It is a capital mistake to theorize before one has data.
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 an old maxim of mine that when you have excluded the impossible, whatever remains, however improbable, must be the truth.
London, that great cesspool into which all the loungers and idlers of the Empire are irresistibly drained.
Mediocrity knows nothing higher than itself, but talent instantly recognizes genius.
My mind rebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram, or the most intricate analysis, and I am in my own proper atmosphere. But I abhor the dull routine of existence. I crave for mental exaltation.
I never guess. It is a shocking habit destructive to the logical faculty.
Nothing clears up a case so much as stating it to another person.
I have seen too much not to know that the impression of a woman may be more valuable than the conclusion of an analytical reasoner.
I have frequently gained my first real insight into the character of parents by studying their children.
How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?
His ignorance was as remarkable as his knowledge.
For strange effects and extraordinary combinations we must go to life itself, which is always far more daring than any effort of the imagination.
Circumstantial evidence is occasionally very convincing, as when you find a trout in the milk, to quote Thoreau's example.
Of all ghosts the ghosts of our old loves are the worst.