Claude Debussy (1862-1918) was trained in the classical European tradition, studying with a student of Chopin. He had the most of such training among the new composers but was nevertheless the most independent, eventually anti-German. "Golliwogg's Cake Walk" from his Children's Corner (1906-1908) works as an "early herald of the incursion jazz was soon to make into European music, while a less than reverent quotation of the Tristan motive represents another aspect of Debussy's nonchalant attitude towards 'serious' music" (Dömling).
Attention given to the character and length of sound vs. the metrical and rhythmic accent makes Debussy's music seem fluid. What matters are the qualities of sound patterns rather than the significance of these in an overall functional scheme: the sensual aural features vs. the criteria of tonal logic. But organically the music is still valid. Debussy tends to choose expressive subjects, as with his Prélude à l'après-midi d'un faune (1892-1894) from the Mallarmé symbolist poem. Although the piece begins with a flute solo, the flute being appropriate as the instrument associated with the faun -- a half human / half goat woodland creature -- the piece in general conveys merely what Debussy called "a general impression of the poem" (qtd. in Bond 499).
Debussy's rich orchestration is seldom massive. There's minimal thematic development and "standing chords." He is credited with a kind of "emancipation of sound," but nasty critics called the style "boneless tonal vibrato." The music is tonal but not from functional tonality. Tonal centers are established but not in traditional ways.
Technically speaking, Debussy uses the ambiguities and parallels allowed with the six-note whole tone scales (vs. seven-note major/minor scale hierarchies). He likes augmented triads (naturally whole-tone) and unresolved seventh and ninth chords.
Attempts were made to follow Debussy and turn his style into a "school": from art history, the term "Impressionism," implied colorful tone painting, shimmering blended instrumental colors. Monet and Manet, Renoir and Cézanne offered personalized impressions of what they saw, washes of color, subtle brushwork, light dances in rhythmic patterns, avoiding hard edges and sharp contrasts. "In impressionistic painting, color takes precedence over line. Similarly, the impressionist style in music is based on a blurring of distinct harmonies, rhythms, and forms" (Bond 498). Of course, Debussy hated this use of the term for his music.
Debussy's music adapted to the functions of background music because of its fluidity and non-assertiveness. It's unobtrusive. (So Art Nouveau and related literary movements may provide a better analogy than "Impressionism.") But Impressionism in music boils down to Debussy himself and some Ravel (1875-1937). Debussy's subtler influence is more profound. "The disassociation of the individual sound event, the elevation of timbre and articulation to a point equal to harmony and melody, the use of constructions free from tonal patterns and based on symmetry, and the consequent building up of new static and associative forms are all important twentieth-century ideas which find a point of origin in the work of Debussy" (Salzman 25).
Works ConsultedBonds, Mark Evan. A History of Music in Western Culture. Upper Saddle River, NJ: Prentice Hall, 2003.
"Claude Debussy and Impressionism." Carolina Classical Connection. http://classicalmus.hispeed.com/articles/debussy.html. 2004.
Dömling, Wolfgang. "Debussy: Works for Piano." Trans. Mary Whittall. Debussy: Weissenberg. West Germany: Deutsche Grammophon, 415 510-2.
Morgan, Robert P., ed. Music and Society: Modern Times. Englewood Cliffs, NJ: Prentice Hall Inc., 1993.
Salzman, Eric. Twentieth-Century Music: An Introduction. 2nd ed. Englewood Cliffs, NJ: Prentice-Hall Inc., 1974.