Existence: Difference between revisions

[[Ontology]] is the philosophical discipline studying the nature and types of existence. Singular existence is the existence of individual entities while general existence refers to the existence of [[concepts]] or [[universals]]. Entities present in space and time have [[Abstract and concrete|concrete]] existence in contrast to abstract entities, like numbers and sets. Other distinctions are between [[Subjunctive possibility|possible]], [[Contingency (philosophy)|contingent]], and [[Metaphysical necessity|necessary]] existence and between [[Matter|physical]] and [[Mind|mental]] existence. The common view is that an entity either exists or not with nothing inbetweenin between, but some philosophers say that there are degrees of existence, meaning that some entities exist to a higher degree than others.

The concept of existence has been discussed throughout the [[history of philosophy]] and already played a role in [[ancient philosophy]], including [[Presocratic philosophy]] in [[Ancient Greece]], [[Hindu philosophy|Hindu]] and [[Buddhist philosophy]] in [[Ancient India]], and [[Daoist philosophy]] in [[ancient China]]. It is relevant to various fields, includingsuch as [[logic]], [[mathematics]], [[epistemology]], [[philosophy of mind]], [[philosophy of language]], and [[existentialism]].

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]] (1928-20241928–2024), 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>

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. Abstract objects, like numbers, sets, and types, have no location in space and time, and lack causal powers.<ref>{{multiref |1={{harvnb|PenelopeMackie|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 while; 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 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>

A further distinction is between merely possible, [[Contingency (philosophy)|contingent]], and [[Metaphysical necessity|necessary]] existence.<ref>{{multiref |1={{harvnb|PenelopeMackie|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 while; 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>

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 onesome view[[Nominalism|nominalists]], all concrete objects have contingent existence while all abstract objects have necessary existence.<ref>{{multiref | {{harvnb|Pruss|Rasmussen|2018|pp=1–4}} | {{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 in order 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 inso orderas 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>

A further distinction is between entitiesEntities that exist on a physical level in contrast to mental entities.<ref>{{harvnb|Penelope|1998|loc=Lead Section}}</ref> Physical entities 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 Idealists| reject{{harvnb|Kelly|2004|pp=[https://books.google.com/books?id=AFwr3CCoqAEC&pg=PA87 this87–88]}} view| and{{harvnb|Smart|2023|loc=Lead giveSection, priviledge§ toTypes of Materialist Theory}} }}</ref> Idealism,{{efn|Some theorists use the mentalterm entities"ontological whileidealism" seeingto physicaldistinguish entitiesit asfrom idealistic views in epistemology.<ref>{{harvnb|Berendzen|2023|p=[https://books.google.com/books?id=C0DAEAAAQBAJ&pg=PA17 17]}}</ref>}} a derivativeminority formview ofin existencecontemporary philosophy,<ref>{{harvnb|Guyer|Horstmann|2023|loc=§ for9. instanceThe 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 mentalthe representationsview that mind is the most basic reality and that the physical world exists only as an appearance to or productsexpression of consciousnessmind, 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 variousseveral ways but that one cannot be reduced to the other.<ref>{{multiref |1= {{harvnb|Kelly|2004|pp=[https://books.google.com/books?id=AFwr3CCoqAEC&pg=PA87 87–88]}} |2={{harvnb|Goldschmidt|Pearce|2017|p=[https://books.google.com/books?id=QgJCDwAAQBAJ&pg=PR9 ix]}} |3={{harvnb|Darvill|2009|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199534043.001.0001/acref-9780199534043-e-1926 Idealism]}} |4={{harvnb|Smart|2023Calef|loc=Lead Section, § Types3. ofDescartes’ Materialist TheoryDualism}} }}</ref>

=== OthersOther 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 while; 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>

Another form of ontological pluralism distinguishes the existence of material objects from the existence of [[space-time]]. According to this view, material objects have relative existence because they exist in space-time while; the existence of space-time itself is not relative in this sense because it just exists without existing within another space-time.<ref>{{harvnb|Casati|Fujikawa|loc=§3. How Many Ways of Being Existent?}}</ref>

Theories of the nature of existence aim to explain what it means for something to exist. TheA central dispute in the academic discourse about the nature of existence is whether it shouldexistence be understood asis a [[Property (philosophy)|property]] of individuals.<ref name="auto2">{{harvnb|Nelson|2022|loc=Lead Section}}</ref> An individual is a unique entity, like [[Socrates]] or a particular apple. A property is something that is attributed to an entity, like "being human" or "being red", and usually expresses a quality or feature of that entity.<ref>{{multiref | {{harvnb|Orilia|Paolini Paoletti|2022|loc=Lead Section}} | {{harvnb|Lowe|2005|p=683}} | {{harvnb|Bigelow|1998|loc=Lead Section}} }}</ref> The two main theories of existence are first-order and second-order theories. First-order theories understand existence as a property of individuals while second-order theories say existence is a second-order property, that is, a property of properties.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=Lead Section}} |2={{harvnb|PenelopeMackie|1998|loc=Lead Section}} |3={{harvnb|Casati|Fujikawa|loc=Lead Section}} |4={{harvnb|Blackburn|2008|loc=[https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095804522 Existence]}} }}</ref>

