Editing Ontological commitment

{{Short description|Object(s) postulated to exist by a given language}}

In [[Formal semantics (natural language)|formal semantics]], an '''ontological commitment''' of a [[language]] is one or more objects [[Axiom|postulated]] to [[Existence|exist]] by that language. The 'existence' referred to need not be 'real', but exist only in a [[universe of discourse]].  As an example, [[Law|legal system]]s use vocabulary referring to '[[legal person]]s' that are collective entities that have rights. One says the legal doctrine has an ''ontological commitment'' to non-singular individuals.<ref name=Schafer/>

In [[information system]]s and [[artificial intelligence]], where an [[Ontology (information science)|ontology]] refers to a specific vocabulary and a set of explicit assumptions about the meaning and usage of these words, an ontological commitment is an agreement to use the shared vocabulary in a coherent and consistent manner within a specific context.<ref name=Guarino/>

In [[philosophy]], a "theory is '''ontologically committed''' to an object only if that object occurs in ''all'' the ontologies of that theory."<ref name=definition/>

== Background ==
The sentence “Napoleon is one of my ancestors” apparently commits us only to the existence of two individuals (i.e., [[Napoleon]] and the speaker) and a line of ancestry between them. The fact that no other people or objects are mentioned seems to limit the “commitment” of the sentence. However, it is well known that sentences of this kind cannot be interpreted in [[first-order logic]], where individual variables stand for individual things. Instead, they must be represented in some [[second-order logic|second-order]] form. In ordinary language, such second-order forms use either grammatical plurals or terms such as “set of” or “group of”.

For example, the sentence involving Napoleon can be rewritten as “any group of people that includes me and the parents of each person in the group must also include Napoleon,” which is easily interpreted as a statement in second-order logic (one would naturally start by assigning a name, such as ''G'', to the group of people under consideration). Formally, collective noun forms such as “a group of people” are represented by [[second-order variable]]s, or by [[first-order variable]]s standing for [[set (mathematics)|sets]] (which are [[well-defined]] objects in [[mathematics]] and logic). Since these variables do not stand for individual objects, it seems we are “ontologically committed” to entities other than individuals — sets, classes, and so on. As [[Willard Van Orman Quine|Quine]] puts it,

<blockquote>the general adoption of class variables of quantification ushers in a theory whose laws were not in general expressible in the antecedent levels of logic. The price paid for this increased power is [[ontological]]: objects of a special and abstract kind, [[viz.]] classes, are now presupposed. Formally it is precisely in allowing [[Quantification (logic)|quantification]] over class variables α, β, etc., that we assume a range of values for these variables to refer to. To be assumed as an entity is to be assumed as a value of a variable. (''Methods of Logic'', 1950, p. 228)</blockquote>

Another statement about individuals that appears “ontologically innocent” is the well-known [[Geach–Kaplan sentence]]: ''Some critics admire only one another.''

==Quine's criterion<!--'Ideological commitment' redirects here-->==

[[Willard Van Orman Quine]] provided an early and influential formulation of ontological commitment:<ref name=Quine2/>
{{quote|If one affirms a statement using a name or other singular term, or an initial phrase of 'existential quantification', like 'There are some so-and-sos', then one must either (1) admit that one is committed to the existence of things answering to the singular term or satisfying the descriptions, or (2) provide a 'paraphrase' of the statement that eschews singular terms and quantification over so-and sos. Quine's criterion can be seen as a logical development of the methods of [[Bertrand Russell]] and [[G.E. Moore]], who assumed that one must accept the existence of entities corresponding to the singular terms used in statements one accepts, unless and until one finds systematic methods of paraphrase that eliminate these terms.<ref name=Loux/>|Michael J. Loux & Dean W. Zimmerman|''The Oxford Handbook of Metaphysics'', 2003, p. 4}}

The purpose of Quine's strategy is to determine just how the ''ontological commitment'' of a theory is to be found. Quine argued that the only ontologically committing expressions are variables bound by a first-order existential quantifier, and natural language expressions which were formalized using variables bound by first-order existential quantifiers.<ref name=Quine0/><ref name=Dejnozka/>

