I know of no more encouraging fact than the unquestionable ability of man to elevate his life by conscious endeavor.
Source: In The Book of Success, ed. Richard Shea, 1993.
-- Henry David Thoreau, (Jul 12 1817-1862), US essayist, poet, naturalist; He is best known for his description of life at Walden Pond, Walden, 1854 and his essay Civil Disobedience, 1849.