View source for Anti-realism

{{short description|Truth of a statement rests on its demonstrability, not its correspondence to an external reality}}
In [[analytic philosophy]], '''anti-realism''' is the position that the truth of a [[Statement (logic)|statement]] rests on its demonstrability through internal logic mechanisms, such as the [[context principle]] or [[intuitionistic logic]], in direct opposition to the [[Philosophical realism|realist]] notion that the truth of a statement rests on its correspondence to an external, independent reality.<ref>[[#Realism (1963)|Realism (1963)]] p. 146</ref> In anti-realism, this external reality is [[hypothesis|hypothetical]] and is not assumed.<ref>[[#Truth (1959)|Truth (1959)]] p. 24 (postscript)</ref><ref>[[Simon Blackburn|Blackburn, Simon]] ([2005] 2008). "realism/anti-realism", ''[[The Oxford Dictionary of Philosophy]]'', 2nd ed. revised, pp. 308–9. Oxford.</ref>  

There are many varieties of anti-realism, such as metaphysical, mathematical, semantic, scientific, moral and epistemic. The term was first articulated by British [[philosopher]] [[Michael Dummett]] in an [[argument]] against a form of [[Philosophical realism|realism]] Dummett saw as 'colorless reductionism'.<ref>[[#Realism (1963)|Realism (1963)]] p. 145</ref>

Anti-realism in its most general sense can be understood as being in contrast to a ''generic realism'', which holds that distinctive objects of a subject-matter exist and have properties independent of one's beliefs and conceptual schemes.<ref>{{Citation|last=Miller|first=Alexander|title=Realism|date=2019|url=https://plato.stanford.edu/archives/win2019/entries/realism/|encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2019|publisher=Metaphysics Research Lab, Stanford University|access-date=2021-09-28}}</ref> The ways in which anti-realism rejects these type of claims can vary dramatically. Because this encompasses statements containing [[abstract object|abstract ideal objects]] (i.e. mathematical objects), anti-realism may apply to a wide range of philosophical topics, from [[Physical body|material objects]] to the theoretical [[entity|entities]] of [[science]], [[mathematical object|mathematical statements]], [[The problem of other minds|mental states, events and processes]], the [[past]] and the [[future]].<ref>[[#Realism (1963)|Realism (1963)]] pp. 147–8</ref>

== Varieties ==
=== Metaphysical anti-realism<!--'Metaphysical anti-realism' and 'Metaphysical antirealism' redirect here--> ===
{{also|Philosophical skepticism}}
One kind of '''metaphysical anti-realism'''<!--boldface per WP:R#PLA--> maintains a [[skepticism]] about the physical world, arguing either: 1) that nothing exists outside the mind, or 2) that we would have no access to a mind-independent reality, even if it exists.<ref>Karin Johannesson, ''[https://books.google.com/books?id=_ZPJb3iipY8C&q=%22anti-realism%22 God Pro Nobis: On Non-metaphysical Realism and the Philosophy of Religion]'', Peeters Publishers, 2007, p. 26.</ref> The latter case often takes the form of a denial of the idea that we can have 'unconceptualised' experiences (see [[Myth of the Given]]). Conversely, most realists (specifically, [[Indirect realism|indirect realists]]) hold that perceptions or [[sense data]] are caused by mind-independent objects. But this introduces the possibility of another kind of skepticism: since our understanding of [[causality]] is that the same effect can be produced by multiple causes, there is a [[Indeterminacy (philosophy)|lack of determinacy]] about what one is really perceiving, as in the [[brain in a vat]] scenario. The main alternative to this sort of metaphysical anti-realism is [[metaphysical realism]].

On a more abstract level, [[model theory|model-theoretic]] anti-realist arguments hold that a given set of [[symbol]]s in a [[theory]] can be mapped onto any number of sets of real-world objects&mdash;each set being a "model" of the theory—provided the relationship between the objects is the same (compare with [[symbol grounding]].)