Attempts have been made to argue that [[predicate (grammar)|predicate]]s are also ontologically committing, and thus that subject-predicate sentences bear additional ontological commitment to [[abstract object]]s such as [[Universality (philosophy)|universal]]s, [[set (mathematics)|sets]], or [[class (philosophy)|classes]]. It has been suggested that the use of meaningful names in nonexistence statements such as "Pegasus does not exist" brings with it an ontological commitment to [[empty name]]s like Pegasus, a quandary referred to as [[Plato's beard]] and escaped by using quantifiers.<ref name=Fogelin/>

This discussion has a connection to the Carnap–Quine argument over analytic and synthetic objects.<ref name=Ryan/> Although Quine refers to 'ontological commitment' in this connection,<ref name=Quine3/> in his rejection of the analytic/synthetic distinction he does not rely upon the formal translation of any particular theory along the lines he has suggested.<ref name=Quine1/>  Instead, Quine argues by using examples that although there are tautological statements in a formal theory, like "all squares are rectangles", a formal theory necessarily contains references to objects that are not tautological, but have external connections. That is, there is an ''ontological commitment'' to such external objects. In addition, the terms used to interpret the application of the theory are not simply descriptions of sensory input, but are statements in a context. That is, inversely, there is an ''ontological commitment'' of these observational objects to the formal theory. As Ryan puts it: "Rather than being divided between contingent synthetic claims and indubitable analytic propositions, our beliefs constitute a continuous range from a periphery of sense-reports to interior concepts that are comparatively theory-laden and general."<ref name=Ryan/>  Thus we end up with Quine's 'flat' ontology that does not see a distinction between analytic and synthetic objects.<ref name=Schaffer/><ref name=Putnam/>

Quine further made a distinction between the ontological commitments of a theory (what the theory says exists) and the '''ideological commitments'''<!--boldface per WP:R#PLA--> of a theory (those concepts, logical or non-logical, that are expressible within the theory).<ref>[https://plato.stanford.edu/entries/ontological-commitment/ "Ontological Commitment"]. ''[[Stanford Encyclopedia of Philosophy]]''.</ref>

===Ontological parsimony===
Whatever process one uses to determine the ontological commitments of a theory, that does not prescribe what ontological commitments one should have. Quine regarded this as a matter of [[epistemology]], which theory one should accept. "Appeal is made to [concerns of] explanatory power, parsimony, conservatism, precision, and so on".<ref name=Routledge/>

Ontological parsimony can be defined in various ways, and often is equated to versions of [[Occam's razor]], a "rule of thumb, which obliges us to favor theories or hypotheses that make the fewest unwarranted, or ''ad hoc'', assumptions about the data from which they are derived."<ref name=Henke/> Glock regards 'ontological parsimony' as one of the 'five main points' of Quine's conception of ontology.<ref name=Glock/>

Following Quine,<ref name=QuineW/> Baker states that a theory, ''T'', is ''ontologically committed'' to items ''F'' if and only if ''T'' entails that ''F′''s exist.  If two theories, ''T<sub>1</sub>'' and ''T<sub>2</sub>'', have the same ontological commitments except that ''T<sub>2</sub>'' is ontologically committed to ''F′''s while ''T<sub>1</sub>'' is not, then ''T<sub>1</sub>'' is more parsimonious than ''T<sub>2</sub>''. More generally, a sufficient condition for ''T<sub>1</sub>'' being more parsimonious than ''T<sub>2</sub>'' is for the ontological commitments of ''T<sub>1</sub>'' to be a proper subset of those of ''T<sub>2</sub>''.<ref name=Baker/>

These ideas lead to the following particular formulation of Occam's razor: 'Other things being equal, if ''T<sub>1</sub>'' is more ontologically parsimonious than ''T<sub>2</sub>'' then it is rational to prefer ''T<sub>1</sub>'' to ''T<sub>2</sub>''.'  While a common formulation stipulates only that entities should not be multiplied beyond necessity, this version by contrast, states that entities should not be multiplied ''other things being equal'', and this is compatible with parsimony being a comparatively weak theoretical virtue.<ref name=Baker/>

