Endurantism or endurance theory is a philosophical theory of persistence and identity. According to the endurantist view material objects are persisting three-dimensional individuals wholly present at every moment of their existence. This conception of an individual as always present, is opposed to perdurantism or four dimensionalism which maintains that an object is a series of temporal parts or stages. Some philosophers argue that perdurantism better accommodates the theory of special relativity. The use of "endure" and "perdure" to distinguish two ways in which an object can be thought to persist can be traced to David Lewis.