In [[ancient Greek philosophy]], [[Problem of universals#Nominalism|nominalist (anti-realist) doctrines]] about [[universals (metaphysics)|universals]] were proposed by the [[Stoics]], especially [[Chrysippus]].<ref>John Sellars, ''Stoicism'', Routledge, 2014, pp. 84–85: "[Stoics] have often been presented as the first nominalists, rejecting the existence of universal concepts altogether. ... For Chrysippus there are no universal entities, whether they be conceived as substantial [[Platonic Forms]] or in some other manner."</ref><ref>{{cite web| url = https://www.iep.utm.edu/chrysipp/| title = Chrysippus – Internet Encyclopedia of Philosophy}}</ref> In [[early modern philosophy]], [[Conceptualism|conceptualist]] anti-realist doctrines about universals were proposed by thinkers like [[René Descartes]], [[John Locke]], [[Baruch Spinoza]], [[Gottfried Wilhelm Leibniz]], [[George Berkeley]], and [[David Hume]].<ref>[[David Bostock (philosopher)|David Bostock]], ''Philosophy of Mathematics: An Introduction'', Wiley-Blackwell, 2009, p. 43: "All of Descartes, Locke, Berkeley, and Hume supposed that mathematics is a theory of our ''ideas'', but none of them offered any argument for this conceptualist claim, and apparently took it to be uncontroversial."</ref><ref>Stefano Di Bella, Tad M. Schmaltz (eds.), ''The Problem of Universals in Early Modern Philosophy'', Oxford University Press, 2017, p. 64 "there is a strong case to be made that Spinoza was a ''conceptualist'' about universals" and p. 207 n. 25: "Leibniz's conceptualism [is related to] the Ockhamist tradition..."</ref> In [[late modern philosophy]], anti-realist doctrines about knowledge were proposed by the [[German idealist]] [[Georg Wilhelm Friedrich Hegel]]. Hegel was a proponent of what is now called [[Semantic inferentialism|inferentialism]]: he believed that the ground for the axioms and the foundation for the validity of the inferences are the right consequences and that the axioms do not explain the consequence.<ref>P. Stekeler-Weithofer (2016), [https://www.sozphil.uni-leipzig.de/cm/philosophie/files/2012/11/StekelerHegelsAnalyticPragmatism.pdf "Hegel's Analytic Pragmatism"] {{Webarchive|url=https://web.archive.org/web/20201103050351/https://www.sozphil.uni-leipzig.de/cm/philosophie/files/2012/11/StekelerHegelsAnalyticPragmatism.pdf |date=2020-11-03 }}, University of Leipzig, pp. 122–4.</ref> Kant and Hegel held conceptualist views about universals.<ref>Oberst, Michael. 2015. "Kant on Universals." ''History of Philosophy Quarterly'' '''32'''(4):335–352.</ref><ref>A. Sarlemijn, ''Hegel's Dialectic'', Springer, 1975, p. 21.</ref> In [[contemporary philosophy]], anti-realism was revived in the form of [[empirio-criticism]], [[logical positivism]], [[Semantic anti-realism (epistemology)|semantic anti-realism]] and scientific [[instrumentalism]] (see below).

===Mathematical anti-realism===
{{main|Mathematical anti-realism}}
{{also|Post rem structuralism}}
In the [[philosophy of mathematics]], realism is the claim that mathematical entities such as 'number' have an observer-independent existence. [[Mathematical empiricism|Empiricism]], which associates numbers with concrete physical objects, and [[Mathematical Platonism|Platonism]], in which numbers are abstract, non-physical entities, are the preeminent forms of mathematical realism.

The "[[epistemic]] argument" against Platonism has been made by [[Paul Benacerraf]] and [[Hartry Field]]. Platonism posits that mathematical objects are ''[[abstract object|abstract]]'' entities. By general agreement, abstract entities cannot interact [[causal]]ly with physical entities ("the truth-values of our mathematical assertions depend on facts involving platonic entities that reside in a realm outside of space-time"<ref>Field, Hartry, 1989, ''Realism, Mathematics, and Modality'', Oxford: Blackwell, p. 68</ref>). Whilst our knowledge of physical objects is based on our ability to [[perception|perceive]] them, and therefore to causally interact with them, there is no parallel account of how mathematicians come to have knowledge of abstract objects.<ref>"Since abstract objects are outside the nexus of causes and effects, and thus perceptually inaccessible, they cannot be known through their effects on us" — [[Jerrold Katz]], ''Realistic Rationalism'', 2000, p. 15</ref><ref>{{Cite web |url=http://www.philosophynow.org/issue81/ |title=Philosophy Now: "Mathematical Knowledge: A dilemma" |access-date=2011-02-14 |archive-url=https://web.archive.org/web/20110207095054/http://philosophynow.org/issue81 |archive-date=2011-02-07 |url-status=dead }}</ref><ref>{{cite book| chapter-url = http://plato.stanford.edu/entries/platonism-mathematics/#EpiAcc| title = Stanford Encyclopedia of Philosophy| chapter = Platonism in the Philosophy of Mathematics| year = 2018| publisher = Metaphysics Research Lab, Stanford University}}</ref>

Field developed his views into [[Mathematical fictionalism|fictionalism]]. Benacerraf also developed the philosophy of [[mathematical structuralism]], according to which there are no mathematical objects. Nonetheless, some versions of structuralism are compatible with some versions of realism.

