ontologists

Ontologists are scholars who study ontology, the branch of philosophy that investigates the nature of being, existence, and the categories of things. They examine what kinds of entities there are, how they are grouped into kinds, and what it means for something to exist. Central topics include universals, substances, properties, relations, time, space, and modality. Ontologists also debate whether certain entities—such as numbers or fictional objects—have being in a sense independent of human thought.

Ontology has roots in ancient philosophy, notably Aristotle, and has developed through medieval, modern, and contemporary periods. Debates include realism versus anti-realism, essentialism, and the nature of abstract entities. In contemporary metaphysics, philosophers analyze the differentiation between concrete and abstract entities, mereology, and the structure of reality.

In information science, ontology denotes a formal specification of a shared conceptualization for a domain. Ontologists or ontology engineers construct ontologies consisting of classes, relations, attributes, and axioms that enable data interoperability and automated reasoning. They use languages such as OWL and standards like RDF to represent knowledge and support Semantic Web applications, knowledge graphs, data integration, and natural language understanding.

Professionals often collaborate with domain experts to model vocabulary, ensure consistency, and validate the ontology against real-world use cases. See also ontology (philosophy), ontology engineering, and semantic web.