To the man who cherishes a secret in his breast, there is a still greater secret unexplored. Our most indifferent acts may be a matter for secrecy, but whatever we do with the utmost truthfulness and integrity, by virtue of its pureness, must be transparent as light.
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. 331, Houghton Mifflin (1906).