Brian the Snail said:
The other thing is that these kinds of debates tend to give the creationists legitimacy- I mean, people will tend to think that if a scientist takes time out to debate him, then they must take him seriously, right? So it leads to the impression that there's an actual scientific debate about creationism vs evolution, then in fact there is none.
This is why I like my approach. Short and quick. My opening statement: "I'll be happy to carry on this debate in a scientific forum." Show the Instructions for Authors pages from the journals.
And then I leave, leaving him to sit there and talk to himself.
It's not that it gives creationists legitimacy that bothers me all that much - moreso, it is the implication that a "public debate" is an any way an acceptable means for doing science that I don't like.
Set up a debate at a biology conference. Creationists are allowed to come to them if they want (just as scientists are allowed to come when the Fellowship of Christian Athletes brings in a creationist speaker), so they can go. You think they will go for it? Of course not, because they know that they will bomb in that forum.
But this type of thing is done on occasion, more or less. I have been to conferences where scientists with completely opposing views have been allowed to present, challenge, and debate. They are also allowed to question each other. It was very informative, and I ended up being persuaded by one side (one interpretation fit the full body of what we know than the other)
The problem is that a public audience just doesn't know enough science to be able to evaluate the validity of some of the arguments. When a creationist says evolution violates the second law of thermo, a lot of people are going to fall for it because all they know about the second law is the oversimplistic version that creationists tell them. Now, a lot of scientists don't really know enough about the second law to say much about it either, but they also know that it's not as simple as it is made out to be, and when people who know and understand the second law tell them that it is not a problem for evolution, they are going to accept it. OTOH, from the public perspective, all they know is that one side says it violates the 2nd law and the other side says it doesn't. Who are they to believe? The ones that go into technobabble about closed systems and Clausius inequalities? Or the one who tells them that left on it's own, their house will tend to get messier as opposed to cleaner? Hey, that makes sense. OTOH, partial derivatives are just math mumbo-jumbo and don't describe the real system.
A creationist a makes a statement about the 2nd law to a scientific audience will be hammered so hard it will probably leave bruises. No, not everyone will disagree with them, but there are going to be some people in the audience who know enough to put them against the wall.
That's where science is going to progress. The goal is not to convince the general audience who know what they want the answer to be, it is to convince people who know a lot but don't know enough about what you are talking about to have a solid opinion.