Cousijn et al. shift persistent identification from the logic of stable naming to that of relational infrastructure. A PID matters not simply because it preserves reference through time, but because metadata can connect publications, datasets, researchers, organisations, instruments and other entities into a graph capable of answering questions that no isolated record could support. The iconic operation is therefore the PID Graph: persistence becomes productive when identifiers acquire edges. Their argument also displaces a narrowly technical account of infrastructure. Repositories, registries, standards, metadata services and communities are mutually dependent components whose value emerges through adoption and interoperability. Particularly important is the maturity model distinguishing mature, emerging and immature PID infrastructures, which makes infrastructural development measurable as a social and technical process rather than a binary state. The paper thus connects FAIR practice to knowledge-graph thinking: scholarly scale becomes epistemically meaningful when accumulation is transformed into structured relational density.
