Unless your student’s religious beliefs impair her work — and you don’t suggest they do — they are irrelevant. You should judge her on her scholarship, not her spiritual life. If she were studying the Sumerians, she might have a hard time working out how they accomplished so much so soon after the earth was formed, what with all those dinosaurs running around trampling the pottery. But this young-earth nonsense need not mar her understanding of, say, Oliver Cromwell or, indeed, much else in your period.

We all harbor irreconcilable ideas. (People are no damn good, but I’m a fine fellow. Being overweight is a grave threat to my health — please pass the doughnuts. Life is short — let’s watch TV.) Yet most of us get along pretty well. (Except for those fat guys stuffing themselves in front of “Deal or No Deal.” They’re no damn good.) What’s more, people have an impressive ability to compartmentalize. If your student can indulge her religious notions in church on Sunday and do great work in the library on Monday, more power to her.

You might regard your year together as a chance to teach a promising scholar to sharpen her critical reasoning, that vital tool of the trade, and thus to reconsider this young-earth nuttiness.