== Recent controversies ==
The standard approach to ontological commitment has been that, once a theory has been regimented and/or "paraphrased" into an agreed "canonical" version,<ref name=Gibson/> which may indeed be in formal logical notation rather than the original language of the theory, ontological commitments can be read off straightforwardly from the presence of certain ontologically committing expressions (e.g. bound variables of existential quantification). Although there is substantial debate about which expressions are ontologically committing,<ref name=French/><ref name=Colyvan/> parties to that debate generally agree that the expressions they prefer are reliable bearers of ontological commitment, imparting ontological commitment to all regimented sentences in which they occur. This assumption has been challenged.

Inwagen has taken issue with Quine's methodology,<ref name=Inwagen/> claiming that this process did not lead to a unique set of fundamental objects, but to several possible sets, and one never could be certain that all the possible sets had been found. He also took issue with Quine's notion of a theory, which he felt was tantamount to suggesting a 'theory' was just a collection of sentences. Inwagen suggested that Quine's approach provided useful tools for discovering what entities were ontological commitments, but that he had not been successful. His attempts are comparable to an "attempt to reach the moon by climbing ever higher trees..."<ref name=Inwagen2/>

It has been suggested that the ontological commitments of a theory cannot be discerned by analysis of the syntax of sentences, looking for ontologically committing expressions, because the true ontological commitments of a sentence (or theory) are restricted to the entities needed to serve as [[truthmaker]]s for that sentence, and the syntax of even a regimented or formalized sentence is not a reliable guide to what entities are needed to make it true.<ref name=Heil/> However, this view has been attacked by Jonathan Schaffer, who has argued that truthmaking is not an adequate test for ontological commitment: at best, the search for the truthmakers of our theory will tell us what is "fundamental", but not what our theory is ontologically committed to, and hence will not serve as a good way of deciding what exists.<ref name=Schaffer1/>

It also has been argued that the syntax of sentences is not a reliable guide to their ontological commitments because English has no form of words which reliably functions to make an existence-claim in every context in which it is used. For example, Jody Azzouni suggests that "There is" does not make any kind of genuine existence-claim when it is used in a sentence such as "There are mice that talk". Since the meaning of the existential quantifier in formal notation is usually explained in terms of its equivalence to English expressions such as "there is" and "there exist", and since these English expressions are not reliably ontologically committing, it comes to seem that we cannot be sure of our theory's ontological commitments even after it has been regimented into a canonical formulation.<ref name=Azzouni/> This argument has been attacked by Howard Peacock,<ref name=Peacock/> who suggests that Azzouni's strategy conflates two different kinds of ontological commitment – one which is intended as a measure of what a theory explicitly claims to exist, and one which is intended as a measure of what is required for the theory to be true; what the ontological costs of the theory are. If ontological commitment is thought of as a matter of the ontological costs of a theory, then it is possible that a sentence may be ontologically committed to an entity even though competent speakers of the language do not recognize the sentence as asserting the existence of that entity. Ontological commitment is not a matter of what commitments one explicitly recognizes, but rather a matter of what commitments are actually incurred.

==See also==
*[[Conceptualization (information science)]]
*[[Holophrastic indeterminacy]]
*[[Indeterminacy of translation]]

== References ==
{{Reflist |refs=
<ref name=Azzouni>
{{cite book|last=Azzouni|first=Jody|title=Deflating Existential Consequence: A Case for Nominalism|year=2004|publisher=Oxford University Press|location=Oxford}}
</ref>

<ref name=Baker>
This section is a slightly modified version of the discussion by {{cite encyclopedia |author=Baker, Alan |title=Simplicity |encyclopedia=The Stanford Encyclopedia of Philosophy (Summer 2011 Edition) |editor=Edward N. Zalta |url=http://plato.stanford.edu/archives/sum2011/entries/simplicity/#OntPar |date=Feb 25, 2010}}
</ref>

