Ontology with Human Subjects Testing: An Empirical Investigation of Geographic Categories

I Introduction Ontology, since Aristotle, has been conceived as a sort of highly general physics, a science of the types of entities in reality, of the objects, properties, categories and relations which make up the world. At the same time ontology has been for some two thousand years a speculative enterprise. It has rested methodologically on introspection and on the construction and analysis of elaborate world-models and of abstract formal-ontological theories. In the work of Quine and others this ontological theorizing in abstract fashion about the world was supplemented by the study, based on the use of logical methods, of the ontological commitments or presuppositions embodied in scientific theories. In recent years both types of ontological study have found application in the world of information systems, for example in the construction of frameworks for knowledge representation and in database design and translation. As ontology is in this way drawn closer to the domain of real-world applications, the question arises as to whether it is possible to use empirical methods in studying ontological theories. More specifically: can we use empirical methods to test the ontological theories embodied in human cognition? In what follows we set forth the outlines of a framework for the formulation and testing of such theories as they relate to the specific domain of geographic objects and categories. Objects, properties, categories and relations are what they are, independently of how people think of them. Some objects, properties, categories and relations, however, are the products of human cognition. This holds not least in the geographic realm, where many of the entities with which we have to deal may be conceived by analogy with shadows cast on the surface of the earth by human practices of specific sorts. In relation to such entities empirical testing makes reasonable sense. We describe a testing methodology in which the more traditional methods of ontology will guide the formulation of questions to be tested and the construction of the framework in which the results of testing shall be expressed. II Theories of Conceptual Organization We begin with the general topic of human cognitive categories such as rabbit, electron, island. Such categories exist in two forms: on the one hand as concepts on the side of human subjects; on the other hand as kinds on the side of reality. On the classical view, dating back to Aristotle, each concept or kind is associated with certain defining attributes or properties which suffice to determine exactly which objects fall within the relevant extension. On more recent views, categorial kinds are to be understood by analogy with a mathematical set. All objects within the extension set are equally representative instances of the category, and for each object or event it is fully determinate whether or not it falls under a given category. Geographers, like other scientists, have typically accepted this model of categories as sets in the mathematical sense, and the model is presupposed for example in work on cartographic data standards (Mark 1993, 1993a). As an account of the categories used by ordinary humans in everyday situations, however, the model has obvious defects. First, and most obviously, not every set in the mathematical sense is a class in the sense of kind or category. Hence we need to go beyond set theory in order to fill this gap. But further, as has been shown by Rosch (1973, 1978) and others (Keil 1979, Estes 1994), for most such categories, and for most people, some members are better examples of the class than are others; furthermore, there is a great degree of agreement among human subjects as to what constitutes good and bad examples. Human cognitive categories often possess a radial structure, having prototypes or more central or typical members surrounded by a penumbra of less central or less typical instances. …