It is very rare that you meet with obstacles in this world which the humblest man has not faculties to surmount. It is true we may come to a perpendicular precipice, but we need not jump off, nor run our heads against it. A man may jump down his own cellar stairs, or dash his brains out against his chimney, if he is mad.
Henry David Thoreau (1817–1862), U.S. philosopher, author, naturalist. A Week on the Concord and Merrimack Rivers (1849), in The Writings of Henry David Thoreau, vol. 1, p. 193, Houghton Mifflin (1906).