Does it really matter if legislatures try to limit or eliminate the teaching of evolution? Is it all that important when school boards try to force science teachers to include non-scientific theories about the development of life alongside evolution in their lessons? Yes, people who care about science, religion, and secularism should care very deeply about efforts by some Christians to get schools to undermine proper science and replace it with theology that is falsely presented as science.
Christian Opposition to Evolutionary Science
Evolutionary theory has been controversial ever since Charles Darwin introduced his ideas about the origins and development of species to Victorian England. It wasn't skeptics and secularists who objected, but the most pious Christians of Victorian society. They didn't object on strictly scientific grounds, though of course Darwin's earliest ideas were susceptible to some scientific critique. No, people's objections were entirely religious in nature — people raised religious objections to a scientific idea as if those objections had any bearing in science.
Matters have changed little over the past century. Those who object to evolutionary theory the most today tend to be people who identify themselves as evangelical or fundamentalist Christians, an amorphous part of Christianity which emphasizes a literal reading of the Bible, very traditional and orthodox beliefs, and the necessity of translating their beliefs into social and political action for the larger purpose of transforming society.
Science vs. Religion
Mainly because of their insistence on reading the Bible more-or-less literally, evangelicals and fundamentalists reject scientific explanations of the origins and diversity of life which conflict with biblical accounts. Evolutionary theory, according to which species evolve and change over time due to natural pressures, is not compatible with a literal reading of the Bible, which claims that all species were created at one time by the special intervention of God.
Naturally, science classes only teach about science, not about religion; therefore, if a science class is going to address the origins and development of life, it will only be through an explanation of evolutionary theory and not through an exegesis of the book of Genesis. Creationists who believe that the diversity of life we see is due to the special creation of their god have come to recognize this and so have adopted a number of strategies in order to fight the teaching of evolution.
One has been to encourage "balanced treatment," the teaching of both evolution and creationism jointly and allowing students to make up their own minds about which way the evidence best leads. Another has been to put "disclaimers" in science texts which emphasize that evolution is a theory and students should keep their minds open. A third strategy has been to develop a scientifically "respectable" form of creationism, commonly known of as Intelligent Design, which supporters hope will get around the restrictions on teaching religion in public schools. Finally, there has also been an effort to have schools simply not teach anything about evolution at all.
Undermining Science in Science Classes
In one way or another, all of these tactics undermine basic science education in at least two ways. The first and most obvious way is the manner in which an education about biology and evolution is diluted, if not eliminated. Evolutionary theory is the central organizing principle of the biological sciences and understanding it is crucial to understanding biology in an overall and general sense. Restricting students' ability to learn about evolution has the consequence of restricting their ability to learn about biology and incorporate what they do learn into a coherent, organized whole.
Creationists' tactics also have a more profound impact on science education which goes beyond biology because they communicate the idea that there is something lacking or something wrong with evolutionary theory, an idea which is not actually true from a scientific standpoint. This causes students to develop very mistaken beliefs about the nature of science, the scientific method, and how scientific research is used. This cheats students out of the proper science education which they deserve.
Attempts to use the law to restrict or dilute the teaching of evolution in public schools matters because science matters. As society relies more and more heavily on science and technology on ever more fundamental levels, it becomes increasingly more important that all citizens receive a proper grounding in science and the scientific method. Science education is becoming a key part of what it means to be a well-informed and well-educated citizen of today; therefore, any effort to temper science education in order to placate a vocal religious group cheats the students, cheats society, and cheats our future.
Abusing Law & Power to Privilege Christianity
Any attempt to undermine science simply because it seems to contradict a traditional Christian belief or to inject traditional Christian beliefs into science classes under the guise of something like "balanced treatment" or "Intelligent Design" necessarily privileges Christianity, Christian beliefs, and of course Christians themselves. It's not just that no religion has any legitimate place in science classes, but government has no legitimate authority to use science to give the impression that it is endorsing, promoting, or privileging any particular religion.
All religions have their creation stories and all of them should be treated equally by the government, which is to say that the government should just ignore them and let individual believers decide what to think about them. No government at any level has any business or authority to single out any one religion’s creation story to teach to children in any context, especially science classes where religion isn't the appropriate subject in the first place.
