The “Mental Compositions used in Composition” (Xenakis)

This article deals with the “cognitivist” issues raised by Xenakis during the period going from Achorripsis (1956-57) to Herma (1960-61), via his reflexions expressed in Formalized Music (published, in its French version, Musiques formelles, in 1963). We will distinguish three issues. The first appears in chapter 1 under the title: “Fundamental Phases of a Musical Work”, when Xenakis asks: “What is the minimum of logical constraints necessary for the construction of a musical process?”. In the next chapter, via the hypothesis concerning the granulary nature of sound, he deals with the functioning of listening. The last issue, dealing with the “mental operations of composition”, is the more developed and concerns chapter 5 (chapter 6 in the American edition), where Xenakis writes: “In this chapter, we shall begin by imagining that we are suffering from a sudden amnesia. We shall thus be able to reascend to the fountain-head of the mental operations used in composition and attempt to extricate the principles that are valid for all sorts of music”, and where he gives out the mechanisms of Herma.