in the Old Testament or Hebrew Bible book of Genesis is literally true and is akin to a scientific explanation for the creation of the Earth and the development of life.
Creation science - A movement that has attempted to uncover scientific evidence to show that the biblical creation story is true. Some in the creation science movement, known as "young Earth creationists," reject not only evolution but also the idea that the universe and the Earth are billions of years old.
Darwinian evolution - The theory, first articulated by Charles Darwin, that life on Earth has evolved through natural selection, a process through which plants and animals change over time by adapting to their environments.
Intelligent design - The belief that life is too complex to have evolved entirely through natural processes and that an outside, possibly divine force must have played a role in the origin and development of life.
Social Darwinism - A belief that Darwin's evolutionary theory can be applied to human society and that groups of people, just like life in the wild, are subject to "survival of the fittest." The now discredited idea influenced many social theories and movements in the late 19th and early 20th centuries, from laissez-faire capitalism to various eugenics movements.
Scientific theory - A statement or principle, honed through scientific observation, reasoning and experimentation, that explains a natural phenomenon.
Theistic evolution - A belief held by some religious groups, including the Catholic Church, that God is the guiding force behind the process of evolution.
This report was written by David Masci, a senior research fellow at the Pew Research Center's Forum on Religion & Public Life.
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