The essay is an experimental study, whose main question is: “What does it mean to think in multi­­plicity and to think in multiple ways?” The authors turn to the works of Georges Aperghis and the books of the philosophers Gilles Deleuze and Felix Guattari as a methodological and terminological base. The recourse to Deleuze and Guattari is justified by the creative, conceptual and personal connections which Aperghis had with the philosophers. One of the funda­mental concepts of their philosophy is the principle of mul­ti­plicity which, like other principles inextricably linked with the rhizome, made it possible to characterize the thinking of Aperghis. Drawing on the analysis of the composer’s pieces, the researchers considered seven principles of multiplicity: the reali­sation principle, the definition principle, the principle of “the wasp and the orchid” principle, the “and...and...and” principle, the principles of connection and heterogeneity in the musical language, the principle of composition and the principle of transformation. Using the philosophers' concepts “body without organs,” “stratum,” “assemblage,” “folding,” as well as the state of “in-between,” the features of Aperghis's musical language and compositional logic are articulated. Three compositions are used as examples: “Récitations,” “Le corps à corps” and “Graffitis.”