sentences:  Sider (1997) uses the term "four-dimensionalism" to refer to perdurantism, but Michael Rea uses the term "four-dimensionalism" to mean the view that presentism is false as opposed to "perdurantism", the view that endurantism is false and persisting objects have temporal parts.Four-dimensionalism is a name for different positions.One of these uses four-dimensionalism as a position of material objects with respect to dimensions.