James McNeill Whistler: The "Ten O'Clock Lecture," 1888:
"Nature contains the elements, in color and form, of all pictures, as the keyboard contains the notes of all music. But the artist is born to pick, and choose, and group with science, these elements, that the result may be beautiful -- as the musician gathers his notes and forms his chords, until he brings forth from chaos glorious harmony. To say to the painter, that Nature is to be taken as she is, is to say to the player, that he may sit on the piano. That Nature is always right, is an assertion, artistically, as untrue, as it is one whose truth is taken for granted. Nature is very rarely right, to such an extent, even that it might almost be said that Nature is usually wrong; that is to say,, the condition of things that shall bring about the perfection of harmony worthy of a picture is rare, and not common at all." from James McNeill Whistler, The Gentle Art of Making Enemies, 1894, pp. 142-143.
Walter Pater: "All art constantly aspires towards the condition of music." The Renaissance. Studies in Art and Poetry, (first published 1873), 1893, p. 106.