Superposition, Entanglement, and Collapse in Performance and Listening: the case of Bach’s Polyphony

This contribution develops a theoretical reflection on the musical score as a space of superposed possibilities, inspired by conceptual models from quantum physics. The investigation focuses on the heuristic application of the concepts of superposition, entanglement, and wavefunction collapse to understand music as a cognitive and experiential phenomenon, particularly in relation to interpretation and listening. The score is conceptualized as an entangled system between the composer’s intentions and the performer’s anticipations, forming a semantically partially undecidable field until the wavefunction collapse occurs through the act of listening, either by the audience or the performer self-monitoring their execution. Listening is thus framed as an observational act that actualizes this space of possibilities into a concrete sonic experience. Furthermore, musical form is not considered an a priori structure but emerges retrospectively once the final note has been performed, in line with phenomenological accounts of musical time (Imberty, 2015). Methodologically, the approach is theoretical and interpretative, integrating perspectives from quantum theory, phenomenology, and contemporary non-classical cognitive musicology (Dalla Chiara et al., 2015; Clarke, 2005). An illustrative case study on J.S. Bach’s polyphony demonstrates how the apparent linearity of the score conceals multiple interpretive possibilities (agogic, timbral, and dynamic) that coexist as potential states in superposition, collapsing into a singular trajectory only through performative and perceptive acts. This study contributes a novel epistemological framework that positions musical form as emergent and co-constituted in the act of listening and performance. Although not computationally implemented, the proposed model offers foundational theoretical ground for future interdisciplinary collaborations bridging algorithmic formalization and epistemic reflection.