It is clear that musicians know about silence in music. Empty bars or parts of bars occur in virtually every musical piece. Rests are an inseparable part of any composition. On a more modest and subtle level, silences mark the transition from one musical sentence to the next by way of caesura. Silence also demarcates the beginning and the end of a piece of music.
 This brief and incomplete summary immediately shows the heterogeneity of silence. Silence and silence do not necessarily match. For that reason alone, silence deserves more attention. As Martin Zenck concludes in 'Dal niente - Vom Verlöschen der Musik' [On the Extinguishing of Music], however, the attention to silence is a peripheral moment in composition and music analysis. By no means is its status equal to sound (cf. Zenck, p.15). The pause in music, identified as an absence of sound, is the exception to the rule that has music designated as the center of the musical spectrum. Eduard Hanslick's famous definition of music as 'die tönend bewegte Form' ['form propelled by sound'] in no way indicates a music that is present in its absence, in non-sound. Sound and silence relate to each other as the essential versus the supplement, as the primary versus the secondary. It seems that not the tritonus (the augmented fourth), but rather silence is the true 'diabolus in musica' in Western music. Contrary to the tritonus, silence was never banned, but its raison d'etre has been thoroughly questioned up until the 20th century. Its function was mainly dramatic or rhetoric. Silence is subordinate to sound, and has for the longest time (still?) been regarded as something less significant.
 An example of how silence remains secondary to sound and music in the theory of music can be found in Thomas Clifton's essay 'The Poetics of Musical Silence'. 'To focus on the phenomenon of musical silence is analogous to deliberately studying the spaces between trees in a forest: somewhat perverse at first, until one realizes that these spaces contribute to the perceived character of the forest itself, and enable us to speak coherently of 'dense' growth or 'sparse' vegetation. In other words, silence is not nothing. It is not the null set. Silence is experienced both as meaningful and as adhering to the sounding position of the musical object' (Clifton, p.163, my italics). Clifton seems to focus our attention on the meaning of silence within music. In a certain sense, an emancipatory move. Upon closer consideration, however, this reading loses significant cogency. Clifton leaves the traditional relationship between sound and silence intact. He continues to operate within the existing hierarchy where silence serves sound. Similar to the spaces between trees, silences that surround tones enable us to hear the sounds. 'The significance of silence is therefore contingent upon a sounding environment', Clifton continues (Clifton, p.163). Silence remains dependent on the world of sound because it is only there that it can acquire meaning. In a summary of the various ways in which silence can function, Clifton discusses 'examples of the way silence is used to express how the music is speaking' and 'the adherence of silence to the grammar of the musical statement' (cf. Clifton, p.173). In both cases, silence is clearly still in the service of sound. Clifton does try to convince his readers of the importance of silence within music, but this importance ultimately serves the sounds, the music. Silence is no longer empty, that is to say, without meaning, but its autonomy - i.e., its non-sound based value - is left unrecognized.
 At the start of the 20th century, the composers of the Second Viennese School, Arnold Schönberg, Anton Webern, and Alban Berg shared a similar outlook on silence. Still, signs of a changing attitude towards silence can be found here. Many compositions by Berg lack a clear closure; rather, they fade into a distance, a void, an infinitude. With that, Berg joins the tradition of many composers from the Romantic era who worked with sounds 'come da lontano', sounds that originate in the distance, thereby suggesting a certain infinity. Even when we no longer hear sounds, the music is still present. However, Berg still thinks of silence as a special and peripheral moment. It only becomes apparent in very special areas of his music, particularly towards closures. And can we maintain that Berg emancipates silence? Clifton rather describes the experience of Berg's fading tones as a sensation of resistance toward the moment when the music will reside only in recollection (cf. Clifton, p.175).
