In language there are no sounds as such; there are only what Ferdinand de Saussure calls images of sound. Language, according to Saussure, maps one configuration of differences, on the plane of sound-imagery, on to another, on the plane of thought, such that for every segment of thought, or concept, there corresponds a specific image. As musical sound permeates the awareness of listeners, it gives shape or form to their very perception of the world. Evidently for Plato and his contemporaries, serious music was an essentially verbal art. The human voice, since it was uniquely capable of articulating the Word of God, was considered to be the only properly musical organ. Today, for those of us schooled in the Western tradition, writing seems very different from musical notation, though as we shall see in a moment it is no easy matter to specify exactly where the difference lies.