There’s nothing as deceptive as an obvious fact.

Sir Arthur Conan Doyle (1859-1930)

Sherlock Holmes

Watson ‘ejaculates’


Watson ‘ejaculates’ twice as often as Sherlock Holmes in Conan Doyle’s stories. There are 23 ejaculations in total, with 11 belonging to Watson. On one occasion, Holmes refers to Watson’s ‘ejaculations of wonder’ being invaluable; on another, Watson ejaculates ‘from his very heart’ in the direction of his fiancée. Holmes is only responsible for six ejaculations, although it is not clear which of the two men ejaculate in the passage below:

So he sat as I dropped off to sleep, and so he sat when a sudden ejaculation caused me to wake up, and I found the summer sun shining into the apartment. The pipe was still between his lips, the smoke still curled upward, and the room was full of a dense tobacco haze, but nothing remained of the heap of shag which I had seen upon the previous night.
The Man with the Twisted Lip, 1891


A chap called Phelps ejaculated three times during the story of The Naval Treaty. The only other ejaculator is Mrs St Clair’s husband, who ejaculates at her from a second-floor window.

Elementary


Sherlock Holmes never said ‘Elementary, my dear Watson!’ Holmes does use the word ‘elementary’ in The Crooked Man (1894) but ‘Elementary, my dear Watson’ itself was coined 21 years later by P.G. Wodehouse in his novel Psmith, Journalist (1915). The phrase is also uttered at the very end of the 1929 film, The Return of Sherlock Holmes, the first Sherlock Holmes sound film.

Sir Arthur Conan Doyle (1859-1930)

If in one hundred years I am only known as the man who invented Sherlock Holmes, then I will have considered my life a failure.

Memory Palace


The current TV adaptation Sherlock depicts Holmes as using the 'memory palace' technique, which has been around since Ancient Greece, where it was known as ‘loci’ (the plural of locus – location). Legend says it was first used by Simonides of Ceos who was the sole survivor of a roof collapsing during a meal. He was able to identify the bodies by remembering who had been sitting where at the table. ‘Loci’ works by placing the things you need to remember inside a building that’s familiar to you – such as your house. If you need to remember to buy light bulbs, the newspaper and milk you could picture a giant light bulb glowing on your front door, then the walls of your hall covered in newspaper and then a lake of milk covering the floor in the kitchen. You can invent a building to use but this adds something else to remember.
 
In the books, Sherlock’s memory palace was a memory attic. In A Study in Scarlet, Holmes says 'I consider that a man’s brain originally is like a little empty attic and you have to stock it with such furniture as you choose.'

Sir Arthur Conan Doyle (1859-1930)

When you have eliminated the impossible, whatever remains, however improbable, must be the truth.

Logical Reasoning


Sherlock Holmes doesn’t use deduction but rather abduction: it’s ‘abductive’, rather than ‘deductive’ reasoning.
 
Deduction means the conclusion is logically certain. e.g. All men are mortal. Alan Davies is a man. Deduction: Alan Davies is mortal.
 
Abduction is when you make a conclusion based on the evidence available but it is not certain. e.g. Alan was wearing an Arsenal scarf earlier; Alan is now crying; Alan cries when Arsenal loses. Abduction: Arsenal must have lost.