The Two Kinds of Evidence in Murder Mysteries

In murder mysteries, there are two kinds of evidence: evidence which tells the detective what happened, and evidence which can get a practical result from society. The practical result is often a criminal conviction, but it need not be; a wedding being called off, the payment of an insurance policy, or the settling of a will all require similar sorts of evidence.

Of the two, it is the former type of evidence, not the latter type, which is of interest to the reader.

The main distinction between the two types of evidence is not really one of the strength of the evidence, that is, of the level of certainty which it conveys. In fact, one of the common features of murder mysteries is the early presence of highly convincing evidence which will convict an innocent person unless the detective uncovers the truth. No, the distinction is not in certainty. The distinction is, rather, what is required knowledge and understanding is required to apprehend the true meaning of the evidence.

Convenient names for the sorts of evidence of which we are speaking might be complex evidence and simple evidence. Complex evidence requires extensive background knowledge and understanding of human nature. Simple evidence does not; it tells its story plainly. (Using this terminology, we can say that it is common for murder mysteries to, early on, have complex evidence which appears to be simple evidence.)

In order to achieve societal action, such as convicting the murderer in a court of law or getting some other legal effect, one must have simple evidence. However, simple evidence is, in murder mysteries, hard to come by. This is, of course, a selective effect. In the case where the murderer’s fingerprints are on the murder weapon, and the murderer was seen killing the victim by multiple witnesses who know the murderer personally, and the murderer was caught immediately afterwards—these are not the stuff of murder mysteries.

Detective stories have the structure of story-within-a-story: the murder is the interior story while its detection is the outer story. Within the outer story, it is frequently the detective’s main purpose in his investigation to try to uncover simple evidence about the inner story. This makes it curious that his success or failure at achieving this goal is (almost) irrelevant to whether the story is a good story.

An excellent example of this is the Poirot story Five Little Pigs. In it, the daughter of a woman who was hanged for murdering her father, seventeen years ago, comes to Poirot asking him to uncover the truth. She just received a letter from her mother, written immediately prior to her execution but entrusted by lawyers to be delivered on her daughter’s 25th birthday, telling her that her mother was innocent.

Poirot undertakes the investigation and interviews all of the people principally concerned. At the end, he explains how all of the evidence which had pointed to the guilt of the woman’s mother actually pointed to the guilt of someone else. That person speaks alone with Poirot, afterwards, and asks him what he intends to do. Poirot says that he will give his conclusions to the authorities, but that it is unlikely that they will pursue it and very unlikely that they will get a conviction. And that’s fine. It’s a very satisfying ending to the story.

But why?

I suspect that the answer (which may be obvious) is that complex evidence is fun, while simple evidence is not fun. It takes brainwork to understand complex evidence, while simple evidence is too easy to be interesting. What matters in a murder mystery is being interesting, not achieving results. Achieving results is, really, the domain of an action story, or possibly a drama. This is why detectives tend to hand their cases off to the police at the end of the story. It’s best if the tedious work happens off-screen.

But there’s an interesting complication to this.

It is not a good story if the detective (and hence the reader) merely finds out what happens without anyone else learning it. Why this is so relates to the detective’s role within the story. As I’ve said before, the detective is Christ figure: the world has been corrupted by the misuse of reason, and the detective enters it in order to restore order to the world through the proper use of reason. So while society need not act, something must be put right. That is, someone beside the detective must learn the truth and be better off for it.

A good example of this is the Sherlock Holmes story The Blue Carbuncle*. It begins with a curious set of coincidences which place the key evidence in front of Sherlock Holmes, and with some investigation he discovers who it was who stole the gemtsone. He invites the man to his room, and he comes. After Holmes confronts him with the evidence, he falls apart and confesses, sobbing. I’ll quote just the last part:

“Get out!” said he.

“What, sir! Oh, Heaven bless you!”

“No more words. Get out!”

And no more words were needed. There was a rush, a clatter upon the stairs, the bang of a door, and the crisp rattle of running footfalls from the street.

“After all, Watson,” said Holmes, reaching up his hand for his clay pipe, “I am not retained by the police to supply their deficiencies. If Horner were in danger it would be another thing; but this fellow will not appear against him, and the case must collapse. I suppose that I am commuting a felony, but it is just possible that I am saving a soul. This fellow will not go wrong again; he is too terribly frightened. Send him to jail now, and you make him a jail-bird for life. Besides, it is the season of forgiveness. Chance has put in our way a most singular and whimsical problem, and its solution is its own reward. If you will have the goodness to touch the bell, Doctor, we will begin another investigation, in which, also a bird will be the chief feature.”

Here there are two aspects to the world which Sherlock Holmes has put right, even though he has produced no evidence for a jury. In the first, the man wrongly accused of the crime will not be convicted of it because the principle witness against him has fled. The second is less certain, but the true criminal may well repent of his crime since he’s seen what evil he’s capable of and still has a chance to make his way in society honestly.

This satisfies the role of the detective as Christ figure. In fact, it even has a curious echo (perhaps intentionally) of the story of Christ and the woman caught in adultery, and how he releases her from the punishment for her crime on the condition that she sins no more. Neither is, strictly speaking, a satisfying story, but they have something else to them—the idea that there is something better than justice. That’s a very tricky notion, because mercy should never be unjust—but at least in the story of the Blue Carbuncle, what was stolen is returned, and so justice is at least mostly satisfied in restitution.

Be that as it may, the primary point under discussion is satisfied. Holmes collects complex evidence which tells him (and thus the reader) the tale, and this is the interesting part. Achieving a practical effect from society is of minor concern.