A central challenge for theories of the nature of existence is an understanding of the possibility of coherently denying the existence of something, like the claimstatement: "Santa Claus does not exist". One difficulty is explaining how the name "Santa Claus" can be meaningful even though there is no Santa Claus.<ref>{{multiref | {{harvnb|PenelopeMackie|1998|loc=§1 Objects and Existence}} | {{harvnb|Nelson|2022|loc=Lead Section, § 1. Frege and Russell: Existence Is Not a Property of Individuals}} }}</ref>

Second-order theories understand existence as a second-order property rather than a first-order property. They are often seen as the the orthodox position in ontology.<ref>{{multiref |1={{harvnb|Casati|Fujikawa|loc=Lead Section, §1. Existence as a Second-Order Property and Its Relation to Quantification}} |2={{harvnb|Blackburn|2008|loc=[https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095804522 Existence]}} }}</ref> For instance, the [[Empire State Building]] is an individual object and "being {{convert|443.2|meters|abbr=out|spell=us}} tall" is a first-order property of it. "Being instantiated" is a property of "being 443.2 meters tall" and therefore a second-order property. According to second-order theories, to talk about existence is to talk about which properties have instances.<ref name="auto">{{multiref |1={{harvnb|Blackburn|2008|loc=[https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095804522 Existence]}} |2={{harvnb|Casati|Fujikawa|loc=§1. Existence as a Second-Order Property and Its Relation to Quantification}} }}</ref> For example, this view says that the sentence "God exists" means "Godhood is instantiated" rather than "God has the property of existing".<ref name="auto4"/>

According to second-order theorists, [[Quantifier (logic)|quantifiers]] rather than [[Predication (philosophy)|predicates]] express existence.<ref>{{multiref |1={{harvnb|Casati|Fujikawa|loc=Lead Section, §1. Existence as a Second-Order Property and Its Relation to Quantification}} |2={{harvnb|PenelopeMackie|1998|loc=§2 The Quantifier Account of Existence}} |3={{harvnb|Blackburn|2008|loc=[https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095804522 Existence]}} |4={{harvnb|Lowe|2005|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-828 Existence]}} }}</ref> Predicates are expressions that apply to and classify objects, usually by attributing features to them, such as "is a butterfly" and "is happy".<ref>{{multiref | {{harvnb|Portner|2006|pp=[https://books.google.com/books?id=E85VAgAAQBAJ&pg=PA141 141–143]}} | {{harvnb|Ellis|2014|pp=[https://books.google.com/books?id=DmLfBQAAQBAJ&pg=PT39 39–40]}} }}</ref> Quantifiers are terms that talk about the quantity of objects that have certain properties. Existential quantifiers express that there is at least one object, like the expressions "some" and "there exists", as in "some cows eat grass" and "there exists an even prime number".<ref>{{multiref | {{harvnb|Magnus|2005|pp=52–53}} | {{harvnb|Uzquiano|2022|loc=Lead Section}} }}</ref> In this regard, existence is closely related to counting because to claimassert that something exists is to claimassert that the corresponding concept has one or more instances.<ref name="auto"/>

Second-order views imply a sentence like "[[egg-laying mammals]] exist" is misleading because the word "exist" is used as a predicate in them. These views say the true logical form is better expressed in reformulations like "there exist entities that are egg-laying mammals". This way, "existence" has the role of a quantifier and "egg-laying mammals" is the predicate. Quantifier constructions can also be used to express negative existential statements; for instance, the sentence "talking tigers do not exist" can be expressed as "it is not the case that there exist talking tigers".<ref>{{harvnb|PenelopeMackie|1998|loc=§2 The Quantifier Account of Existence}}</ref>

Many ontologists accept that second-order theories provide a correct analysis of many types of existential sentences. It is, however, controversial whether it is correct for all cases.<ref>{{multiref |1={{harvnb|PenelopeMackie|1998|loc=§2 The Quantifier Account of Existence}} |2={{harvnb|Blackburn|2008|loc=[https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095804522 Existence]}} }}</ref> Some problems relate to assumptions associated with everyday language about sentences like "[[Ronald McDonald]] does not exist". This type of statement is called ''negative singular existential'' and the expression ''Ronald McDonald'' is a [[singular term]] that seems to refer to an individual. It is not clear how the expression can refer to an individual if, as the sentence claimsasserts, this individual does not exist. According to a solution philosopher [[Bertrand Russell]] (1872—1970) proposed, singular terms do not refer to individuals but are [[Theory of descriptions|descriptions of individuals]]. This theory states negative singular existentials deny an object matching the descriptions exists without referring to a non-existent individual. Following this approach, the sentence "Ronald McDonald does not exist" expresses the idea: "it is not the case there is a unique happy hamburger clown".<ref>{{multiref |1={{harvnb|Nelson|2022|loc=§ 1. Frege and Russell: Existence Is Not a Property of Individuals}} |2={{harvnb|PenelopeMackie|1998|loc=§2 The Quantifier Account of Existence}} |3={{harvnb|Nelson|2022|loc=§ 1. Frege and Russell: Existence Is Not a Property of Individuals}} }}</ref>

According to first-order theories, existence is a property of individuals. These theories are less-widely accepted than second-order theories but also have some influential proponents. There are two types of first-order theories; according to: Meinongianism, existence is a property of some but not all entities, which implies there are nonexistent entities; according toand universalism, existence is a universal property exemplified by every entity.<ref>{{multiref |1={{harvnb|Casati|Fujikawa|loc=Lead Section, §2. Existence as a First-Order Property and Its Relation to Quantification}} |2={{harvnb|Nelson|2022|loc=Lead Section}} }}</ref>

