Knowledge Representation and the Logical Basis of Ontology

Abstract

Ontology as an outgrowth of the field of philosophy became a focus of application in healthcare terminologies in the 1990s and represents an important advance to the field. The increased rigor that formal definitions bring to terminologies improves our methodology in several distinct ways. First, it allows us to auto-classify the terminology which enables us to appropriately classify all concepts to all of the hierarchies to which they should belong. Second, it allows us to identify collisions or case where two concepts have the same formal definitions. This should lead to further definition of at least one of the concepts or combining the two concepts into one prior to release of that version of the terminology. Third, it allows us to reason or operate on the content of the terminology. This includes asking questions of the terminology such as is a concept subsumed by another concept within the terminology or is a relationship between two concepts valid for that combination of operands and specifications. The formal definitions allow us to formulate rules at the highest level within the hierarchy where they should apply and then to take advantage of the explosions to capture all of the relevant individual cases. This mathematically represents the transitive reflexive closure on subsumption. As an example, it might include all forms of Asthma including the root concept, Asthma itself and its subtypes such as Exercise-induced Asthma.