Semantic Externalism

Jesper Kallestrup

• Publisher: Routledge
• Year: 2013
• ISBN:
  9781136819421
• Edition: 1
• Topic: Languages & Linguistics
• Subtopic: Linguistic Semantics
• Index: Languages & Linguistics

Semantic externalism is the view that the meanings of referring terms, and the contents of beliefs that are expressed by those terms, are not fully determined by factors internal to the speaker but are instead bound up with the environment.

The debate about semantic externalism is one of the most important but difficult topics in philosophy of mind and language, and has consequences for our understanding of the role of social institutions and the physical environment in constituting language and the mind. In this long-needed book, Jesper Kallestrup provides an invaluable map of the problem. Beginning with a thorough introduction to the theories of descriptivism and referentialism and the work of Frege and Kripke, Kallestrup moves on to analyse Putnam's Twin Earth argument, Burge's arthritis argument and Davidson's Swampman argument. He also discusses how semantic externalism is at the heart of important topics such as indexical thoughts, epistemological skepticism, self-knowledge, and mental causation.

Including chapter summaries, a glossary of terms, and an annotated guide to further reading, Semantic Externalism an ideal guide for students studying philosophy of language and philosophy of mind.

1

Descriptivism

1.1 Descriptivism Expounded

Some linguistic expressions serve the purpose of referring to objects outside of language. For instance, the proper names ‘David Cameron’, ‘West Port’ and ‘Edinburgh’ refer to the Prime Minister, my favourite pub and the Scottish capital city, respectively.¹ As these terms purport to pick out a single object, they are singular referring terms. Individuals, pubs and cities are concrete, tangible objects. Other singular referring terms pick out events or even abstract objects. Think of ‘Tour de France’ or ‘1 metre’. Definite descriptions of the form ‘the F’ might also naturally be thought of as singular referring devices. For instance, ‘the current US president’ picks out Barack Obama. In contrast, the general term ‘lemon’ refers to all and only fruit of the kind Citrus limon, and the general term ‘tiger’ refers to all and only cats of the kind Panthera tigris. As these terms purport to pick out more than one object, they are plural referring terms. Such terms have extensions, which are the sets of objects to which they correctly apply. Specifically, ‘lemon’ and ‘tiger’ are natural kind terms, which have as their extension all and only instances or members of an underlying physical, chemical or biological kind.² Such kinds are more or less mind-independent demarcations that group objects together at various levels of generality. For instance, my mother is a member of the increasingly more general natural kinds Homo sapiens, mammal and living creature. Arguably, if an object belongs to a natural kind, then such membership is an essential property of that object. My mother could undergo various changes pertaining to her physical appearance or psychological profile, but she could not possibly cease to be a human being. However, to use a metaphor, not all plural referring terms carve nature at her joints in the way natural kind terms do. Non-natural kind terms pick out instances of artefactual kinds. Thus ‘sofa’ picks out long upholstered seats with a back and arms, and ‘carburettor’ picks out any device that blends air and fuel for an internal combustion engine. In these cases, there are no common, underlying scientific kinds, e.g. some sofas are made of metal and wool, others of oak and leather. What matters for something to count as a sofa or a carburettor is not its physical constitution, but whether it fits the job description or plays a certain functional role characteristic of sofas or carburettors.

Having distinguished these kinds of referring terms, let us now turn to their semantics. When it comes to referring terms, semantics has to do with those aspects of meaning that are relevant for their reference. Frege (1964/1893) thought that every linguistic expression possessed a reference of a kind appropriate to its category. For instance, declarative sentences refer to their truth-values, which he called ‘the True’ and ‘the False’.³ That is to say, such sentences are sentential names of the abstract entities the True and the False. And Frege took predicates to refer to concepts, which on his view are functions whose value, for every object as argument, is a truth-value. There is no need to follow Frege here. Some types of linguistic expressions are intuitively not referential. Predicates have extensions, e.g. all red things fall within the extension of ‘being red’, and sentences have truth-values, e.g. ‘Ben Nevis is 1,344 metres’ is true. The semantics of predicates or sentences thus pertains to those aspects of meaning that are relevant for their extension or truth-value, respectively.

If we ignore Frege’s quirky terminology and instead take the most basic semantic value to be the truth-value of a sentence, then we can understand semantics as the theory of how the truth or falsity of a sentence is determined by the semantic values of the expressions that compose that sentence. In other words, the semantic value of an expression consists in the contribution it makes to the truth or falsity of a sentence in which it occurs. The semantic value of a singular referring term is naturally identified with its reference, and the semantic value of a predicate is naturally identified with its extension.

