Editing Existence (section)

=== Concrete and abstract ===
There is an influential distinction in ontology between [[abstract and concrete|concrete and abstract objects]]. Many concrete objects, like rocks, plants, and other people, are encountered in everyday life. They exist in space and time. They [[Causality|have effects]] on each other, like when a rock falls on a plant and damages it, or a plant grows through rock and breaks it. Abstract objects, like numbers, sets, and types, have no location in space and time, and lack causal powers.<ref>{{multiref |1={{harvnb|Mackie|1998|loc=Lead Section}} |2={{harvnb|Falguera|Martínez-Vidal|Rosen|2022|loc=[https://plato.stanford.edu/entries/abstract-objects/ lead section, § 1. Introduction]}} |3={{harvnb|Faye|2013|pp=[https://books.google.com/books?id=ftrmBQAAQBAJ&pg=PA89 89–91]}} |4={{harvnb|Prior|2006|pp=498–499}} }}</ref> The distinction between concrete objects and abstract objects is sometimes treated as the most-general division of being.<ref>{{harvnb|Lowe|2005a|pp=670–671}}</ref>

The existence of concrete objects is widely agreed upon but opinions about abstract objects are divided. [[Philosophical realism|Realists]] such as [[Plato]] accept the idea that abstract objects have independent existence.<ref>{{multiref |1={{harvnb|Belfiore|2016|p=[https://books.google.com/books?id=IQp5DQAAQBAJ&pg=PA110 110]}} |2={{harvnb|Faulkner|Gregersen|2017|p=[https://books.google.com/books?id=5-JhDwAAQBAJ&pg=PA298 298]}} |3={{harvnb|Prior|2006|pp=498–499}} }}</ref> Some realists say abstract objects have the same mode of existence as concrete objects; according to others, they exist in a different way.<ref>{{multiref |1={{harvnb|Van Inwagen|2023}} |2={{harvnb|Prior|2006|pp=493, 498–499}} }}</ref> [[Anti-realism|Anti-realists]] state that abstract objects do not exist, a view that is often combined with the idea that existence requires a location in space and time or the ability to causally interact.<ref>{{multiref |1={{harvnb|Casati|Fujikawa|loc=§2a. Meinongianism}} |2={{harvnb|Plebani|2013|p=[https://books.google.com/books?id=pkNb_3NYyz0C&pg=PA5 5]}} }}</ref>