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5. Theory of Logic / G. Quantification / 4. Substitutional Quantification

[quantifiers range over expressions instead of objects]

23 ideas
Contradiction arises from Frege's substitutional account of second-order quantification [Dummett on Frege]
     Full Idea: The contradiction in Frege's system is due to the presence of second-order quantification, ..and Frege's explanation of the second-order quantifier, unlike that which he provides for the first-order one, appears to be substitutional rather than objectual.
     From: comment on Gottlob Frege (Grundgesetze der Arithmetik 1 (Basic Laws) [1893], §25) by Michael Dummett - Frege philosophy of mathematics Ch.17
     A reaction: In Idea 9871 Dummett adds the further point that Frege lacks a clear notion of the domain of quantification. At this stage I don't fully understand this idea, but it is clearly of significance, so I will return to it.
The values of variables can't determine existence, because they are just expressions [Ryle, by Quine]
     Full Idea: Ryle objected somewhere to my dictum that 'to be is to be the value of a variable', arguing that the values of variables are expressions, and hence that my dictum repudiates all things except expressions.
     From: report of Gilbert Ryle (works [1950]) by Willard Quine - Reply to Professor Marcus p.183
     A reaction: I have a lot of sympathy with Ryle's view, and I associate it with the peculiar Millian view that we can somehow replace a name in a sentence with the actual physical object. Objects can't be parts of sentences - and maybe they can't be 'values'.
If quantification is all substitutional, there is no ontology [Quine]
     Full Idea: Ontology is meaningless for a theory whose only quantification is substitutionally construed.
     From: Willard Quine (Ontological Relativity [1968], p.64), quoted by Thomas Hofweber - Ontology and the Ambitions of Metaphysics 03.5.1 n18
     A reaction: Hofweber views it as none the worse for that, since clearly lots of quantification has no ontological commitment at all. But he says it is rightly called 'a nominalists attempt at a free lunch'.
You can't base quantification on substituting names for variables, if the irrationals cannot all be named [Quine]
     Full Idea: A customary argument against quantification based on substitution of names for variables refers to the theorem of set theory that irrational numbers cannot all be assigned integers. Although the integers can all be named, the irrationals therefore can't.
     From: Willard Quine (Philosophy of Logic [1970], Ch.6)
     A reaction: [He names Ruth Marcus as a source of substitutional quantification] This sounds like more than a mere 'argument' against substitutional quantification, but an actual disproof. Or maybe you just can't quantify once you run out of names.
Some quantifications could be false substitutionally and true objectually, because of nameless objects [Quine]
     Full Idea: An existential quantification could turn out false when substitutionally construed and true when objectually construed, because of there being objects of the purported kind but only nameless ones.
     From: Willard Quine (Philosophy of Logic [1970], Ch.6)
     A reaction: (Cf. Idea 9025) Some irrational numbers were his candidates for nameless objects, but as decimals they are infinite in length which seems unfair. I don't take even pi or root-2 to be objects in nature, so not naming irrationals doesn't bother me.
Either reference really matters, or we don't need to replace it with substitutions [Quine]
     Full Idea: When we reconstrue quantification in terms of substituted expressions rather than real values, we waive reference. ...but if reference matters, we cannot afford to waive it as a category; and if it does not, we do not need to.
     From: Willard Quine (Reply to Professor Marcus [1962], p.183)
     A reaction: An odd dilemma to pose. Presumably the substitution account is an attempt to explain how language actually works, without mentioning dubious direct ontological commitment in the quantifiers.
Quine thought substitutional quantification confused use and mention, but then saw its nominalist appeal [Quine, by Marcus (Barcan)]
     Full Idea: Quine at first regarded substitutional quantification as incoherent, behind which there lurked use-mention confusions, but has over the years, given his nominalist dispositions, come to notice its appeal.
     From: report of Willard Quine (works [1961]) by Ruth Barcan Marcus - Nominalism and Substitutional Quantifiers p.166
Maybe a substitutional semantics for quantification lends itself to nominalism [Marcus (Barcan)]
     Full Idea: It has been suggested that a substitutional semantics for quantification theory lends itself to nominalistic aims.
     From: Ruth Barcan Marcus (Nominalism and Substitutional Quantifiers [1978], p.161)
Substitutional language has no ontology, and is just a way of speaking [Marcus (Barcan)]
     Full Idea: Translation into a substitutional language does not force the ontology. It remains, literally, and until the case for reference can be made, a façon de parler. That is the way the nominalist would like to keep it.
     From: Ruth Barcan Marcus (Nominalism and Substitutional Quantifiers [1978], p.166)
A true universal sentence might be substitutionally refuted, by an unnamed denumerable object [Marcus (Barcan)]
     Full Idea: Critics say if there are nondenumerably many objects, then on the substitutional view there might be true universal sentences falsified by an unnamed object, and there must always be some such, for names are denumerable.
     From: Ruth Barcan Marcus (Nominalism and Substitutional Quantifiers [1978], p.167)
     A reaction: [See Quine 'Reply to Prof. Marcus' p.183] The problem seems to be that there would be names which are theoretically denumerable, but not nameable, and hence not available for substitution. Marcus rejects this, citing compactness.
Substitutional quantification is just a variant of Tarski's account [Wallace, by Baldwin]
     Full Idea: In a famous paper, Wallace argued that all interpretations of quantifiers (including the substitutional interpretation) are, in the end, variants of that proposed by Tarski (in 1936).
