Ontology

Philosophical Origins

The idea of ontology originated with Aristotle, in his book on metaphysics, which discusses what is beyond physics (i.e., the empirical). In the 19th and 20th centuries, phenomenology focused on the phenomena [Page 327]as the following: What are objects, and what relations exist between objects? What abstractions lead from individuals to classes? A database schema that describes the classes of things and their attributes stored in a database is a simple ontology. The goal of ontological studies in information science is to give guidelines to avoid inconsistencies in the description of the data, because inconsistencies in the data description lead to difficulties in the data collection and invalid conclusions when using the data people can observe and gradually moved toward questions about what it means for something to exist. In the early 1900s, a group of philosophers, the Wiener Kreis (“Vienna Circle”), connected the philosophical tradition with mathematical and formal approaches and led to the development of analytical philosophy.

Philosophical ontology discusses the nature of space and time and of being and nothingness. The goal is to identify a set of noncontradictory assumptions, called ontological commitments, on which all knowledge rests. In recent years, the focus has been on the construction of formal (axiomatic) systems for space based on mereology, studying the “part-of” relation, from which inferential calculus for topological relations in GIS derives.

Formal Ontology

Formal ontology focuses on a few relations in ontology and gives them formal definitions:

• The “is-a” relation, which is found in taxonomies (e.g., Socrates is a human) and permits the logical deduction from properties of the class (e.g., A property of “human” is being mortal), from which we conclude properties of the individual (Socrates is mortal).
• The “part-of” relation (e.g., The tail is part of Dibble the cat), which gives rise to other logical derivations (e.g., The cat is furry; therefore, the tail is furry).

The goal of ontological studies in philosophy is to give a single, consistent, and comprehensive logical account for the existence of all things. However, the desired generality causes difficulties because the existence of live, physical objects like Socrates and Dibble is very different from the existence of a headache or abstract concepts like the number π, freedom, and so on. Recently, efforts have been focused on including events and actions and on formalizing the “is-a” and “part-of” relations between events (e.g., getting dressed is part of the “getting up in the morning” event).

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