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. [...] It is a mistake to think that that little room has elastic walls and can distend to any extent. [...] It is of the highest importance, therefore, not to have useless facts elbowing out the useful ones.
There was a brisk northern wind, heavy and wet with the salt of the sea, and he felt, as he turned his face to it, fresh life and strength surging in his blood and bracing his limbs.
To that Providence, my sons, I hereby commend you, and I counsel you by way of caution to forbear from crossing the moor in those dark hours when the powers of evil are exalted.
It is a mistake to confound strangeness with mystery. The most commonplace crime is often the most mysterious because it presents no new or special features from which deductions may be drawn. This murder would have been infinitely more difficult to unravel had the body of the victim been simply found lying in the roadway without any of those outré and sensational accompaniments which have rendered it remarkable. These strange details, far from making the case more difficult, have really had the effect of making it less so.
What can we know? What are we all? Poor silly half-brained things peering out at the infinite, with the aspirations of angels and the instinct of beasts.
If I had never touched Holmes, who has tended to obscure my higher work, my position in literature would at the present moment be a more commanding one.
Well, well, my dear fellow, be it so. We have shared this same room for some years, and it would be amusing if we ended by sharing the same cell. (...)
His incredible untidiness, his addiction to music at strange hours, his occasional revolver practice within doors, his weird and often malodorous scientific experiments, and the atmosphere of violence and danger which hung around him made him the very worst tenant in London.
One forms provisional theories and waits for time or fuller knowledge to explode them. A bad habit, Mr. Ferguson, but human nature is weak. Sherlock Holmes speaking with Dr. Watson.
If the fresh facts come to our knowledge all fit themselves into the scheme, then our hypothesis may gradually become a solution. Sherlock Holmes speaking with Dr. Watson.
The 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.