(I suspect that part of the reason why The Adventure of the Blue Carbuncle ends as it does is that, though it predates Fr. Knox’s decalogue, it violates rule #6 (“no accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right”). The Adventure of the Blue Carbuncle is predicated upon a series of accidents, all of which help the detective. If he achieved a practical societal effect, his reputation would benefit by pure chance. By letting the criminal go, he remains in anonymity and so the accidents which help him produce only an interesting set of circumstances.)


*A carbuncle is a red gemstone, most often a garnet, so a blue carbuncle is something of a contradiction in terms. The story suggests it is a blue diamond, though it could be a blue garnet or even a blue sapphire.

Mystery Commandment #10: Disguises

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The tenth commandment of Detective fiction is:

Twin brothers, and doubles generally, must not appear unless we have been duly prepared for them.

In his 1939 commentary on his decalogue, Fr. Knox said:

The dodge is too easy, and the supposition too improbable. I would add as a rider, that no criminal should be credited with exceptional powers of disguise unless we have had fair warning that he or she was accustomed to making up for the stage. How admirably is this indicated, for example, in Trent’s Last Case!

A few of these commandments have, over the years, become less applicable simply because people have developed the good sense to not violate them. I think that this commandment may be the one for which that is most the case. I can’t think of a story I’ve read—good or bad—in which twins and other doubles appear.

Well, that’s not quite true. There’s an episode of Scooby Doo where a woman was being framed as a witch by her (unknown) twin sister. And there was a Poirot where a murderer established her alibi by having a famous impersonator pretend to be her at a dinner party—but that certainly follows the commandment since the main thing we know about the impersonator is that she was extraordinarily skilled at pretending to be other people. But those are the only two examples which come to mind.

I should note that I’m thinking about really skillful disguises, where a person can interact with others, in person, for quite some time, and be taken to be someone else who wasn’t really there. Minor disguise, by contrast, is a fairly common device in mysteries. It’s a time-honored tradition to have the murderer pretend to be the victim so as to fake the time of death to a later time for which the murderer has an alibi. So much so that these days if a person overhears a conversation the victim was having through a closed door, or saw the victim doing something but at a great distance and with his face obscured but you could tell it was him because of the bright red scarf he always wore, one’s first thought is that it was the murderer pretending to be the victim. In such a case, woe to anyone who has an alibi for the time the murder is supposed to have happened.

With regard to twins, Fr. Knox’s commentary is interesting: “The dodge is too easy, and the supposition too improbable.” These are two different objections, and not particularly related to each other, though I think the conjunction is important here.

The first objection—that the dodge is too easy—is interesting because it is in a sense the essence of a twist that it is something which explains a lot once you know it. But this is not an intellectual twist; it is, rather, a natural twist. It is an oddity of nature that there should be such things as identical twins. And it is the essence of a mystery that the thing unraveled should have been twisted by the hand of man, not of God. It is legitimate to try to understand the mysteries of God, but it is a very different book in which that is done.

The second objection—the supposition is too improbable—is also interesting because it is the heart and soul of a mystery that the obvious solution is not the correct solution. And twins are not that uncommon. According to the statistics I found when googling, about 1 in 250 births is of identical twins. It’s possible that it’s a little less common in England, but this is not so uncommon that no one would think of it. It’s not nearly as esoteric as, say, a poison which hasn’t been discovered by science yet.

I think it’s the combination of being uncommon and explaining everything which makes it unfair. It’s not the sort of thing so likely that anyone in the story will do anything to rule it out, and it certainly will explain away just about anything inconvenient in the story. As such it’s a perennial possibility that the reader has no good way to rule out. That being the case, it should be ruled out as a matter of course and positive hints as to its possibility included if one is going to go down that route.

Mystery Commandment #9: The Watson

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The ninth commandment of Detective fiction is:

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.

In his 1939 commentary on his decalogue, Fr. Knox said:

This is a rule of perfection; it is not of the esse of the detective story to have a Watson at all. But if he does exist, he exists for the purpose of letting the reader have a sparring partner, as it were, against whom he can pit his brains. ‘I may have been a fool,’ he says to himself as he puts the book down, ‘but at least I wasn’t such a doddering fool as poor old Watson.’

This is an interesting commandment because, as Fr. Knox notes in his commentary, a Watson is entirely optional. Plenty of good detective stories have no Watson. In fact, thinking over my favorite detective series, the only one which has a Watson is Sherlock Holmes—that is, the only Watson in my favorite detective stories is the original.

Occasionally Poirot had Captain Hastings, but he’s much rarer in the actual Poirot stories than he is in the David Suchet TV series. In the Lord Peter Wimsey stories Charles Parker was more of a co-detective than a Watson and Harriet Vane certainly was a co-detective. Hugh Berringar was a co-detective with Cadfael. Jessica Fletcher usually didn’t have anyone investigating with her and the gang in Scooby Doo was a team.

Interestingly, I’ve also read all but one of Fr. Knox’s Miles Bredon mysteries and there is no Watson character in those, either. His wife is sometimes his foil, but she is generally a co-detective, using very complementary skills to his.

As something of an aside, but also somewhat on point, police characters who occupy an in-between state as a sort-of Watson and a sort-of co-detective don’t seem to last. I’m basing this on an admittedly small sample size, but in Lord Peter Wimsey Charles Parker was a major character in the first two books, a fairly prominent character in the third, then progressively dwindled in significance until he becomes just a minor footnote in the last few (he married Lord Peter’s sister before his slide into irrelevance).

In the Miles Bredon stories, Inspector Leyland is a major character in the first two novels, then a mostly ancillary character in the third, and absent entirely from the fourth and fifth novels.

By contrast, the at first under-sheriff and later sheriff Hugh Beringar is absent from only a few Cadfael stories—The Summer of the Danes and Brother Cadfael’s Penance come to mind—which are, admittedly, later on, but The Holy Thief is between them and Hugh is a significant character in it.