====Counterarguments<!--'Realistic rationalism' redirects here-->====
Anti-realist arguments hinge on the idea that a satisfactory, [[Naturalism (philosophy)|naturalistic]] account of thought processes can be given for mathematical reasoning. One line of defense is to maintain that this is false, so that mathematical reasoning uses some special [[Intuition (knowledge)|intuition]] that involves contact with the [[Platonic realm]], as in the argument given by [[Sir Roger Penrose]].<ref>{{cite web |title=Review of |url=http://www.c2.com/cgi/wiki?TheEmperorsNewMind}} [[The Emperor's New Mind]].</ref>

Another line of defense is to maintain that abstract objects are relevant to mathematical reasoning in a way that is non causal, and not analogous to perception. This argument is developed by [[Jerrold Katz]] in his 2000 book ''Realistic Rationalism''. In this book, he put forward a position called '''realistic rationalism'''<!--boldface per WP:R#PLA-->, which combines metaphysical realism and [[rationalism]].

A more radical defense is to deny the separation of physical world and the platonic world, i.e. the [[mathematical universe hypothesis]] (a variety of [[mathematicism]]). In that case, a mathematician's knowledge of mathematics is one mathematical object making contact with another.

=== Semantic anti-realism ===
{{main|Semantic anti-realism (epistemology)}}
The term "[[Semantic anti-realism (epistemology)|anti-realism]]" was introduced by [[Michael Dummett]] in his 1963 paper "Realism" in order to re-examine a number of classical philosophical disputes, involving such doctrines as [[nominalism]], [[Platonic realism]], [[idealism]] and [[phenomenalism]]. The novelty of Dummett's approach consisted in portraying these disputes as analogous to the dispute between [[intuitionism (philosophy of mathematics)|intuitionism]] and [[Platonism]] in the [[philosophy of mathematics]].

According to intuitionists (anti-realists with respect to mathematical objects), the [[truth]] of a mathematical statement consists in our ability to prove it. According to Platonic realists, the truth of a statement is proven in its correspondence to [[Objectivity (philosophy)|objective]] reality. Thus, intuitionists are ready to accept a statement of the form "P or Q" as true [[Disjunction and existence properties|only if we can prove P or if we can prove Q.]] In particular, we cannot in general claim that "P or not P" is true (the [[law of excluded middle]]), since in some cases [[Gödel's incompleteness theorems|we may not be able to prove the statement "P" nor prove the statement "not P"]]. Similarly, intuitionists object to the [[existence property]] for classical logic, where one can prove <math>\exists x.\phi(x)</math>, without being able to produce any term <math>t</math> of which <math>\phi</math> holds.

Dummett argues that this notion of truth lies at the bottom of various classical forms of anti-realism, and uses it to re-interpret [[phenomenalism]], claiming that it need not take the form of [[reductionism]].

Dummett's writings on anti-realism draw heavily on the later writings of [[Ludwig Wittgenstein]], concerning meaning and rule following, and can be seen as an attempt to integrate central ideas from the ''[[Philosophical Investigations]]'' into the constructive tradition of [[analytic philosophy]] deriving from [[Gottlob Frege]].

===Scientific anti-realism<!--'Scientific anti-realism' and 'Scientific antirealism' redirect here-->===
{{also|Semantic anti-realism (philosophy of science)}}
In [[philosophy of science]], anti-realism applies chiefly to claims about the non-reality of "unobservable" entities such as [[electron]]s or [[gene]]s, which are not detectable with human senses.<ref>{{Cite book|title=The Social Construction Of What?|last=Hacking|first=Ian|publisher=Harvard University Press|year=1999|pages=84}}</ref><ref>{{Cite book|title=Philosophy of Science: A Very Short Introduction|last=Okasha|first=Samir|publisher=Oxford University Press|year=2002}}</ref>

One prominent variety of '''scientific anti-realism'''<!--boldface per WP:R#PLA--> is [[instrumentalism]], which takes a purely agnostic view towards the existence of unobservable entities, in which the unobservable entity X serves as an instrument to aid in the success of theory Y and does not require proof for the existence or non-existence of X.

