Creationists concede the credibility of science when they insist on teaching creationism as science and not religion or philosophy.
They adopt names like "creation science" in the hopes of riding the coattails of science to credibility, while rejecting the methods and assumptions that earned science this credibility in the first place.
If they want to use the name "science," they must use scientific standards. Those standards require that any scientific theory be testable and subject to being disproven. Creationism clearly does not make the cut.