by Nathan Cornelius
At first, this piece presents an opaque surface to the listener’s ear, “like a dense, impenetrable cobweb,” to use the composer’s own words. It is almost impossible to tell when the first two voices are joined by a third, then a fourth, until eventually eight independent parts are all singing the same note. Gradually, one by one, the voices diverge to different notes, creating clusters that are sometimes chromatic (as at 0:30) and sometimes diatonic (as at 0:45). Ligeti instructs each voice to sneak in imperceptibly, with the result that the listener does not perceive the discrete entries and exits of the voices, but only clusters gradually building up and then dissolving again.
This method of constructing the texture fulfills one of Ligeti’s main compositional goals. Ligeti was critical of the hyper-serial music of composers such as Boulez, where the exact timing, volume, and articulation of each individual note carry great significance. Instead, Ligeti sought to create music based on larger processes which were directly audible to the listener, and Lux aeterna is clearly music built of textures, not notes. Nevertheless, the score is very precisely notated, full of quintuplets and sextuplets. In each section of the piece, the different voices follow a strict canon, singing the same pitches in the same order with different rhythms. It turns out that Ligeti follows a complex set of rules specifically designed to give the piece a smooth texture, neither experiencing any sudden change in the density of attacks nor making the timing of any individual attack predictable.
Thanks to these rules, Ligeti’s complex polyphonic writing produces an effect that is anything but polyphonic. Ligeti explains, “The polyphonic structure does not actually come through, you cannot hear it; it remains hidden in a microscopic, under-water world, to us inaudible… All in all, you cannot hear my music as it appears on paper. Of course, while actually composing each piece I worked on what we hear, as we hear it.” A serial composer such as Boulez might construct a complex set of “rules” or a matrix, like a carefully engineered machine, and then simply let it run and generate the piece as it willed. In contrast, Ligeti was constantly tinkering with his machine, tweaking the rules until they produced results that perfectly matched his conception of what the piece should sound like. The strict canons and evenly distributed attacks were for him merely a means to an end, a carefully designed process for creating the elusive textures and floating rhythms that for him symbolized the timelessness of eternal light.
 György Ligeti, Ligeti in Conversation, trans. Gabor J. Schabert, et al. (London: Ernst Eulenburg, Ltd., 1983), 14.
 For a lucid analysis of this, see Benjamin R. Levy, “‘Rules as Strict as Palestrina’s’: The Regulation of Pitch and Rhythm in Ligeti’s Requiem and Lux aeterna,” Twentieth-Century Music 10, no. 2 (2013), 203-230.
 Ligeti, Ligeti in Conversation, 14-15.