=== Moral anti-realism ===
In the [[Ethics|philosophy of ethics]], moral anti-realism (or moral irrealism) is a [[Meta-ethics|meta-ethical]] doctrine that there are no objective [[Morality|moral values]] or normative facts. It is usually defined in opposition to [[moral realism]], which holds that there are objective moral values, such that a moral claim may be either true or false. Specifically the moral anti-realist is committed to denying at least one of the following three statements: <ref>{{Citation|last=Joyce|first=Richard|title=Moral Anti-Realism|date=2016|url=https://plato.stanford.edu/archives/win2016/entries/moral-anti-realism/|encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2016|publisher=Metaphysics Research Lab, Stanford University|access-date=2021-03-08}}</ref><ref>{{Cite book|last= Vayrynen |first= Pekka |url=https://www.worldcat.org/oclc/61151356|title=Encyclopedia of philosophy|date=2006|publisher=Thomson Gale/Macmillan Reference USA|others=Donald M. Borchert|isbn=0-02-865780-2|edition=2nd|location=Detroit|oclc=61151356 |pages = 379–382 |quote=No single description is likely to capture all realist views, but a reasonably accurate rule is to understand moral realism as the conjunction of three theses: The semantic thesis: The primary semantic role of moral predicates (such as "right" and "wrong") is to refer to moral properties (such as rightness and wrongness), so that moral statements (such as "honesty is good" and "slavery is unjust") purport to represent moral facts, and express propositions that are true or false (or approximately true, largely false and so on).  The alethic thesis: Some moral propositions are in fact true.  The metaphysical thesis: Moral propositions are true when actions and other objects of moral assessment have the relevant moral properties (so that the relevant moral facts obtain), where these facts and properties are robust: their metaphysical status, whatever it is, is not relevantly different from that of (certain types of ordinary non-moral facts and properties).}}</ref>

# ''The Semantic Thesis:'' Moral statements have meaning, they express propositions, or are the kind of things that can be true or false.
# ''The Alethic Thesis:'' Some moral propositions are true.
# ''The Metaphysical Thesis'': The metaphysical status of moral facts is robust and ordinary, not importantly different from other facts about the world.

Different version of moral anti-realism deny different statements: specifically, [[non-cognitivism]] denies the first claim, arguing that moral statements have no meaning or truth content,<ref>{{Cite book|last= Harrison|first=Ross|url=https://www.worldcat.org/oclc/57283356|title=The Oxford companion to philosophy|date=2005|others=Ted Honderich|isbn=0-19-926479-1|edition=2nd|location=Oxford|oclc=57283356|quote= This one is used to designate that family of ethical positions in which it is supposed that moral judgements do not possess truth-value and hence can not be known.  An example of a non-cognitivist position is emotivism; that is, the claim that moral judgements are merely expressions of emotion.}}</ref> [[Error Theory|error theory]] denies the second claim, arguing that all moral statements are false,<ref>{{Citation|last=Joyce|first=Richard|title=Moral Anti-Realism|date=2016|url=https://plato.stanford.edu/archives/win2016/entries/moral-anti-realism/|encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2016|publisher=Metaphysics Research Lab, Stanford University|access-date=2021-03-10 |quote = The moral error theorist thinks that although our moral judgments aim at the truth, they systematically fail to secure it. The moral error theorist stands to morality as the atheist stands to religion.}}</ref> and [[ethical subjectivism]] denies the third claim, arguing that the truth of moral statements is mind dependent.<ref>{{Cite book |url=https://www.worldcat.org/oclc/61151356|title=Encyclopedia of philosophy |last= Harrison |first=Jonathan |date=2006|publisher=Thomson Gale/Macmillan Reference USA |editor-last=Borchert|editor-first=Donald M.  |isbn=0-02-865780-2|edition=2nd |location=Detroit|oclc=61151356 |quote= A subjectivist ethical theorist is a theory according to which moral judgements about men or their actions are judgements about the way people react to these men and actions - that is, the way they think or feel about them. }}</ref>

