View source for Willard Van Orman Quine

{{Short description|American philosopher and logician (1908–2000)}}
{{Use mdy dates|date=November 2023}}
{{Infobox philosopher
| region           = [[Western philosophy]]
| era              = [[20th-century philosophy]]
| image            = Willard Van Orman Quine on Bluenose II in Halifax NS harbor 1980.jpg
| caption          = Quine in 1980
| name             = Willard Van Orman Quine
| birth_date       = {{birth date|mf=yes|1908|6|25}}
| birth_place      = [[Akron, Ohio]], U.S.
| death_date       = {{death date and age|mf=yes|2000|12|25|1908|6|25}}
| death_place      = [[Boston]], [[Massachusetts]], U.S.
| spouse           = {{plainlist|
* {{marriage|Naomi Clayton|1932|1947|end=div}}
* {{marriage|Marjorie Boynton|1948|1998|end=died}}
}}
| education        = [[Oberlin College]] ([[Bachelor of Arts|BA]])<br />[[Harvard University]] ([[PhD]])
| institutions     = [[Harvard University]]
| school_tradition = [[Analytic philosophy|Analytic]]<br />[[Mathematical nominalism]] (1947)<ref name=SEP-Nom/><br />[[Mathematical quasi-empiricism]] (1960)<br />[[Immanent realism]]<ref>{{Cite encyclopedia |title=Scientific Realism and Antirealism |encyclopedia=Internet Encyclopedia of Philosophy |url=https://iep.utm.edu/scientific-realism-antirealism/ |language=en-US}}</ref><br />[[Neopragmatism]]<ref>{{Cite encyclopedia |title=Pragmatism |encyclopedia=Internet Encyclopedia of Philosophy |url=https://iep.utm.edu/pragmati/ |language=en-US}}</ref><br />[[Empiricism]]<br>[[Anti-foundationalism]]<ref name="Poston">{{Cite encyclopedia |title=Foundationalism |encyclopedia=Internet Encyclopedia of Philosophy |url=https://iep.utm.edu/foundationalism-in-epistemology/ |last=Poston |first=Ted |language=en-US}}</ref><br />[[Logical behaviorism]]<ref>{{cite SEP |url-id=behaviorism |title=Behaviorism}}</ref>
| main_interests   = [[Logic]], [[ontology]], [[epistemology]], [[philosophy of language]], [[philosophy of mind]], [[philosophy of mathematics]], [[philosophy of science]], [[set theory]]
| notable_ideas    = {{collapsible list|
[[New Foundations]], [[abstract objects]], [[indeterminacy of translation]] ([[holophrastic indeterminacy]], [[inscrutability of reference]], [[ontological relativity]], ''[[gavagai]]''), [[radical translation]], [[referential transparency]], [[naturalized epistemology]], [[meta-ontology]], [[ontological commitment|ontological]]/[[ideological commitment]],<ref>{{Cite book |last=Willard Van Orman Quine |title=Confessions of a Confirmed Extensionalist: And Other Essays |publisher=Harvard University Press |year=1983 |isbn=0674030842 |pages=315 ''ff'' |chapter=Chapter 22: Ontology and ideology revisited |chapter-url=https://books.google.com/books?id=8cnG59X1ntQC&pg=PA315}}</ref> [[natural kind]], [[semantic ascent]], [[Quine's paradox]], [[Duhem–Quine thesis]], [[Quine–Putnam indispensability thesis]], [[semantic holism]] ([[confirmation holism]], [[web of belief]], [[hold come what may]]), [[extensionalism]], [[problem of empty names]], [[propositional attitude]], [[two dogmas of empiricism]], [[principle of charity]], [[cognitive synonymy]], [[:de:Beobachtungssatz|observational statement]], [[mathematical quasi-empiricism]], [[Quine–McCluskey algorithm]], [[Quine–Morse set theory]], [[vivid designator]], [[predicate functor logic]], [[Quasi-quotation|Quine quotation]], [[Quine corners]], [[Quine atom]], [[Plato's beard]], [[existential generalization]] and [[universal instantiation]], [[Quine's classification of paradoxes|veridical vs. falsidical paradoxes]]<ref>{{Cite book |last=Quine |first=W. V. |title=The Ways of Paradox, and Other Essays |publisher=Random House |year=1966 |location=New York |chapter=The Ways of Paradox |chapter-url=https://archive.org/details/waysofparadoxoth0000quin |chapter-url-access=registration}}</ref>
}}
| influences       = [[Bertrand Russell]], [[Rudolf Carnap]], [[Alfred Tarski]], [[Vienna Circle]], [[Clarence Irving Lewis|C. I. Lewis]],<ref name="SEP-CIL">{{Cite encyclopedia|title=Clarence Irving Lewis |encyclopedia=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |url=https://plato.stanford.edu/archives/spr2021/entries/lewis-ci/ |last=Hunter |first=Bruce |date=2021 |edition=Spring 2021}}</ref> [[Alfred North Whitehead|A. N. Whitehead]], [[B. F. Skinner]], [[Pierre Duhem]]
| influenced       = [[Noam Chomsky]], [[Roger Gibson]], [[Donald Davidson (philosopher)|Donald Davidson]], [[Daniel Dennett]], [[David Lewis (philosopher)|David Lewis]], [[Penelope Maddy]], [[Hilary Putnam]], [[Richard Rorty]], [[Dagfinn Føllesdal]], [[Gilbert Harman]], [[Hao Wang (academic)|Hao Wang]], [[Peter van Inwagen]], [[Shunsuke Tsurumi]]
| awards           = [[Rolf Schock Prizes|Rolf Schock Prize in Logic and Philosophy]] {{small|(1993)}}<br />[[List of Kyoto Prize winners|Kyoto Prize]] <small>(1996)</small>
| thesis_title      = The Logic of Sequences: A Generalization of Principia Mathematica
| thesis_url        = https://www.researchgate.net/publication/271047938_Quine_W_V_The_logic_of_sequences_A_generalization_of_Principia_mathematica_Harvard_dissertations_in_philosophy_Garland_Publishing_New_York_and_London_1990_xi_290_pp
| thesis_year       = 1932
| doctoral_advisor  = [[Alfred North Whitehead]]
| academic_advisors = [[Clarence Irving Lewis|C. I. Lewis]]<ref name=SEP-CIL/>
| doctoral_students = [[David Lewis (philosopher)|David Lewis]], [[Gilbert Harman]], [[Dagfinn Føllesdal]], [[Hao Wang (academic)|Hao Wang]], [[Burton Dreben]], [[Charles Parsons (philosopher)|Charles Parsons]], [[John Myhill]], [[Robert McNaughton]]
| notable_students  = [[Donald Davidson (philosopher)|Donald Davidson]], [[Daniel Dennett]]
}}

'''Willard Van Orman Quine''' ({{IPAc-en|k|w|aɪ|n}}; known to his friends as "Van";<ref name="mactutor">{{MacTutor|id=Quine|date=October 2003}}</ref> June 25, 1908 – December 25, 2000) was an American philosopher and [[logician]] in the [[analytic philosophy|analytic tradition]], recognized as "one of the most influential philosophers of the twentieth century".<ref>{{Cite news |last=Lehmann-Haupt |first=Christopher |date=2000-12-29 |title=W. V. Quine, Philosopher Who Analyzed Language and Reality, Dies at 92 |language=en-US |work=The New York Times |url=https://www.nytimes.com/2000/12/29/arts/w-v-quine-philosopher-who-analyzed-language-and-reality-dies-at-92.html |access-date=2023-11-21 |issn=0362-4331}}</ref> He was the Edgar Pierce Chair of Philosophy at [[Harvard University]] from 1956 to 1978.

