Editing Existence (section)

== Types of existing entities ==
Many discussions of the [[Theory of categories|types of existing entities]] revolve around the definitions of different types, the existence or nonexistence of entities of a specific type, the way entities of different types are related to each other, and whether some types are more fundamental than others.<ref>{{multiref |1={{harvnb|Van Inwagen|2023}} |2={{harvnb|Hofweber|2023|loc=§ 3.1 Different Conceptions of Ontology}} |3={{harvnb|Livingston|Cutrofello|2015|pp=[https://books.google.com/books?id=yztcCwAAQBAJ&pg=PT63 63–64]}} |4={{harvnb|Gibson|1998|pp=3–4}} }}</ref> Examples are the existence or nonexistence of [[soul]]s; whether there are abstract, fictional, and universal entities; and the existence or nonexistence of [[possible world]]s and objects besides the actual world.<ref>{{multiref |1={{harvnb|Van Inwagen|2023}} |2={{harvnb|Prior|2006|p=493}} |3={{harvnb|Gibson|1998|pp=3–4}} }}</ref> These discussions cover the topics of the basic stuff or constituents underlying all reality and the most general features of entities.<ref>{{harvnb|Hofweber|2023|loc=§ 3.1 Different Conceptions of Ontology}}</ref>

=== Singular and general ===
There is a distinction between singular existence and general existence. Singular existence is the existence of individual entities. For example, the sentence "[[Angela Merkel]] exists" expresses the existence of one particular person. General existence pertains to general concepts, properties, or [[universals]].{{efn|Universals are general features that express what different individual entities are like. For example, a [[banana]] and a [[sunflower]] are individual entities that both exemplify the universal ''yellow''.<ref>{{multiref | {{harvnb|MacLeod|Rubenstein|loc=Lead Section}} | {{harvnb|Cowling|2019|loc=Lead Section}} | {{harvnb|Loux|Crisp|2017|pp=17–19}} }}</ref>}} For instance, the sentence "politicians exist" states the general term "politician" has instances without referring to a particular politician.<ref>{{multiref | {{harvnb|Lambert|1994|pp=3–4}} | {{harvnb|Rescher|1957|pp=65–69}} | {{harvnb|Jubien|2004|pp=[https://books.google.com/books?id=uoCh8mpbZO4C&pg=PA52 52–53]}} }}</ref>

Singular and general existence are closely related to each other, and some philosophers have tried to explain one as a special case of the other. For example, according to Frege, general existence is more basic than singular existence. One argument in favor of this position is that singular existence can be expressed in terms of general existence. For instance, the sentence "Angela Merkel exists" can be expressed as "entities that are identical to Angela Merkel exist", where the expression "being identical to Angela Merkel" is understood as a general term. Philosopher [[Willard Van Orman Quine]] (1908–2000) defends a different position by giving primacy to singular existence and arguing that general existence can be expressed in terms of singular existence.<ref>{{harvnb|Lambert|1994|pp=3–4}}</ref>

A related question is whether there can be general existence without singular existence. According to philosopher Henry S. Leonard (1905–1967), a property only has general existence if there is at least one actual object that instantiates{{efn|A property is instantiated if an entity has this property.<ref>{{harvnb|Orilia|Paolini Paoletti|2022|loc=Lead Section}}</ref>}} it. Philosopher [[Nicholas Rescher]] (1928–2024), by contrast, states that properties can exist if they have no actual instances, like the property of "being a unicorn".<ref>{{multiref |1={{harvnb|Rescher|1957|pp=65–69}} |2={{harvnb|Hailperin|1967|p=251}} }}</ref> This question has a long philosophical tradition in relation to the existence of universals. According to [[Platonists]], universals have general existence as [[Platonic forms]] independently of the particulars{{efn|A particular is an individual unique entity, like [[Socrates]] or [[the Moon]]. Unlike universals, they cannot exist at several places at the same time.<ref>{{multiref | {{harvnb|MacLeod|Rubenstein|loc=Lead Section, § 1a. The Nature of Universals}} | {{harvnb|Campbell|2006|loc=§ Particularity and Individuality}} | {{harvnb|Maurin|2019|loc=Lead Section}} }}</ref>}} that exemplify them. According to this view, the universal of redness exists independently of the existence or nonexistence of red objects.<ref>{{multiref |1={{harvnb|Gibson|1998|pp=133–134}} |2={{harvnb|Balaguer|2016|loc=[https://plato.stanford.edu/entries/platonism/#1 § 1. What is Platonism?]}} }}</ref> [[Aristotelianism]] also accepts the existence of universals but says their existence depends on particulars that instantiate them and that they are unable to exist by themselves. According to this view, a universal that is not present in the space and time does not exist.<ref>{{harvnb|Gibson|1998|p=138}}</ref> According to [[nominalists]], only particulars have existence and universals do not exist.<ref>{{harvnb|Gibson|1998|pp=3–4, 137}}</ref>

