Wednesday, September 5, 2012

15. Cause & Effect



“We imagined what might have happened, acted upon the supposition, and find ourselves justified.”
“Silver Blaze”

Conan Doyle begins the Memoirs with ‘Silver Blaze,” which remains a favorite among fans and scholars alike. The story is also notable for being one of the more elaborately plotted mystery stories in the canon, containing both a detailed description of Holmes’s method and a satisfying dénouement. Significant to the plotting of the story is the presence of Inspector Gregory of Scotland Yard, a detective who Holmes, uncharacteristically, holds in higher esteem then most police.

Further differentiating “Blaze” from other stories is the fact that Holmes and Watson enter in the case some time after Gregory has conducted a full and, importantly for Holmes, competent investigation. Thus, the narrative of the story is able to combine features of the canon not often seen together, taking elements from the “countryside” stories, wherein Holmes and Watson collect and analyze physical evidence, such as “The Boscombe Valley Mystery” and adding elements of the “armchair” or “consulting” stories like “A Case of Identity”, where Holmes dazzles his compatriots by quickly producing a solution from a few minute details. The result provides an opportunity for Conan Doyle to provide more characters, conflicting motives, red herrings, and build suspense without those titillating details compromising the story’s central plot—in this case, a missing racehorse.
 
As opposed to the solely “armchair” stories where there may be one crucial tidbit, passed over by others, that Holmes is able to identify and extrude to prove his hypotheses, “Silver Blaze” has many. For this reason, many logicians have focused on this story as emblematic of the Holmes method. Furthermore, although there is ample evidence from the earliest canonical sources (i.e., A Study in Scarlet), it is “Silver Blaze” that is most often cited by scholars as an indication that Holmes’s own description of his method as “deduction” is, in fact, not quite accurate (see, especially, Marcello Truzzi’s 1973 article “Sherlock Holmes: Applied Social Psychologist”, in The Humanities as Sociology: An Introductory Reader). Rather, what Holmes enacts, in “Blaze” and elsewhere, is a highly evolved form of abduction.

We may illustrate this through the definitions provided by noted philosopher Charles Sanders Peirce in his 1878 article for Popular Science Monthly entitled “Deduction, Induction and Hypothesis:”

Deduction.
Rule: All the beans from this bag are white.
Case: These beans are from this bag.
Result: These beans are white.
Induction.
Case: These beans are from this bag.
Result: These beans are white.
Rule: All the beans from this bag are white.
Hypothesis.
Rule: All the beans from this bag are white.
Result: These beans are white.
Case: These beans are from this bag.


What Peirce describes as “hypothesis” is, in fact, abductive reasoning, or the inferring of a cause from an observed effect as an explanation of that effect. It is, for Peirce, simply “guessing” the case from: 1.) knowledge or commonsensical appreciation of the conditions (i.e., the “rule”) and some observed “result.” Perhaps one of the most popular and widely known examples of this principle of logic comes from “Silver Blaze” itself—what has come to be known as “the curious incident of the dog in the night-time.”

For the logician David Hitchcock, writing in the 1992 issue of the journal Argumentation, in this famous example, Holmes excels not because of some otherworldly ability to determine cause from effect, but rather at determining which information is most relevant to making that causal link, or, put more simply, Holmes uses a bit of information (such as what a dog does at night) to help confirm his “guess” about a larger bit of information (i.e., how a horse disappeared).

As criminologist Ted Palys writes in the 2003 edition of his commonly used methods textbook Research Decisions:

The gathering of preliminary data is followed by attempts at induction, with inferences regarding particular data combining to generate a preliminary theory. Unlike Inspector Gregory, Holmes doesn’t fall into the trap of prematurely accepting an induced theory, but continues to engage in a dialectic of theory and data that specifically includes generating and considering evidence that might disconfirm the theory. The process of analytic induction leads to the generation of a theory that is consistent, or at least not inconsistent, with all available evidence. Holmes then deduces the evidence that should exist if the theory is true, so that actual observation of concrete evidence …will allow him to test the adequacy of his evolving theory.

Thus, Holmes, like Peirce, demonstrates that there is not a single logical form from which abduction (or hypothesis testing or “guessing”) follows. It is rather a combination of logical methods, observations, and inferences, the speed and accuracy of which elevate Holmes’s method to near fantastical heights. 

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