Quine was a teacher of logic and [[set theory]]. He was famous for his position that [[First-order logic|first order logic]] is the only kind worthy of the name, and developed his own system of mathematics and set theory, known as [[New Foundations]]. In the [[philosophy of mathematics]], he and his Harvard colleague [[Hilary Putnam]] developed the [[Quine–Putnam indispensability argument]], an argument for the [[Philosophy of mathematics#Empiricism|reality of mathematical entities]].<ref name="plato.stanford.edu">Colyvan, Mark, [http://plato.stanford.edu/archives/fall2004/entries/mathphil-indis/ "Indispensability Arguments in the Philosophy of Mathematics"], The Stanford Encyclopedia of Philosophy (Fall 2004 Edition), Edward N. Zalta (ed.).</ref> He was the main proponent of the view that philosophy is not [[conceptual analysis]], but continuous with science; it is the abstract branch of the empirical sciences. This led to his famous quip that "[[philosophy of science]] is philosophy enough".<ref>{{Cite journal |last=Quine |first=W. V. |date=August 28, 2023 |title=Mr. Strawson on Logical Theory |url=https://www.jstor.org/stable/2251091 |journal=Mind |volume=62 |issue=248 |pages=433–451 |jstor=2251091}}</ref> He led a "systematic attempt to understand science from within the resources of science itself"<ref name="iep" /> and developed an influential [[naturalized epistemology]] that tried to provide "an improved scientific explanation of how we have developed elaborate scientific theories on the basis of meager sensory input".<ref name="iep">{{Cite encyclopedia |year=2009 |title=Quine, Willard Van Orman: Philosophy of Science |encyclopedia=Internet Encyclopedia of Philosophy |url=https://iep.utm.edu/quine-sc/ |language=en-US}}</ref> He also advocated holism in science, known as the [[Duhem–Quine thesis]].

His major writings include the papers "On What There Is" (1948), which elucidated [[Bertrand Russell]]'s [[theory of descriptions]] and contains Quine's famous dictum of [[Ontology|ontological]] commitment, "To be is to be the value of a [[Variable (mathematics)|variable]]", and "[[Two Dogmas of Empiricism]]" (1951), which attacked the traditional [[analytic-synthetic distinction]] and reductionism, undermining the then-popular [[logical positivism]], advocating instead a form of [[semantic holism]] and [[ontological relativity]]. They also include the books ''The Web of Belief'' (1970), which advocates a kind of [[coherentism]], and ''[[Word and Object]]'' (1960), which further developed these positions and introduced Quine's famous [[indeterminacy of translation]] thesis, advocating a [[behaviorist]] [[Meaning (philosophy of language)|theory of meaning]].

==Biography==
Quine's parents were Robert Cloyd Quine and Harriet Ellis Van Orman. Quine grew up in [[Akron, Ohio]], where he lived with his parents and older brother Robert Cloyd. His father was a manufacturing entrepreneur (founder of the Akron Equipment Company, which produced tire molds) and his mother was a schoolteacher and [[housewife]].<ref name="Quine 2004, pg 1">{{Cite book |url=https://www.cambridge.org/core/product/identifier/9781139000505/type/book |title=The Cambridge Companion to Quine |series=Cambridge Companions to Philosophy |date=2004-03-29 |publisher=Cambridge University Press |isbn=978-0-521-63056-6 |editor-last=Gibson, Jr |editor-first=Roger F. |pages=1 |doi=10.1017/ccol0521630568}}</ref><ref name="mactutor" /> Quine became an atheist around the age of 9<ref>''The Time of My Life: An Autobiography'', p. 14.</ref> and remained one for the rest of his life.<ref>{{cite book|last1=Quine|first1=Willard Van Orman|title=The Philosophy of W.V. Quine|last2=Hahn|first2=Lewis Edwin|publisher=Open Court|year=1986|isbn=978-0812690101|page=6|quote=In my third year of high school I walked often with my new Jamaican friends, Fred and Harold Cassidy, trying to convert them from their Episcopalian faith to atheism.}}</ref>

=== Education ===
Quine received his [[Bachelor of Arts|B.A.]] ''[[summa cum laude]]'' in mathematics from [[Oberlin College]] in 1930, and his Ph.D. in philosophy from [[Harvard University]] in 1932. His thesis supervisor was [[Alfred North Whitehead]]. He was then appointed a [[Harvard Junior Fellow]], which excused him from having to teach for four years. During the academic year 1932–33, he travelled in Europe thanks to a Sheldon Fellowship, meeting Polish logicians (including [[Stanislaw Lesniewski]] and [[Alfred Tarski]]) and members of the [[Vienna Circle]] (including [[Rudolf Carnap]]), as well as the [[logical positivism|logical positivist]] [[A. J. Ayer]].<ref name="mactutor" /> It was in [[Prague]] that Quine developed a passion for philosophy, thanks to Carnap, whom he defined as his "true and only {{lang|fr|[[maître à penser]]}}".<ref>{{Cite book |title=The American Philosopher: Conversations with Quine, Davidson, Putnam, Nozick, Danto, Rorty, Cavell, MacIntyre, Kuhn |last=Borradori |first=Giovanna |author-link=Giovanna Borradori |publisher=University of Chicago Press |date=1994 |pages=30–31 |isbn=978-0-226-06647-9}}</ref>

=== World War II ===
Quine arranged for [[Alfred Tarski|Tarski]] to be invited to the September 1939 [[Unity of Science]] Congress in Cambridge, for which the Jewish Tarski sailed on the last ship to leave [[Gdańsk|Danzig]] before [[Invasion of Poland|Nazi Germany invaded Poland]] and triggered [[World War II]]. Tarski survived the war and worked another 44 years in the US. During the war, Quine lectured on logic in [[Brazil]], in Portuguese, and served in the [[United States Navy]] in a [[military intelligence]] role, deciphering messages from German submarines, and reaching the rank of lieutenant commander.<ref name="mactutor" /> Quine could lecture in French, German, Italian, Portuguese, and Spanish as well as his native English.

=== Personal ===
He had four children by two marriages.<ref name="mactutor" /> Guitarist [[Robert Quine]] was his nephew.

