 The two most popular accounts of persistence are perdurance theory (perdurantism) and endurance theory (endurantism). Perdurantists believe that ordinary things like animals, boats and planets have temporal parts (things persist by ‘perduring’). Endurantists believe that ordinary things do not have temporal parts; instead, things are wholly present whenever they exist (things persist by ‘enduring’). This looks like a straightforward ontological disagreement, a dispute about what exists. Perdurantists think that objects have both spatial and temporal parts, while endurantists think that they only have spatial parts.