It’s interesting to contrast the character of Hugh Beringar with Charles Parker and Inspector Leyland because it gets somewhat to the problems with a partial-Watson. By contrast to the other two, Hugh Beringar was intelligent and quick-witted. A scene which particularly stands out in my memory was from Saint Peter’s Faire, where after telling Cadfael that he too had deduced something Cadfael did, he said, “I may not pick up on all the subtleties but since knowing you’ve I’ve had to keep my wits about me” (or words to that effect). Since he was intelligent he was allowed to have a personality.

Charles Parker and Inspector Leyland, by contrast, partially serving the function of a Watson, couldn’t really have much in the way of personality. An everyman simply can’t be very distinctive or he ceases to be an everyman. It’s not, of course, strictly true that Charles Parker had no personality—we did learn that he read theology in his off hours to relax from his official duties. But we never found out that he learned anything from it; this passtime never informed anything he said.

Leyland didn’t even have any hobbies that I can recall reading about.

What makes these police inspectors different from Watson was, I think, the nature of their attachment to the detective—happenstance. Watson, by contrast, was attached to Holmes by friendship. Oh, granted, Charles Parker was in theory a friend of Wimsey, but we never saw any of it and Wimsey wasn’t really the sort of man to have friends. Holmes and Watson, by contrast, really loved each other and were comrades. Watson accompanied Holmes purely because he was devoted to him and Holmes brought him because Watson was his friend.

Cadfael and Hugh form an interesting comparison to both; Hugh was an officer of the law but also a close friend of Cadfael. In fact, Hugh and Cadfael were close enough that Cadfael was godfather to Hugh’s first son. Even when Hugh had no part in an investigation he might show up to spend Cadfael merely for the pleasure of company. And therein we see what’s necessary for a police friend to stay a character—his office must be his secondary connection to the detective, even if it was his original connection.

It is not viable, long-term, to have the same police inspector working with the same detective on every case. (Though I will grant that Monk made it work to some degree, since Monk was a consultant. Ditto for Sean Spencer in Psyche. That said, police consultants come with their own problems since they need to operate under police rules, and there’s an inherent tension with the police constantly hiring someone to do their job for them. Psych got around this by being a comedy and playing this tension for laughs.)

So coming back to the Watson in a story—I think that Fr. Knox is mostly correct, but a true Watson is the exception rather than the rule. It is common for detectives to not act entirely on their own—it is not good for man to be alone—but co-detectives are far more common and I think generally a better choice. And co-detectives should be intelligent; they are characters on their own, but they are also somewhat of a stand-in for the reader helping the detective and who would prefer to think himself incompetent?

Either way, it works much better for the detective and his associates to have a genuine affection for each other.

Detective Commandment #8: Clues

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The eighth commandment of Detective fiction is:

The detective must not light on any clues are not instantly produced for the inspection of the reader.

In his 1939 commentary on his commandments, Fr. Knox said:

Any writer can make a mystery by telling us that at this point the great Picklock Holes suddenly bent down and picked up from the ground an object which he refused to let his friend see. He whispers ‘Ha!’ and his face grows grave – all that is illegitimate mystery – making. The skill of the detective author consists in being able to produce his clues and flourish them defiantly in our faces: ‘There!’ he says, ‘what do you make of that?’ and we make nothing.

I agree with this commandment, though with some reservations.

Before I get into that, I want to mention a fun fact about where the word “clue” comes from: it was originally “clew,” which meant a ball of yarn or thread. It came to have its current meaning from the story of Theseus and the Minotaur, when Ariadne gave Theseus a ball of yarn—a clew—which enabled him to get out of the maze in which the Minotaur lived. A clew was thus, by metaphor, something which enabled someone to get out of a maze of confusion by following it. (The spelling “clue” came about in the 16th century.)

To begin with my agreement: something I’ve talked about before in my discussion of these commandments is the difference between mystery and mere obscurantism. A mystery is a thing which internal consistency. This internal consistency makes it is possible, through learning some of the pieces, to figure out the rest. Mere obscurantism is just a form of “I’m thinking of a number, try to guess which. It was 7.73792555161789434!” There’s no skill involved in defying someone else to read your mind.

This, along with Commandment #6 (accidents), may be one of the most often broken commandments. Writing mysteries is hard, and resorting to cheap tricks is a perennial temptation. That said, there are ways to break this commandment which are not cheating.

The one which comes to mind first is where the clue is mere confirmation of the detective’s theory. It does have to be a theory which is not only supported by the evidence but the only theory which is—otherwise it violates Commandment #6—but as long as the clue is merely confirmation of what the reader should have guessed, its being withheld is only a way of being playful and signaling to the reader that all of the requisite clues have now been shown.

This does (basically) require a Watson character that the detective is encouraging to guess the solution; if the story is told from an omniscient perspective rather than the perspective of the Watson, this is harder to pull off. The author may have to resort to speaking directly to the reader, as Sayers did in my least favorite of her books (The Five Red Herrings), “Here Lord Peter Wimsey told the Sergeant what he was to look for and why, but as the intelligent reader will readily supply these details for himself, they are omitted from this page.”

The other way to violate this commandment—fairly—which I can think of is not very significant, but is probably worth mentioning. There is nothing wrong with the detective withholding clues for a short time. If the detective finds several things and refuses to reveal them in the presence of witnesses but waits until he’s alone with his confidant, there is no harm in this. There is no great benefit either, of course, but it can be used to create some drama because of suspicion falling on whoever it was the detective did not want to see the clue.

