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Carlo Rovelli (1956–)

Rovelli built relational quantum mechanics — properties exist only through interaction, there is no observer-independent state, what is real is constituted through encounter rather than sitting behind it. His anti-foundationalism — “the foundation of science is not certainty but radical uncertainty about our own knowledge” — refused the final vocabulary from within physics. And his engagement with philosophy, from Nagarjuna to Heidegger to the pre-Socratics, makes him a rare working physicist who takes the relational turn seriously across disciplines. Where Kant asked how the mind structures experience, Rovelli asks how interaction structures reality — and the answer drops the privileged observer entirely. SPLectrum reads its relational stance in the same current.

Carlo Rovelli (1956–). Theoretical physicist and philosopher of science. Born in Verona, he was politically active in the Italian student movements of the 1970s — founding free radio stations, co-authoring a book on the Bologna protests, briefly detained for refusing military service. He studied physics at Bologna and Padova, held a joint appointment in physics and the history and philosophy of science at Pittsburgh, and has been based at Aix-Marseille University since 2000. Also affiliated with the Perimeter Institute, the Rotman Institute of Philosophy, and the Santa Fe Institute. One of the few working physicists with a sustained, serious engagement with philosophy — he has argued publicly that physics needs philosophy and philosophy needs physics (“Einstein would have never done relativity without having read all the philosophers”). The anti-authoritarian political stance and the anti-foundationalist physics are not unrelated — a consistent suspicion of fixed structures, whether political or physical.

Key concepts

Loop quantum gravity. Co-founded with Lee Smolin, building on Abhay Ashtekar’s reformulation of general relativity. Space is not continuous but composed of discrete quanta, woven into spin networks. Area and volume are quantised — space has a granular structure at the Planck scale. The theory is background-independent: it does not presuppose a fixed spacetime. With Reisenberger (1997) and later with Engle, Pereira, and Livine (2008), Rovelli developed the spinfoam approach — a sum-over-histories formulation for quantum gravity.

Relational quantum mechanics (RQM). Published in International Journal of Theoretical Physics (1996). The quantum state of a system is always relative to another physical system. There is no observer-independent state, just as there is no observer-independent velocity in classical mechanics. Properties exist only through interactions. This dissolves the measurement problem by rejecting the notion of a single, absolute quantum state. The interpretation has been further developed by van Fraassen and Bitbol.

Time. A sustained programme across multiple works. With Alain Connes, Rovelli developed the thermal time hypothesis (1994): in a generally covariant quantum theory, there is no fundamental time variable. Time emerges from the thermodynamic state of the system — specifically, from incomplete knowledge. The mathematical framework derives a time-flow from a thermal state using the Tomita-Takesaki theorem. “Time is ignorance.” In The Order of Time (2018), he dismantles our intuitions systematically: there is no universal “now,” time runs at different speeds at different altitudes, at the fundamental level the equations contain no time variable. The direction of time appears only through entropy — “the distinction between past and future is not present in the basic grammar of the world.” In “Memory and Entropy” (Entropy 24(8):1022, 2022), he formalised the connection between irreversibility and traces: three conditions for memory (systems separation, temperature differences, long thermalisation times), and a central mechanism — trace formation transforms low entropy into available information. All macroscopic information ultimately traces back to the universe’s past low-entropy state.

Nagarjuna and relational ontology. In Helgoland (2021), Rovelli devotes a chapter to the second-century Buddhist philosopher Nagarjuna, whose Mulamadhyamakakarika argues that nothing exists independently — things are “empty” of intrinsic existence and exist only through relations. Rovelli reads this as a resonance with RQM — suggestive rather than systematic, an exploratory connection rather than a developed philosophical position. “Nagarjuna has given us a formidable conceptual tool for thinking about the relationality of quanta.” Rovelli’s broader position has affinities with ontic structural realism — relations are primary, not things — though he frames it through interactions rather than formal structures.

Anaximander and the nature of science. In Anaximander (2011/2023), Rovelli argues that the sixth-century BCE thinker inaugurated scientific thinking — not by finding the right answer but by introducing a mode of rational, naturalistic inquiry that rejected supernatural explanation. The essence of science is “learned rebellion”: building on predecessors while questioning them. “The foundation of science is not certainty but the very opposite, a radical uncertainty about our own knowledge.”

Where Rovelli stops

Rovelli’s relational quantum mechanics drops the privileged observer — but it stays within physics. Properties exist through interaction, but interaction in RQM is physical: one system measuring another. The move is the same as SPLectrum’s — no absolute state, no view from nowhere — but SPLectrum takes it into territory physics does not reach: meaning, sharing, the growth of complexity through interrelating languages. Rovelli points toward this himself through Nagarjuna and his philosophical writing, but the physics alone does not get there.

Key works

See also: Relational quantum mechanics · The Turn in Science · The seed and Philosophy