 For most of this entry, I focus on “pure” or “absolute” music—instrumental music that has no non-musical aspects, elements, or accompaniments. Most of the philosophers whose work is discussed below also put the focus here, for at least three reasons. The first is that pure music often presents the most difficult philosophical problems. It is less puzzling how a musical setting of a maudlin text could be expressive of sadness, for instance, than how a piece of music without even a programmatic text could be, since the emotional expression could somehow be transferred to the music from the text. The second reason is that, though the problems are more difficult, the solutions are likely to be more easily evaluated in the pure case. Just as apportioning blame is easier when one person is responsible for a crime than when the blame must be divided between a number of conspirators, the success of a solution to the problem of musical expressiveness may be clearer if it can explain the expressiveness of pure music. Thirdly, it is certain that the expressiveness of pure music will play a role in the expressiveness of “impure” music. Though its text may contribute to the expressiveness of a song, for instance, the musical aspects of the song must play some role. A maudlin text set to a jauntily upbeat melody will clearly not have the same overall expressiveness as the same text set to a plodding dirge. Though I have used expressiveness as an example here, these same points will apply to discussions of musical understanding and value. There may also be interesting questions about the ontology of “impure” music, but it is not clear they will be of the same kind as those about the expressiveness, understanding, and value of such music. (For a sustained critique of this general approach, see Ridley 2004.)