What is the theme in Casting the Runes, and Other Ghost Stories by M. R. James?

Supernatural vs. Reason os one of the primary themes running through all of the stories in M.R. James' collection, Casting the Runes and other Ghost Stories, is that of the supernatural versus reason or common sense. The protagonists of the story frequently start out either directly disbelieving or wary of anything supernatural. They tend to be cultured gentlemen who are more concerned with research or their work than investigating mysteries they may come across. However, through their experiences, they quickly become believers.