So, I happened across this post at CrimeReads: IN DEFENSE OF THE SUPERNATURAL IN DETECTIVE FICTION, by John Connolly.
Connolly says: My second error, [my friend] believed, was to have mixed the mystery genre with the supernatural. Whatever its benefits or disadvantages to me, either commercially or creatively, he believed that this simply should not have been done. For him, the supernatural had no place in the mystery novel …
Connolly then refers to the “Ten Commandments of Detective Fiction,” promulgated by Ronald Knox in 1929. I’m not sure I’d heard of them, so I looked them up. Here they are, with commentary at the link that I’m removing for the sake of brevity, but those comments are worth reading if you have time to click through.
1. The criminal must be someone mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to follow.
2. All supernatural or preternatural agencies are ruled out as a matter of course.
3. Not more than one secret room or passage is allowable.
4. No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.
.5. No Chinaman must figure in the story.
6. No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.
7. The detective must not himself commit the crime.
8. The detective must not light on any clues which are not instantly produced for the inspection of the reader.
9. The stupid friend of the detective, the Watson, must not conceal any thoughts which pass through his mind; his intelligence must be slightly, but very slightly, below that of the average reader.
10. Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.
My basic responses:
Although the murderer is always mentioned at some point, I’m sure I’ve read many mysteries where he or she was not mentioned “early” by any definition of the term that seems reasonable. Only one secret passage? That’s kind of chintzy. After reading The Moonstone, I agree about the Chinaman; I’d forgotten what a go-to stereotype the “Chinaman” was in literature of the period. Hidden clues are not rare, but are indeed annoying and authors should perhaps follow Rule 8 more closely. I hate stupid sidekicks and prefer Watson-type characters to be more intelligent, not less, than the average reader. Yes, the author had better foreshadow evil twins.
But let’s talk about the supposed exclusion of supernatural elements.
I guess the belief among authors of contemporary detective fiction, or acquiring editors of that subgenre, that “real” detective fiction should not include those elements, is probably one major factor in the rise of Urban Fantasy that is also detective fiction. This is, I’m pretty sure, the majority of all UF. Jim Butcher’s Dresden Files, say. Mike Carey’s The Devil You Know. Liz William’s Detective Inspector Chen novels. Lots of examples.
So when Ronald Knox ruled out supernatural influences, he was evidently completely wrong about what readers will accept in detective fiction, as obviously lots of readers are happy to read detective fiction that includes the supernatural. And when the post by Connolly at CrimeReads defends the use of supernatural elements, his defense appears unnecessary.
Not only that, but in fact I can think of several other mystery subgenres where supernatural elements are important. There’s an important ghost in the Wisteria Tearoom mysteries by Patrice Greenwood, which is a cozy mystery series, and it’s hard to imagine readers objecting.
Basically I think that it depends on the setting and the mood and the style of the novel, but that if they fit, then supernatural influences are fine in any mystery subgenre. For example, certain elements that smack of deus ex machina don’t ring true in Beverly Connor’s forensic anthropology mysteries, and overt supernatural influences would be way out of tune with the series, but ghosts are really quite common in cozies and fit into those quite well.
And if the author wants to throw in multiple labyrinths of secret passages, that’s fine with me too.