Elementary Method

Lore & Background

Holmes observes the dress and attitude of his clients and suspects, noting skin marks such as tattoos, contamination such as ink stains or clay on boots, emotional state and physical condition, and from these he works out their origins and recent history. The stories always call this "deduction", but Holmes mostly relies on abduction, inferring an explanation for the details he has observed, though he reasons deductively as well. His guiding principle, stated in The Sign of Four, is: "When you have eliminated the impossible, whatever remains, however improbable, must be the truth." In "A Scandal in Bohemia" he rebukes Watson: "you see, but you do not observe."

Reader's Guide

Holmes is particularly skilled in the analysis of trace evidence and other physical evidence: footprints, hoof prints and shoe and tyre impressions, tobacco ashes and cigarette butts, handwriting, and typewritten letters compared to expose a fraud. Because much of this evidence is on a small scale, he often uses a magnifying glass at the scene and an optical microscope at his Baker Street lodgings. He has a flair for showmanship and often keeps his methods and evidence hidden until the last possible moment so as to impress observers. Conan Doyle repeatedly said that Holmes was inspired by Joseph Bell, a surgeon at the Royal Infirmary of Edinburgh who, like Holmes, was noted for drawing broad conclusions from minute observations.

Did You Know?

• The exact phrase 'Elementary, my dear Watson' does not appear in Arthur Conan Doyle's original stories.
• Holmes often remarks that his conclusions are "elementary" and occasionally calls Watson "my dear Watson"; William Gillette is widely considered to have originated the famous phrase.
• One study of Holmes's methods against mid- to late-19th-century criminology found that they were based on existing methods and techniques, though sometimes ahead of what official investigative departments were formally using.