When I feel well and in a good humor, or when I am taking a drive or walking after a good meal, or in the night when I cannot sleep, thoughts crowd into my mind as easily as you could wish. – Wolfgang Amadeus Mozart

Impressions arriving at the brain make it enter into activity, just as food falling into the stomach excites it to more abundant secretion of gastric juice. – Pierre Cabanis, translated from French

Some minds are made of blotting-paper: you can write nothing on them distinctly. They swallow the ink, and you find a large spot. – Augustus William Hare and Julius Charles Hare, Guesses at Truth, by Two Brothers

Some minds seem almost to create themselves, springing up under every disadvantage and working their solitary but irresistible way through a thousand obstacles. – Washington Irving, The Sketch Book, 1820