À mon chevet is a series of posts featuring a quote from whatever book is on my nightstand at the moment.
In this nothingness lies (though it is more in the nature of a metaphysical speculation than these concrete examples I have just been discussing) the final Tristan connection in Pelléas. The Tristan progression originated as a breath, the breath, as Wagner said, that 'blurs the clarity of the heavens ... grows, condenses, and solidifies, until finally the whole world confronts me in its impenetrable bulk'. Debussy reverses this process; he liquefies, dissolves, and diminishes, until the impenetrable bulk of the Tristan world vanishes into the empty nothingness from which it had been summoned. And Pelléas has its 'nothingness motif' -- a single tone. As a part of every other motif, or merely an intervallic oscillation, it is omnipresent; it permeates the loose-knit texture more thoroughly than the Welt-Atem or Tristan progression does Wagner's essentially symphonic score -- without, however, binding it together. It is in fact the embodiment of the whole disintegratory, anti-matter emptiness which the work, by its means, consists of as well as expresses. The richness of Wagner's score is already implicit in the progression of the Welt-Atem; the Welt-Atem is pregnant with the abundance and profusion of the accomplished work. By contrast the parsimony of means in Debussy's fully achieved work implies the possibility of a reduction to the central minimum, the nothingness of a single tone.In summing up his analysis of Wagner's (unacknowledged) influence on Pelléas et Mélisande, Holloway quotes an apt aphorism attributed to Lichtenberg: "To do just the opposite is also a form of imitation and the definitions of imitation ought by rights to include both." Holloway has the goods in tangible score analysis that show passages in Wagner's operas filtered into Debussy's score, but he does not push his case too far, in light of Debussy's later professed anti-Wagnerism. When Holloway knows that he is making a speculative leap, he says so, and it rarely feels like a stretch. The rest of the book, no less interesting, concerns other Debussy works, including Le Martyre de Saint Sébastien and the ballet Jeux.
-- Robin Holloway, Debussy and Wagner, p. 135