In the case of "creation science", the evidence shows that what it claims and teaches is wrong. Believers can maintain their faith in "creation science" by ignoring the evidence, even denying that the evidence even exists -- Faith's persistent arguments about geology are a prime example of this. On a certain level, they cannot help but know that their beliefs are false, because otherwise they wouldn't know to engage their selective blindness to the evidence -- I have also witnessed "selective stupidity" in which an obviously intelligent creationist would suddenly be unable to understand a very simple English statement.
If creationists really believed that 'creation science' was true they would rush to do research into biology, geology, palaeontology, astronomy, cosmology, etc. because they would expect to find evidence for separately created species, for flood geology, and for a young Earth and a young universe. The fact that they don't try to do research in these sciences shows that they know that they will not find this evidence; it also shows that, as you say, on a certain level they can't help but know that their beliefs are false.