“It is now common for otherwise sophisticated evolutionary thinkers to simultaneously claim that strictly naturalistic evolution (of one form or another) is a fact, and that anything else is ruled out a priori. Evolutionists say that evolution is a fact and that non-natural theories do not qualify as science and cannot even be evaluated. [4]”
“a priori” here used means simply, “you agree with me that evolution is a fact, a fact that makes any other conflicting explanation false, then we have a discussion”.
That is precisely what I have in mind when I call neo-Darwinian evolution a faith-based religion. It has been so right from the beginning.