Re: teaching intelligent design
1. "Science" used to mean "knowledge obtained by the scientific method."
Later, "scientific" became synonymous with "credible" because the method reliably yielded credible results that everyone could see.
Today, creationists want to ride the coattails of science to credibility by teaching creationism or its variants in science classes.
But they reject the scientific method that made "scientific" synonymous with "credible" in the first place. Their statements are therefore not scientific and therefore not credible, no matter where they are taught.
2. You can't directly observe evolution but you can directly observe the benefits that humans reaped from evolutionary theory. All modern biology and medicine is based on evolution. To see this you don't need to dig through fossils; just dig through medical journals and see how often they mention evolution.
(Experiments on mice only make sense if mice and humans share key biological mechanisms derived from a common ancestor.) Who cares if evolution actually happened or not, if medicines developed using the theory of evolution reliably cure real people?
3. Creationists are not just saying, "evolution doesn't explain everything."
They're saying, "evolution doesn't explain some things -- so God must exist -- and it must be the God of the Bible -- and it must be the God of the Bible as we understand him -- so the religious decrees that we derive from the Bible must be the law of the land." Each of these steps is a giant leap of faith, much bigger than any gaps in evolutionary theory. Poking holes in evolution does not make any of the remaining inferences any more believable.