Somewhat of a philosophical divide developed during the Romantic Period among musicians who advocated absolute music and those who supported program music. These terms were coined by Richard Wagner as he sought to explain the difference between his Gesamtkunstwerk theory and composers whom he considered stuck in the past.
Advocates of absolute music say that music should be performed for its own sake, listened to and enjoyed for the simple beauty of the art. Composers in this philosophical school tended to write works in more of a traditional Classical style, often maintaining recognizable forms and structures. Some generally absolutist composers included Johannes Brahms, Robert and Clara Schumann, and Felix Mendelssohn.
Program music, on the other hand, suggests that music should be representational, that it should be about something. Music in this view should tell a story or further some non-musical narrative. Composers of program music included Franz Liszt and of course, Wagner himself.
Does music need to be representational to be meaningful?