Sherlock Holmes Handbook. Christopher Redmond
sometimes, it seems, Watson did not — they are evident in passages throughout the Canon, or systematically set out in Brad Keefauver’s book The Elementary Methods of Sherlock Holmes (1987). Keefauver considers Holmes’s immense general knowledge, his reference library, his readiness to compare the present case to precedents in criminal activity, his use of disguise, and other stratagems and resources. But the essence of Holmes’s detective ability lay in the data he was able to collect and the reasoning in which he engaged.
Chiefly, Holmes worked from facts. “I cannot make bricks without clay,” he said once; and over and over again, “It is a capital mistake to theorize in advance of the facts.” And for him facts were usually tiny things — a burnt match in the mud, the torn and ink-stained finger of a glove:
I can never bring you to realize the importance of sleeves, the suggestiveness of thumb-nails, or the great issues that may hang from a bootlace.... Never trust to general impressions, my boy, but concentrate yourself upon details. My first glance is always at a woman’s sleeve. In a man it is perhaps better first to take the knee of the trouser. [“A Case of Identity”]
In using such a procedure to size up a client or a suspicious character, Holmes is following the example of Doyle’s medical mentor, Joseph Bell. It is a technique exactly suited to the Victorian age, a period of many specialized trades, and to the British multiplicity of social classes and local customs. In a modern, homogenized North America, where all classes dress alike and only a few people work in trades that leave such marks as the weaver’s tooth or the compositor’s left thumb, a Sherlock Holmes might have a much more difficult task.
The observation of trifles is not limited to assessing profession and character. Holmes uses it particularly in examining the scene of a crime, engaging in the famous “floor-walk” with his “powerful convex lens” in search of tiny objects: a pill in A Study in Scarlet, “what seemed to me to be dust” (but was tobacco ash) in “The Boscombe Valley Mystery.” Footprints and other traces are a specialty. The ability to see details, rather than “general impressions,” makes it possible for Holmes to understand the significance of a chip on a railing in “Thor Bridge,” and of beeswing in a wineglass in “The Abbey Grange.”
Writing in the journal Endeavour in 2004, Laura Snyder, a specialist in the history and philosophy of science, assesses whether Holmes can fairly be called a pioneering “scientific detective.” She concludes in part:
Rather than inventing forensic science, the Holmes stories instead presented the “science of criminal detection” in a positive light in Britain. This was particularly important after the 1859 Smethurst case, in which a leading toxicologist had been forced to admit that his earlier findings ... had been mistaken....
Sherlock Holmes did not invent forensic science, but he probably did more than any other person, fictional or not, to portray it as a valuable tool.
Sir Bernard Spilsbury (1877–1947), dubbed by one biographer “the father of forensics,” will be disappointed to hear it.
Finally, of course, Holmes has the knowledge of previous cases, and his general knowledge of society, to help him focus his attention:
“How did you see that?”
“Because I looked for it.” [“The Dancing Men”]
What he does not have is the improbable, detailed knowledge of every science, craft, and art seen in such later detectives as R. Austin Freeman’s Dr. Thorndyke. Holmes is widely read and experienced, but chiefly in the areas that he knows will come in handy. His methods strongly resemble those of the physician, writes Kathryn Montgomery Hunter in Doctors’ Stories (1991): he compares the symptoms of his current case to those of many previous cases, his own and those of other investigators, before making a diagnosis and prescribing treatment. Chapter V of the present work includes some consideration of the state of science in Holmes’s time.
The form of reasoning Holmes uses, which he variously calls “deduction,” “logical synthesis,” and “inference,” is certainly not the same as the traditional formal logic, which is a form of mathematics developed in the middle ages, concerned not with truth but with consistency. The simplest example of a “syllogism,” the form into which logic casts its ideas, is this:
All dogs are mortal.
The Hound of the Baskervilles is a dog.
Therefore the Hound of the Baskervilles is mortal.
The first two statements, or “premises,” lead to the conclusion; thus the syllogism is logically sound. A second syllogism,
Scotland Yard inspectors are detectives.
Sherlock Holmes is a detective.
Therefore Sherlock Holmes is a Scotland Yard inspector.
is unsound because of what logic calls “the fallacy of the undistributed middle.” The premises may or may not be true, but either way they do not prove the conclusion. On the other hand, a logically sound syllogism can have wildly untrue premises, and thus demonstrate nothing about the truth of the conclusion.
Holmes rarely works in this way, although he speaks of it: “From a drop of water, a logician could infer the possibility of an Atlantic or a Niagara.” If traditional logic is “deduction,” a moving from the general to the specific, from cause to effect, then Holmes’s method is really “induction,” moving from the specific to the general, from effect to cause. (“The grand thing is to be able to reason backwards,” he says in A Study in Scarlet.) The nineteenth-century American philosopher Charles Sanders Peirce spoke of induction as moving from “case” and “result” to “rule”: “These beans are from this bag. These beans are white. [Therefore,] all the beans from this bag are white.” Peirce also offered a third form of logic, abduction: “All the beans from this bag are white. These beans are white. These beans are from this bag.” As philosophers Umberto Eco and Thomas A. Sebeok, along with colleagues, explain in The Sign of Three: Dupin, Holmes, Peirce (1983), Holmes is strongly inclined to that sort of logic, as in “The Second Stain”:
Here is one of the three men whom we had named as possible actors in this drama, and he meets a violent death during the very hours when we know that that drama was being enacted. The odds are enormous against its being coincidence. No figures could express them. No, my dear Watson, the two events are connected.
But neither induction nor abduction is rigorously valid: the process is prone to error, coincidences do happen, and an effect can have many causes.
As Keefauver demonstrates, Holmes frequently works through “deduction” in a different sense: imagining as many explanations for the facts as possible, then deducting (eliminating) the less promising. In his most famous dictum (“The Beryl Coronet”) he alludes to this process: “When you have excluded the impossible, whatever remains, however improbable, must be the truth.” The danger of course is deeming something “impossible” when it is not. Holmes often does that, but such is the art of the detective story that he never goes wrong in his leaps.
THE MYTH AND THE HERO. To call Sherlock Holmes the “hero” of the Canonical stories is more than simply to observe that he is the central figure. A hero is someone who acts in a cause, such as freedom or justice, and according to certain conventions. One classic statement of the hero “pattern” is that of Lord Raglan (in The Hero, 1936), who finds twenty-two common features in the stories of figures from Oedipus to King Arthur. Holmes can be seen to have about thirteen of those features, a higher score than Siegfried’s, and equal to that of Robin Hood. He “prescribes laws,” for example (The Whole Art of Detection), nothing is known of his childhood, nothing is known of his death.
Many of Raglan’s “heroes” are supposed gods. Holmes is not presented as a god (although G.K. Chesterton wrote about his apotheosis in “Sherlock Holmes the God” as early as 1935), or even as a king, but merely as “the head of his profession.” However,