It is also possible to separate the finding of a clue and the realization that it was a clue as long as the detective is also in the dark at the time it was found. Supposing that there was a penny on a night stand which was a clue, and it was hidden among some other coins, the detective could pick them all up and put them into a bag without noticing the penny, only to realize that the penny might be significant and then to look into the bag to look at the dates on all the coins present. In a technical sense the clue would have been discovered earlier, but only revealed later. This is fair enough in a mystery novel, so long as the detective reveals the clue when he finally looks closely enough at it to notice its significance.

Mystery Commandment #7: Detective Murderers

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The seventh commandment of detective fiction is:

The detective must not himself commit the crime.

In his 1939 commentary on his decalogue, Fr. Knox said:

This applies only where the author personally vouches for the statement that the detective is a detective; a criminal may legitimately dress up as a detective, as in The Secret of Chimneys, and delude the other actors in the story with forged references.

In many ways this is a counterpart to the first commandment, specifically the part about “but must not be anyone whose thoughts the reader has been allowed to know”, so some of that analysis will apply here.

Incidentally, I can’t help but wonder what Fr. Knox would have thought of the final Poirot novel, Curtain. (Technically, it should be noted, the detective in the novel is Captain Hastings, not Poirot, and there is more than one murderer in the story.) It seems like Agatha Christie made a habit of violating Fr. Knox’s ten commandments and doing it in a way that worked.

Be that as it may, I agree whole-heartedly with this commandment. Having the detective commit the crime destroys the basic structure of a detective story and turns it into a weird mockery of itself; a detective who merely investigates himself becomes nothing but an empty puzzle with no meaning or value.

Having said that, this commandment is one of the least transgressed commandments in detective fiction. There’s a highly practical element to this: most people write series of detective stories featuring the same detective. Having the detective be the murderer once will ruin the enjoyment for the readers of any subsequent stories; having him be the murderer more than once will ruin even the surprise. Who would read a story in which the central mystery was the foregone conclusion of a twist which can be relied upon? So the mere fact that mysteries are written as series tends to safeguard writers from this bad decision. It is true that sometimes self-interest will do the work of virtue.

Mystery Commandment #6: Accidents

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The sixth commandment of detective fiction is:

No accident must ever help the detective, nor must he ever have an unaccountable intuition which proves to be right.

In his 1939 commentary on his decalogue, Fr. Knox said:

That is perhaps too strongly stated; it is legitimate for the detective to have inspirations which he afterwards verifies, before he acts on them, by genuine investigation. And again, he will naturally have moments of clear vision, in which the bearings of the observations hitherto made will become suddenly evident to him. But he must not be allowed, for example, to look for the lost will in the works of the grandfather clock because an unaccountable instinct tells him that that is the right place to search. He must look there because he realizes that that is where he would have hidden it himself if he had been in the criminal’s place. And in general it should be observed that every detail of his thought – process, not merely the main outline of it, should be conscientiously audited when the explanation comes along at the end.

This may be the commandment in Fr. Knox’s decalogue with which I agree most strongly (with a few caveats). Curiously, along with Commandment #8 (the detective must not conceal evidence from the reader), this may be the commandment which is most often broken in detective fiction.

I agree with it because the whole point of a detective is to detect, not merely to be the recipient of pure luck. Pure luck is the domain of comedies or, in some curious cases, of tragedies. It is not the domain of detective fiction. And I should note that this is true whether one is talking about play-fair detective fiction or not. Even if the reader has no earthly way to guess the solution to the problem, the detective should.

This really gets to the question of what a detective story is. A Franciscan friar to is a good friend of mine suggested that the fundamental structure of a detective story is that some villain, through the misuse of reason, has disturbed the natural order of things and that the detective, through the right use of a superior reason, restores the right ordering of things. It is, fundamentally, the Christian story—humanity has messed up the world and God condescends with us to restore it.

This structure to the detective story only works if it is the detective whose right use of reason restores the natural order. Luck and unaccountable intuitions are to detective fiction what the Gnostic and later Arian heresies were to Christianity. Just as those heresies turned Christ into a creature and thus from a savior into a mere conduit of information, luck and unaccountable intuitions turn the detective from a savior into a mere conduit of information. If Christ is a creature, and the detective merely a lucky fool, neither is capable of saving himself, let alone us.

This rule is violated so often precisely because writing detective fiction is hard. This is especially true of mystery novels. As I’ve mentioned elsewhere, mystery novels and mystery short stories are fundamentally different creatures. The short story is a puzzle at the end of which—preferably on the next page—is a solution. The novel must be the tale of the assembly of all the clues necessary to solve the problem or the author must pick whether he wants the story to be unsolvable or to drag on long after it should have finished.

But to make a mystery novel the tale of the assembly of all the necessary clues, there must be some reason why the clues satisfy two opposing conditions:

  1. They are not readily available
  2. They are available

There are a variety of ways to satisfy these two—if not, there would be no detective fiction—but they tend to boil down to a few generalities:

  1. You have to figure out where to look.
  2. The clue doesn’t exist yet.
  3. You already have the clue but it doesn’t mean anything until you find additional evidence satisfying some other condition on this list.

(To be clear, how one goes about doing these things are what make the story, and there are endless ways to do these in fresh and interesting ways.)

The second type of clue—the clue only coming into existence later in the story—requires a certain type of story to work; specifically, one where the murderer is still active. It’s a great type of story, but if it’s not the story one is writing, it’s not an available option. And in that case, we’re left with #1 and #3. And the obtaining of clues which make other clues significant in #3 will resolve into #1, most of the time, because otherwise it’s a police procedural, not a detective story.

So the big trick to writing a mystery story is really figuring out where to look for clues. And the mystery writer is hung, to some degree, on the horns of a dilemma: if the location of the clues are obvious, anyone could follow them up. If the location of the clues are not obvious, why on earth would the detective think to look for them where they are?

