Few minds are sunlike, sources of light in themselves and to others: many more are moons that shine with a borrowed radiance. One may easily distinguish the two: the former are always full; the latter only now and then, when their suns are shining full upon them. – Augustus William Hare and Julius Charles Hare, Guesses at Truth, by Two Brothers

When people will not weed their own minds, they are apt to be overrun with nettles. – Horace Walpole, letter to the Countess of Ailesbury, 1779 July 10th

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

Men are not prisoners of fate, but prisoners of their own minds. – Franklin D. Roosevelt