<ref name=definition>
{{cite book |title=The Cambridge Dictionary of Philosophy |url=https://archive.org/details/cambridgediction00audi |url-access=limited |edition=Paperback 2nd |page= [https://archive.org/details/cambridgediction00audi/page/n663 631] |chapter=Ontological commitment |isbn=0521637228 |editor=Robert Audi  |year=1999}} A shortened version of that definition is as follows:
:The '''ontological commitments''' of a theory are those things which occur in all the ''ontologies'' of that theory. To explain further, the [[ontology]] of a theory consists of the objects the theory makes use of. A dependence of a theory upon an object is indicated if the theory fails when the object is omitted. However, the ontology of a theory is not necessarily unique. A theory is '''ontologically committed''' to an object only if that object occurs in ''all'' the ontologies of that theory. A theory also can be ''ontologically committed'' to a class of objects if that class is populated (not necessarily by the same objects) in all its ontologies.
</ref>

<ref name=Dejnozka>
Of course, this description is not understandable unless one knows what ''first-order existential quantifiers'' are and what is meant by saying they are ''bound''. An approachable discussion of these matters is found in {{cite book |author=Jan Dejnožka |chapter=Chapter 1: Introduction   |title=The Ontology of the Analytic Tradition and Its Origins: Realism, Possibility, and Identity in Frege, Russell, Wittgenstein, and Quine |url=https://books.google.com/books?id=cI0d7Cgj0BAC&pg=PA1 |pages=1 ''ff'' |isbn=0822630532 |year=1996 |publisher=Rowman & Littlefield }}
</ref>

<ref name=Fogelin>
{{cite book |title=The Cambridge Companion to Quine |author=Robert J Fogelin |url=https://books.google.com/books?id=Kvw-n1JIXHkC&pg=PA36 |page=36 |isbn=	0521639492 |year=2004 |publisher=Cambridge University Press}}
</ref>

<ref name=French>
{{cite book |chapter=Quine's Ladder: Two and a half pages from the ''Philosophy of Logic'' |author= Marion David |chapter-url=https://books.google.com/books?id=xZO_BJuSzq0C&pg=PA274 |pages=274 ''ff'' |isbn=978-1405191456 |year=2008 |title=Midwest Studies in Philosophy, Truth and its Deformities (Volume XXXII) |editor1=Peter A. French |editor2=Howard Wettstein |publisher= Wiley-Blackwell}}
</ref>

<ref name=Colyvan>
{{cite book |title=The Indispensability of Mathematics |author=Mark Colyvan |chapter=§4.2 What is it to be indispensable? |pages=76 ''ff'' |chapter-url=https://books.google.com/books?id=OBs-TSFopLkC&pg=PA76 |isbn=0198031440 |publisher=Oxford University Press |year=2001}}
</ref>

<ref name=Gibson>
{{cite book |title=Naturalism, Reference and Ontology: Essays in Honor of Roger F. Gibson |chapter=Quine vs. Quine: Canonical notation, paraphrase, and regimentation |page=171 |author=Alex Ornstein |editor=Chase B Wrenn |isbn=978-1433102295 |year=2008 |chapter-url=https://books.google.com/books?id=7hv-twrMHUgC&pg=PA171 |publisher=Peter Lang Publishing, Inc}}
</ref>

<ref name=Glock>
{{cite book |title=Quine and Davidson on Language, Thought, and Reality |chapter-url=https://books.google.com/books?id=6gUY1YNf_qEC&pg=PA41 |pages=41–47 |chapter=§1: Ontological commitment and ontological parsimony |author=Hans-Johann Glock |publisher=Cambridge University Press |year=2004 |isbn=1139436732 }}
</ref>

<ref name=Guarino>
{{cite book |chapter=Formal ontology and information systems |author=Nicola Guarino |chapter-url=https://books.google.com/books?id=Wf5p3_fUxacC&pg=PA3 |pages=3 ''ff'' |title=Formal Ontology in Information Systems: Proceedings of the First International Conference (FIOS'98), June 6–8, Trento, Italy |year=1998 |isbn=	9051993994 |publisher=IOS Press}}
</ref>

