This is part of a Scientific American article on the movie Expelled, which I mentioned in a prior post. But I want to quote this part that explains well why science doesn't and can't support intelligent design theory:
"5) Science does not reject religious or "design-based" explanations because of dogmatic atheism.
Expelled frequently repeats that design-based explanations (not to mention religious ones) are "forbidden" by "big science." It never explains why, however. Evolution and the rest of "big science" are just described as having an atheistic preference.
Actually, science avoids design explanations for natural phenomena out of logical necessity. The scientific method involves rigorously observing and experimenting on the material world. It accepts as evidence only what can be measured or otherwise empirically validated (a requirement called methodological naturalism). That requirement prevents scientific theories from becoming untestable and overcomplicated.
By those standards, design-based explanations rapidly lose their rigor without independent scientific proof that validates and defines the nature of the designer. Without it, design-based explanations rapidly become unhelpful and tautological: "This looks like it was designed, so there must be a designer; we know there is a designer because this looks designed."
A major scientific problem with proposed ID explanations for life is that their proponents cannot suggest any good way to disprove them. ID "theories" are so vague that even if specific explanations are disproved, believers can simply search for new signs of design. Consequently, investigators do not generally consider ID to be a productive or useful approach to science."