Computational Models for Ontology

Is it possible to construct a computational model how ontology ‘works’? Most ontologies cover only a small part of reality – can we construct computational models which demonstrate how reality and knowledge about reality are linked? What would such a computational model contribute to the current discussion? Many practical ontologies are computational models – from database schema to the data descriptions in AI programs. They are used to describe how a certain subset of reality is conceptualized, usually in a software application. A computational model for an ontology must bring together reality and the knowledge of this reality as it is used in, e.g., a computer program. In this contribution I describe computational models of reality and cognitive agents, and trace the different aspects of the ontology, from reality to the beliefs of agents. In this model, we can precisely determine what terms like ‘reality’, ‘Cognitive Agent’, ‘data’, ‘Beliefs (Knowledge)’, etc., mean. The distinction between ontology and epistemology can be drawn exactly. The computational model is constructed in a multi-agent framework, where it is possible to model an external reality and agents which interact with this reality in a systematic way. Simple interactions with the model are possible to demonstrate that the formal construction performs as expected from real world experience. Individual parts of the computational model have been realized and used to discuss particular applications; we are currently integrating the different parts to a single comprehensive model as described here. The paper lists a number of ontological commitments, mostly self evident and derived from daily experience of interacting with the world, which were used during the construction of the computational model. These can help to identify the smallest, simplest set of commitments to build into an ontology. Tier O: human-independent reality Tier 1: observation of physical world Tier 2: objects with properties Tier 3: social reality Tier 4: subjective knowledge Fig. 1. Five tiers of ontology