Meinongianism, iswhich describes existence as a viewproperty aboutof existencesome but not all entities, was first formulated by [[Alexius Meinong]]. Its main claimassertion is that there are some entities that do not exist, meaning [[objecthood]] is independent of existence. Proposed examples of nonexistent objects are merely possible objects such as flying pigs, as well as fictional and mythical objects like Sherlock Holmes and Zeus. According to this view, these objects are real and have being, even though they do not exist.<ref>{{multiref |1={{harvnb|Casati|Fujikawa|loc=§2a. Meinongianism}} |2={{harvnb|Lowe|2005|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-828 Existence]}} }}</ref> Meinong states there is an object for any combination of properties. For example, there is an object that only has the single property of "being a singer" with no additionalother properties. This means neither the attribute of "wearing a dress" nor the absence of it applies to this object. Meinong also includes impossible objects like round squares in this classification.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=§ 2. Meinongianism}} |2={{harvnb|Casati|Fujikawa|loc=§2a. Meinongianism}} }}</ref>

According to Meinongians, sentences describing Sherlock Holmes and Zeus refer to nonexisting objects. They are true or false depending on whether these objects have the properties ascribed to them.<ref>{{multiref |1={{harvnb|Casati|Fujikawa|loc=§2a. Meinongianism}} |2={{harvnb|Lowe|2005|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-828 Existence]}} |3={{harvnb|Küng|2012|p=[https://books.google.com/books?id=mprnCAAAQBAJ&pg=PA208 208]}} }}</ref> For instance, the sentence "Pegasus has wings" is true because having wings is a property of Pegasus, even though Pegasus lacks the property of existing.<ref name="auto1">{{harvnb|PenelopeMackie|1998|loc=§1 Objects and Existence}}</ref>

One key motivation of Meinongianism is to explain how negative singular existentials like "Ronald McDonald does not exist" can be true. Meinongians accept the idea that singular terms like "Ronald McDonald" refer to individuals. For them, a negative singular existential is true if the individual it refers to does not exist.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=§ 2. Meinongianism}} |2={{harvnb|PenelopeMackie|1998|loc=§1 Objects and Existence}} }}</ref>

An influential argument in favor of universalism is that the claim that todenial denyof the existence of something is contradictory. This conclusion follows from the premises that one can only deny the existence of something by referring to that entity and that one can only refer to entities that exist.<ref name="auto5"/>

Universalists have proposed different ways of interpreting negative singular existentials. According to one view, names of fictional entities like "Ronald McDonald" refer to [[abstract object]]s, which exist even though they do not exist in space and time. This means, when understood in a strict sense, all negative singular existentials are false, including the claimassertion that "Ronald McDonald does not exist". Universalists can interpret such sentences slightly differently in relation to the context. In everyday life, for example, people use sentences like "Ronald McDonald does not exist" to express the idea that Ronald McDonald does not exist as a concrete object, which is true.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=§ 3. An Anti-Meinongian First-Order View}} |2={{harvnb|Casati|Fujikawa|loc=§2b. Universalism}} }}</ref> Another approach is to claimunderstand negative singular existentials areas neither true nor false but [[Meaning (philosophy)|meaningless]] because their singular terms do not refer to anything.<ref>{{harvnb|Nelson|2022|loc=§ 3. An Anti-Meinongian First-Order View}}</ref>

While philosopherPhilosopher [[Aristotle]] (384–322 BCE) accepted Plato's idea that forms are different from matter, but he challenged the claimidea that forms have a higher type of existence. Instead, he believed forms cannot exist without matter.<ref>{{multiref |1={{harvnb|Trott|2019|pp=[https://books.google.com/books?id=SHsxEAAAQBAJ&pg=PA109 109–110]}} |2={{harvnb|Grayling|2019|loc=§ Aristotle}} }}</ref> He stated: "being is said in many ways" and explored how different types of entities have different modes of existence. For example, he distinguished between [[Ousia|substances]] and their [[Accident (philosophy)|accidents]], and between [[potentiality and actuality]].<ref>{{multiref | {{harvnb|Daly|2009|pp=[https://books.google.com/books?id=Bt99AgAAQBAJ&pg=PA228 228–229]}} | {{harvnb|Menn|2021|loc=§1. The Senses of Being and the Necessity of Δ. 7}} | {{harvnb|Kung|1986|pp=[https://www.jstor.org/stable/27743750 3–4]}} }}</ref>{{efn|Unlike abstract possibility, potentiality is real power possessed by a thing to undergo certain changes. For example, an [[acorn]] has the potential to become a fully grown [[oak]] but not an [[elm]].<ref>{{multiref | {{harvnb|Cohen|Reeve|2021|loc=§ 12. Actuality and Potentiality}} | {{harvnb|Ackrill|2005|p=[https://books.google.com/books?id=Nq7lGO4Fn4kC&pg=PA34 34]}} }}</ref>}}