What then does reference consist in? Reference is a unique relation between a singular or general term and one or more extralinguistic objects. Reference is the most direct way for language to latch onto reality. Indeed the reference of a complex expression is determined by the reference of its constituents and their mode of composition. Reference is subject to the following compositionality principle:

(ComRef)

The truth-value of a sentence is determined by the reference (or semantic value) of its component parts and the way in which they are combined.

The last clause is important since it matters how the very same component parts are conjoined. The sentence ‘Thomas hit James’ may be true, while the sentence ‘James hit Thomas’ is false. It follows from (ComRef) that the truth-value of a sentence will remain invariant if co-referential component terms are substituted while everything else stays the same. Terms that have the same reference are interchangeable without change in truth-value. For instance, since the sentence ‘Bono is the lead singer of U2’ is true, and Bono also goes under the name ‘Paul David Hewson’, the sentence ‘Paul David Hewson is the lead singer of U2’ is guaranteed also to be true. Here is a substitution principle for reference:

(SubRef)

If the sentence ‘a is F’ is true and a = b, then the sentence ‘b is F’ is also true.

We can say that reference is a property that a term possesses only if it can be used in certain sentences that have a truth-value. To use Frege’s example, given that the positive, non-fictive sentence ‘William Tell shot an apple off his son’s head’ lacks a truth-value, the term ‘William Tell’ lacks a reference. Of course predicates can also be used in sentences that have a truth-value, e.g. ‘is red’ as in the false sentence ‘Buckingham Palace is red’. If we wish to depart from Frege’s framework when it comes to predicates, the fact that a term can be used in a sentence that has a truth-value should not be sufficient for it to count as possessing a reference.

What then is the meaning of a referring term? By ‘meaning’ we mean the semantic content of a term, i.e. that aspect of its overarching meaning which is relevant for determining the referent, if any, of that term. Meaning is what determines reference. Some aspects of this broader notion of meaning are semantically irrelevant in this way. The name ‘Bono’ might give rise to attitudes of artistic approval which are absent in the case of ‘Paul David Hewson’. One historically influential view is descriptivism, which has been defended in various versions by Russell (1994/1905), Strawson (1950), Searle (1958), Dummett (1978: Ch. 9), Kroon (1987), Lewis (1972, 1984, 1997), Jackson (1998a, 2004) and others; indeed its roots can be traced back to Frege (1994a/1892). The idea is that the meaning of a referring term is descriptive in nature. More precisely, the meaning of a referring term ‘a’ is given by a set of definite descriptions: ‘the F’, ‘the G’, ‘the H’, etc. For instance, the meaning of ‘Aristotle’ is something like: the famous philosopher of antiquity, the teacher of Alexander the Great, the author of Nicomachean Ethics, etc. According to descriptivism, the descriptive content of a referring term ‘a’ plays two distinct roles: it is what a competent speaker S knows when she understands ‘a’, and it is what determines the reference of ‘a’. Descriptivism is both a theory of meaning and a theory of reference. On the face of it, this view seems to blur the distinction between the first-order question of what the meaning and reference of a term is from the second-order question of what makes it the case that a term has the meaning and reference that it does. To use Stalnaker’s terminology (1997: 535–38), the first-order question is answered by a descriptive semantics, and the second-order question is answered by a foundational semantics. In taking descriptive content to be the meaning of a referring term and also to be what makes that term have the reference it has, it looks as if the question ‘what is the semantics for the term?’ is conflated with the question ‘what makes it the case that that term in our language has this semantics?’ However, descriptivists such as Jackson (1998a) by no means reject that distinction. They only insist that descriptive content can play a role in answering both questions.

Let’s begin with the theory of meaning. When S understands the proper name ‘Aristotle’, she knows its meaning. That name is synonymous with the descriptions ‘the famous philosopher of antiquity’, ‘the teacher of Alexander the Great’, ‘the author of Nicomachean Ethics’, etc., and so those are what S knows in virtue of understanding the name. That is to say, S understands the name ‘Aristotle’ if and only if S knows that Aristotle was the famous philosopher of antiquity who taught Alexander the Great and wrote Nicomachean Ethics. And the kind of knowledge S has is a priori – knowledge that is independent of any empirical evidence. If S is competent with ‘Aristotle’, then she knows a priori that, say, Aristotle taught Alexander the Great. The speaker S could not grasp the meaning of ‘Aristotle’ while it is an open question for S whether Aristotle taught Alexander the Great. For what makes the name have the meaning it has is the fact that competent speakers mentally associate these descriptions with it. And if grasping the meaning of ‘Aristotle’ involves associating the description ‘the teacher of Alexander the Great’ with that name, understanding the name suffices for knowing that Aristotle is the teacher of Alexander the Great. In short, following descriptivism, meaning is fully determined by competent speakers’ mental associations. On this view, meaning is firmly in the mind of competent speakers.