Quine was politically conservative, but the bulk of his writing was in technical areas of philosophy removed from direct political issues.<ref>''[[The Wall Street Journal]]'', [http://www.wvquine.org/wvq-obit3.html obituary] for W. V. Quine – January 4, 2001</ref> He did, however, write in defense of several conservative positions: for example, he wrote in defense of [[moral censorship]];<ref>''Quiddities: An Intermittently Philosophical Dictionary'', entry for Tolerance (pp. 206–208).</ref> while, in his autobiography, he made some criticisms of American postwar academics.<ref>"Paradoxes of Plenty" in ''Theories and Things'', p. 197.</ref><ref>''The Time of My Life: An Autobiography'', pp. 352–353.</ref>

=== Harvard ===
At Harvard, Quine helped supervise the Harvard [[graduate theses]] of, among others, [[David Lewis (philosopher)|David Lewis]], [[Gilbert Harman]], [[Dagfinn Føllesdal]], [[Hao Wang (academic)|Hao Wang]], [[Hugues LeBlanc]], [[Henry Hiz]] and [[George Myro]]. For the academic year 1964–1965, Quine was a fellow on the faculty in the Center for Advanced Studies at [[Wesleyan University]].<ref>[http://www.wesleyan.edu/libr/schome/FAs/ce1000-137.html "Guide to the Center for Advanced Studies Records, 1958–1969"] {{webarchive|url=https://web.archive.org/web/20170314083709/http://www.wesleyan.edu/libr/schome/FAs/ce1000-137.html |date=March 14, 2017 }}. Weselyan University. Wesleyan.edu. Accessed March 8, 2010.</ref> In 1980
Quine received an [[Honorary degree|honorary doctorate]] from the Faculty of Humanities at [[Uppsala University]], Sweden.<ref>{{Cite web | url=http://www.uu.se/en/about-uu/traditions/prizes/honorary-doctorates/ |title = Honorary doctorates – Uppsala University, Sweden| date=June 9, 2023 }}</ref>

Quine's student Dagfinn Føllesdal noted that Quine suffered from memory loss towards his final years. The deterioration of his short-term memory was so severe that he struggled to continue following arguments. Quine also had considerable difficulty in his project to make the desired revisions to ''Word and Object''. Before passing away, Quine noted to [[Morton White]]: "I do not remember what my illness is called, Althusser or [[Alzheimer]], but since I cannot remember it, it must be Alzheimer." He died from the illness on Christmas Day in 2000.<ref>{{Cite book |last=Quine |first=Willard Van Orman |url=https://direct.mit.edu/books/book/3991/word-and-object |title=Word and Object |date=2013 |publisher=The MIT Press |isbn=978-0-262-31279-0 |language=en |doi=10.7551/mitpress/9636.001.0001}}</ref><ref>{{cite web | url=https://www.latimes.com/archives/la-xpm-2000-dec-31-me-6890-story.html | title=Willard van Orman Quine; Renowned Philosopher | website=[[Los Angeles Times]] | date=December 31, 2000 }}</ref>

==Work==
Quine's Ph.D. thesis and early publications were on [[formal logic]] and [[set theory]]. Only after World War II did he, by virtue of seminal papers on [[ontology]], [[epistemology]] and language, emerge as a major philosopher. By the 1960s, he had worked out his "[[naturalized epistemology]]" whose aim was to answer all substantive questions of knowledge and meaning using the methods and tools of the natural sciences. Quine roundly rejected the notion that there should be a "first philosophy", a theoretical standpoint somehow prior to natural science and capable of justifying it. These views are intrinsic to his [[philosophical naturalism|naturalism]].

Like the majority of analytic philosophers, who were mostly interested in systematic thinking, Quine evinced little interest in the [[Western canon|philosophical canon]]: only once did he teach a course in the history of philosophy, on [[David Hume]], in 1946.<ref>{{Cite journal|title=Quine's 1946 Lectures on Hume |last=Pakaluk |first=Michael |journal=Journal of the History of Philosophy |volume=27 |date=1989 |issue=3 |pages=445–459|doi=10.1353/hph.1989.0050 |s2cid=171052872 }}</ref>{{Clarify|reason=These words mean nothing to non-experts: 'logical positivist', 'philosophical canon', and 'Hume'. What is this sentence trying to tell me?|date=October 2014}}

===Logic===

Over the course of his career, Quine published numerous technical and expository papers on formal logic, some of which are reprinted in his ''Selected Logic Papers'' and in ''The Ways of Paradox''. His most well-known collection of papers is ''From A Logical Point of View''. Quine confined logic to classical bivalent [[first-order logic]], hence to truth and falsity under any (nonempty) [[universe of discourse]]. Hence the following were not logic for Quine:

* Higher-order logic and set theory. He referred to [[higher-order logic]] as "set theory in disguise";
* Much of what ''[[Principia Mathematica]]'' included in logic was not logic for Quine.
* Formal systems involving [[intension]]al notions, especially [[modal logic|modality]]. Quine was especially hostile to modal logic with [[Quantification (logic)|quantification]], a battle he largely lost when [[Saul Kripke]]'s [[Kripke semantics|relational semantics]] became canonical for [[modal logic]]s.

Quine wrote three undergraduate texts on formal logic:
* ''Elementary Logic''. While teaching an introductory course in 1940, Quine discovered that extant texts for philosophy students did not do justice to [[quantification theory]] or [[first-order predicate logic]]. Quine wrote this book in 6 weeks as an ''[[ad hoc]]'' solution to his teaching needs.
* ''Methods of Logic''. The four editions of this book resulted from a more advanced undergraduate course in logic Quine taught from the end of World War II until his 1978 retirement.
* ''Philosophy of Logic''. A concise and witty undergraduate treatment of a number of Quinian themes, such as the prevalence of use-mention confusions, the dubiousness of [[modal logic|quantified modal logic]], and the non-logical character of higher-order logic.

''Mathematical Logic'' is based on Quine's graduate teaching during the 1930s and 1940s. It shows that much of what ''[[Principia Mathematica]]'' took more than 1000 pages to say can be said in 250 pages. The proofs are concise, even cryptic. The last chapter, on [[Gödel's incompleteness theorem]] and [[Tarski's indefinability theorem]], along with the article Quine (1946), became a launching point for [[Raymond Smullyan]]'s later lucid exposition of these and related results.

Quine's work in logic gradually became dated in some respects. Techniques he did not teach and discuss include [[analytic tableau]]x, [[recursion#Functional recursion|recursive function]]s, and [[model theory]]. His treatment of [[metalogic]] left something to be desired. For example, ''Mathematical Logic'' does not include any proofs of [[soundness]] and [[completeness (logic)|completeness]]. Early in his career, the notation of his writings on logic was often idiosyncratic. His later writings nearly always employed the now-dated notation of ''Principia Mathematica''. Set against all this are the simplicity of his preferred method (as exposited in his ''Methods of Logic'') for determining the satisfiability of quantified formulas, the richness of his philosophical and linguistic insights, and the fine prose in which he expressed them.

Most of Quine's original work in formal logic from 1960 onwards was on variants of his [[predicate functor logic]], one of several ways that have been proposed for doing logic without [[Quantification (logic)|quantifier]]s. For a comprehensive treatment of predicate functor logic and its history, see Quine (1976). For an introduction, see ch.&nbsp;45 of his ''Methods of Logic''.

Quine was very warm to the possibility that formal logic would eventually be applied outside of philosophy and mathematics. He wrote several papers on the sort of [[Boolean algebra (logic)|Boolean algebra]] employed in [[electrical engineering]], and with [[Edward J. McCluskey]], devised the [[Quine–McCluskey algorithm]] of reducing [[Boolean equation]]s to a minimum covering sum of [[prime implicant]]s.

