A specialization of both localized spatial thing and thing existing stably in time (qq.v.). Each instance of location is a spatial enduring thing at which an event can occur or a situation can obtain. Positive examples include planets, the borders between countries, human beings, rocks, and atoms. Negative example include situations, events, abstract objects, and regions of space that exclusively act as possible locations for other spatial objects (see spatial region). An important specialization of location is place (q.v.). The salient distinction between places (instances of place) and locations (instances of location) is that places are assumed to have relatively permanent locations, whereas locations need not have permanent locations. Thus, from the perspective of someone standing on a beach, the crest of a breaking wave can be a location at which foaming is occuring (thus an location), but it cannot be such a place (i.e. it cannot be an instance of place).