Arthur Conan Doyle Quotes: Sources, Meanings & Themes
Browse quotations by Arthur Conan Doyle with named works, context notes, meanings and recurring themes.
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“It is a capital mistake to theorize before one has data.”
Meaning & context
Holmes argues that explanations should follow evidence because an early theory can tempt a person to force later facts into a preferred story.
Source details
“A Scandal in Bohemia,” The Adventures of Sherlock Holmes (1891), Project Gutenberg #1661. Holmes immediately warns that premature theorizing leads people to twist facts to suit theories; it is fictional detective dialogue.
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“The world is full of obvious things which nobody by any chance ever observes.”
Meaning & context
Holmes distinguishes mere visibility from real observation: information can be plainly present and still go unused when attention remains superficial.
Source details
The Hound of the Baskervilles, Chapter III, “The Problem,” Project Gutenberg #2852. Sherlock Holmes says that the world is full of obvious things nobody observes after inferring from Watson’s clean clothes and boots that he spent the rainy day indoors, then asks Watson to infer where Holmes himself has been. It remains fictional detective dialogue illustrating Holmes’s observational method rather than a universal scientific rule.
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“When you have eliminated the impossible whatever remains, however improbable, must be the truth.”
Meaning & context
Holmes presents elimination as a reasoning discipline: once genuinely impossible explanations are removed, attention must turn to the remaining explanation even when it initially seems unlikely.
Source details
The Sign of the Four, Chapter VI, ‘Sherlock Holmes Gives a Demonstration,’ Project Gutenberg #2097. Holmes tells Watson that after eliminating impossible entry routes, ‘whatever remains, however improbable, must be the truth,’ then applies the precept to the locked-room investigation and the hole in the roof. It is fictional detective reasoning in a specific evidential setup, not a universal rule that any improbable remaining hypothesis is automatically true without sound premises or exhaustive elimination.