Editing Ontology (section)

=== Realism and anti-realism ===
{{main|Philosophical realism|Anti-realism}}
The term ''realism'' is used for various theories{{efn|They are usually distinguished by combining them with a qualifier to express which type is meant, as in  ''ontological realism'', ''mathematical realism'', and ''moral realism''. The qualifiers are sometimes left out if the meaning is clear in the context.<ref>{{harvnb|Niiniluoto|2002|pp=1–2, 21, 25–26, 28–29}}</ref>}} that affirm that some kind of phenomenon is real or has mind-independent existence. Ontological realism is the view that there are [[Subjectivity and objectivity (philosophy)|objective]] facts about what exists and what the nature and categories of being are. Ontological realists do not make claims about what those facts are, for example, whether elementary particles exist. They merely state that there are mind-independent facts that determine which ontological theories are true.<ref>{{multiref | {{harvnb|Niiniluoto|2002|pp=1–2, 21, 25–26}} | {{harvnb|Chalmers|2009|pp=77–78}} | {{harvnb|Sider|2009|pp=385–386}} }}</ref> This idea is denied by ontological anti-realists, also called ontological deflationists, who say that there are no substantive facts one way or the other.<ref>{{multiref | {{harvnb|Chalmers|2009|pp=77–78}} | {{harvnb|Sider|2009|pp=385–386}} }}</ref> According to philosopher [[Rudolf Carnap]], for example, ontological statements are relative to language and depend on the ontological framework of the speaker. This means that there are no framework-independent ontological facts since different frameworks provide different views while there is no objectively right or wrong framework.<ref>{{multiref | {{harvnb|Chalmers|2009|p=78}} | {{harvnb|Hofweber|2023|loc=§ 4.4 Carnap’s rejection of ontology. (L1) meets (O4) and (the end of?) (O2)}} }}</ref>

[[File:Sanzio 01 Plato Aristotle.jpg|thumb|alt=Fresco showing Plato and Aristotle|[[Plato]] (left) and [[Aristotle]] (right) disagreed on whether universals can exist without matter.]]

In a more narrow sense, realism refers to the existence of certain types of entities.<ref>{{harvnb|Niiniluoto|2002|pp=1–2, 21, 25–26, 28–29}}</ref> Realists about universals say that universals have mind-independent existence. According to [[Theory of forms|Platonic realists]], universals exist not only independent of the mind but also independent of particular objects that exemplify them. This means that the universal ''red'' could exist by itself even if there were no red objects in the world. Aristotelian realism, also called [[moderate realism]], rejects this idea and says that universals only exist as long as there are objects that exemplify them. [[Conceptualism]], by contrast, is a form of anti-realism, stating that universals only exist in the mind as concepts that people use to understand and categorize the world. [[Nominalism|Nominalists]] defend a strong form of anti-realism by saying that universals have no existence. This means that the world is entirely composed of particular objects.<ref>{{multiref | {{harvnb|MacLeod|Rubenstein|loc=Lead Section, § 2. Versions of Realism, § 3. Versions of Anti-Realism}} | {{harvnb|Bigelow|1998a|loc=§ 4. Nominalism and Realism}} | {{harvnb|Loux|Crisp|2017|pp=17–19, 45}} | {{harvnb|Niiniluoto|2002|pp=28–29}}}}</ref>

[[Mathematical realism]], a closely related view in the [[philosophy of mathematics]], says that mathematical facts exist independently of human language, thought, and practices and are discovered rather than invented. According to mathematical Platonism, this is the case because of the existence of [[mathematical objects]], like numbers and sets. Mathematical Platonists say that mathematical objects are as real as physical objects, like atoms and stars, even though they are not accessible to [[empirical observation]].<ref>{{multiref | {{harvnb|Blanchette|1998|loc=Lead Section}} | {{harvnb|Moore|1998|loc=Lead Section}} | {{harvnb|Balaguer|2009|p=[https://books.google.com/books?id=mbn35b2ghgkC&pg=PA36 36]}} | {{harvnb|Linnebo|2024|loc=Lead Section}} }}</ref> Influential forms of mathematical anti-realism include conventionalism, which says that mathematical theories are trivially true simply by how mathematical terms are defined, and game [[Formalism (philosophy of mathematics)|formalism]], which understands mathematics not as a theory of reality but as a game governed by rules of string manipulation.<ref>{{multiref | {{harvnb|Balaguer|2009|pp=[https://books.google.com/books?id=mbn35b2ghgkC&pg=PA36 36, 44]}} | {{harvnb|Weir|2024|loc=Lead Section}} }}</ref>

[[Modal realism]] is the theory that in addition to the actual world, there are countless [[possible world]]s as real and concrete as the actual world. The primary difference is that the actual world is inhabited by us while other possible worlds are inhabited by our [[Counterpart theory|counterparts]]. Modal anti-realists reject this view and argue that possible worlds do not have concrete reality but exist in a different sense, for example, as abstract or fictional objects.<ref>{{multiref | {{harvnb|Borghini|2016|pp=[https://books.google.com/books?id=Ifw8CwAAQBAJ&pg=PA91 91–93]}} | {{harvnb|Chihara|2001|pp=[https://doi.org/10.1093/acprof:oso/9780199246557.003.0005 142–143]}} | {{harvnb|Parent|loc=Lead section}} }}</ref>

[[Scientific realism|Scientific realists]] say that the scientific description of the world is an accurate representation of reality.{{efn|The exact definition of the term is disputed.<ref>{{harvnb|Chakravartty|2017|loc=§ 1. What is Scientific Realism?}}</ref>}} It is of particular relevance in regard to things that [[Unobservable|cannot be directly observed]] by humans but are assumed to exist by scientific theories, like electrons, forces, and laws of nature. [[Scientific anti-realism]] says that scientific theories are not descriptions of reality but [[Instrumentalism|instruments]] to predict observations and the outcomes of experiments.<ref>{{multiref | {{harvnb|Chakravartty|2017|loc=Lead Section, § 1. What is Scientific Realism?}} | {{harvnb|Liston|loc=Lead Section, § 6b. The Observable-Unobservable Distinction}} | {{harvnb|Okasha|2016|pp=[https://books.google.com/books?id=GMqSDAAAQBAJ&pg=PA54 54–55]}} }}</ref>

[[Moral realism|Moral realists]] claim that there exist mind-independent moral facts. According to them, there are objective principles that determine which behavior is morally right. [[Moral anti-realism|Moral anti-realists]] either claim that moral principles are subjective and differ between persons and cultures, a position known as [[moral relativism]], or outright deny the existence of moral facts, a view referred to as [[moral nihilism]].<ref>{{multiref | {{harvnb|DeLapp|loc=Lead Section, § 4a. Moral Realisms, § 4b. Moral Relativisms}} | {{harvnb|Sayre-McCord|2023a|loc=Lead Section}} | {{harvnb|Gowans|2021|loc=Lead Section, § 2. Forms and Arguments}} | {{harvnb|Westacott|loc=Lead Section}} | {{harvnb|Dreier|2007|pp=240–241}} }}</ref>