There is a basic distinction, in the realm of spatial boundaries, between bona fide boundaries on the one hand, and fiat boundaries on the other. The former are just the physical boundaries of old. The latter are exemplified especially by boundaries induced through human demarcation, for example in the geographic domain. The classical problems connected with the notions of adjacency, contact, separation and division can be resolved in an intuitive way by recognizing this two-sorted ontology of boundaries. Bona fide boundaries (...) yield a notion of contact that is effectively modeled by classical topology; the analogue of contact involving fiat boundaries calls, however, for a different account, based on the intuition that fiat boundaries do not support the open/closed distinction on which classical topology is based. In the presence of this two-sorted ontology it then transpires that mereotopology—topology erected on a mereological basis—is more than a trivial formal variant of classical point-set topology. (shrink)

Philosophers in the field of analytic metaphysics have begun gradually to come to terms with the fact that there are entities in a range of categories not dreamt of in the set-theory and predicate-logic-based ontologies of their forefathers. Examples of such “entia minora” would include: boundaries, places, events, states holes, shadows, individual colour- and tone-instances (tropes), together with combinations of these and associated simple and complex universal species or essences, states of affairs, judgment-contents, and myriad abstract structures of the sorts (...) which are studied by the mathematical sciences. How, as hunter-gatherer ontologists, are we to bring order into this vast array? How are we to gauge the ontological merits of given candidate entities, and how are we to understand their relation to entities of more humdrum sorts? Meinong, it turns out, offers a very simple answer to all of these questions. (shrink)