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| In the ] and ], the '''ontological commitments''' of a theory are those things which |
In the ] and ], the '''ontological commitments''' of a theory (or sentence) are those things which must exist for the theory or sentence to be true. In other words, the ontological commitments of a theory are those entities whose existence is necessitated, presupposed, or implied by the theory. An expression or form of words is described as “ontologically committing” if a use of that expression in a declarative sentence adds to the ontological commitments associated with that sentence. | ||
| {{cite book |title=The Cambridge Dictionary of Philosophy |edition=Paperback 2nd |page= 631 |chapter=Ontological commitment |isbn=0521637228 |editor=Robert Audi |year=1999}} | |||
| </ref> An expression or form of words is described as “ontologically committing” if a use of that expression in a declarative sentence adds to the ontological commitments associated with that sentence. | |||
| There is considerable debate about which elements of language are ontologically committing. Quine (the originator of the term “ontological commitment”) 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. However, attempts have been made to argue that ]s are also ontologically committing, and thus that subject-predicate sentences bear additional ontological commitment to ]s such as ]s, ], or ]. Additionally, 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 ]s. | There is considerable debate about which elements of language are ontologically committing. Quine (the originator of the term “ontological commitment”) 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. However, attempts have been made to argue that ]s are also ontologically committing, and thus that subject-predicate sentences bear additional ontological commitment to ]s such as ]s, ], or ]. Additionally, 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 ]s. | ||
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| The sentence “Napoleon is one of my ancestors” apparently commits us only to the existence of two individuals (i.e., ] 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 ], where individual variables stand for individual things. Instead, they must be represented in some ] form. In ordinary language, such second-order forms use either grammatical plurals or terms such as “set of” or “group of”. | The sentence “Napoleon is one of my ancestors” apparently commits us only to the existence of two individuals (i.e., ] 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 ], where individual variables stand for individual things. Instead, they must be represented in some ] 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 ]s, or by ]s standing for ] (which are ] objects in ] 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. | 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 ]s, or by ]s standing for ] (which are ] objects in ] 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 ] puts it, | ||
| Before proceeding, the term ''variables of quantification'' has to be introduced. These include words like 'something', 'nothing', 'everything'. One value of such words is that they allow the translation of sentences like ‘There ''is'' an author of ''Quintessence''’ into a form that does not appear to assert the existence of the author, into a different form, such as ‘Someone wrote ''Quintessence''’. Likewise, ‘There ''is no'' author of ''Quintessence''’ simply means ‘No-one wrote ''Quintessence''’ and avoids any implication that such an author must exist, even if just in our minds, to allow us to deny their existence, avoiding a peril of language called ].<ref name=Quintessence> {{cite book |author=Willard Van Orman Quine |editor=Roger F. Gibson, Jr., ed |title=Quintessence: Basic Readings from the Philosophy of W. V. Quine |pages=181-182 |url=http://books.google.ca/books?id=-Xl7cUQGAUcC&pg=PA251&lpg=PA181 |title=Quintessence |chapter=Chapter 9: On what there is |isbn=0674010485 |year=2004 |publisher=Harvard University Press}}</ref> | |||
| With this term in mind, as ] 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 ]: objects of a special and abstract kind, ] classes, are now presupposed. Formally it is precisely in allowing ] 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. ('']'' p. 228)</blockquote> | <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 ]: objects of a special and abstract kind, ] classes, are now presupposed. Formally it is precisely in allowing ] 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. ('']'' p. 228)</blockquote> | ||
Revision as of 10:24, 25 March 2013
In the philosophy of language and metaphysics, the ontological commitments of a theory (or sentence) are those things which must exist for the theory or sentence to be true. In other words, the ontological commitments of a theory are those entities whose existence is necessitated, presupposed, or implied by the theory. An expression or form of words is described as “ontologically committing” if a use of that expression in a declarative sentence adds to the ontological commitments associated with that sentence.
There is considerable debate about which elements of language are ontologically committing. Quine (the originator of the term “ontological commitment”) 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. However, attempts have been made to argue that predicates are also ontologically committing, and thus that subject-predicate sentences bear additional ontological commitment to abstract objects such as universals, sets, or classes. Additionally, 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 fictional objects.
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 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 variables, or by first-order variables standing for 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 Quine puts it,
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 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 p. 228)
Another statement about individuals that appears “ontologically innocent” is the well-known Geach–Kaplan sentence: Some critics admire only one another.
Ontological innocence
Many philosophers dispute whether we are committed to such entities at all. They argue that all assertions are “ontologically innocent” — that they are committed only to the existence of the entities which they actually assert.
There is a considerable and growing body of literature on so-called plural reference and plural quantification. It seems counter-intuitive that a sentence such as “some people admire only each other” commits us to the existence of anything but people. Advocates of ontological innocence see in the grammatical plural simply another way to refer to exactly the same things that the singular form commits us to.
Interpretations of negative existential statements have proved more difficult. See empty names for an overview of the problem.
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, 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, 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 from two directions.
First, 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 truthmakers 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. However, this view has been attacked by Jonathan Shaffer, 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.
Second, it 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. This argument has been attacked by Howard 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.
References
- Quine, W.V.O. (1952) Methods of Logic, London.
- Heil, J. (2003). From an ontological point of view. Oxford: Oxford University Press.
- Shaffer, Jonathan. "Truthmaker Commitments" (PDF).
- Azzouni, Jody (2004). Deflating Existential Consequence: A Case for Nominalism. Oxford: Oxford University Press.
- Peacock, Howard (2011). "Two Kinds of Ontological Commitment". The Philosophical Quarterly. 61 (242): 79–104.