But descriptivism is also a theory of reference in that descriptive content is what determines reference: a particular object is the referent of a referring term if and only if that object satisfies all the associated descriptions. These individually necessary and jointly sufficient descriptions express descriptive properties, e.g. ‘the famous philosopher of antiquity’ expresses the property of being the famous philosopher of antiquity.⁴ So, put differently, what determines whether an object is the referent of a term is whether that object instantiates all those descriptive properties, e.g. what determines whether someone is the referent of ‘Aristotle’ is whether he was the famous philosopher of antiquity, taught Alexander the Great, authored Nicomachean Ethics, etc. Assuming a definite description ‘the F’ is an expression that refers to a unique object, if no object at all is F, or if two or more objects are F, then ‘the F’ fails to refer. This poses a problem about uniqueness for descriptivism. As Plato was also a famous philosopher of antiquity, there is no single famous philosopher of antiquity. But on this view ‘Aristotle’ refers to an object just in case it uniquely satisfies all these descriptions, including ‘the famous philosopher of antiquity’. So, it looks like ‘Aristotle’ turns out to lack a reference. One solution is to think of the set of definite descriptions as a cluster in the sense that ‘Aristotle’ refers to an object just in case it satisfies most of these descriptions. That way ‘Aristotle’ will refer to Aristotle even if one of the associated definite descriptions fails to uniquely pick out Aristotle, or even if one such description uniquely picks out someone else. This cluster version of descriptivism was invented by Searle (1958), but has subsequently been developed by Lewis (1972, 1984) who took the cluster to comprise a disjunction of conjunctions of most of the descriptions. So, to simplify matters, suppose the three descriptions ‘the F’, ‘the G’ and ‘the H’ constitute the cluster assigned to the name ‘a’. Then an object is the referent of ‘a’ just in case that object satisfies either ‘the F’ and ‘the G’, or ‘the F’ and ‘the H’, or ‘the G’ and ‘the H’.

We have so far been using proper names as examples, but descriptivism is also a view about general terms. Take the natural kind term ‘water’. On this view, the meaning of ‘water’ consists in descriptive content which is both what competent speakers know when they understand the term and what determines its reference. The term ‘water’ is synonymous with a definite description of the form: ‘the clear, potable, tasteless liquid that fills the oceans and falls from the sky, etc.’ In the following ‘the watery stuff’ will be used instead as an abbreviation, where ‘watery’ captures all these superficial, readily observable properties of water. So, a competent speaker S understands ‘water’ if and only if she knows that water is the watery stuff. As S is associating this complex description with ‘water’, she can know a priori that water has these watery properties. Moreover, following descriptivism, ‘water’ will pick out anything that satisfies ‘the watery stuff’, or at least anything satisfying enough of the descriptions encapsulated by that phrase. In other words, anything instantiating all or enough of the descriptive properties expressed by these descriptions will be picked out by ‘water’, and so count as water. For example, on Earth H₂O satisfies most if not all of these descriptions, and so H₂O is what the inhabitants on Earth refer to when they use ‘water’ in various sentences.

1.2 The Identity Argument

In Section 1.1 we presented descriptivism but adduced nothing in its support. In Sections 1.2 and 1.3 we present arguments that supposedly buttress the descriptivist outlook. Why do we need meaning over and above reference, and in particular why do we need descriptive content? Can we not just identify meaning with what we in Section 1.1 called ‘semantic value’? In particular, what’s wrong with Mill’s view (1963/1843) that the meaning of a referring term is nothing but its reference? In Frege’s famous article (1994a/1892) “On Sense and Reference”, he made a crucial distinction between sense (German ‘Sinn’) and reference (German ‘Bedeutung’). Frege thought that unless referring terms were associated with distinct senses, we could not explain what it is that a speaker S knows when she competently understands these terms. In contrast, according to referentialism, meaning is nothing over and above reference.⁵ On this view, to know the meaning of a referring term is to know its reference. In this work (1994a/ 1892) Frege advanced his identity argument, which is targeted at referentialism. It aims to show that to know the reference of a term is to know more than is involved in knowing its sense. The identity argument is presented as a challenge to explain how true identity statements can be informative. Consider:

1. (1) Hesperus is Hesperus.
2. (2) Hesperus is Phosphorus.⁶

The propositions expressed by the sentences in (1) and (2) intuitively differ in how informative they are. Propositions, remember, are the semantic contents that sentences express. While (1) is trivial, (2) is an interesting piece of information. It is perfectly possible for a rational speaker to grasp both proposition...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright
• Dedication
• Contents
• Acknowledgements
• Introduction
• Chapter 1. Descriptivism
• Chapter 2. Referentialism
• Chapter 3. From language to thought
• Chapter 4. Varieties of narrow and wide content
• Chapter 5. Self-knowledge
• Chapter 6. Scepticism
• Chapter 7. Mental causation
• Glossary
• Notes
• Bibliography
• Index