There are, of course, ways to unhook oneself from the horns of this dilemma; this commandment forbids the author from simply waving the problem away.

This post is already long enough, but I will mention the ways to unhook oneself from this dilemma, if briefly (and, I should note, they generally work best when combined):

  • Specialized knowledge—this runs the risk of being simply esoteric, rather than mysterious, but in a detective story which is more educational than adventurous, the detective giving away the requisite knowledge when he comes across the clue can make for an enjoyable story. Detectives are, after all, supposed to be not merely brilliant, but also learned. And mystery readers do, as a rule, enjoy learning things. They do need to be real things, though (see rule #4, poisons).
  • Psychological insight—Probably the best example of this is Chesterton’s Father Brown mysteries. If the detective can think like the criminal he will be able to predict what the criminal did and therefore where to look for clues.
  • Gaining the trust of people who have clues—this can easily be done badly (chiefly where the person shouldn’t need his trust to be gained), but it is an extremely workable way to withhold clues for a time. This all too often is an occasion for the detective to become a liar, though; gaining trust under false pretenses is distressingly common in detective fiction.
  • Legwork needed—This is a case where the insight of the detective leads to knowing, not exactly where a clue is, but a small number of places to look. It will take time to explore all of the possibilities until finding the clue. (This works best when there is some reason the possibilities must be investigated by the detective himself, generally to be found elsewhere on this list.)
  • Labwork, police work, etc—chemical analysis of substances, the interviewing of every lawyer in London or everyone living within three blocks of the murder, etc. all take a lot of time. When this is done off-screen, it produces space in which the detective can be doing something interesting. N.B. That interesting thing that the detective does while the poor off-screen laborers toil in the clue-mines should be something that either explains the clue when it comes in or else the arrival of the clue should have no value other than to explain what the detective found while he was occupying the reader’s attention. Anyone can cavort with an attractive member of the opposite sex for a few days until the solution to the problem they have not advanced a wit falls into their lap.
  • Delayed clues—this needs to be used with extreme care because it can easily become cheating, but clues which only show up once the post office has delivered them, or after some device with a timer reveals them, can work. The clue absolutely has to be mysterious on its own, and require everything the detective did in the interim to be meaningful, or the author has wasted the reader’s time until the clue shows up. The reverse could, in theory, work; but it doesn’t work. That is, the previous work being mysterious until the clue shows up in the mail will always feel like a cheap deus ex machina. In either case, there has to be a very good reason why the clue was intentionally delayed, and moreover, it absolutely cannot be the clue which solves the mystery.

There are probably other ways, too, though they’re likely to be some sort of variant on the methods above. And I want to stress again that giving a general description of the structure in no way implies that the stories must be formulaic or un-creative; the beauty of any story is in its specifics. It is no more saying that a story is formulaic because there are only so many workable structures for their plots than it saying that all people look alike to say that all men have the same bones in their skeleton. A man without a skull is not bold and daring, and a man with a skull is not boring and repetitive. It’s what’s inside his skull that really counts.

Mystery Commandment #5: Chinamen

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The fifth commandment of mystery fiction is:

No Chinaman must figure in the story.

In his 1939 commentary on his decalogue, Fr. Knox said:

Why this should be so I do not know, unless we can find a reason for it in our western habit of assuming that the Celestial is over-equipped in the matter of brains, and under-equipped in the matter of morals. I only offer it as a fact of observation that, if you are turning over the pages of a book and come across some mention of ‘the slit-like eyes of Chin Loo’, you had best put it down at once; it is bad. The only exception which occurs to my mind—there are probably others—is Lord Ernest Hamilton’s Four Tragedies of Memworth.

This is a rule that, in its specifics, is really only about a time and place in which most of us do not live (England in the 1920s and 1930s). But I think we can both generalize it and answer the question of why it was so at the same time.

Let’s start by looking at the phrase which Fr. Knox suggests is a sufficient warning-sign of a bad book: “the slit-like eyes of Chin Loo”.

The first thing to notice about this phrase is that it’s simply wrong. The epicanthic fold typical of the Chinese (and others) looks different than the eyes of those who don’t have them, but it really does not make the eye look like a slit. Eyes look like slits when the eyelid is mostly closed, and this is true of all human beings. Saying that the Chinese were “slit-eyed” was a sort of cant, not an actual description.

One of the curious things about literary traditions (whether in the printed word or in movies and television) is how much it is possible for storytelling to reference other stories, rather than real life. It can be a valuable sort of short-hand, but it can also perpetuate entirely fake atmospheres and backstories.

And the slit-eyed Chin Loo is, I suspect, exactly this sort of reference to an evocative but bad story. I have no idea where the unrealistic Chinaman first appeared in English fiction, but I strongly suspect that it was in a very vividly told story, all the more vivid for being new. This will have impressed people, who borrow elements of the story for themselves, and among those whose experience of the world—or at least of the Chinese—comes primarily from books rather than from people, this becomes its own sort of reality.

So we have the first element of why a book which references “the slit-like eyes of Chin Loo” is a bad book—it is a book which is fictionalizing, not real life, but another book. This is fine for satires, of course, since that’s what a satire is—but a satire is all about the distance between another book and reality. As we have a copy of a copy of a copy, the distance to reality will get further and further without the author realizing it.

(There is, also, the simple correlation that lazy authors rarely write good books, but I pass that observation as uninteresting.)

