section_path: Topics/Space, time, and change
section_name: Space, time, and change
paragraph_text: Space, time, and change
  
  Space and time are dimensions that entities occupy. Spacetime realists state that space and time are fundamental aspects of reality and exist independently of the human mind. This view is rejected by spacetime idealists, who hold that space and time are constructions of the human mind in its attempt to organize and make sense of reality. Spacetime absolutism or substantivalism understands spacetime as a distinct object, with some metaphysicians conceptualizing it as a box that contains all other entities within it. Spacetime relationism, by contrast, sees spacetime not as an object but as relations between objects, such as the spatial relation of being next to and the temporal relation of coming before.
  
  In the metaphysics of time, an important contrast is between the A-series and the B-series. According to the A-series theory, the flow of time is real, meaning that events are categorized into the past, present, and future. The present keeps moving forward in time and events that are in the present now will change their status and lie in the past later. From the perspective of the B-series theory, time is static and events are ordered by the temporal relations earlier-than and later-than without any essential difference between past, present, and future. Eternalism holds that past, present, and future are equally real while according to presentists, only entities in the present exist.
  
  Material objects persist through time and change in the process, like a tree that grows or loses leaves. The main ways of conceptualizing persistence through time are endurantism and perdurantism. According to endurantism, material objects are three-dimensional entities that are wholly present at each moment. As they change, they gain or lose properties but remain the same otherwise. Perdurantists see material objects as four-dimensional entities that extend through time and are made up of different temporal parts. At each moment, only one part of the object is present but not the object as a whole. Change means that an earlier part is qualitatively different from a later part. For example, if a banana ripens then there is an unripe part followed by a ripe part.