===Set theory===
While his contributions to logic include elegant expositions and a number of technical results, it is in [[set theory]] that Quine was most innovative. He always maintained that mathematics required set theory and that set theory was quite distinct from logic. He flirted with [[Nelson Goodman]]'s [[nominalism]] for a while<ref>Nelson Goodman and W. V. O. Quine, [http://www.ditext.com/quine/stcn.html "Steps Toward a Constructive Nominalism"], ''Journal of Symbolic Logic'', 12 (1947): 105–122.</ref> but backed away when he failed to find a nominalist grounding of mathematics.<ref name="SEP-Nom">{{Cite encyclopedia |title=Nominalism in the Philosophy of Mathematics |encyclopedia=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |url=https://plato.stanford.edu/archives/fall2020/entries/nominalism-mathematics/ |last=Bueno |first=Otávio |date=2020 |edition=Fall 2020}}</ref>

Over the course of his career, Quine proposed three axiomatic set theories.
* [[New Foundations]], NF, creates and manipulates sets using a single axiom schema for set admissibility, namely an axiom schema of stratified comprehension, whereby all individuals satisfying a stratified formula compose a set. A stratified formula is one that [[type theory]] would allow, were the [[ontology]] to include types. However, Quine's set theory does not feature types. The metamathematics of NF are curious. NF allows many "large" sets the now-canonical [[ZFC]] set theory does not allow, even sets for which the [[axiom of choice]] does not hold. Since the axiom of choice holds for all finite sets, the failure of this axiom in NF proves that NF includes infinite sets. The consistency of NF relative to other formal systems adequate for mathematics is an open question, albeit that a number of candidate proofs are current in the NF community suggesting that NF is equiconsistent with [[Zermelo set theory]] without Choice. A modification of NF, [[New Foundations|NFU]], due to R. B. Jensen and admitting [[urelement]]s (entities that can be members of sets but that lack elements), turns out to be consistent relative to [[Peano arithmetic]], thus vindicating the intuition behind NF. NF and NFU are the only Quinean set theories with a following. For a derivation of foundational mathematics in NF, see Rosser (1952);
* The set theory of ''Mathematical Logic'' is NF augmented by the [[proper class]]es of [[von Neumann–Bernays–Gödel set theory]], except axiomatized in a much simpler way;
* The set theory of ''Set Theory and Its Logic'' does away with stratification and is almost entirely derived from a single axiom schema. Quine derived the foundations of mathematics once again. This book includes the definitive exposition of Quine's theory of virtual sets and relations, and surveyed axiomatic set theory as it stood circa 1960.

All three set theories admit a universal class, but since they are free of any [[hierarchy]] of [[Type (metaphysics)|types]], they have no need for a distinct universal class at each type level.

Quine's set theory and its background logic were driven by a desire to minimize posits; each innovation is pushed as far as it can be pushed before further innovations are introduced. For Quine, there is but one connective, the [[Sheffer stroke]], and one quantifier, the [[universal quantifier]]. All polyadic [[Predicate (mathematical logic)|predicates]] can be reduced to one dyadic predicate, interpretable as set membership. His rules of proof were limited to [[modus ponens]] and substitution. He preferred [[logical conjunction|conjunction]] to either [[disjunction]] or the [[Material conditional|conditional]], because conjunction has the least semantic ambiguity. He was delighted to discover early in his career that all of first order logic and set theory could be grounded in a mere two primitive notions: [[set abstraction|abstraction]] and [[inclusion (set theory)|inclusion]]. For an elegant introduction to the parsimony of Quine's approach to logic, see his "New Foundations for Mathematical Logic", ch.&nbsp;5 in his ''From a Logical Point of View''.

=== Metaphysics ===
Quine has had numerous influences on contemporary [[metaphysics]]. He coined the term "[[Abstract and concrete|abstract object]]".<ref>{{cite book|last=Armstrong|first=D. M.|title=Sketch for a systematic metaphysics|year=2010|publisher=Oxford University Press|location=Oxford|isbn=9780199655915|page=2}}</ref> He also, in his famous essay ''[https://en.wikisource.org/wiki/On%20What%20There%20Is On What There is]'', coined the term "[[Plato's beard]]" to refer to the problem of [[empty name]]s: 

Suppose now that two philosophers, McX and I, differ over [[ontology]]. Suppose McX maintains there is something which I maintain there is not. McX can, quite consistently with his own point of view, describe our difference of opinion by saying that I refuse to recognize certain entities...When I try to formulate our difference of opinion, on the other hand, I seem to be in a predicament. I cannot admit that there are some things which McX countenances and I do not, for in admitting that there are such things I should be contradicting my own rejection of them...This is the old Platonic riddle of nonbeing. Nonbeing must in some sense be, otherwise what is it that there is not? This tangled doctrine might be nicknamed ''Plato's beard'': historically it has proved tough, frequently dulling the edge of Occam’s razor.<ref>{{cite book |last1=van Inwagen |first1=Peter |last2=Zimmerman |first2=Dean W. |title=Metaphysics: the big questions |date=2008 |publisher=Blackwell |location=Malden, Mass. |isbn=978-1-4051-2586-4 |page=28-29 |edition=2. rev. and expanded |url=https://www.wiley.com/en-gb/Metaphysics%3A+The+Big+Questions%2C+2nd+Edition-p-9781405125864 }}</ref>

Quine was unsympathetic, however, to the claim that saying 'X does not exist' is a tacit acceptance of X's existence and, thus, a contradiction. Appealing to [[Bertrand Russell]] and his theory of "singular descriptions", Quine explains how Russell was able to make sense of "complex descriptive names" ('the present King of France', 'the author of ''Waverly''{{'}}, etc.) by thinking about them as merely "fragments of the whole sentences". For example, 'The author of ''Waverly'' was a poet' becomes 'some thing is such that it is the author of ''Waverly'' and was a poet, and nothing else is such that it is the author of ''Waverly'''.<ref>{{cite book |last1=van Inwagen |first1=Peter |last2=Zimmerman |first2=Dean W. |title=Metaphysics: the big questions |date=2008 |publisher=Blackwell |location=Malden, Mass. |isbn=978-1-4051-2586-4 |page=31 |edition=2. rev. and expanded |url=https://www.wiley.com/en-gb/Metaphysics%3A+The+Big+Questions%2C+2nd+Edition-p-9781405125864 }}</ref>

Using this sort of analysis with the word '[[Pegasus]]' (that which Quine is wanting to assert does not exist), he turns Pegasus into a description. Turning the word 'Pegasus' into a description is to turn 'Pegasus' into a predicate, to use a term of [[First-order logic]]: i.e. a property. As such, when we say 'Pegasus', we are really saying 'the thing that is Pegasus' or 'the thing that ''Pegasizes'''. This introduces, to use another term from logic, bound variables (ex: 'everything', 'something,' etc.) As Quine explains, bound variables, "far from purpoting to be names specifically...do not purport to be names at all: they refer to entities generally, with a kind of studied ambiguity peculiar to themselves."<ref>{{cite book |last1=van Inwagen |first1=Peter |last2=Zimmerman |first2=Dean W. |title=Metaphysics: the big questions |date=2008 |publisher=Blackwell |location=Malden, Mass. |isbn=978-1-4051-2586-4 |page=31-32 |edition=2. rev. and expanded |url=https://www.wiley.com/en-gb/Metaphysics%3A+The+Big+Questions%2C+2nd+Edition-p-9781405125864 }}</ref>

Putting it another way, to say 'I hate everything' is a very different statement than saying 'I hate Bertrand Russell', because the words 'Bertrand Russell' are a [[proper name]] that refer to a very specific person. Whereas the word 'everything' is a placeholder. It does not refer to a specific entity or entities. Quine is able, therefore, to make a meaningful claim about Pegasus' nonexistence for the simple reason that the placeholder (a thing) happens to be empty. It just so happens that the world does not contain a thing that is such that it is winged and it is a horse. 