=== 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>

=== 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>

=== Physical and mental ===
Entities that exist on a physical level include objects encountered in everyday life, like stones, trees, and human bodies, as well as entities discussed in [[modern physics]], like electrons and protons.<ref>{{harvnb|Mackie|1998|loc=Lead Section}}</ref>{{efn|According to the [[Standard Model]] of [[particle physics]], [[elementary particles]] together with the [[four fundamental forces]] acting on them are the most basic constituents of the universe. [[String theory]] provides an alternative explanation by focusing one-dimensional [[String (physics)|strings]] and their interactions.<ref>{{multiref | {{harvnb|Martin|Wells|2022|pp=[https://books.google.com/books?id=xVyYEAAAQBAJ&pg=PA1 1–4]}} | {{harvnb|Schwichtenberg|2017|pp=[https://books.google.com/books?id=bipBDwAAQBAJ&pg=PA8 7–8]}} | {{harvnb|Chang|2024|pp=[https://books.google.com/books?id=c2L8EAAAQBAJ&pg=PA247 247]}} }}</ref>}} Physical entities can be observed and measured; they possess mass and a location in space and time.<ref>{{multiref |1={{harvnb|Smart|2023|loc=Lead Section, §Types of Materialist Theory}} |2={{harvnb|Markosian|2009|pp=[https://books.google.com/books?id=lQ2xDwAAQBAJ 486–487]|loc=Physical Object}} }}</ref> Mental entities like perceptions, experiences of pleasure and pain as well as beliefs, desires, and emotions belong to the realm of the mind; they are primarily associated with conscious experiences but also include unconscious states like unconscious beliefs, desires, and memories.<ref>{{multiref | {{harvnb|Kim|2006|loc=[https://philpapers.org/rec/KIMPOM-3 § 1. Introduction]}} | {{harvnb|Addis|2013|pp=[https://books.google.com/books?id=Vk6ZEN6vByUC&pg=PA49 49–50]}} | {{harvnb|Searle|2004|p=[https://books.google.com/books?id=5G_iBwAAQBAJ&pg=PT183 183]}} }}</ref>

The [[mind–body problem]] concerns the ontological status of and relation between physical and mental entities and is a frequent topic in [[metaphysics]] and [[philosophy of mind]].{{efn|Philosophy of mind is the branch of philosophy that studies the nature of mental phenomena and how they are related to the physical world.<ref>{{multiref | {{harvnb|Lowe|2000|pp=[https://books.google.com/books?id=mH12kYm1RKAC&pg=PA1 1–2]}} | {{harvnb|Crumley|2006|pp=[https://books.google.com/books?id=Yf4eAAAAQBAJ&pg=PA2 2–3]}} }}</ref>}} According to [[materialists]], only physical entities exist on the most-fundamental level. Materialists usually explain mental entities in terms of physical processes; for example, as brain states or as patterns of neural activation.<ref>{{multiref | {{harvnb|Kelly|2004|pp=[https://books.google.com/books?id=AFwr3CCoqAEC&pg=PA87 87–88]}} | {{harvnb|Smart|2023|loc=Lead Section, § Types of Materialist Theory}} }}</ref> Idealism,{{efn|Some theorists use the term "ontological idealism" to distinguish it from idealistic views in epistemology.<ref>{{harvnb|Berendzen|2023|p=[https://books.google.com/books?id=C0DAEAAAQBAJ&pg=PA17 17]}}</ref>}} a minority view in contemporary philosophy,<ref>{{harvnb|Guyer|Horstmann|2023|loc=§ 9. The Fate of Idealism in the Twentieth Century}}</ref> rejects matter as ultimate and views the mind as the most basic reality.<ref>{{harvnb|Sprigge|1998|loc=Lead Section|ps=, "Idealism is now usually understood in philosophy as the view that mind is the most basic reality and that the physical world exists only as an appearance to or expression of mind, or as somehow mental in its inner essence."}}</ref> [[Dualists]] like [[René Descartes]] (1596–1650) believe both physical and mental entities exist on the most-fundamental level. They state they are connected to one another in several ways but that one cannot be reduced to the other.<ref>{{multiref | {{harvnb|Kelly|2004|pp=[https://books.google.com/books?id=AFwr3CCoqAEC&pg=PA87 87–88]}} | {{harvnb|Calef|loc=Lead Section, § 3. Descartes’ Dualism}} }}</ref>

=== Other types ===
Fictional entities are entities that exist as inventions inside works of [[fiction]].{{efn|Some [[empiricist]] philosophers also include entities that are [[Unobservable|not directly observable]], like powers and moral obligations.<ref>{{harvnb|Lamarque|1998|loc=Lead Section}}</ref>}} For example, [[Sherlock Holmes]] is a fictional character in [[Arthur Conan Doyle]]'s book ''[[A Study in Scarlet]]'' and [[flying carpets]] are fictional objects in the folktales ''[[One Thousand and One Nights]]''.<ref>{{multiref | {{harvnb|Kroon|Voltolini|2023|loc=Lead Section}} | {{harvnb|Lamarque|1998|loc=Lead Section}} | {{harvnb|Prior|2006|p=493}} }}</ref> According to anti-realism, fictional entities do not form part of reality in any substantive sense. Possibilists, by contrast, see fictional entities as a subclass of possible objects; creationists say that they are artifacts that depend for their existence on the authors who first conceived them.<ref>{{multiref | {{harvnb|Kroon|Voltolini|2023|loc=§ 1. The Metaphysics of Fictional Entities}} | {{harvnb|Lamarque|1998|loc=§ 2. Deflationary theories, § 3. Hospitable theories}} }}</ref>

[[Intentionality#The problem of intentional inexistence|Intentional inexistence]] is a similar phenomenon concerned with the existence of objects within mental states. This happens when a person perceives or thinks about an object. In some cases, the [[intentional object]] corresponds to a real object outside the mental state, like when accurately perceiving a tree in the garden. In other cases, the intentional object does not have a real counterpart, like when thinking about [[Bigfoot]]. The [[problem of intentional inexistence]] is the challenge of explaining how one can think about entities that do not exist since this seems to have the paradoxical implication that the thinker stands in a [[Relation (philosophy)|relation]] to a nonexisting object.<ref>{{multiref | {{harvnb|Jacob|2023|loc=2. Intentional inexistence}} | {{harvnb|Kriegel|2007|pp=307–308}} | {{harvnb|O’Madagain|loc=§ 2. Intentional Objects}} }}</ref>