Quantum Mechanics is arguably one of the most successful theories in the history of science, for its predictions are confirmed by countless experiments, making it a cornerstone of contemporary physics. However, a century after its inception, the theory still challenges our classical worldview, offering a counterintuitive description of nature at microscopic scales. Contrary to classical mechanics, where objects are individually distinguishable and possess well-defined attributes at all times, QM speaks about indistinguishable systems with indeterminate properties, superposed states, and non-local interactions. Unsurprisingly, then, questions concerning its ontology, i.e., what fundamentally exists, are still vividly discussed to this day.

Despite its empirical success, however, physicists and philosophers alike enquire whether QM should be considered a true description of the natural world, because this theory is affected by conceptual conundrums and formal difficulties (e.g., the measurement problem). To address such issues, new quantum interpretations emerged from the 1950s. Among the many existing alternatives, here we consider a widely discussed framework that turns thirty this year, Carlo Rovelli’s Relational Quantum Mechanics (RQM).

RQM is motivated by Rovelli’s work in loop quantum gravity, where spacetime is not a substance existing per se, but rather it emerges from a dynamic network of relations, providing a relational perspective of it.