I cannot forecast to you the action of Russia. It is a riddle wrapped in a mystery inside an enigma...-- Winston Churchill (or maybe his speech-writer(s), BBC broadcast, 1939.
The primary definitions of Churchill's three metaphors for Russia from Dictionary.com are as follows:
RIDDLE: "a question or statement so framed as to exercise one's ingenuity in answering it or discovering its meaning; conundrum."
MYSTERY: "anything that is kept secret or remains unexplained or unknown."
ENIGMA: "a puzzling or inexplicable occurrence or situation."
Macmillan Online has the following:
RIDDLE: " a question that seems impossible or silly but has a clever or funny answer"
MYSTERY: " something that you are not able to understand, explain, or get information about"
ENIGMA: "someone or something that is mysterious and difficult to understand"
With infinite time and patience I could probably list out all cited definitions to these three overlapping yet different words. But even if I did so, and determined that there is a statistically dominant definition for each, I don't think those statistically-arrived-at definitions would cancel out my conviction that Churchill's three words have a particular function in that speech about Russia. In short, in order to make his point about the unfathomability of Russia, Churchill chooses three words that all connote unfathomability in increasingly greater degrees. And this becomes important to my theory of literary causality in that each of the three phenomenalities the degree of intelligibility becomes greater.
Just as a "riddle" is a perplexing arrangement of words that does (as Macmillan says) does finally have some rational or quasi-rational answer, the domain of the naturalistic is one in which all objects and situations, however perplexing they may be at a given time, are ultimately intelligible to reason.
A "mystery," as both cited definitions note, does not automatically have an answer-- which might mean that the majority of the ratiocinative works generally called "mysteries" perhaps ought to have been called "riddles," since almost all of them have answers of some sort. The two cited definitions place an emphasis on the attempt of a subject to gain knowledge or information that is hard of access. There is no guarantee, as with a literal riddle, that the mystery will be unveiled, though I would argue that this does not mean it cannot be. Further, not all mysteries are revealed as plays upon rational understanding, as with the set of initiation ceremonies known as the Eleusianian Mysteries.
Of the two cited definitions for "enigma," I believe that Macmillan's is essentially identical to its definition for "mystery," so I disagree with it. Dictionary.com's suits me more in that it suggests that the "occurrence or situation" referenced may be not just temporarily unknowable, but may be permanently "puzzling or inexplicable."
Now, the best way to show how this eventuates in the world of literature is to focus on how intelligibility is reflected in the narrative function of "the anomaly." Once again, I draw upon the definition supplied by academic Frank Cioffi:
This reality [of a traditional narrative] is disrupted by some anomaly or change--invasion, invention, or atmospheric disturbance, for example--and most of the story involves combating or otherwise dealing with this disruption.
Unlike Cioffi-- who does note that anomalies can stem from such mundane factors "such as family, the love ethic, manly heroism, the American Way, and the like"-- I link the nature of the anomaly to its function within a bifurcated causality, one comprised of both a regularity aspect and an intelligibility aspect. In recent essays I've given copious examples as to how narratives conform to, bend, or break with the regularity aspect, but the "riddle, mystery, enigma" progression suggests to me a way to provide a structure for the differing degrees of intelligibility.
In this essay, I attempted to assess to employ an argument about "degrees of probability" the same way I now advocate "degrees of intelligibility." I don't dismiss the arguments re: evidential probability, but they are not as useful as I had hoped to catch the affective distinctions between the three phenomenalities. But the examples I provided work just as well for this current argument:
Sticking only with the Doyle stories this time:
THE FIVE ORANGE PIPS is a naturalistic RIDDLE. The conspiracy Holmes unmasks is one that is fully intelligible to reason, and once the answer is known, it has no further repercussions.
THE HOUND OF THE BASKERVILLES is an uncanny MYSTERY. In the earlier essay I argued then, and still argue, that "the explanation of the Hound via the rules of ordinary causality, while it serves a valid narrative purpose, does not dismiss the affective sense of strangeness from the narrative."
THE ADVENTURE OF THE CREEPING MAN is a marvelous ENIGMA, because the anomaly around which the plot is structured is something outside the rules of "causality's regularity aspect," i.e., "a special drug that can somehow transfer the attributes of an animal to a man." This level of intelligibility is enigmatic and insoluble specifically because the author must introduce some "fudge factor" that allows him to justify the appearance and/or behavior of the anomaly.
I should note that the sheer number of "fudge factors" is irrelevant to the degree of enigmatic intelligibility. It's quite true that Jules Verne did not need to provide as many "fudge-factors" in justifying the existence of his imagined submarine as H.G. Wells did in justifying the existence of gravity-nullifying Cavorite in FIRST MEN IN THE MOON-- nor does it matter, contrary to Verne's opinion, that in real life human beings could and did create real submarines, while no one has come close to synthesizing anything like Cavorite. Both devices are equally marvelous, and equally enigmatic, within the sphere of the fictional universe their authors create.
I should also note that in some narratives it's possible that an uncanny or marvelous situation or entity may appear as a "throwaway," rather than being as central to the narrative as Cioffi's anomalies are. In this essay I reviewed two films in which marvelous occurrences or entities appear within the scope of comparatively mundane storylines. But I tend to think that even when an uncanny or marvelous item intrudes upon a naturalistic framework in this marginal manner, they still transfer their qualities to the whole, as much as if they were central to the narrative.