Ontologie der Grenzen ausgedehnter Gegenstände

Is a lake’s surface made of water or air? When two extended objects are in contact, do their boundaries coincide? Is a new boundary created when an extended object is split? These and many other problems in the ontology of boundaries are grounded in the common assumption that boundaries are the outermost parts of extended objects. The author argues that this problematic assumption should be abandoned in favour of a relational view of boundaries.