In "Art/Sciences, Allianges", Xenakis formulates the link between the arts, and between art and science, already affirmed in his own works: he uses the compositional methods of Metastasis in order to realize the shells of the Phillips Pavillion. 'Allianges' in French means alloy, but it is to be interpreted more as 'synthesis', than in the sense of a perfect fusion between parts. The base of this fusion is Pithagorean math, with his implied links between arithmetics, astronomy, geometry and music. In the following articles collected in "Musiques Formelles" the word 'formalization' is substituted with 'axiomatization'. An entirely 'axiomatic' composition in the opus of Xenakis is Nomos Alpha. Examples of 'axiomatics' developed by the composer is the 'reticulum theory', on whose base has been realized the first part of Jonchaies, and the 'vectorial spaces'.
If it is possible to compare exactly composition and theory in Xenakis, it's because the idea of formalization, of 'mechanism', has a practical goal. There is an independence of theory from composition, as in hindustani music "a book of theory cannot be distinguished from a book of religious teachings and [...] the purely theoretical instructions the musician obtains are almost exclusively aesthetical, not technical [...] since he finds a practical instruction among an active musician" [Derek Bailey: Improvisation and practice in music, Da Capo Press, 1993]. A reference to an improvised style of music helps us to hint at the distance between this world and the one of Xenakis ("The expression aleatory music today means improvised music. Using this way the word 'alea', that in scientifical terms implies casuality, means making an abuse, and it reflects a counterfeiting and sentimental attitude" [Iannis Xenakis, "Ad Libitum", in The World of Music, vol. 9, no. 1, 1967]) and to have a clue on John Cage ("he introduced a new freedom in music, and its realitazion, as it happened in painting with Jackson Pollock" [Iannis Xenakis, "Su John Cage", 1993, in "Universi del Suono", Ricordi, 2003]).
Xenakis developed first of all a compositional method, the 'stochastic theory' – the use of function of distribution of probability in order to compose instrumental music, then the theory of games, the symbolic logic, the groups theory, the reticula theory, the stochastic dynamic synthesis – the use of functions of distribution of possibilities applied to the synthesis of sound, the theory of arborescence, the theory of brownian movements, the theory of cellular robots, and finally the UPIC system (Poliagogic Unit of CEMAMu), a technological invention.
It's now time to look closer to some compositions, in order to verify how theory and compositional practice intertwine. Metastasis, whose title means 'after the stasis', it's a composition for orchestra of 61 instruments: 12 winds, 7 percussions played by 3 musicians, 46 strings, and it's long about 9 minutes. It ain't a stochastic composition, but a piece based on the idea of continuity and discontinuity, something of interest for Parmenides and, after, Albert Einstein – the relationship between matter and energy: if you modify one of the two variables, you act also on the other, and at the same time the composition is influenced by Olivier Messiaen and his theory of rhythms. In 1954 Xenakis was still studying composition with him.
The ideas of rhythms and of continuity/discontinuity help Xenakis to put together the linear perception of the music with a relativistic vision of time. It all starts from the sounds of nature, about whom Xenakis wrote in his writings about stochastic music. The aim of the composer is to "blow up the frames of representation" [Makis Solomos, Apollo e Dioniso, gli scritti di Xenakis, in "Universi del suono", Ricordi, 2003] so to obtain that the events you listen are not evoked or represented, but burst in through music. We're not that far from Antonin Artaud's 'Theatre of Cruelty'. If in Pléiades-Mélanges, as an example, at a certain point we can hear a group of percussions that hint to something that can remember the shuffling of horses, while the ones coming immediately before can evoke some war drums, their value is never descriptive, exactly as it occurs in baroque music.
"The textures act directly, without passing through language, through representation, through codification: they provoke a physical shock. Their violence is a mean to divert the listening from the research of a 'meaning' [...]. There's no need to look for a reality outside the perceptible". [Ibid.]There's no duality, in Xenakis, between nature and culture: nature is the only thing that exists, and if there is tension, conflict, it is because "composing is a fight [...] a fight to produce something interesting". From there it comes the hint to the inner time, and the interest of the composer for the evolution of human perception, starting from the study of the perception of the time in prehistoric societies and the attention on Jean Piaget's experiences on the development of that perception in children. The time itself is nothing more than a surface phenomenon of a deeper reality, the movement ('déplacement'), what Xenakis try to reproduce with his music.
Strings open Metastasis in unison, before they part in 46 different segments, one for each instrument. Intensity, register and density are the variables on which the score lingers, taking the place of progressive linearity of traditional scores, included serial scores. First and third movement of the composition doesn't have a theme or a motif, relying entirely on the force of the idea of time. The second movement, instead, has a melodic element played by the strings, and conceived following the dodecaphonic method of Schonberg and elaborated using the Fibonacci series, a technique that Bartòk used for some of his own themes. The score has been written on a cartesian diagram, then translated tri-dimentionally into the structrure of the Phillips Pavillion.
Pithoprakta ('acts of probability') is born from the idea of developing musically a sound matter using the applications of Boltzmann and Maxwell and the Newton calculation of temperature and pressure of gas. The composition is conceived as a modulation from order to disorder, realized through a 'swarming of molecules' whose parameters submitted to the calculation of probabilities are density and degrees of order, whose diagram has been realized thinking about gaussian distribution of the height. The two compositions are the result of a reflection towards the problem of how to realize a musical work making tabula rasa of the previous compositional methods. "To compose is to fight" said Xenakis, "a fight for the existence. A fight to be. When instead I imitate the past, I do nothing in reality, so I don't exist. [...] The difference is the proof of existence, of knowledge, is participation to the things in the world". [Bàlint Andràs Varga, "Conversations with Iannis Xenakis, Faber & Faber, 1996]