David Friedman writes:
"Before denouncing that as an intellectually indefensible position, it's worth asking what fraction of those who believe in the theory of evolution could accurately explain it—let alone do a competent job of describing the evidence for it. My impression is that most believers in evolution, like most believers in creationism, base their belief not on their own knowledge and thought but on what they have been told by the authorities they respect."
I recently heard a person loudly denouncing those who did not realize Darwinian evolution was "a proven fact." Here's a true believer whose is hugely ignorant of the history of science. No scientific theory is ever a proven fact -- it's the best guesss we've made so far, if it's the currently held theory.