Of course, creationists immediately do claim to understand it - they say, without physical evidence to prove it, that all living things were created by God.
That enormous, deliberate confusion is not what I am posting about today, however. I wanted to raise an important objection to this argument, one that I have never heard phrased this way before.
Here is how the Alabama Board of Education phrased it in a disclaimer that appeared as a sticker in high school biology textbooks used in Alabama:
By the way, when Oklahoma was considering adopting the same disclaimer, biology professor (and devout Catholic) Kenneth Miller of Brown University did an excellent job debunking it. The fundamental objection here is that because no one was there, we don't know what really happened.
This textbook discusses evolution, a controversial theory, which some scientists present as scientific explanation for the origin of living things, such as plants and humans.
No one was present when life first appeared on earth. Therefore, any statement about life's origins should be considered as theory, not fact.
The word evolution may refer to many types of change. Evolution describes changes that occur within a species. (White moths, for example, may evolve into gray moths). This process is micro evolution, which can be observed and described as fact. Evolution may also refer to the change of one living thing into another, such as reptiles into birds. This process, called macro evolution, has never been observed and should be considered a theory. Evolution also refers to the unproven belief that random, undirected forces produced a world of living things.
There are many unanswered questions about the origin of life, which are not mentioned in your textbook, including: Why did the major groups of animals suddenly appear in the fossil record, known as the Cambrian Explosion? Why have no new major groups of living things appeared in the fossil record in a long time? Why do major groups of plants and animals have no transitional forms in the fossil record? How did you and all living things come to possess such a complete and complex set of instructions for building a living body? Study hard and keep an open mind. Someday you may contribute to the theories of how living things appeared on earth.
We may think this is a ridiculous objection - and we would be right - but we have to take it seriously. Millions of people believe this about evolution, and it is our duty to show them why it is a ridiculous objection.
When I hear this objection, I like to ask people a question. Do you watch crime shows like CSI? The detectives were not there when the crime was committed. So how do they know who is guilty? (Alternatively, you can ask them about real crimes. Pick your favorite serial killer, and ask 'How do you know that he killed all those people, if no one was there when it happened?'.)
The detectives figure out who committed the crime by carefully studying the crime scene. They take photos and fingerprints, and try to reconstruct the suspect's movements. They look for people who had the motive and opportunity to commit the crime. They construct an EVIDENCE-BASED THEORY* to explain the crime.
Research into biology fits much the same pattern. Researchers study the scene (the fossil record) looking for clues (fossils), and compare what they saw at the scene to what they can see today (modern organisms). They construct an evidence-based theory (evolution) to explain the evidence they saw. Over time, more and more evidence has come in, and it has always been consistent with the theory. If evidence ever comes in that is not consistent with the theory, they'll rethink the theory. But so far, nothing explains living things in the world we live in like evolution does.
Many scientists and supporters of science have bravely defended evolution in the face of anger and threats from the other side. But I've never heard the analogy between evolution research and crime scene investigation made in quite the way I've just made it. Hopefully it can be an addition to the debate that will resonate with some people.
Remember, as Drek said earlier: When science supporters fight back, we win every time.
*Incidentally, I'm convinced that part of the trouble people have with the word "theory" is how it is used in detective shows on TV. In many shows, about 2/3 of the way through, someone says "I have a theory" - and more often than not, it turns out to be wrong.