 With Webern, too, sound remains the primary aspect of composing even though the presence of multiple rests within his works disperses the sound to a great extent. However, this does not seem to be the result of an intended use or a conscious emancipation of silence, but of the way in which the tone material is processed. Dedication to a previously chosen twelve-tone row implies that variation is primarily reserved for the rhythmic part. It is obvious that rests will then play a more important role (cf. Veselinovic-Hofman, p.4). Nevertheless, Webern's work definitely presents an emancipatory moment with regard to silence. In his Variationen für Klavier, opus 27, for example, he treats silence as sound: the performer is instructed to speed up during a rest before pausing. (I am referring to the third part of the composition, bars 43-45. An accelerando in bar 43 is maintained in the silent bar 44. The initial tempo is taken up again in bar 45 that begins with a rest.)
 A third example. Schönberg. Is silence structurally revalued in his Sechs kleine Klavierstücken, Opus 19, no.2 (Play music)? The piece begins with a rest. A rest after silence, after the silence that is outside the composition, after the solemn silence with which the piece is welcomed. (Below the score, Schönberg indeed asks for a long pause after each movement, a pause that is not motivated by considerations of performing practice.) This rest is not an accidental phenomenon or a necessary respite, but an event deliberately considered in the framework of the composition (cf. Veselinovic-Hofman, p.3). The rests that alternate with the third g-b in the rhythmic motif from bar 1 (a pianissimo third on the border of audibility) form an essential part of the musical sentence. When the sounding third breaks the silence, and the silence in turn breaks the sound, the two engage in a mutual relation that knows no hierarchical distinction. Still, a problem remains. This line of reasoning can only be sustained as long as one knows the score. Veselinovic-Hofman rightfully points out that the first pause cannot immediately be recognized as a musical moment, a moment within the composition, through listening (cf. Veselinovic-Hofman, p.3). Even though the rest serves a structural function within the work, the listener who is not familiar with the score will most likely assume Opus 19, no.2 (Play music) starts with the first sounding third at the second beat of the first bar. (It seems that the listener only becomes aware of the importance and impact of silence - silence regarded as the absence of 'musical' sounds within a musical work - when these sounds are extremely delayed as in John Cage's composition Waiting) (Play music.) The opening rest in Opus 19, no.2 (Play music) becomes significant at the moment when sound occurs; therefore, according to Veselinovic-Hofman, silence remains supplementary to sound. The change that takes place in this piece, however - a change that is noticeable only when the score is studied (and possibly kept in memory during a subsequent listening) - is that the rest acts essentially supplementary with respect to its hierarchical relation to sound. The rest remains subordinate to the 'musical' sounds, but no longer functions as an amorphous, meaningless silence; the significance of the rest is the absence of sound (cf. Veselinovic-Hofman, p.4).
 According to Zenck, the 20th century exhibits a radical change of the paradigm according to which theorists and composers appreciate the hierarchical relation between sound and silence. I am not concerned with passing final judgment on whether or not this change takes place in Opus 19, no.2 (Play music), or whether Schönberg's composition is the first in which a reversal in the hierarchical relation between sound and silence possibly takes place. The extensive presence of rests and silence in his composition enables one to read Opus 19, no.2 (Play music) with this possible reversal in mind. First reading: sound above silence. Silence assumes its contours through sounds that outline its boundaries (make it sound). Something needs to sound in order to know that there is silence in between or around. Second reading: silence above sound. Analogous to the idea that in a material sense, it is the spaces between the words that make a text possible as a text, silence constitutes the condition for the musical sign. It is a space that provides a condition for music to spread, a Da-sein that promotes the development of sounds. 'What makes a wheel a wheel is the space between the spokes' (Lao-Tse).
 More or less by coincidence, more or less at random, I will focus on a string quartet by Italian composer Luigi Nono entitled, Fragmente - Stille, An Diotima) (Play music). This piece hovers between sound and silence. In other words, the sound is mediated by non-sound while the silence is mediated by sound. This enables a twofold reading: one that takes sound as the primary aspect of the work; the other starts from silence with sound as its supplementary component.
 The encounter with this process of listening, the encounter with silence, can be considered a principal idea of Fragmente - Stille, An Diotima) (Play music). Music itself accomplishes the rearrangement or reversal of the initial conceptual hierarchy between sound and silence. A deconstructive strategy. Deconstruction at work within music.