Evolutionists are offended at the charge that the “theory of evolution” is not factual but merely a theory, an educated guess. There are other theories they point out, like the “theory of relativity” from Einstein. In the field of science a theory is a model of interpretation that explains something in the natural world.
Science is knowledge, as the original word means. Scientists like to think their models are well established by facts and should have predictive powers. A good theory should be “falsifiable” in a laboratory setting. It needs to be either provable or proven to be false (falsifiable). But much of the theory of evolution has not been provable in lab testing. In fact, the testable factors of the current belief that mutation is the driving agent for change (Neo-Darwinism) have been “disproved,” according to Oxford Professor Denis Noble. If this is true, the “how” of evolution is still unknown.
Still, it is the position of this creation ministry to never challenge the theory of evolution based upon the charge that “a theory is simply a guess.” In science it has tended to me more than that.