====Rejection of the analytic–synthetic distinction====
{{See also|Two Dogmas of Empiricism#Analyticity and circularity|l1=Two Dogmas of Empiricism}}
In the 1930s and 40s, discussions with [[Rudolf Carnap]], [[Nelson Goodman]] and [[Alfred Tarski]], among others, led Quine to doubt the tenability of the distinction between "analytic" statements<ref>{{Cite book|title=Carnap, Tarski, and Quine at Harvard: Conversations on Logic, Mathematics, and Science|last=Frost-Arnold|first=Greg|publisher=Open Court|year=2013|isbn=9780812698374|location=Chicago|page=89}}</ref>—those true simply by the meanings of their words, such as "No bachelor is married"— and "synthetic" statements, those true or false by virtue of facts about the world, such as "There is a cat on the mat."<ref name="Quine 1961 p. 22">{{cite book | last=Quine | first=W. V. | title=From a Logical Point of View: Nine Logico-Philosophical Essays, Second Revised Edition | publisher=Harvard University Press | series=Harper torchbooks | year=1961 | isbn=978-0-674-32351-3 | url=https://books.google.com/books?id=OalXwuw3MvMC | pages=22}}</ref> This distinction was central to [[logical positivism]]. Although Quine is not normally associated with [[verificationism]], some philosophers believe the tenet is not incompatible with his general philosophy of language, citing his Harvard colleague [[B. F. Skinner]] and his analysis of language in ''[[Verbal Behavior (book)|Verbal Behavior]]''.<ref>{{Cite journal |last=Prawitz |first=Dag |date=1994|title=Quine and verificationism |url=http://www.tandfonline.com/doi/abs/10.1080/00201749408602369 |journal=Inquiry |language=en |volume=37 |issue=4 |pages=487–494 |doi=10.1080/00201749408602369 |issn=0020-174X}}</ref> But Quine believes, with all due respect to his "great friend"<ref name="Burrhus">{{Cite book |title=The American Philosopher: Conversations with Quine, Davidson, Putnam, Nozick, Danto, Rorty, Cavell, MacIntyre, Kuhn |last=Borradori |first=Giovanna |author-link=Giovanna Borradori |publisher=University of Chicago Press |date=1994 |page=35 |isbn=978-0-226-06647-9}}</ref> Skinner, that the ultimate reason is to be found in neurology and not in behavior. For him, behavioral criteria establish only the terms of the problem, the solution of which, however, lies in [[neurology]].<ref name="Burrhus" />

Like other analytic philosophers before him, Quine accepted the [[definition]] of "analytic" as "true in virtue of meaning alone". Unlike them, however, he concluded that ultimately the definition was [[circular definition|circular]]. In other words, Quine accepted that analytic statements are those that are true by definition, then argued that the notion of truth by definition was unsatisfactory.

Quine's chief objection to analyticity is with the notion of [[cognitive synonymy]] (sameness of meaning). He argues that analytical sentences are typically divided into two kinds; sentences that are clearly logically true (e.g. "no unmarried man is married") and the more dubious ones; sentences like "no bachelor is married". Previously it was thought that if you can prove that there is synonymity between "unmarried man" and "bachelor", you have proved that both sentences are logically true and therefore self evident. Quine however gives several arguments for why this is not possible, for instance that "bachelor" in some contexts mean a [[Bachelor of Arts]], not an unmarried man.<ref name="Quine 1961 p. 22-23, 28">{{cite book | last=Quine | first=W. V. | title=From a Logical Point of View: Nine Logico-Philosophical Essays, Second Revised Edition | publisher=Harvard University Press | series=Harper torchbooks | year=1961 | isbn=978-0-674-32351-3 | url=https://books.google.com/books?id=OalXwuw3MvMC | pages=22–23, 28}}</ref>

====Confirmation holism and ontological relativity====
Colleague [[Hilary Putnam]] called Quine's [[indeterminacy of translation]] thesis "the most fascinating and the most discussed philosophical argument since [[Immanuel Kant|Kant]]'s ''[[Critique of Pure Reason|Transcendental Deduction of the Categories]]''".<ref>{{Cite journal |last=Putnam |first=Hilary |title=The refutation of conventionalism |journal=Noûs  |volume=8 |number=1 |date=March 1974 |pages= 25–40 |jstor=2214643 |doi=10.2307/2214643}}  Reprinted in {{cite book |last=Putnam |first=Hilary |date=1979 |isbn=0521295513 |title=Philosophical Papers; Volume 2: Mind, Language and Reality |publisher=Cambridge University Press |chapter=Chapter 9: The refutation of conventionalism |pages=153–191 |chapter-url=https://books.google.com/books?id=_0W5ByvEPEgC&pg=PA159}} Quote on p. 159.
</ref> The central theses underlying it are [[ontological relativity]] and the related [[doctrine]] of [[confirmation holism]]. The premise of confirmation [[holism]] is that all theories (and the propositions derived from them) are [[underdetermination|under-determined]] by empirical data (data, [[Sense data|sensory-data]], evidence); although some theories are not justifiable, failing to fit with the data or being unworkably complex, there are many equally justifiable alternatives. While the [[Ancient Greece|Greeks]]' assumption that (unobservable) [[Homer]]ic gods exist is false, and our supposition of (unobservable) [[electromagnetic radiation|electromagnetic waves]] is true, both are to be justified solely by their ability to explain our observations.

The ''[[gavagai]]'' [[thought experiment]] tells about a linguist, who tries to find out, what the expression ''gavagai'' means, when uttered by a speaker of a yet unknown, native language upon seeing a rabbit. At first glance, it seems that ''gavagai'' simply translates with ''rabbit''. Now, Quine points out that the background language and its referring devices might fool the linguist here, because he is misled in a sense that he always makes direct comparisons between the foreign language and his own. However, when shouting ''gavagai'', and pointing at a rabbit, the natives could as well refer to something like ''undetached rabbit-parts'', or ''rabbit-[[Trope (philosophy)|tropes]]'' and it would not make any observable difference. The behavioural data the linguist could collect from the native speaker would be the same in every case, or to reword it, several translation hypotheses could be built on the same sensoric stimuli.