The other thing we can see in the phrase “the slit-like eyes of Chin Loo” is a cheap form of exoticism which, in detective stories, is often a means of obscurantism. By obscurantism, I mean making the story appear mysterious, not by creating a tangle, but simply by referring to knowledge not commonly held, but if known, makes the entire thing clear from the beginning. For example, if you knew at the outset of a story that the Mexican mocking tarantula leaves a bite that looks exactly like the byte of the (east Asian) king cobra and moreover that it is driven into a fury whenever a red-headed woman sings “hush little baby” at night, the death of a red-headed woman whose window was open and who bears what looks like the bite of a king cobra, and who moreover was in the habit of singing “hush little baby” each night for some reason, would not be a mystery at all. No more than a person who died of a dog bite where there is a vicious dog nearby would be.

A mystery requires an apparent contradiction, at least of the evidence to a probably innocent person, but better yet an apparent contradiction to telling us who the murderer is. In extreme cases it can be an apparent contradiction to there being a murder at all. It should not be, simply, the ignorance of the reader to the obvious solution.

The worst form of obscurantism, it should be noted, is the obscurantism of purely fictitious knowledge. It is bad enough when a man looks to have died of natural causes but was actually poised by a rare but real poison that, had the reader known of it, would have been obvious from the start. It’s simply intolerable when the poison doesn’t really exist. (But about poisons specifically, that’s rule #4.) And this goes equally well for motives. The specifics of the motive will, necessarily, be fictitious. This is owing to the fact that all the people in the story are fictitious. But the type of motive must be real. If the victim transgressed a point of honor which is not a point of honor among any real people, this is simply cheating.

And here we come to Mr. Loo, who, in being so exotic, can be made to be anything the author needs in the moment. He can kill because he’s a member of a sect whose dark god demands it, or because of some arcane business deal back in China, or because of some strange rule in the triad in which Mr. Loo is an agent. He has easy access to poisons we don’t know about, ways of killing use hair-thin needles or even just properly applied pressure, and all sorts of other means of killing about which the reader can know nothing because they are made up, but which the author does not necessarily feel is cheating because they were first made up in other books. He may interfere with evidence for arcane reasons of Chinese superstition. In short, being completely fake, he may be anything and the reader has no way of guessing what.

So I think that the other generalization of this rule is also a generalization of rule #4—the people must be fake but the motivations, tools, reactions, etc. of those fake people must all be real.

Mystery Commandment #4: Poisons and Devices

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The fourth commandment of mystery fiction is:

No hitherto undiscovered poisons may be used, nor any appliance which will need a long scientific explanation at the end.

In his 1939 commentary on the commandments, Fr. Knox said, about this:

There may be undiscovered poisons with quite unexpected reactions on the human system, but they have not been discovered yet, and until they are they must not be utilized in fiction; it is not cricket. Nearly all the cases of Dr. Thorndyke, as recorded by Mr. Austin Freeman, have the minor medical blemish; you have to go through a long science lecture at the end of the story in order to understand how clever the mystery was.

With regard to poisons, building on my earlier musings on poisons, I think the poisons really in question are those which ape death by natural causes. A heretofore undiscovered poison which kills in a way that is unmistakably by poison—if the victim’s face turns neon yellow, then he can’t breathe and, gasping, dies, then afterwards his entire body becomes fluorescent green and glows int he dark for two full days—I suspect that this would be cricket. It would be odd, to be sure, but there is certainly no clue being hidden from the reader. The author would just about have to go out of his way to have the detective recognize this fictional poison but not tell the reader about how it can be obtained and administered.

The real problem, I think, is a fictional poison which mimics natural causes. The fictional poison is, in this case, indistinguishable from magic, as far as the reader is concerned. The author can invent any fictional poison with any properties that he wants, so there is no way for the reader to guess what fictional poison the author invented.

Even this could be managed, though, with a bit of work. The trick would be to require that some poison must be deducible, and further, what innocent place the murderer hid the poison must also be deducible. I think it would have to culminate in the detective trying to force the murderer to eat the innocent thing and having him refuse. (Probably an alternative is trying the food out on a guinea pig, but in these sensitive days animal testing may not go over well with audiences.)

I think the case against the long science lecture at the end is more self-evident. The purpose of mystery fiction is to be fun, not to take the place of a college course. The other problem with coming at the end is that the mystery was thus cheating; if the long science lecture couldn’t have come earlier without giving away the plot, the mystery was mysterious only by being esoteric. There is no real difference here with require a long lecture in art history or reading the Chinese language; if the solution is easy given a certain set of background knowledge, the mystery is mysterious only by being obscure. And being obscure is the easiest thing in the world.

It is sometimes possible to work in a long science lecture at the beginning or in the middle of a work of detective fiction, since this becomes more interesting by clearly being a possible key to the problem, and moreover its placement prevents the author from being merely obscure instead of mysterious. That said, it’s probably still best to avoid it, or at least break it up into pieces.

Mystery Commandment #3

In this series, I examine the Mystery Decalogue of Fr. Ronald Knox.

The third commandment of mystery fiction is:

Not more than one secret room or passage is allowable.

Fr. Knox’s 1939 commentary was:

I would add that a secret passage should not be brought in at all unless the action takes place in the kind of house where such devices might be expected. When I introduced one into a book myself, I was careful to point out beforehand that the house had belonged to Catholics in penal times. Mr. Milne’s secret passage in The Red House Mystery is hardly fair; if a modern house were so equipped – and it would be villainously expensive – all the countryside would be quite certain to know about it.

The secret passage was a common feature of detective fiction in the golden age of detective fiction (the inter-war period, roughly, 1919-1939), at least in English detective fiction. It’s far less common in American detective fiction for the reason which Fr. Knox mentions—it would be extraordinarily expensive to build a secret passage into a modern house. In very modern times it’s probably a little more doable, though it likely would have difficulty passing building codes and inspection (especially since inspections for house construction happen in phases, before the drywall is put up to conceal the interior of the walls).