     From: report of Wallace, J (On the Frame of Reference [1970]) by Thomas Baldwin - Interpretations of Quantifiers
     A reaction: A significant-looking pointer. We must look elsewhere for Tarski's account, which will presumably subsume the objectual interpretation as well. The ontology of Tarski's account of truth is an enduring controversy.
The substitutional quantifier is not in competition with the standard interpretation [Kripke, by Marcus (Barcan)]
     Full Idea: Kripke proposes that the substitutional quantifier is not a replacement for, or in competition with, the standard interpretation.
     From: report of Saul A. Kripke (A Problem about Substitutional Quantification? [1976]) by Ruth Barcan Marcus - Nominalism and Substitutional Quantifiers p.165
Substitutional quantification is just standard if all objects in the domain have a name [Bostock]
     Full Idea: Substitutional quantification and quantification understood in the usual 'ontological' way will coincide when every object in the (ontological) domain has a name.
     From: David Bostock (Philosophy of Mathematics [2009], 7.3 n23)
Substitutional existential quantifier may explain the existence of linguistic entities [Parsons,C]
     Full Idea: I argue (against Quine) that the existential quantifier substitutionally interpreted has a genuine claim to express a concept of existence, which may give the best account of linguistic abstract entities such as propositions, attributes, and classes.
     From: Charles Parsons (A Plea for Substitutional Quantification [1971], p.156)
     A reaction: Intuitively I have my doubts about this, since the whole thing sounds like a verbal and conventional game, rather than anything with a proper ontology. Ruth Marcus and Quine disagree over this one.
On the substitutional interpretation, '(∃x) Fx' is true iff a closed term 't' makes Ft true [Parsons,C]
     Full Idea: For the substitutional interpretation of quantifiers, a sentence of the form '(∃x) Fx' is true iff there is some closed term 't' of the language such that 'Ft' is true. For the objectual interpretation some object x must exist such that Fx is true.
     From: Charles Parsons (A Plea for Substitutional Quantification [1971], p.156)
     A reaction: How could you decide if it was true for 't' if you didn't know what object 't' referred to?
We can quantify over fictions by quantifying for real over their names [Lewis]
     Full Idea: Substitutionalists simulate quantification over fictional characters by quantifying for real over fictional names.
     From: David Lewis (Noneism or Allism? [1990], p.159)
     A reaction: I would say that a fiction is a file of conceptual information, identified by a label. The label brings baggage with it, and there is no existence in the label.
Nominalists like substitutional quantification to avoid the metaphysics of objects [Jacquette]
     Full Idea: Some substitutional quantificationists in logic hope to avoid philosophical entanglements about the metaphysics of objects, ..and nominalists can find aid and comfort there.
     From: Dale Jacquette (Intro to III: Quantifiers [2002], p.143)
     A reaction: This has an appeal for me, particularly if it avoids abstract objects, but I don't see much problem with material objects, so we might as well have a view that admits those.
Substitutional universal quantification retains truth for substitution of terms of the same type [Jacquette]
     Full Idea: The substitutional interpretation says the universal quantifier is true just in case it remains true for all substitutions of terms of the same type as that of the universally bound variable.
     From: Dale Jacquette (Intro to III: Quantifiers [2002], p.143)
     A reaction: This doesn't seem to tell us how it gets started with being true.
Substitutional quantification is referential quantification over expressions [Fine,K]
     Full Idea: Substitutional quantification may be regarded as referential quantification over expressions.
     From: Kit Fine (Quine on Quantifying In [1990], p.124)
     A reaction: This is an illuminating gloss. Does such quantification involve some ontological commitment to expressions? I feel an infinite regress looming.
We might reduce ontology by using truth of sentences and terms, instead of using objects satisfying models [Shapiro]
     Full Idea: The main role of substitutional semantics is to reduce ontology. As an alternative to model-theoretic semantics for formal languages, the idea is to replace the 'satisfaction' relation of formulas (by objects) with the 'truth' of sentences (using terms).
     From: Stewart Shapiro (Foundations without Foundationalism [1991], 9.1.4)
     A reaction: I find this very appealing, and Ruth Barcan Marcus is the person to look at. My intuition is that logic should have no ontology at all, as it is just about how inference works, not about how things are. Shapiro offers a compromise.
Substitutional quantification is metaphysical neutral, and equivalent to a disjunction of instances [Williamson]
     Full Idea: If quantification into sentence position is substitutional, then it is metaphysically neutral. A substitutionally interpreted 'existential' quantification is semantically equivalent to the disjunction (possibly infinite) of its substitution instances.
     From: Timothy Williamson (Truthmakers and Converse Barcan Formula [1999], §2)
     A reaction: Is it not committed to the disjunction, just as the objectual reading commits to objects? Something must make the disjunction true. Or is it too verbal to be about reality?
The substitution view of quantification says a sentence is true when there is a substitution instance [Orenstein]
     Full Idea: The substitution view of quantification explains 'there-is-an-x-such-that x is a man' as true when it has a true substitution instance, as in the case of 'Socrates is a man', so the quantifier can be read as 'it is sometimes true that'.
     From: Alex Orenstein (W.V. Quine [2002], Ch.5)
     A reaction: The word 'true' crops up twice here. The alternative (existential-referential) view cites objects, so the substitution view is a more linguistic approach.
Quantification can't all be substitutional; some reference is obviously to objects [Hofweber]
     Full Idea: The view that all quantification is substitutional is not very plausible in general. Some uses of quantifiers clearly seem to have the function to make a claim about a domain of objects out there, no matter how they relate to the terms in our language.
     From: Thomas Hofweber (Inexpressible Properties and Propositions [2006], 2.1)
     A reaction: Robust realists like myself are hardly going to say that quantification is just an internal language game.