Quine concluded his "[[Two Dogmas of Empiricism]]" as follows:
<blockquote>
As an empiricist I continue to think of the conceptual scheme of science as a tool, ultimately, for predicting future experience in the light of past experience. Physical objects are conceptually imported into the situation as convenient intermediaries not by definition in terms of experience, but simply as irreducible posits comparable, epistemologically, to the gods of Homer …. For my part I do, qua lay physicist, believe in physical objects and not in Homer's gods; and I consider it a scientific error to believe otherwise. But in point of epistemological footing, the physical objects and the gods differ only in degree and not in kind. Both sorts of entities enter our conceptions only as cultural posits.
</blockquote>

Quine's ontological [[relativism]] (evident in the passage above) led him to agree with [[Pierre Duhem]] that for any collection of [[empirical evidence]], there would always be many theories able to account for it, known as the [[Duhem–Quine thesis]]. However, Duhem's [[holism]] is much more restricted and limited than Quine's. For Duhem, [[underdetermination]] applies only to [[physics]] or possibly to [[natural science]], while for Quine it applies to all of human knowledge. Thus, while it is possible to verify or [[falsifiability|falsify]] whole theories, it is not possible to verify or falsify individual statements. Almost any particular statement can be saved, given sufficiently radical modifications of the containing theory. For Quine, scientific thought forms a [[Coherentism|coherent]] web in which any part could be altered in the light of empirical evidence, and in which no empirical evidence could force the revision of a given part.

====Existence and its contrary====
The [[Empty name|problem of non-referring names]] is an old puzzle in philosophy, which Quine captured when he wrote,

<blockquote>A curious thing about the ontological problem is its simplicity. It can be put into three Anglo-Saxon monosyllables: 'What is there?' It can be answered, moreover, in a word—'Everything'—and everyone will accept this answer as true.<ref>W. V. O. Quine, "[[:s:On What There Is|On What There Is]]", ''The Review of Metaphysics'' '''2'''(5), 1948.</ref></blockquote>

More directly, the controversy goes:
<blockquote>
How can we talk about [[Pegasus]]? To what does the word 'Pegasus' refer? If our answer is, 'Something', then we seem to believe in mystical entities; if our answer is, 'nothing', then we seem to talk about nothing and what sense can be made of this? Certainly when we said that Pegasus was a mythological winged horse we make sense, and moreover we speak the truth! If we speak the truth, this must be truth ''about something''. So we cannot be speaking of nothing.
</blockquote>

Quine resists the temptation to say that non-referring terms are meaningless for reasons made clear above. Instead he tells us that we must first determine whether our terms refer or not before we know the proper way to understand them. However, [[Czesław Lejewski]] criticizes this belief for reducing the matter to empirical discovery when it seems we should have a formal distinction between referring and non-referring terms or elements of our domain. Lejewski writes further:
<blockquote>
This state of affairs does not seem to be very satisfactory. The idea that some of our rules of inference should depend on empirical information, which may not be forthcoming, is so foreign to the character of logical inquiry that a thorough re-examination of the two inferences [existential generalization and universal instantiation] may prove worth our while.
</blockquote>

Lejewski then goes on to offer a description of [[free logic]], which he claims accommodates an answer to the problem.

Lejewski also points out that free logic additionally can handle the problem of the empty set for statements like <math>\forall x\,Fx \rightarrow \exists x\,Fx</math>. Quine had considered the problem of the empty set unrealistic, which left Lejewski unsatisfied.<ref>Czeslaw Lejewski, "Logic and Existence". ''British Journal for the Philosophy of Science'', Vol. 5 (1954–1955), pp. 104–119.</ref>

==== Ontological commitment ====
The notion of [[ontological commitment]] plays a central role in Quine's contributions to ontology.<ref>{{cite book |last1=Craig |first1=Edward |title=Routledge Encyclopedia of Philosophy |date=1996 |publisher=Routledge |url=https://philpapers.org/rec/BEAREO |chapter=Ontological commitment}}</ref><ref>{{cite web |last1=Simons |first1=Peter M. |title=Ontology |url=https://www.britannica.com/topic/ontology-metaphysics |website=Encyclopedia Britannica |access-date=December 13, 2020 |language=en}}</ref> A theory is ontologically committed to an entity if that entity must exist in order for the theory to be true.<ref name="Bricker">{{cite web |last1=Bricker |first1=Phillip |title=Ontological Commitment |url=https://plato.stanford.edu/entries/ontological-commitment/ |website=The Stanford Encyclopedia of Philosophy |publisher=Metaphysics Research Lab, Stanford University |access-date=December 13, 2020 |date=2016}}</ref> Quine proposed that the best way to determine this is by translating the theory in question into [[first-order predicate logic]]. Of special interest in this translation are the logical constants known as [[existential quantification|existential quantifiers]] ('{{math|∃}}'), whose meaning corresponds to expressions like "there exists..." or "for some...". They are used to [[First-order logic#Free and bound variables|bind the variables]] in the expression following the quantifier.<ref>{{cite book |last1=Magnus |first1=P. D. |last2=Ichikawa |first2=Jonathan Jenkins |title=Forall X |date=2020 |publisher=Creative Commons: Attribution-ShareAlike 3.0 |url=https://philpapers.org/rec/MAGFXU |chapter=V. First-order logic|edition=UBC }}</ref> The ontological commitments of the theory then correspond to the variables bound by existential quantifiers.<ref>{{cite book |last1=Schaffer |first1=Jonathan |title=Metametaphysics: New Essays on the Foundations of Ontology |publisher=Oxford University Press |pages=347–383 |url=https://philpapers.org/rec/SCHOWG |chapter=On What Grounds What|year=2009 }}</ref> For example, the sentence "There are electrons" could be translated as "{{math|∃''x'' ''Electron''(''x'')}}", in which the bound variable ''x'' ranges over electrons, resulting in an ontological commitment to electrons.<ref name="Bricker"/> This approach is summed up by Quine's famous dictum that "[t]o be is to be the value of a variable".<ref name="Quine">{{cite journal |last1=Quine |first1=Willard Van Orman |title=On What There Is |journal=Review of Metaphysics |date=1948 |volume=2 |issue=5 |pages=21–38 |url=https://philpapers.org/rec/QUIOWT-7}}</ref> Quine applied this method to various traditional disputes in ontology. For example, he reasoned from the sentence "There are prime numbers between 1000 and 1010" to an ontological commitment to the existence of numbers, i.e. [[Philosophy of mathematics#Mathematical realism|realism]] about numbers.<ref name="Quine"/> This method by itself is not sufficient for ontology since it depends on a theory in order to result in ontological commitments. Quine proposed that we should base our ontology on our best scientific theory.<ref name="Bricker"/> Various followers of Quine's method chose to apply it to different fields, for example to "everyday conceptions expressed in natural language".<ref>{{cite book |last1=Inwagen |first1=Peter van |title=Oxford Studies in Metaphysics, Volume 1 |date=2004 |publisher=Clarendon Press |pages=107–138 |url=https://philpapers.org/rec/VANATO-2 |chapter=A Theory of Properties}}</ref><ref>{{cite book |last1=Kapelner |first1=Zsolt-kristof |title=Reconciling Quinean and neo-Aristotelian Metaontology |date=2015 |url=http://www.etd.ceu.hu/2015/kapelner_zsolt-kristof.pdf |chapter=3. Quinean Metaontology}}</ref>

====Indispensability argument for mathematical realism====
In [[philosophy of mathematics]], he and his Harvard colleague [[Hilary Putnam]] developed the [[Quine–Putnam indispensability argument|Quine–Putnam indispensability thesis]], an argument for the [[Philosophy of mathematics#Empiricism|reality of mathematical entities]].<ref name="plato.stanford.edu" />