<ref name=Heil>
{{cite book|last=Heil|first=J.|title=From an ontological point of view|year=2003|publisher=Oxford University Press|location=Oxford}}
</ref>

<ref name=Henke>
{{cite book |title=Handbook of Paleoanthropology: Primate evolution and human origins: Volume 2 |author=Kaila E Folinsbee|editor=Winfried Henke |chapter=Quantitative approaches to phylogenetics; §5.2: Fount of stability and confusion: A synopsis of parsimony in systematics |chapter-url=https://books.google.com/books?id=vhoRdbTrjc8C&pg=PA168 |page=168 |isbn=978-3540324744 |year=2007 |publisher=Springer |display-authors=etal}}
</ref>

<ref name=Inwagen>
{{cite journal |title=Meta-ontology |author=Peter Van Inwagen |url=http://andrewmbailey.com/pvi/Meta-ontology.pdf |journal=Erkenntnis |volume=48 |pages=233–250 |year=1998 |issue=2/3 |doi=10.1023/a:1005323618026}}
</ref>

<ref name=Inwagen2>
{{cite book |title=Oxford Studies in Metaphysics : Volume 4 |chapter=Chapter 6: Quine's 1946 lecture on nominalism |pages=125 ''ff'' |isbn=978-0191562310 |author=Peter van Inwagen |publisher=Oxford University Press |year= 2008 |editor=Dean Zimmerman |chapter-url=https://books.google.com/books?id=kivYOG_0vmwC&pg=PA125 |quote=Quine has endorsed several closely related theses that I have referred to, collectively, as his "meta-ontology". These are...those of his theses that pertain to the topic "ontological commitment" or "ontic commitment".}}
</ref>

<ref name=Loux>
{{cite book |title=The Oxford Handbook of Metaphysics |author1=Michael J. Loux |author2=Dean W. Zimmerman |editor1=Michael J. Loux |editor2=Dean W. Zimmerman |chapter=Introduction |chapter-url=https://books.google.com/books?id=cgVVvyQ4lIMC&pg=PR4 |isbn=0199284229 |publisher=Oxford Handbooks Online |year=2005}}
</ref>

<ref name=Peacock>
{{cite journal|last=Peacock|first=Howard|title=Two Kinds of Ontological Commitment|journal=The Philosophical Quarterly|year=2011|volume=61|issue=242|pages=79–104|doi=10.1111/j.1467-9213.2010.665.x}}
</ref>

<ref name=Putnam>
See for example, {{cite book |title=Philosophy of Quine: General, reviews, and analytic/synthetic, Volume 1 |pages=252 ''ff'' |author=Hilary Putnam |chapter=The analytic and the synthetic  |orig-year=1962 |chapter-url=https://books.google.com/books?id=efvWNDajvs4C&pg=PA252 |editor=Dagfinn Fllesdal |isbn=0815337388 |publisher=Taylor & Francis |year=2001}}
</ref>

<ref name=Quine0>
 {{cite book |author=Willard Van Orman Quine |year=1983 |title=Confessions of a Confirmed Extensionalist: And Other Essays |chapter=Chapter 22: Ontology and ideology revisited  |pages=315 ''ff'' |isbn=0674030842 |publisher=Harvard University Press |chapter-url=https://books.google.com/books?id=8cnG59X1ntQC&pg=PA315}}
</ref>

<ref name=Quine1>
{{cite book |title=From a Logical Point of View: Nine Logico-philosophical Essays |author=Willard Van Orman Quine |chapter-url=https://books.google.com/books?id=OalXwuw3MvMC&pg=PA20 |pages=20 ''ff'' |chapter=Chapter 2: Two dogmas of empiricism |isbn=	0674323513 |year=1980 |publisher=Harvard University Press |edition =2nd}} See [http://www.ditext.com/quine/quine.html this]
</ref>

