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.

The chief proof of man's real greatness lies in his perception of his own smallness.

I had hardly expected so dolichocephalic a skull or such well-marked supra-orbital development. Would you have any objection to my running my finger along your parietal fissure? A cast of your skull, sir, until the original is available, would be an ornament to any anthropological museum. It is not my intention to be fulsome, but I confess that I covet your skull.

Education never ends, Watson. It is a series of lessons, with the greatest for the last.

"I have seen those symptoms before," said Holmes, throwing his cigarette into the fire. "Oscillation upon the pavement always means an affaire de coeur."

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.

We balance probabilities and choose the most likely. It is the scientific use of the imagination.