Examples of anti-realist moral theories might be:<ref>{{Citation|last=Joyce|first=Richard|title=Moral Anti-Realism|date=2016|url=https://plato.stanford.edu/archives/win2016/entries/moral-anti-realism/|encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2016|publisher=Metaphysics Research Lab, Stanford University|access-date=2019-07-25}}</ref>
{{cols|colwidth=20em}}
*[[Ethical subjectivism]]
*[[Non-cognitivism]]
*[[Emotivism]]
*[[Universal prescriptivism|Prescriptivism]]
*[[Quasi-realism]]
*[[Projectivism]]
*[[Moral fictionalism]]
*[[Moral nihilism]]
*[[Moral skepticism]]
{{colend}}
There is a debate as to whether [[moral relativism]] is actually an anti-realist position. While many versions deny the metaphysical thesis, some do not, as one could imagine a system of morality which requires you to obey the written laws in your country.<ref>{{Citation|last=Joyce|first=Richard|title=Moral Anti-Realism (Supplement on Moral Objectivity and Moral Relativism)|date=2016|url=https://plato.stanford.edu/entries/moral-anti-realism/moral-objectivity-relativism.html |encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2016|publisher=Metaphysics Research Lab, Stanford University|access-date=2021-03-08 |quote= In all cases, it may be that what determines the difference in the relevant contexts is something “mind-dependent”—in which case it would be anti-realist relativism—but it need not be; perhaps what determines the relevant difference is an entirely mind-independent affair, making for an objectivist (and potentially realist) relativism.}}</ref> Such a system would be a version of moral relativism, as different individuals would be required to follow different laws, but the moral facts are physical facts about the world, not mental facts, so they are metaphysically ordinary. Thus, different versions of moral relativism might be considered anti-realist or realist.<ref>{{Citation|last=Joyce|first=Richard|title=Moral Anti-Realism (Supplement on Moral Objectivity and Moral Relativism)|date=2016|url=https://plato.stanford.edu/entries/moral-anti-realism/moral-objectivity-relativism.html |encyclopedia=The Stanford Encyclopedia of Philosophy|editor-last=Zalta|editor-first=Edward N.|edition=Winter 2016|publisher=Metaphysics Research Lab, Stanford University|access-date=2021-03-08 |quote= Moral relativism is sometimes thought of as a version of anti-realism, but (short of stipulating usage) there is no basis for this classification; it is better to say that some versions of relativism may be anti-realist and others may be realist.}}</ref>

===Epistemic anti-realism===
{{See also|Metaepistemology}}
Just as moral anti-realism asserts the nonexistence of normative facts, epistemic anti-realism asserts the nonexistence of facts in the domain of [[epistemology]].<ref name="IEP Ep">{{cite web |title=Metaepistemology |url=https://www.iep.utm.edu/meta-epi/ |website=Internet Encyclopedia of Philosophy |access-date=24 June 2020}}</ref> Thus, the two are now sometimes grouped together as "metanormative anti-realism".<ref name="IEP Ep"/> Prominent defenders of epistemic anti-realism include [[Hartry Field]], [[Simon Blackburn]], Matthew Chrisman, and [[Allan Gibbard]], among others.<ref name="IEP Ep"/>

==See also==
{{div col}}
* [[Arend Heyting]]
* [[Constructivist epistemology]]
* [[Crispin Wright]]
* [[Critical realism (philosophy of perception)]]
* [[Luitzen Egbertus Jan Brouwer]]
* [[Metaepistemology]]
* [[Michael Dummett]]
* [[Münchhausen trilemma]]
* [[Neil Tennant (philosopher)]]
* [[Philosophical realism]]
* [[Quasi-realism]]
{{div end}}

== References ==
{{reflist}}

==Bibliography==
* {{cite book | author=Michael Dummett | title=Truth and Other Enigmas | publisher=Harvard University Press | year=1978 | ref=Dummett(1978) |url=https://books.google.com/books?id=ln_olVVLPm8C&q=%22anti-realism%22| isbn=9780674910768 }}
** {{citation | author=Michael Dummett | title=Truth | year=1963 | ref=Truth (1959) }}. reprinted, pp.&nbsp;1–24.
** {{citation | author=Michael Dummett | title=Realism | year=1963 | ref=Realism (1963) }}. reprinted, pp.&nbsp;145–165.
** {{citation | author=Michael Dummett | title=Platonism | year=1967 | ref=Platonism (1967) }}. reprinted, pp.&nbsp;202–214.
* Lee Braver (2007). ''[https://books.google.com/books?id=YIG-HyP3tesC A Thing of This World: a History of Continental Anti-Realism],'' Northwestern University Press: 2007.
* Ian Hacking (1999). ''[https://books.google.com/books?id=XkCR1p2YMRwC&q=%22anti-realism%22 The Social Construction of What?]''. Harvard University Press: 2001.
* Samir Okasha (2002). ''[https://books.google.com/books?id=Zkq1DAAAQBAJ&q=%22anti-realism%22 Philosophy of Science: A Very Short Introduction]''. Oxford University Press.

==External links==
*{{IEP|sci-real|Scientific Realism and Antirealism}}
* [http://plato.stanford.edu/entries/realism-sem-challenge/ Semantic challenges to realism] in the Stanford Encyclopedia of Philosophy

{{Idealism}}
{{Metaphysics}}
{{Philosophy of science}}

{{DEFAULTSORT:Anti-Realism}}
[[Category:Philosophical realism]]
[[Category:Idealism]]
[[Category:Metaphysics of science]]
[[Category:Metatheory of science]]
[[Category:Epistemology of science]]