Absolute music (sometimes abstract music) is music that is not explicitly "about" anything; in contrast to program music, it is non-representational. The idea of absolute music developed at the end of the 18th century in the writings of authors of early German Romanticism, such as Wilhelm Heinrich Wackenroder, Ludwig Tieck and E. T. A. Hoffmann but the term was not coined until 1846 where it was first used by Richard Wagner in a programme to Beethoven's Ninth Symphony.

The aesthetic ideas underlying absolute music derive from debates over the relative value of what was known in the early years of aesthetic theory as the fine arts. Kant, in his Critique of Judgment, dismissed music as "more a matter of enjoyment than culture" and "less worth in the judgement of reason than any other of the fine arts" because of its lack of conceptual content, thus treating as a deficit the very feature of music that others celebrated. Johann Gottfried Herder, in contrast, regarded music as the highest of the arts because of its spirituality, which he attributed to the invisibility of sound. The ensuing arguments among musicians, composers, music historians and critics continue today.

A group of Romantics consisting of Johann Gottfried Herder, Johann Wolfgang Goethe, Jean Paul Richter and E.T.A. Hoffmann gave rise to the idea of what can be labeled as "spiritual absolutism". In this respect, instrumental music transcends other arts and languages to become the discourse of a 'higher realm', an idea expressed in Hoffmann's review of Beethoven's 5th Symphony, published in 1813. These thinkers believed that music could be more emotionally powerful and stimulating without words. According to Richter, music would eventually 'outlast' the word.

Formalism is the concept of music for music's sake, or that music's 'meaning' is entirely in its form. In this respect, music has no extra-musical meaning at all and is enjoyed by appreciation of its formal structure and technical construction. The 19th century music critic Eduard Hanslick argued that music could be enjoyed as pure sound and form, and that it needed no connotation of extra-musical elements to warrant its existence. He argued that in fact, these extra-musical ideas and images detracted from the beauty of the music.

Music has no subject beyond the combinations of notes we hear, for music speaks not only by means of sounds, it speaks nothing but sound.

— Eduard Hanslick

Formalism therefore rejected genres such as opera, song and tone poems as they conveyed explicit meanings or programmatic imagery. Symphonic forms were considered more aesthetically pure. (The choral finale of Beethoven's Ninth Symphony, as well as the programmatic Sixth Symphony, became problematic to formalist critics who had championed the composer as a pioneer of the Absolute, especially with the late Beethoven string quartets). Carl Dahlhaus described absolute music as music without a "concept, object, and purpose".

Richard Wagner ironically was a vocal opponent of absolute music, a phrase he coined. Wagner considered the choral finale of Beethoven's Ninth Symphony to be the proof that music works better with words, famously saying: "Where music can go no further, there comes the word ... the word stands higher than the tone." Wagner also called Beethoven's Ninth Symphony the death knell of the symphony, for he was far more interested in combining all forms of art with his Gesamtkunstwerk.