Kinds of Ontologies and the Role of Taxonomies

Philosophical ontology (also ‘metaphysics’) explores general questions concerning the nature of being; applied ontology concerns more specific questions pertaining to entities in specific domains. Applied ontology takes over from philosophy the central role of taxonomies and each applied ontology is built around a hierarchy of types and subtypes (an is_a hierarchy). Applied ontologies are organized along the dimensions of 1. greater and lesser generality, and 2. intended use. Concerning 1. we distinguish between top-level and domain ontologies. Top-level ontologies are domain-neutral; including terms such as ‘object’ or ‘process’ having maximally general scope. Domain ontologies are domain specific (comprising terms such as ‘molecule’ or ‘catheter’). Concerning 2. we distinguish between reference and application ontologies. Reference ontologies are designed to be re-used in distinct application ontologies, themselves built to address specific needs. We address the role of these different ontologies in assisting with heterogeneous data-management and promoting interoperability among information systems.