Editing Existence (section)

=== Possible, contingent, and necessary ===
A further distinction is between merely possible, [[Contingency (philosophy)|contingent]], and [[Metaphysical necessity|necessary]] existence.<ref>{{multiref |1={{harvnb|Mackie|1998|loc=Lead Section}} |2={{harvnb|Gibson|1998|pp=157–158}} |3={{harvnb|Jubien|2004|pp=[https://books.google.com/books?id=uoCh8mpbZO4C&pg=PA49 49, 52]}} }}</ref> An entity has necessary existence if it must exist or could not fail to exist. This means that it is not possible to newly create or destroy necessary entities. Entities that exist but could fail to exist are contingent; merely possible entities do not exist but could exist.<ref>{{multiref | {{harvnb|Gibson|1998|pp=157–158}} | {{harvnb|Pruss|Rasmussen|2018|pp=1–2}} | {{harvnb|Jubien|2004|p=[https://books.google.com/books?id=uoCh8mpbZO4C&pg=PA52 52]}} }}</ref>

{{multiple image |perrow=2 / 1 |total_width=300 |image1=Avicenna lithograph - cropped.png |alt1=Lithograph of Avicenna |link1=Avicenna |image2=Thomas Aquinas by Carlo Crivelli.png |alt2=Painting of Thomas Aquinas |link2=Thomas Aquinas |footer=[[Avicenna]] and [[Thomas Aquinas]] argued that God has necessary existence.}}

Most entities encountered in ordinary experience, like telephones, sticks, and flowers, have contingent existence.<ref>{{harvnb|Pruss|Rasmussen|2018|pp=1–2}}</ref> The contingent existence of telephones is reflected in the fact that they exist in the present but did not exist in the past, meaning that it is not necessary that they exist. It is an open question whether any entities have necessary existence.<ref>{{harvnb|Pruss|Rasmussen|2018|pp=1–4}}</ref> According to some [[Nominalism|nominalists]], all concrete objects have contingent existence while all abstract objects have necessary existence.<ref>{{harvnb|Cowling|2017|pp=[https://books.google.com/books?id=-DAlDwAAQBAJ&pg=PA82 82–83]}}</ref>

According to some theorists, one or several necessary beings are required as the explanatory foundation of the cosmos. For instance, the philosophers [[Avicenna]] (980–1037) and [[Thomas Aquinas]] (1225–1274) say that God has necessary existence.<ref>{{multiref |1={{harvnb|Gibson|1998|pp=157–158}} |2={{harvnb|Pruss|Rasmussen|2018|pp=1–6}} |3={{harvnb|Haan|2020|p=[https://books.google.com/books?id=XV75DwAAQBAJ&pg=PA381 381]}} |4={{harvnb|Turner|2004|p=[https://books.google.com/books?id=Dik3_ZjWo-MC&pg=PA238 238]}} }}</ref> A few philosophers, like [[Baruch Spinoza]] (1632–1677), see [[Pantheism|God and the world as the same thing]], and say that all entities have necessary existence to provide a unified and rational explanation of everything.<ref>{{multiref | {{harvnb|Lin|2018|p=[https://books.google.com/books?id=OWIwDwAAQBAJ&pg=PA152 152]}} | {{harvnb|Nadler|2023|loc=§ 2.1 God or Nature}} }}</ref>

There are many academic debates about the existence of merely possible objects. According to [[actualism]], only actual entities have being; this includes both contingent and necessary entities but excludes merely possible entities.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=§3. An Anti-Meinongian First-Order View}} |2={{harvnb|Jubien|2004|pp=[https://books.google.com/books?id=uoCh8mpbZO4C&pg=PA49 49–50]}} }}</ref> [[Possibilism (philosophy)|Possibilists]] reject this view and state there are also merely possible objects besides actual objects.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=§2. Meinongianism}} |2={{harvnb|Jubien|2004|pp=[https://books.google.com/books?id=uoCh8mpbZO4C&pg=PA49 49–50]}} }}</ref> For example, metaphysician [[David Lewis (philosopher)|David Lewis]] (1941–2001) states that possible objects exist in the same way as actual objects so as to provide a robust explanation of why statements about what is possible and necessary are true. According to him, possible objects exist in possible worlds while actual objects exist in the actual world. Lewis says the only difference between possible worlds and the actual world is the location of the speaker; the term "actual" refers to the world of the speaker, similar to the way the terms "here" and "now" refer to the spatial and temporal location of the speaker.<ref>{{multiref | {{harvnb|Lowe|2005|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-828 Existence]}} | {{harvnb|Weatherson|2021|loc=§ 6. Modal Metaphysics}} }}</ref>

The problem of contingent and necessary existence is closely related to the ontological question of [[why there is anything at all]] or why is there something rather than [[nothing]]. According to one view, the existence of something is a contingent fact, meaning the world could have been totally empty. This is not possible if there are necessary entities, which could not have failed to exist. In this case, global nothingness is impossible because the world needs to contain at least all necessary entities.<ref>{{multiref | {{harvnb|Lowe|2005|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-828 Existence]}} | {{harvnb|Casati|Fujikawa|loc=Lead Section, §4. Why Is There Something Rather Than Nothing?}} | {{harvnb|Sorensen|2023|loc=Lead Section, §1. Why Is There Something Rather Than Nothing?}} | {{harvnb|Pruss|Rasmussen|2018|pp=4–5}}}}</ref>