Diabolus in memoria: Observations Regarding the use of the Tritone in Debussy's Endings

The tritone was a valuable resource for composers at the beginning of the 20th century. Research on possible combinations of intervals facilitated the exploration of innovative harmonic concatenations, established new forms of stability and created harmonies without the usual tonal tensions. The symmetry of the tritone in the circle of fifths and the chromatic scale stimulated reflection amongst numerous theorists. In France, literature, even on classical writing, helped moderate the traditional restrictions on the use of the interval, downscaling the perception of dissonance; the diffusion of Javanese music after the Universal Exposition in Paris also led to an increasing and significant interest in the overlaying of the extended fourth (or the diminished fifth). Claude Debussy solidly entered this very lively debate in the first decade of the 20th century, experimenting with different uses of the interval (in harmony and melody). Often the finales of his instrumental pages present a tritonisation of thematic material with the aim of producing a time gap: small cracks in the harmonic fabric which indicate a membrane between present and past (La flûte de Pan, Prélude à l'après-midi d'un faune, Nuages, La Boîte à joujou, Des pas sur la neige, Pelléas et Mélisande). All the examples mentioned demonstrate a frequent interest in the use of the tritone in memory processes. The impression is that Debussy systematically links the interval to the past, with the aim of evoking a fleeing retroactive thought. It is not the normal cyclical closings of French music in the late 19th century when reminiscence served to lend coherence to a composition, explicitly attracting the attention of the listener (especially in Franck's music). Debussy favours involuntary memory, rather than latent connections which slip under conscious perception; and the tritone helps set in motion this fruitful and complex mechanism.