Philosopher and psychologist [[Franz Brentano]] (1838–1917) agreed with Kant's criticism and his claimposition that existence is not a real predicate. Brentano used this idea to develop his theory of judgments, which states all judgments are existential judgments; they either affirm or deny the existence of something. He stated judgments like "some zebras are striped" have the logical form "there is a striped zebra" while judgments like "all zebras are striped" have the logical form "there is not a non-striped zebra".<ref>{{multiref |1={{harvnb|Kriegel|2018|pp=[https://books.google.com/books?id=Yz5MDwAAQBAJ&pg=PA103 103–104, 119]}} |2={{harvnb|Brandl|Textor|2022|loc=Lead Section, §1.3 Part III: Existential Judgements, §2. Brentano and His Precursors on Existential Judgement}} |3={{harvnb|Rollinger|2013|p=[https://books.google.com/books?id=6FJFBgAAQBAJ&pg=PA226 226]}} |4={{harvnb|Husserl|2019|p=[https://books.google.com/books?id=ikqzDwAAQBAJ&pg=PA184 184]}} }}</ref>

Willard Van Orman Quine (1908–2000) followed Frege and Russell in accepting existence as a second-order property. He drew a close link between existence and the role of quantification in formal logic.<ref>{{multiref |1={{harvnb|Lowe|2005|loc=[https://www.oxfordreference.com/display/10.1093/acref/9780199264797.001.0001/acref-9780199264797-e-828 Existence]}} |2={{harvnb|Casati|Fujikawa|loc=§2a. Meinongianism}} }}</ref> He applied this idea to scientific theories and stated a scientific theory is committed to the existence of an entity if the theory quantifies over this entity. For example, if a theory in biology claimsasserts that "there are populations with genetic diversity", this theory has an ontological commitment to the existence of populations with genetic diversity.<ref>{{harvnb|Casati|Fujikawa|loc=§1. Existence as a Second-Order Property and Its Relation to Quantification, §2a. Meinongianism}}</ref> Alexius Meinong (1853–1920) was an influential critic of second-order theories and developed the alternative view that existence is a property of individuals and that not all individuals have this property.<ref>{{multiref |1={{harvnb|Nelson|2022|loc=Lead Section}} |2={{harvnb|Casati|Fujikawa|loc=§2a. Meinongianism}} }}</ref>

Many schools of thought in Eastern philosophy discuss the problem of existence and its implications. For instance, the ancient [[Hindu philosophy|Hindu]] school of [[Samkhya]] articulated a metaphysical dualism according to which the two types of existence are pure consciousness (''[[Purusha]]'') and matter (''[[Prakriti]]''). Samkhya explains the manifestation of the universe as the interaction between these two principles.<ref>{{multiref |1={{harvnb|Leaman|2002|pp=[https://books.google.com/books?id=_4crBgAAQBAJ&pg=PA77 77–78]}} |2={{harvnb|Perrett|2016|loc=§ The Classical Period of Indian Philosophy}} |3={{harvnb|Ruzsa|2023|loc=Lead Section, §4. Metaphysics}} |4={{harvnb|Eraly|2011|pp=[https://books.google.com/books?id=te1sqTzTxD8C&pg=PA514 514–516]}} }}</ref> The [[Vedic]] philosopher [[Adi Shankara]] (c. 700–750 CE) developed a different approach in his school of [[Advaita Vedanta]]. Shankara defended a metaphysical monism by claimingdefining the divine (''[[Brahman]]'') isas the ultimate reality and the only existent. According to this view, the impression that there is a universe consisting of many distinct entities is an illusion (''[[Maya (religion)|Maya]]'').<ref>{{multiref | {{harvnb|Perrett|2016|loc=§ The Medieval Period of Indian Philosophy}} | {{harvnb|Dalal|2021|loc=Lead Section, § 1. Life and Works}} | {{harvnb|Menon|loc=Lead Section}} | {{harvnb|Dalal|2010|p=[https://books.google.com/books?id=DH0vmD8ghdMC&pg=PA6 6]}}}}</ref> The essential features of ultimate reality are described as ''[[Sat Chit Ananda]]''—meaning existence, consciousness, and bliss.<ref>{{multiref |1={{harvnb|Vanamali|2015|pp=[https://books.google.com/books?id=QGAoDwAAQBAJ&pg=PT53 53–54]}} |2={{harvnb|Reddy|2020|p=[https://books.google.com/books?id=tRveDwAAQBAJ&pg=PA110 110]}} |3={{harvnb|Sastry|2022|p=[https://books.google.com/books?id=LXmUEAAAQBAJ&pg=PT38 38]}} }}</ref>

A central doctrine in [[Buddhist philosophy]] is called the "[[three marks of existence]]", which are ''[[anicca|aniccā]]'' (impermanence), ''[[anattā]]'' (absence of a permanent self), and ''[[dukkha]]'' (suffering). ''Aniccā'' is the doctrine that all of existence is subject to change, meaning everything changes at some point and nothing lasts forever. ''Anattā'' expresses a similar state in relation to persons by claimingstating that people do not have a permanent identity or a separate self. Ignorance about ''aniccā'' and ''anattā'' is seen as the main cause of ''dukkha'' by leading people to form attachments that cause suffering.<ref>{{multiref |1={{harvnb|Smith|Worden|2003|p=[https://books.google.com/books?id=8emELTpHWSEC&pg=PA18 18]}} |2={{harvnb|Gómez|2007|p=[https://books.google.com/books?id=sQULdfIlBIYC&pg=PA110 110]}} |3={{harvnb|Allen|2015|p=[https://books.google.com/books?id=Tw2VCgAAQBAJ&pg=PA114 114]}} }}</ref>