The form of the argument is as follows.
#One must have [[ontological]] commitments to ''all'' entities that are indispensable to the best scientific theories, and to those entities ''only'' (commonly referred to as "all and only").
#Mathematical entities are indispensable to the best scientific theories. Therefore,
#One must have ontological commitments to mathematical entities.<ref name="MMM">Putnam, H. ''Mathematics, Matter and Method. Philosophical Papers'', vol. 1. Cambridge: Cambridge University Press, 1975. 2nd. ed., 1985.</ref>

The justification for the first premise is the most controversial. Both Putnam and Quine invoke [[naturalism (philosophy)|naturalism]] to justify the exclusion of all non-scientific entities, and hence to defend the "only" part of "all and only". The assertion that "all" entities postulated in scientific theories, including numbers, should be accepted as real is justified by [[confirmation holism]]. Since theories are not confirmed in a piecemeal fashion, but as a whole, there is no justification for excluding any of the entities referred to in well-confirmed theories. This puts the [[nominalism|nominalist]] who wishes to exclude the existence of [[Set (mathematics)|sets]] and [[non-Euclidean geometry]], but to include the existence of [[quark]]s and other undetectable entities of physics, for example, in a difficult position.<ref name="MMM" />

===Epistemology===
Just as he challenged the dominant analytic–synthetic distinction, Quine also took aim at traditional [[normative]] [[epistemology]]. According to Quine, traditional epistemology tried to justify the sciences, but this effort (as exemplified by [[Rudolf Carnap]]) failed, and so we should replace traditional epistemology with an empirical study of what sensory inputs produce what theoretical outputs:<ref>{{cite encyclopedia|chapter-url=http://plato.stanford.edu/entries/epistemology-naturalized/#2|title=Naturalized Epistemology|chapter=Naturalism in Epistemology|encyclopedia=stanford.edu|publisher=Metaphysics Research Lab, Stanford University|year=2017}}</ref> 
<blockquote>Epistemology, or something like it, simply falls into place as a chapter of psychology and hence of natural science. It studies a natural phenomenon, viz., a physical human subject. This human subject is accorded a certain experimentally controlled input—certain patterns of irradiation in assorted frequencies, for instance—and in the fullness of time the subject delivers as output a description of the three-dimensional external world and its history. The relation between the meager input and the torrential output is a relation that we are prompted to study for somewhat the same reasons that always prompted epistemology: namely, in order to see how evidence relates to theory, and in what ways one's theory of nature transcends any available evidence... But a conspicuous difference between old epistemology and the epistemological enterprise in this new psychological setting is that we can now make free use of empirical psychology.<ref>{{Cite book |title=Ontological Relativity and Other Essays |last=Quine |first=Willard Van Orman |publisher=Columbia University Press |date=1969 |pages=82–83 |isbn=0-231-08357-2}}</ref></blockquote>

As previously reported, in other occasions Quine used the term "neurology" instead of "empirical psychology".<ref name="Burrhus" />

Quine's proposal is controversial among contemporary philosophers and has several critics, with [[Jaegwon Kim]] the most prominent among them.<ref>[http://plato.stanford.edu/entries/epistemology-naturalized/ "Naturalized Epistemology"]. Stanford Encyclopedia of Philosophy. Plato.stanford.edu. July 5, 2001. Accessed March 8, 2010.</ref>

==In popular culture==
* A [[computer program]] whose output is its own source code is called a "[[Quine (computing)|quine]]" after Quine. This usage was introduced by [[Douglas Hofstadter]] in his 1979 book, ''[[Gödel, Escher, Bach: An Eternal Golden Braid]]''.
* Quine is a recurring character in the webcomic "[[Existential Comics]]".<ref name=ExistentialComics>{{cite web|author=C. Mohler|url=http://existentialcomics.com/comic/36| title=Existential Comics: The Sighting| website= Existential Comics|access-date=November 24, 2014}}</ref>
* Quine was selected for inclusion in the [[Committee for Skeptical Inquiry]]'s "Pantheon of Skeptics", which celebrates contributors to the cause of [[scientific skepticism]].<ref>{{cite web|title=The Pantheon of Skeptics|url=http://www.csicop.org/about/the_pantheon_of_skeptics|website=CSI|publisher=[[Committee for Skeptical Inquiry]]|access-date=April 30, 2017|archive-url=https://web.archive.org/web/20170131054129/http://www.csicop.org/about/the_pantheon_of_skeptics|archive-date=January 31, 2017|url-status=live}}</ref>

==Bibliography==

===Selected books===
* 1934 ''A System of Logistic''. Harvard Univ. Press.<ref>{{cite journal|author=Church, Alonzo|author-link=Alonzo Church|title=Review: ''A System of Logistic'' by Willard Van Orman Quine|journal=Bull. Amer. Math. Soc.|year=1935|volume=41|issue=9|pages=598–603|url=http://www.ams.org/bull/1935-41-09/S0002-9904-1935-06146-4/S0002-9904-1935-06146-4.pdf|doi=10.1090/s0002-9904-1935-06146-4|doi-access=free}}</ref>
* 1951 (1940). ''Mathematical Logic''. Harvard Univ. Press. {{ISBN|0-674-55451-5}}.
* 1980 (1941). ''Elementary Logic''. Harvard Univ. Press. {{ISBN|0-674-24451-6}}.
* {{wikicite|ref={{harvid|Quine|1982}}|reference=1982 (1950). ''Methods of Logic''. Harvard Univ. Press.}}
* 1980 (1953). [https://archive.org/download/FromALogicalPointOfView/QuineFromALogicalPointOfViewText.pdf ''From a Logical Point of View'']. Harvard Univ. Press. {{ISBN|0-674-32351-3}}. Contains "[http://www.ditext.com/quine/quine.html Two dogmas of Empiricism.]"
* 1960 ''[[Word and Object]]''. MIT Press; {{ISBN|0-262-67001-1}}. The closest thing Quine wrote to a philosophical treatise. Ch.&nbsp;2 sets out the [[indeterminacy of translation]] thesis.
* 1969 (1963). ''Set Theory and Its Logic''. Harvard Univ. Press. 
* 1966. ''Selected Logic Papers''. New York: Random House.
* 1976 (1966). ''The Ways of Paradox''. Harvard Univ. Press. 
* 1969 ''Ontological Relativity and Other Essays''. Columbia Univ. Press. {{ISBN|0-231-08357-2}}. Contains chapters on [[ontological relativity]], [[naturalized epistemology]], and [[natural kind]]s.
* 1970 (2nd ed., 1978). With J. S. Ullian. ''The Web of Belief''. New York: Random House.
* 1986 (1970). ''The Philosophy of Logic''. Harvard Univ. Press. 
* 1974 (1971). ''[[The Roots of Reference]]''. Open Court Publishing Company {{ISBN|0-8126-9101-6}} (developed from Quine's [[Carus Lectures]]).
* 1981. ''Theories and Things''. Harvard Univ. Press.
* 1985. ''The Time of My Life: An Autobiography''. Cambridge, The MIT Press. {{ISBN|0-262-17003-5}}. 
* 1987. ''Quiddities: An Intermittently Philosophical Dictionary''. Harvard Univ. Press. {{ISBN|0-14-012522-1}}. A work of essays, many subtly humorous, for lay readers, very revealing of the breadth of his interests.
* 1992 (1990). ''Pursuit of Truth''. Harvard Univ. Press. A short, lively synthesis of his thought for advanced students and general readers not fooled by its simplicity. {{ISBN|0-674-73951-5}}.
* 1995. ''From Stimulus to Science''. Harvard Univ. Press. {{ISBN|0-674-32635-0}}.
* 2004. ''Quintessence: Basic Readings from the Philosophy of W V Quine''. Harvard Univ. Press.
* 2008. ''Confessions of a Confirmed Extensionalist and Other Essays''. Harvard Univ. Press.

