Online supplement to LMJ23 (2013) Leonardo Music Journal, MIT Press Journals | http://mitpressjournals.org/lmj Online supplement to LMJ23 (2013) MIT Press Journals | http://mitpressjournals.org/lmj Page 1 Sonic Possible Worlds by Salomé Voegelin, <mail@salomevoegelin.net>. This paper was originally presented at the 2011 Sound Art Theories Symposium (SATS 2011), organized by the Sound Department of The School of the Art Institute of Chicago, November 2011. The symposium presented thirteen papers on a wide range of approaches to current theoretical work in the area of sound as art and art as sound. A selection of the papers can be viewed at <mitpressjournals.org/toc/lmj/-/23>. ABSTRACT: This essay introduces the idea of Possible World theory as a potential strategy to engage in and debate sound: sonic works and the acoustic environment as well as musical compositions. The suggestion is that possible world theory allows for a consideration of the soundscape and sonic works as environments, as sonic worlds that offer an alternative view—a possible and even an impossible view—challenging and augmenting what we pragmatically refer to as the actual world, which is invariably legitimised and situated within a visual and linguistic understanding. The benefit of Possible World theory for sound art is understood to lie in its ability to analyze what is “proposed” by sound: It allows for an exploration of the “then what . . .” of a sonic “if that . . .” rather than limiting itself to the notion of one actuality. Additionally, Possible World theory’s modal approach, the idea that possible worlds exist in a universe of mutually accessible and thus cross-referential worlds, allows the listener not only to access sonic works as environments, as sonic worlds, but to be able to compare and cross-reference a variety of different sonic works understood as worlds within one sonic universe—establishing a comparative field that can facilitate the analysis of diverse sonic works across genres and times. Listening to this comparative field positions its diverse sonic works as possible sonic worlds in relation to phenomenological life- worlds, taking care of the perceptual reality of what is possible in the ephemerality of the unseen. Introduction In this text I will put forward the idea that Possible World theory can be employed for the theorisation and comparative analysis of the soundscape, sound art and music. The suggestion is that the explorative potential of possible worlds, and in particular its focus on reality and contingency, usefully enables the interpretation of the soundscape and sonic works as environments, as sonic worlds that invite a different engagement and propose an alternative perception of the work and the world. The idea that these possible worlds exist in a universe of mutually accessible and thus cross-referential worlds offers the opportunity to critically compare and cross-reference a variety of different sonic works, understood as worlds within one sonic universe: facilitating the critical discussion and theorisation of sonic works across genres and times within one comparative analytical field. I endeavour to persuade the reader of my reasons for using modal philosophy to critically approach sound work, and then outline my method, which is influenced and borrowed from literary studies and game design theory. Having established my motivation and hopefully convinced the reader of my approach and its potential, I want to position these sonic possible worlds in relation to phenomenological life-worlds. The idea that logic’s possible worlds are