Direct and indirect evidence in science

Perhaps you should make the creationist define what are, after all, his terms.If he can't or won't, then he might as well be talking about flubnar and non-flubnar evidence.

Creationists usually go to greater lengths to conceal the meaninglessness of their statements.You could always try telling him that the evidence for evolution is stronger than that for other scientific theories in that the evidence for evolution is toticromulent whereas that for other theories is merely metacromulent.

Since astronomy also proves facts that he finds unpalatable, he would presumably be happy to handicap them in this way.