<ref name=Quine2>
{{cite journal |author=Quine, W. V. |year=1948 |title=On What There Is |journal= Review of Metaphysics |volume=2 |pages=21–38}} Reprinted in {{cite book |title=From a Logical Point of View: Nine Logico-philosophical Essays |publisher= Harvard University Press |year= 1980 |pages=1–19 |isbn=0674323513 |edition=2nd |url=https://books.google.com/books?id=OalXwuw3MvMC&pg=PA1}} Online on [[s:On What There Is|Wikisource]].
</ref>

<ref name=Quine3>
{{cite journal |author=Quine, W. V.|year=1951 |title=On Carnap's views on ontology |journal= Philosophical Studies |volume=2 |issue=5 |pages=65–72 |doi=10.1007/bf02199422|s2cid=170241527 }} Reprinted in {{cite book |title=The Ways of Paradox |pages=[https://archive.org/details/waysofparadox00quin/page/203 203]–211 |author=Willard Van Orman Quine |url=https://archive.org/details/waysofparadox00quin |url-access=registration |isbn=0674948378 |chapter=Chapter 9: On Carnap's views on ontology |year=1976 |publisher=Harvard University Press |edition=2nd}}
</ref>

<ref name=QuineW>
{{cite book |title=Theories and Things |author= Willard Van Quine |isbn=0674879260 |year=1981 |publisher=Harvard University Press |edition=3rd  |pages=[https://archive.org/details/theoriesthings00quin/page/144 144]''ff'' |url=https://archive.org/details/theoriesthings00quin|url-access=registration }} Cited by Alan Baker.
</ref>

<ref name=Routledge>
{{cite book |author=Alex Orenstein |title=Routledge Encyclopedia of Philosophy |pages=8 ''ff'' |chapter=Quine, Willard Van Orman |editor=Edward Craig |isbn= 0415073103 |year=1998 |volume=8}} See also [[Models of scientific inquiry#Choice of a theory|Choice of a theory]].
</ref>

<ref name=Ryan>
{{cite book |title=American Philosophy: An Encyclopedia |chapter=Analytic: Analytic/Synthetic |author=Frank X Ryan |chapter-url=https://books.google.com/books?id=KmUTkreTEQsC&pg=PA36 |pages=36–39 |editor1=John Lachs |editor2=Robert B. Talisse |isbn=020349279X |publisher=Psychology Press |year=2004}}
</ref>

<ref name=Schafer>
{{cite book |chapter=Invariance principles and the community of heirs |author=Burkhard Schäfer |chapter-url=https://books.google.com/books?id=Wf5p3_fUxacC&pg=PA108 |pages=108 ''ff'' |isbn=9051993994 |year=1998 |editor=N Guarino |title=Formal Ontology in Information Systems: Proceedings of the 1st International Conference June 6-8, 1998, Trento, Italy|publisher=IOS Press }}
</ref>

<ref name=Schaffer>
{{cite book |author=Jonathan Schaffer |author-link=Jonathan Schaffer |chapter=On What Grounds What Metametaphysics |title=Metametaphysics |url=http://www.jonathanschaffer.org/grounds.pdf |editor=Chalmers |editor2=Manley |editor3=Wasserman |isbn=978-0199546046 |publisher=Oxford University Press |year=2009 |pages=347–83 }} Reprinted by Philosopher’s Annual 29, eds. Grim, Charlow, Gallow, and Herold; also reprinted in Metaphysics: An Anthology, 2nd edition, eds. Kim, Korman, and Sosa (2011), 73-96: Blackwell.) Contains an analysis of Quine and proposes that questions of ''existence'' are not fundamental.
</ref>

<ref name=Schaffer1>
{{cite web|last=Shaffer|first=Jonathan|title=Truthmaker Commitments|url=http://www.jonathanschaffer.org/commitment.pdf}}
</ref>
}}

==External links==
*{{cite SEP |url-id=ontological-commitment |title=Ontological Commitment |last=Bricker |first=Phillip}}
*[http://philpapers.org/browse/ontological-commitment Ontological commitment], a category in [[Philosophical Papers]] maintained by Henry Laycock

[[Category:Ontology]]
[[Category:Philosophy of language]]
[[Category:Logic]]