The sole purpose of art is infinite

E. T. A. Hoffmann wrote in 1813 that instrumental music

is the most romantic of all the arts  – one might almost say, the only genuinely romantic one – for its sole subject is the infinite.  The lyre of Orpheus opened the portals of Orcus – music discloses to man an unknown realm, a world that has nothing in common with the external sensual world that surrounds him, a world which he leaves behind him all definite feelings to surrender himself to an inexpressible language.

Oliver Strunck, ed. Source Readings in Music History (New York, 1950), pp. 775-76.  Cited in : Plantinga, Leon (1984) Romantic Music.  New York: Norton, p.14.