=== OthersOther traditions ===

The disciplines of [[epistemology]], [[philosophy of mind]], and [[philosophy of language]] deal with [[Mental representation|mental]] and linguistic representations in their attempt to understand the nature of knowledge, the mind, and language. This brings with it the problem of reference or how representations can refer to existing objects. Examples of such representations are beliefs, thoughts, perceptions, words, and sentences. For instance, in the sentence "Barack Obama is a Democrat", the name "Barack Obama" refers to a particular individual. InThe relationproblem toof perception,reference also affects the problemepistemology of referenceperception. questionsIn whetherparticular, andthis toconcerns whatthe extentproblem of whether perceptual impressions putestablish thea perceiver indirect contact with reality by presenting existing objects rather than illusions.<ref>{{multiref |1={{harvnb|Urban|2014|p=[https://books.google.com/books?id=xLS3AwAAQBAJ&pg=PT33 33]}} |2={{harvnb|Raftopoulos|Machamer|2012|pp=[https://books.google.com/books?id=80ZitZBNao4C&pg=PA1 1–2, 142]}} |3={{harvnb|Michaelson|Reimer|2022|loc=Lead Section, § 1. Introduction}} |4={{harvnb|Audi|2006|loc=§ Epistemology, § Philosophy of Mind, § Philosophy of Language}} }}</ref>

[[Existentialism]] is a school of thought that explores the nature of human existence. One ofAmong its key ideas is that [[existence precedes essence]],. meaningThis means that existence is more basic than essence. andAs a result, the nature and purpose of human beings are not pre-existing but develop in the process of living. According to this view, humans are thrown into a world that lacks pre-existing intrinsic meaning. They must determine for themselves their purpose and what [[Meaning of life|meaning their life]] should have. Existentialists use this idea to explore the role of freedom and responsibility in actively shaping one's life.<ref>{{multiref |1={{harvnb|Burnham|Papandreopoulos|loc=Lead Section, §1c. Freedom, §1e. Existence, §1f. Irrationality/Absurdity}} |2={{harvnb|Aho|2023|loc=Lead Section}} }}</ref> [[Feminist existentialism|Feminist existentialists]] investigate the effects of [[gender]] on human existence, for example, on the experience of freedom.<ref>{{multiref | {{harvnb|Ritzer|Stepnisky|2017|pp=[https://books.google.com/books?id=xK74DQAAQBAJ&pg=PA298 298–299]}} | {{harvnb|Quinan|2016}} }}</ref> Influential existentialists include [[Søren Kierkegaard]] (1813–1855), [[Friedrich Nietzsche]] (1844–1900), [[Jean-Paul Sartre]] (1905–1980), and [[Simone de Beauvoir]] (1908–1986).<ref>{{multiref | {{harvnb|Burnham|Papandreopoulos|loc=§ Key Existentialist Philosophers}} | {{harvnb|Aho|2023|loc=Lead Section}} }}</ref> Existentialism has influenced various reflections on the role of human existence in [[sociology]]. Existentialist sociology examines the ways humans experience the social world and [[Social constructionism|construct reality]].<ref>{{harvnb|Melnikov|Kotarba|2015|loc=[https://onlinelibrary.wiley.com/doi/10.1002/9781405165518.wbeose083.pub2 Existential Sociology]}}</ref> Existence theory is a relatively recent approach that focuses on the temporal aspect of existence in society. andIt explores how the existential milestones to which people aspire influence their lives.<ref>{{multiref | {{harvnb|Baert|Morgan|Ushiyama|2022|pp=7–8}} | {{harvnb|Flisbäck|Bengtsson|2024|pp=1–2}} }}</ref>

Many debates in theology revolve around the existence of the divine, and various arguments have been presented for and against God's existence. [[Cosmological argument]]s state that God must exist as the first cause to explain facts about the existence and aspects of the universe.<ref>{{multiref | {{harvnb|Reichenbach|2023|loc=Lead Section}} | {{harvnb|Ratzsch|Koperski|2023|loc=§ 1. Introduction}} }}</ref> According to [[teleological argument]]s, the only way to explain the order and complexity of the universe and human life is by reference to God as the [[intelligent design]]er.<ref>{{harvnb|Ratzsch|Koperski|2023|loc=§ 1. Introduction}}</ref> An influential argument against the existence of God relies on [[the problem of evil]] since it is not clear how evil could exist if there was an all-powerful, all-knowing, and benevolent God.<ref>{{harvnb|Beebe|loc=Lead Section}}</ref> Another argument points to a lack of concrete evidence for God's existence.<ref>{{harvnb|Clark|loc=§ 2. The Evidentialist Objection to Belief in God}}</ref>

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* {{cite web |last1=Kroon |first1=Fred |last2=Voltolini |first2=Alberto |title=Fictional Entities |url=https://plato.stanford.edu/entries/fictional-entities/ |website=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |access-date=28 April 2024 |date=2023 |archive-date=June 17, 2024 |archive-url=https://web.archive.org/web/20240617060209/https://plato.stanford.edu/entries/fictional-entities/ |url-status=live }}

