“Evolution” in the Darwinist usage implies a completely naturalistic metaphysical system, in which matter evolved to its present state of organized complexity without any participation by a Creator. But “evolution” also refers to much more modest concepts, such as microevolution and biological relationship. The tendency of dark moths to preponderate in a population when background trees are dark therefore demonstrates evolution — and also demonstrates, by semantic transformation, the naturalistic descent of human beings from bacteria.

If critics are sophisticated enough to see that population variations have nothing to do with major transformations, Darwinists can disavow the argument from microevolution and point to relationship as the “fact of evolution.” Or they can turn to biogeography, and point out that species on offshore islands closely resemble those on the nearby mainland. Because “evolution” means so many different things, almost any example will do. The trick is always to prove one of the modest meanings of the term, and treat it as proof of the complete metaphysical system.

Phillip Johnson, Darwin on Trial, p. 153