But more to the point, there isn’t really much of any reason to put a secret passage into a house built at pretty much any time in America. In medieval England they were built into castles because castles were military fortifications and having an escape hole can be a good idea in a siege. During the time when the English monarchy was persecuting Catholic priests and executing them, recusant Catholics (in the aristocracy) would install priest holes and secret passages for getting priests into and out of their houses because getting the sacraments was worth a lot of money and trouble.

Houses in America were never designed as military fortifications—American houses were all constructed in the age of the canon—and it was never so illegal to be a Catholic in America that one had to hide priests in secret rooms to protect their lives from a police force which actively searched for them.

Basically, while in old English buildings secret passages might be a holdover from a time when they made sense, there was never a time in America where a secret passage in a house was anything but an eccentricity.

It is just doable to put a secret passage in an American house as an eccentricity—a rich old man who liked to spy on his guests, that sort of thing—but about the only place one can actually find secret passages in American buildings are related to the speakeasies during prohibition. However, those will pretty much all have been disassembled by now since commercial architecture (in America) doesn’t tend to last. The other problem is that a secret passage from, say, a nickel-and-dime store into what used to be a speakeasy and is now a storage room or perhaps a jewelry store or a hair salon doesn’t have a ton of possibility.

It has some possibility, of course. I don’t think it would work for two businesses which are open at the same time, but perhaps going from a closed business to kill someone in the open business could work. That said, the field of possible suspects is likely to be either too big or too small, depending on whether the store was broken into (or, equivalently, a customer stayed behind closing) or someone had to have the key to it.

Having said all of this, secret passages serve an odd function even in English mysteries. One of their principle uses is as a solution to a locked room mystery. The problem with them as such a solution is that they border on magic. The author can put the secret passage from anywhere to anywhere—with respect to the plot, if not precisely with respect to the architecture of the house—much like a magic spell can overcome any limitations (such as a locked room) without giving away anything about the sorcerer.

That said, a secret passage can still be interesting if it has some sort of complicated lock and there are clues to how to solve the lock to open the secret passage. And I’m happy to say that such a mystery would comply with Fr. Knox’s rule, since the existence of the secret passage must be known in order for the clues as to how one finds and opens the secret passage to make any sense at all.

Mystery Commandment #2

In this series, I will be examining the Mystery Decalogue of Fr. Ronald Knox.

The second commandment of mystery fiction is:

All supernatural or preternatural agencies are ruled out as a matter of course.

Father Knox’s 1939 commentary on this was:

To solve a detective problem by such means would be like winning a race on the river by the use of a concealed motor-engine. And here I venture to think there is a limitation about Mr. Chesterton’s Father Brown stories. He nearly always tries to put us off the scent by suggesting that the crime must have been done by magic; and we know that he is too good a sportsman to fall back upon such a solution. Consequently, although we seldom guess the answer to his riddles, we usually miss the thrill of having suspected the wrong person.


When it comes to committing the murder, I think that this is a fairly non-controversial rule. If there are ghosts who can kill people in the story, then one of two possibilities must be the case:

  1. We know about this from the beginning.
  2. We find out about it later.

If #1 is the case, there is no mystery to a locked-room mystery, or really any murder in the haunted house at all. If #2, this violates the first commandment, since we will not have met the murderer early on in the story.

There is the further problem that the demands of justice do not obtain. If there are spirits who are free to kill the living wandering around, they do not have any particular obligation to us to leave us alive. And as a matter of practice, the solution to the mystery is entirely academic, since one cannot put a ghost in prison.

Similarly, the detective receiving the solution to the problem from omniscient or clairvoyant beings is simply not interesting as an intellectual puzzle. One can try to match wits with the detective, but not with God. And really, there’s no difference between between having a ghost tell the detective the solution to the problem and having a living witness to the crime. And no one would write a murder mystery in which the solution was someone who saw the murder came and told the solution to the detective. After all, in that case, he’s at best a stenographer, not a detective.

There is, however, an exception to the rule, if one wants to put a book simultaneously into both mystery and paranormal genres—it would work to have a ghost be the client of the detective. There are some limits to this, of course—it would be hard to have the ghost unaware of who stabbed him to death, for example. But it could certainly work to have the ghost want to know who poisoned him, or who set a trap which killed him, etc. It would offer a fair amount of leeway, too, for how paranormal one wanted the story to be. The ghost could have no interaction with the detective other than kicking off the mystery, in which case it could be questionable whether there even is a ghost. On the other end of the spectrum, the ghost could become the side-kick of the detective, taking advantage of his ability to walk through walls to do detection which is too dangerous or simply unavailable to the detective, but the detective providing the brains of the operation. As a matter of personal taste, it’s not the sort of story I want to write, but it’s definitely doable.

Though it’s not about the command itself, I think a work is in order about Fr. Knox’s commentary on Chesterton’s Father Brown mysteries. I think he slightly mischaracterizes what Chesterton was doing when characters in the story would suggest magic or ghosts as the solution. I do not think that Chesterton was trying to fool the reader, any more than Scooby Doo was trying to fool the audience. Rather, I think Chesterton was setting an atmosphere.

There are two environments in which a detective can operate: one of ignorance, and one of confusion. The people can know nothing, and turn to the detective, or the people can be mistaken, and need the detective to correct them. Many of the classic detective stories are the former. A body is found, there are no witnesses and no fingerprints—who did it? But there is the other sort, where people are sure that someone did it, and the detective must prove them wrong. And this is what Chesterton was setting up.

There is also simply the fun of the thing. Chesterton loved to play with the stereotype of faith-vs-reason and the hard-headed skeptic vs. the credulous priest. And it’s fun because the stereotype is wrong. It is, generally, the skeptics who are credulous. And quite often, it should be added, the priests who are skeptical.