* {{cite book |last1=Küng |first1=Guido |chapter=Ingarden on Language and Ontology (A Comparison with some Trends in Analytic Philosophy) |editor-last1=Tymieniecka |editor-first1=Anna-Teresa |title=The Later Husserl and the Idea of Phenomenology: Idealism-Realism, Historicity and Nature Papers and Debate of the International Phenomenological Conference Held at the University of Waterloo, Canada, April 9–14, 1969 |date=2012 |publisher=Springer Science & Business Media |isbn=978-94-010-2882-0 |chapter-url=https://books.google.com/books?id=mprnCAAAQBAJ&pg=PA208 |language=en |access-date=1 September 2023 |archive-date=29 August 2023 |archive-url=https://web.archive.org/web/20230829081448/https://books.google.com/books?id=mprnCAAAQBAJ&pg=PA208 |url-status=live }}

* {{cite book |last1=Lajul |first1=Wilfred |editor1-last=Ukpokolo |editor1-first=Isaac E. |title=Themes, Issues and Problems in African Philosophy |publisher=Springer |isbn=978-3-319-40796-8 |chapter-url=https://books.google.com/books?id=1PUODgAAQBAJ&pg=PA29 |language=en |chapter=African Metaphysics: Traditional and Modern Discussions |date=2017 |access-date=May 21, 2024 |archive-date=June 17, 2024 |archive-url=https://web.archive.org/web/20240617060210/https://books.google.com/books?id=1PUODgAAQBAJ&pg=PA29#v=onepage&q&f=false |url-status=live }}

* {{cite book |last1=Lamarque |first1=Peter |chapter=Fictional entities |url=https://www.rep.routledge.com/articles/thematic/fictional-entities/v-1 |title=Routledge Encyclopedia of Philosophy |access-date=24 March 2024 |language=en |date=1998 |doi=10.4324/9780415249126-M021-1 |isbn=978-0-415-25069-6 |publisher=Routledge |archive-date=April 28, 2024 |archive-url=https://web.archive.org/web/20240428121741/https://www.rep.routledge.com/articles/thematic/fictional-entities/v-1 |url-status=live }}

* {{cite book |last1=Lenzen |first1=Wolfgang |chapter=Free Epistemic Logic |editor-last1=Morscher |editor-first1=E. |editor-last2=Hieke |editor-first2=A. |title=New Essays in Free Logic: In Honour of Karel Lambert |date=2013 |publisher=Springer Science & Business Media |isbn=978-94-015-9761-6 |chapter-url=https://books.google.com/books?id=zn3oCAAAQBAJ&pg=PA118 |language=en |access-date=1 September 2023 |archive-date=16 August 2023 |archive-url=https://web.archive.org/web/20230816072052/https://books.google.com/books?id=zn3oCAAAQBAJ&pg=PA118 |url-status=live }}

* {{cite book |last1=Martin |first1=Stephen P. |last2=Wells |first2=James D. |title=Elementary Particles and Their Interactions |publisher=Springer Nature |isbn=978-3-031-14368-7 |url=https://books.google.com/books?id=xVyYEAAAQBAJ&pg=PA1 |language=en |date=2022 |access-date=June 5, 2024 |archive-date=June 17, 2024 |archive-url=https://web.archive.org/web/20240617060210/https://books.google.com/books?id=xVyYEAAAQBAJ&pg=PA1#v=onepage&q&f=false |url-status=live }}

* {{cite book |last1=Melnikov |first1=Andrey |last2=Kotarba |first2=Joseph A. |editor1-last=Ritzer |editor1-first=George |title=The Blackwell Encyclopedia of Sociology |publisher=Wiley |isbn=978-1-4051-2433-1 |url=https://onlinelibrary.wiley.com/doi/10.1002/9781405165518.wbeose083.pub2 |language=en |chapter=Existential Sociology |date=2015 |doi=10.1002/9781405165518.wbeose083.pub2 |access-date=April 30, 2024 |archive-date=April 30, 2024 |archive-url=https://web.archive.org/web/20240430114904/https://onlinelibrary.wiley.com/doi/10.1002/9781405165518.wbeose083.pub2 |url-status=live }}

* {{cite book |last1=Montague |first1=Michelle |chapter=Intentionality: From Brentano to Representionalism |editor-last1=Kind |editor-first1=Amy |title=Philosophy of Mind in the Twentieth and Twenty-First Centuries: The History of the Philosophy of Mind |volume=6 |date=2018 |publisher=Routledge |isbn=978-0-429-01938-8 |chapter-url=https://books.google.com/books?id=oDhjDwAAQBAJ&pg=PT236 |language=en |access-date=1 September 2023 |archive-date=16 August 2023 |archive-url=https://web.archive.org/web/20230816072054/https://books.google.com/books?id=oDhjDwAAQBAJ&pg=PT236 |url-status=live }}

* {{cite web |last1=O’Madagain |first1=Cathal |title=Intentionality |url=https://iep.utm.edu/intentio/ |website=Internet Encyclopedia of Philosophy |access-date=28 April 2024 |issn=2161-0002 |archive-date=April 28, 2024 |archive-url=https://web.archive.org/web/20240428121740/https://iep.utm.edu/intentio/ |url-status=live }}

