"In solving a problem of this sort, the grand thing is to be able to reason backwards. That is a very useful accomplishment, and a very easy one, but people do not practise it much. In the every-day affairs of life it is more useful to reason forwards, and so the other comes to be neglected. There are fifty who can reason synthetically for one who can reason analytically...Let me see if I can make it clearer. Most people, if you describe a train of events to them, will tell you what the result would be. They can put those events together in their minds, and argue from them that something will come to pass. There are few people, however, who, if you told them a result, would be able to evolve from their own inner consciousness what the steps were which led up to that result. This power is what I mean when I talk of reasoning backwards, or analytically."
Sherlock Holmes Quote
-A Study in Scarlet
-Chapter 7 - Conclusion
Do Not Theorized Before Gathering Data
"It is a capital mistake to theorize before you have all the evidence. It biases the judgment."
Sherlock Holmes Quote
-A Study in Scarlet
"It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts."
Sherlock Holmes Quote
-A Scandal in Bohemia
"Let me run over the principal steps. We approached the case, you remember, with an absolutely blank mind, which is always an advantage. We had formed no theories. We were simply there to observe and to draw inferences from our observations."
Sherlock Holmes Quote
-The Adventure of the Cardboard Box
Do Not Reason From Insufficient Data
"Data! Data! Data!" he cried impatiently. "I can't make bricks without clay."
Sherlock Holmes Quote
-The Adventure of the Copper Beeches
"I had," he said, "come to an entirely erroneous conclusion, my dear Watson, how dangerous it always is to reason from insufficient data."
Sherlock Holmes Quote
-The Adventure of the Speckled Band
Data
"There is nothing like first-hand evidence."
Sherlock Holmes Quote
-A Study in Scarlet
Notice Trifles
"You know my method. It is founded upon the observation of trifles."
Sherlock Holmes Quote
-The Bascombe Valley Mystery
"They say that genius is an infinite capacity for taking pains," he remarked with a smile. "It's a very bad definition, but it does apply to detective work."
Sherlock Holmes Quote
-A Study in Scarlet
"It has long been an axiom of mine that the little things are infinitely the most important."
Sherlock Holmes Quote
-A Case of Identity
Obvious Facts Can be Deceptive
"There is nothing more deceptive than an obvious fact."
Sherlock Holmes Quote
-The Bascombe Valley Mystery
Don't Just See, Observe!
"The world is full of obvious things which nobody by any chance ever observes."
Sherlock Holmes Quote
-The Hound of the Baskervilles
Chapter 3: "The Problem
'You see, but you do not observe. The distinction is clear.'
Sherlock Holmes Quote
-A Scandal in Bohemia
Avoid Emotion
"Detection is, or ought to be, an exact science, and should be treated in the same cold and unemotional manner."
Sherlock Holmes Quote
-The Sign of Four
'The emotional qualities are atagonistic to clear reasoning.'
Sherlock Holmes Quote
-The Sign of Four
Recognize Vital Facts
"It is of the highest importance in the art of detection to be able to recognize, out of a number of facts, which are incidental and which vital. Otherwise your energy and attention must be dissipated instead of being concentrated."
Sherlock Holmes Quote
-The Reigate Puzzle
Eliminate the Impossible and What Remains Is Truth
"Eliminate all other factors, and the one which remains must be the truth."
Sherlock Holmes Quote
-The Sign of Four
Chapter 1: "The Science of Deduction"
"How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?"
Sherlock Holmes Quote
-The Sign of Four
'...when you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.'
Sherlock Holmes Quote
-The Blanched Soldier
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'It is an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.'
Sherlock Holmes Quote
-The Beryl Coronet
Additional Notes
"Nothing clears up a case so much as stating it to another person."
Sherlock Holmes Quote
-Silver Blaze
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"I have already explained to you that what is out of the common is usually a guide rather" than a hindrance."
Sherlock Holmes Quote
-A Study in Scarlet
-Chapter 7 - Conclusion
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'"he more outre' and grotesque an incident is the more carefully it deserves to be examined, and the very point which appears to complicate a case is, when duly considered and scientifically handled, the one which is most likely to elucidate it."
Sherlock Holmes
-The Hound of the Baskervilles
Chapter 15 - "A Retrospection"
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"Any truth is better than indefinite doubt."
Sherlock Holmes Quote
-The Yellow Face
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"I never guess. It is a shocking habit — destructive to the logical faculty"
Sherlock Holmes Quote
-The Sign of Four
All quotes on this web site were written by Sir Arthur Conan Doyle unless otherwise stated.
