If we knew all the laws of Nature, we should need only one fact, or the description of one actual phenomenon, to infer all the particular results at that point.
Source: Walden, The Pond in Winter, 1854.
-- 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.