* {{cite book |last1=Pack |first1=Justin |title=Environmental Philosophy in Desperate Times |publisher=Broadview Press |isbn=978-1-77048-866-3 |url=https://books.google.com/books?id=nP18EAAAQBAJ&pg=PA162 |language=en |date=2022 |access-date=May 21, 2024 |archive-date=June 17, 2024 |archive-url=https://web.archive.org/web/20240617060211/https://books.google.com/books?id=nP18EAAAQBAJ&pg=PA162#v=onepage&q&f=false |url-status=live }}

* {{cite book |last1=Parkin |first1=Alan J. |title=Essential Cognitive Psychology (Classic Edition) |publisher=Psychology Press |isbn=978-1-135-00511-5 |url=https://books.google.com/books?id=cbEpAAAAQBAJ&pg=PA238 |language=en |date=2013 |edition=Classic }}

* {{cite book |last1=Portner |first1=Paul |chapter=Meaning |editor-last1=Fasold |editor-first1=Ralph |editor-last2=Connor-Linton |editor-first2=Jeffrey |title=An Introduction to Language and Linguistics |date=2006 |publisher=Cambridge University Press |isbn=978-1-107-71766-4 |chapter-url=https://books.google.com/books?id=E85VAgAAQBAJ&pg=PA156 |language=en |access-date=2024-02-15 |archive-date=2024-02-15 |archive-url=https://web.archive.org/web/20240215165203/https://books.google.com/books?id=E85VAgAAQBAJ&pg=PA156 |url-status=live }}

* {{cite book |last1=Quinan |first1=Christine L. |title=The Wiley Blackwell Encyclopedia of Gender and Sexuality Studies |publisher=Wiley |isbn=978-1-4051-9694-9 |edition=1 |url=https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118663219.wbegss665 |language=en |chapter=Feminism, Existential |date=2016 |pages=1–3 |doi=10.1002/9781118663219.wbegss665 |access-date=May 23, 2024 |archive-date=June 17, 2024 |archive-url=https://web.archive.org/web/20240617060212/https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118663219.wbegss665 |url-status=live }}

* {{cite book |last1=Raftopoulos |first1=Athanassios |last2=Machamer |first2=Peter |title=Perception, Realism, and the Problem of Reference |date=2012 |publisher=Cambridge University Press |isbn=978-0-521-19877-6 |url=https://books.google.com/books?id=80ZitZBNao4C&pg=PA1 |language=en |access-date=1 September 2023 |archive-date=16 August 2023 |archive-url=https://web.archive.org/web/20230816072047/https://books.google.com/books?id=80ZitZBNao4C&pg=PA1 |url-status=live |chapter=Reference, Perception, and Realism }}

* {{cite book |last1=Reck |first1=Johann Georg |chapter=Ek-sistenz |title=Wörterbuch der Psychotherapie |date=2000 |pages=155–156 |doi=10.1007/978-3-211-99131-2_412 |publisher=Springer |isbn=978-3-211-99130-5 |chapter-url=https://books.google.com/books?id=ZpkdBgAAQBAJ&pg=pa156PA156 }}

* {{cite book |last1=Reddy |first1=V. Ananda |chapter=The Metaphysical Foundations of Sri Aurobindo's Vision of the Future of Humanity |editor-last1=Mahapatra |editor-first1=Debidatta Aurobinda |title=The Philosophy of Sri Aurobindo: Indian Philosophy and Yoga in the Contemporary World |date=2020 |publisher=Bloomsbury Publishing |isbn=978-1-350-12487-5 |chapter-url=https://books.google.com/books?id=tRveDwAAQBAJ&pg=PA110 |language=en |access-date=1 September 2023 |archive-date=17 August 2023 |archive-url=https://web.archive.org/web/20230817085528/https://books.google.com/books?id=tRveDwAAQBAJ&pg=PA110 |url-status=live }}

* {{cite book |last1=Ritzer |first1=George |last2=Stepnisky |first2=Jeffrey |title=Modern Sociological Theory |publisher=SAGE |isbn=978-1-5063-2561-3 |url=https://books.google.com/books?id=xK74DQAAQBAJ&pg=PA298 |language=en |date=2017 |access-date=May 23, 2024 |archive-date=May 23, 2024 |archive-url=https://web.archive.org/web/20240523164607/https://books.google.com/books?id=xK74DQAAQBAJ&pg=PA298 |url-status=live }}

* {{cite book |last1=Schwichtenberg |first1=Jakob |title=Physics from Symmetry |publisher=Springer |isbn=978-3-319-66631-0 |url=https://books.google.com/books?id=bipBDwAAQBAJ&pg=PA8 |language=en |date=2017 |access-date=June 5, 2024 |archive-date=June 5, 2024 |archive-url=https://web.archive.org/web/20240605111131/https://books.google.com/books?id=bipBDwAAQBAJ&pg=PA8 |url-status=live }}

* {{cite book |last1=Shūzō |first1=Kuki |chapter=Contingency |editor-last1=Heisig |editor-first1=James W. |editor-last2=Kasulis |editor-first2=Thomas P. |editor-last3=Maraldo |editor-first3=John C. |title=Japanese Philosophy: A Sourcebook |date=2011 |publisher=University of Hawaii Press |isbn=978-0-8248-3707-5 |chapter-url=https://books.google.com/books?id=GVgEEAAAQBAJ&pg=PA830 |language=en |access-date=1 September 2023 |archive-date=11 August 2023 |archive-url=https://web.archive.org/web/20230811074249/https://books.google.com/books?id=GVgEEAAAQBAJ&pg=PA830 |url-status=live }}