===Important articles===
* 1946, "Concatenation as a basis for arithmetic". Reprinted in his ''Selected Logic Papers''. Harvard Univ. Press.
* 1948, "[[:s:On What There Is|On What There Is]]", ''[[Review of Metaphysics]]'' '''2'''(5) ([https://www.jstor.org/stable/20123117 JSTOR]). Reprinted in his 1953 ''From a Logical Point of View''. Harvard University Press.<ref>In this paper, Quine explicitly connected each of the three main medieval ontological positions, namely [[Philosophical realism|realism]]/[[conceptualism]]/[[nominalism]], with one of three dominant schools in modern philosophy of mathematics: [[logicism]]/[[intuitionism]]/[[Formalism (philosophy of mathematics)|formalism]] respectively.</ref>
* 1951, "[[Two Dogmas of Empiricism]]", ''[[The Philosophical Review]]'' '''60''': 20–43. Reprinted in his 1953 ''From a Logical Point of View''. Harvard University Press.
* 1956, "Quantifiers and Propositional Attitudes", ''[[Journal of Philosophy]]'' '''53'''. Reprinted in his 1976 ''Ways of Paradox''. Harvard Univ. Press: 185–196.
* 1969, "Epistemology Naturalized" in ''Ontological Relativity and Other Essays''. New York: Columbia University Press: 69–90.
* "Truth by Convention", first published in 1936. Reprinted in the book, ''Readings in Philosophical Analysis'', edited by [[Herbert Feigl]] and [[Wilfrid Sellars]], pp.&nbsp;250–273, ''[[Appleton-Century-Crofts]]'', 1949.

==Filmography==
* [[Bryan Magee]] (host), ''[[Men of Ideas]]'': "The Ideas of Quine", BBC, 1978.
* Rudolf Fara (host), ''In conversation: W. V. Quine'' (7 videocassettes), Philosophy International, Centre for Philosophy of the Natural and Social Sciences, [[London School of Economics]], 1994.

==See also==
{{Portal|Philosophy}}
* [[Definitions of philosophy]]
* [[List of American philosophers]]

==Notes==
{{Reflist|35em}}

==Further reading==
* {{cite book |title=The Cambridge companion to Quine |editor-first=Roger F. |editor-last=Gibson |editor-link=Roger Gibson |isbn=0521639492 |year=2004 |publisher=[[Cambridge University Press]] |url=https://books.google.com/books?id=Kvw-n1JIXHkC}}
* {{cite book |author-first=Roger F. |author-last=Gibson |date=1988 |title=The Philosophy of W. V. Quine: An Expository Essay |location=Tampa |publisher=[[University of South Florida]]}}
* {{cite book |author-first=Roger F. |author-last=Gibson |date=1988 |title=Enlightened Empiricism: An Examination of W. V. Quine's Theory of Knowledge |location=Tampa |publisher=[[University of South Florida]]}}
* {{cite book |author-first=Roger F. |author-last=Gibson |date=2004 |title=Quintessence: Basic Readings from the Philosophy of W. V. Quine |publisher=[[Harvard University Press]]}}
* {{cite book |editor-last1=Gibson |editor-first1=Roger F. |editor-last2=Barrett |editor-first2=R. |date=1990 |title=Perspectives on Quine |location=Oxford |publisher=[[Blackwell Publishing]]}}
* [[Paul Gochet|Gochet, Paul]], 1978. ''Quine en perspective'', Paris, Flammarion.
* [[Peter Godfrey-Smith|Godfrey-Smith, Peter]], 2003. ''Theory and Reality: An Introduction to the Philosophy of Science''.
* [[Ivor Grattan-Guinness|Grattan-Guinness, Ivor]], 2000. ''The Search for Mathematical Roots 1870–1940''. Princeton University Press.
* [[Paul Grice|Grice, Paul]] and [[Peter Strawson]]. "In Defense of a Dogma". ''The Philosophical Review 65'' (1965).
* Hahn, L. E., and Schilpp, P. A., eds., 1986. ''The Philosophy of W. V. O. Quine'' (The Library of Living Philosophers). Open Court.
* Köhler, Dieter, 1999/2003. ''[http://www.ub.uni-heidelberg.de/archiv/3548 Sinnesreize, Sprache und Erfahrung: eine Studie zur Quineschen Erkenntnistheorie]''. Ph.D. thesis, Univ. of Heidelberg.
* {{cite journal |author=MacFarlane, Alistair |author-link=Alistair MacFarlane |date=Mar–Apr 2013 |title=W. V. O. Quine (1908-2000) |journal=[[Philosophy Now]] |volume=95 |pages=35–36 }}
* [[Murray Murphey]], ''The Development of Quine's Philosophy'' (Heidelberg, Springer, 2012) (Boston Studies in the Philosophy of Science, 291).
* {{cite book |last=Orenstein |first=Alex |title=W.V. Quine |year=2002 |publisher=Princeton University Press}}
* [[Hilary Putnam|Putnam, Hilary]]. "The Greatest Logical Positivist". Reprinted in ''Realism with a Human Face'', ed. James Conant. Cambridge, MA: Harvard University Press, 1990.
* [[John Barkley Rosser|Rosser, John Barkley]], "The axiom of infinity in Quine's new foundations", ''Journal of Symbolic Logic'' 17 (4):238–242, 1952.
* {{cite book |last=Verhaeg |first=Sander |title=[[Working from Within: The Nature and Development of Quine's Naturalism]] |year=2018 |publisher=Oxford University Press}}

==External links==
{{sister project links|wikt=no|n=no|b=no|v=no}}
* [http://www.wvquine.org/ WVQuine.org]
* [http://plato.stanford.edu/entries/quine/ Willard Van Orman Quine] at the ''[[Stanford Encyclopedia of Philosophy]]''
* {{cite IEP |url-id=quine-an |title=Quine's Rejection of the Analytic/Synthetic Distinction}}
* "[http://www.iep.utm.edu/quine-sc/ Quine's Philosophy of Science]" at the ''[[Internet Encyclopedia of Philosophy]]''
* [http://plato.stanford.edu/entries/quine-nf/ Quine's New Foundations] at the ''[[Stanford Encyclopedia of Philosophy]]''
* {{MathGenealogy|id=73831}}
* [https://www.theguardian.com/obituaries/story/0,,416245,00.html Obituary from ''The Guardian'']
* [http://www.philosopher.eu/texts/quine-on-what-there-is-summary/ Summary and Explanation of "On What There Is"]
* [http://www.ditext.com/quine/quine.html "Two Dogmas of Empiricism"]
* [http://sveinbjorn.org/simple_theories_of_a_complex_world "On Simple Theories Of A Complex World"]

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[[Category:United States Navy officers]]
[[Category:Philosophers from Ohio]]
[[Category:Corresponding fellows of the British Academy]]
[[Category:Philosophers of linguistics]]
[[Category:Members of the American Philosophical Society]]