This may be best summed up in one of my favorite passages from the Father Brown mysteries, specifically in the first, The Blue Cross. (To give context, Flambeau is the arch criminal who tried to steal the eponymous blue cross from Fr. Brown but was foiled, and Fr. Brown explained various thieves’s tricks which to defend the blue cross he employed or was prepared for Flambeau to try, some of which even Flambeau hadn’t heard of.)

“How in blazes do you know all these horrors?” cried Flambeau.
The shadow of a smile crossed the round, simple face of his clerical opponent.
“Oh, by being a celibate simpleton, I suppose,” he said. “Has it never struck you that a man who does next to nothing but hear men’s real sins is not likely to be wholly unaware of human evil?”


If you like murder mysteries, you might like murder mystery, The Dean Died Over Winter Break.

tddowb

Mystery Commandment #1

In this series, I will be examining the Mystery Decalogue of Fr. Ronald Knox.

The first commandment of mystery fiction is:

I. 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.

In his 1939 commentary on his Decalogue, Fr. Knox said:

The mysterious stranger who turns up from nowhere in particular, from a ship as often as not, whose existence the reader had no means of suspecting from the outset, spoils the play altogether. The second half of the rule is more difficult to state precisely, especially in view of some remarkable performances by Mrs. Christie. It would be more exact to say that the author must not imply an attitude of mystification in the character who turns out to be the criminal.

The spirit of the first part is, I think, fairly obvious: the reader must have some chance of figuring out the solution and having some idea that the character who turns out to be the murderer exists is a necessary (though not, except in badly written mysteries, a sufficient) condition for that.

There is, however, an exception to this rule: where the specific identity of the murderer is of no great consequence. If the solution to the problem is some salient characteristic of the murderer, rather than his name, it is fair play to have not introduced his name before so long as the salient characteristic was introduced. For example, if the conclusion of the mystery is that it must have been a policeman who committed the crime, it’s not cheating to have not mentioned the particular policeman before. I should note that this regards the actual plunging of the dagger; it won’t work if the policeman acted alone. It does work, however, if the policeman was acting on behalf of a character we’ve already met.

So a possible reformulation of the rule is that at least one of the criminals must have been mentioned in the early part of the story. If the murderer acted alone, this becomes the rule which Fr. Knox set down. In the case of conspiracies, however, one can omit the pawns from appearing in the early part of the story. One cannot, however, omit them entirely. If the dagger was plunged into the victim by the man cleaning his chimney acting in the pay of his nephew, we do not need to meet the chimneysweep early on, but we do need to learn fairly early on that he had his chimney swept.

I should note that it is less tricky to pull this off if the Chimneysweep turns up dead halfway through the novel.

With regard to the other half of the rule, I think that Fr. Knox’s clarification—that the author must not imply an attitude of mystification in the character who turns out to be the criminal—is quite right. To do this would be to lie to the reader. There is a genre called the unreliable narrator genre, of course, but I’ve never heard of this being done well in mysteries.

(The problem is that nothing can compel the unreliable narrator to eventually reveal the truth. You could, however, have multiple narrators. Probably the best example would be the memoirs of the murderer, which contain lies that misdirect the reader, followed by a postscript explaining which parts were lies, written by the police detective after the murderer’s execution.)

Probably the book which Fr. Knox is referring to, by the way, is Agatha Christie’s The Murder of Roger Ackroyd. (There’s no point in spoiler warnings since the context inherently gives away the plot twist.) It is narrated by Dr. Sheppard, who assists Poirot in his investigations, and rather famously concludes with Poirot identifying Dr. Sheppard as the murderer. Christie makes it work by having the novel being written in real-time during the case; thus when Poirot reveals that Dr. Sheppard was the murderer the novel was almost entirely finished; he needed only some minutes to complete it where he admitted his guilt. And it should be noted that Sheppard was chronicling what Poirot did and said, he was not himself actively engaged in trying to solve the crime.

This does raise a curious point, though, that the attitude of mystification which is forbidden is in the murderer’s private thoughts—whether known through omniscent narration or first-person narration—not in the murderer’s actions. It is perfectly permissible for the murderer to have the external attitude of mystification. In fact, it is fine for the murderer to actively investigate the crime in order to throw suspicion off of himself.

I will say, though, that on the last part I tend to find that ruse disappointing. I prefer mysteries in which the good guys are actually good. I realize that in a sense this goes against the heart of the mystery novel—which is figuring out which apparently good person isn’t—but I prefer a mystery story in which there is some solid foundation in the rough waves of deception.


If you like murder mysteries, you might like murder mystery, The Dean Died Over Winter Break.

The Detective Decalogue of Fr. Ronald Knox

If one reads about the golden age of detective fiction (roughly, the inter-war period, circa 1919-1939), one is apt to come across some of the formulations of rules for detective fiction written then. As I’ve noted, detective fiction has from its inception been a self-referential genre, and it was talked about even more outside of the pages of the mystery novel than inside them.

One of the most famous lists of rules is the Decalogue (ten commandments) set down by Fr. Ronald Knox. They are:

1. The criminal must be mentioned in the early part of the story, but must not be anyone whose thoughts the reader has been allowed to know.
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 himself must not commit the crime.
8. The detective must not light on any clues are not instantly produced for the inspection of the reader.
9. The stupid friend of the detective, the Watson, must not conceal from the reader 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.

I propose to go through each of these in one post per rule (which I will eventually link here) and discuss them. In aid whereof, this page which has some of Fr. Knox’s own commentary on his rules (years after he wrote them) will be especially interesting.

I should note that in general I agree with the Decalogue. My intention is not criticism but consideration—to look at the purpose of the rule and as such when it can be broken in good faith.