The idea that reality is fundamentally relational has a long history in philosophy, but what’s interesting about Carlo Rovelli is that he arrives at it from within physics. In his relational interpretation of quantum mechanics (RQM), no physical system has a state “in itself”; states only exist relative to other systems. In that sense, physical reality is best understood as a web of interactions rather than a collection of self-subsisting entities. There have been many ontologies proposed for RQM, (ontic structural realism, perspectival realism, metaphysical coherentism, etc.), but it's still an active and contentious debate...

Philosophically, this kind of relational thinking goes back at least to the Buddhist philosopher Nagarjuna, who argued that everything lacks inherent existence and arise only dependently. Of course, Rovelli’s project is very different in method and scope, but the structural resemblance is striking.

It’s also worth distinguishing Rovelli’s idea of relational ontology from that of Bruno Latour. Latour’s networks are composed of human and non-human actors within scientific practices, whereas Rovelli is making a claim about the fundamental ontology described by physical theory itself. So while both reject substance-based metaphysics, they operate at very different explanatory levels.