Could you draw and post that Venn diagram, Randy?
So there, Bick!
Thank you, Michael.
Anyone else think it looks like a beach ball being cross-sectioned?
I think non-supernatural horror would include titles like The Lodger by Marie Belloc Lowndes, Psycho by Robert Bloch, Silence of the Lambs & Red Dragon by Thomas Harris, probably In the Cut by Susanna Moore and I think you can argue that Blood Meridian by Cormac McCarthy fits, too.
There are short works that also fit: "The Sea Raiders" by H. G. Wells, "The Traveling Grave" by L. P. Hartley, "Two Bottles of Relish" by Lord Dunsany and, one of my favorites, "The Hands of Mr. Ottermole" by Thomas Burke. When horror writers start listing favorite works of horror, they list several stories/novels that are non-supernatural that inspired their work.
This, of course, is a recurrent debate. Can horror be non-supernatural? I think so, but I'm willing to sub-genrify and call them tales of terror.