* {{cite book |last1=Sinclair |first1=Rebekah |editor1-last=Dhillon |editor1-first=Jaskiran |title=Indigenous Resurgence: Decolonialization and Movements for Environmental Justice |publisher=Berghahn Books |isbn=978-1-80073-247-6 |chapter-url=https://books.google.com/books?id=yhwrEAAAQBAJ&pg=PA96 |language=en |chapter=Righting Names: The Importance of Native American Philosophies of Naming for Environmental Justice |date=2022 |access-date=May 21, 2024 |archive-date=May 7, 2024 |archive-url=https://web.archive.org/web/20240507030212/https://books.google.com/books?id=yhwrEAAAQBAJ&pg=PA96 |url-status=live }}

* {{cite book |last1=Smith |first1=Barry |last2=Mulligan |first2=Kevin |last3=Simons |first3=Peter |editor1-last=Monnoyer |editor1-first=Jean-Maurice |title=Metaphysics and Truthmakers |date=2013 |publisher=Walter de Gruyter |isbn=978-3-11-032691-8 |chapter-url=https://books.google.com/books?id=RNg2n2yVrCUC&pg=PA9 |language=en |access-date=24 September 2023 |archive-date=17 December 2023 |archive-url=https://web.archive.org/web/20231217195807/https://books.google.com/books?id=RNg2n2yVrCUC&pg=PA9 |url-status=live |chapter=Truth-Makers }}

* {{cite web |last1=Uzquiano |first1=Gabriel |title=Quantifiers and Quantification |url=https://plato.stanford.edu/entries/quantification/ |website=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |access-date=30 April 2024 |date=2022 |archive-date=June 17, 2024 |archive-url=https://web.archive.org/web/20240617060212/https://plato.stanford.edu/entries/quantification/ |url-status=live }}

* {{cite book |last1=Vallicella |first1=William F. |chapter=Existence: Two Dogmas of Analysis |editor-last1=Novotný |editor-first1=Daniel D. |editor-last2=Novák |editor-first2=Lukáš |title=Neo-Aristotelian Perspectives in Metaphysics |date=2014 |publisher=Routledge |isbn=978-1-134-63009-7 |chapter-url=https://books.google.com/books?id=2QBgAwAAQBAJ&pg=PA46 |language=en |access-date=1 September 2023 |archive-date=20 August 2023 |archive-url=https://web.archive.org/web/20230820104707/https://books.google.com/books?id=2QBgAwAAQBAJ&pg=PA46 |url-status=live }}

* {{cite book |last1=Van Inwagen |first1=Peter |chapter=McGinn on Existence |editor-last1=Bottani |editor-first1=Andrea |editor-last2=Davies |editor-first2=Richard |title=Modes of Existence: Papers in Ontology and Philosophical Logic |date=2013 |publisher=Walter de Gruyter |isbn=978-3-11-032753-3 |chapter-url=https://books.google.com/books?id=15LIl3X8SnUC&pg=PA126 |language=en |access-date=1 September 2023 |archive-date=29 August 2023 |archive-url=https://web.archive.org/web/20230829081449/https://books.google.com/books?id=15LIl3X8SnUC&pg=PA126 |url-status=live }}

* {{cite book |last1=Vinogradov |first1=I. M. |last2=Karatsuba |first2=A. A. |chapter=The Method of Trigonometric Sums in Number Theory |title=Algebra, Mathematical Logic, Number Theory, Topology |publisher=American Mathematical Society |isbn=978-0-8218-3096-3 |chapter-url=https://books.google.com/books?id=rSay9ZPucccC&pg=PA8 |language=en |date=1986 |access-date=April 8, 2024 |archive-date=April 8, 2024 |archive-url=https://web.archive.org/web/20240408083147/https://books.google.com/books?id=rSay9ZPucccC&pg=PA8 |url-status=live }}

* {{cite journal |last1=Yagisawa |first1=Takashi |title=Précis of Worlds and Individuals, Possible and Otherwise |journal=Analytic Philosophy |date=2011 |volume=52 |issue=4 |pages=270–272 |doi=10.1111/j.2153-960X.2011.00534.x |url=https://philpapers.org/rec/YAGPOW |access-date=2023-09-01 |archive-date=2023-08-30 |archive-url=https://web.archive.org/web/20230830123531/https://philpapers.org/rec/YAGPOW |url-status=live |issn=2153-9596 }}

* {{cite book |last1=Yao |first1=Zhihua |chapter=The Cognition of Nonexistent Objects: Five Yogācāra Arguments |editor-last1=Liu |editor-first1=Jeeloo |editor-last2=Berger |editor-first2=Douglas |title=Nothingness in Asian Philosophy |date=2014 |publisher=Routledge |isbn=978-1-317-68383-4 |chapter-url=https://books.google.com/books?id=NZjOAwAAQBAJ&pg=PA140 |language=en |access-date=1 September 2023 |archive-date=11 August 2023 |archive-url=https://web.archive.org/web/20230811074249/https://books.google.com/books?id=p5nOAwAAQBAJ&pg=PT150 |url-status=live }}