We explore the concept of meaning in applied ontologies using possible world semantics. We begin by analyzing the nature of possible worlds in the influential framework proposed by Guarino, Oberle and Staab: interpreting an ontology involves selecting, from the set of logically possible worlds, a subset of worlds that are metaphysically possible according to the ontology – ideally corresponding to the set of worlds that are metaphysically possible according to the ontology’s creator. We argue that this framework is limited to analytic statements and should be extended to encompass synthetic statements. The analytic/synthetic distinction, we suggest, can itself be understood in terms of the necessary/contingent distinction using metaphysically possible worlds. We propose a dual framework for introducing terms in ontology development, integrating both descriptivism and Kripke’s theory of rigid designators. This framework accommodates a posteriori analytic statements, implying that the meaning of a term may be unknown even to its creator. Finally, we distinguish two distinct roles that labels can play in ontology development: either as rigid designators that carry semantic weight, or as mere human-readable tags serving as proxies for underlying descriptions.

According to meaning holism, the meanings of all the words in a language are interdependent. If this was true, then the very practice of building largely interconnected set of ontologies would be threatened. We examine here the extent of the severity of meaning holism for ontology engineering, based on a definition of the meaning of a class term in an ontology, with regard to the classical analytic/synthetic distinction. We show that meaning holism is not as pervasive in ontologies as traditionally assumed in philosophy of language when interpreting the meaning of a class term as a collection of statements expressing necessary conditions on this term. Still, meaning holism presents substantial challenges for ontology engineering and requires mitigation strategies. We also investigate the related phenomenon of indeterminacy of reference and show how anchoring formal ontologies in natural language can mitigate this problem, even if not fully control it.

According to meaning holism, the meanings of all of the words in a language are interdependent. If this was true, then the very practice of building largely interconnected set of ontologies would be threatened. We examine here the extent of the severity of meaning holism for ontology engineering, based on several definitions of the meaning of a class term in an ontology, with regard to the classical analytic/synthetic distinction. We show that meaning holism is not as pervasive in ontologies as traditionally assumed in philosophy of language, and that a conception of meaning of a class term as a collection of statements expressing necessary conditions on this term limits meaning holism further. Still, meaning holism presents substantial challenges for ontology engineering and requires mitigation strategies. We also investigate the related phenomenon of indeterminacy of reference and show how anchoring formal ontologies in natural language can mitigate this problem, even if not fully control it.

This article provides the basis of a formal axiomatic system for a mereology of informational entities based on the idea of information fillers that can occupy information slots, such as the same word that can be used in different sentences. It is inspired by Karen Bennett’s mereological system that enables a whole to have a part “twice over”, but differs from it in several key points, such as the acceptance of empty slots, and the possibility for slots to have slots. Information slots are analyzed as informational entities that can carry aboutness.