2. Linguistics and Science
For the purposes of this article one can make a distinction between two methods of constructing a scientific theory of language: an externalist approach and an internalist approach. The classic arguments for externalism are found in Putnam (1975), Burge (1979), and Kripke (1980)[6]
. The main externalist claim is that mental states are individuated by reference to environmental features or social contexts, and therefore in order for a person to have intentional mental states they must be related to the environment in the right way. Externalism entails that if two individuals are physically identical their respective utterances of, say, water, can still have different meanings if the relevant features of their environment are different.
Externalism has become a widely held position that is especially popular within the philosophies of mind and language. Indeed, some feel that “externalism has been so successful that the primary focus of today’s debate is not so much on whether externalism is right or wrong, but rather on what its implications are” (Wikforss, 2008, p. 158), and that “Over the past 30 years much of the philosophical community has become persuaded of the truth of content externalism“ (Majors & Sawyer, 2005, p. 257). Externalism has thus become “almost an orthodoxy in the philosophy of mind” (Farkas, 2003, p. 187).
Internalism, on the other hand, holds that, for the purposes of scientific inquiry into language, the internal properties of the human mind are the relevant and fruitful subject matter of scientific research. Internalism (more specifically, Chomskyan internalism) has thus recast the notion of language qua social phenomenon or abstract object into a form that is susceptible to empirical scientific inquiry. Hinzen provides the following succinct definition of Chomskyan internalism:
Internalism is an explanatory strategy that makes the internal structure and constitution of the organism a basis for the investigation of its external function and the ways in which it is embedded in an environment. (2006, p. 139)
Internalism thus studies the internal structure and mechanisms of an organism; the external environment comes into the picture when the internal processes are ascribed content by the theorist, thus explaining how the internal mechanisms constitute a cognitive process in a particular environment. Such content ascriptions vary with the theorist’s interests and aims, but the (ascription of) content is not an essential part of the internalist theory itself (cf. Egan, 1995).
I discuss below the scientific claims and merits of externalism and Chomskyan internalism and the consequences that the creative aspect of language use has in regard to each qua scientific theory. I argue that whatever merits externalism may possess and despite its popularity, it is unable to provide a fruitful framework for a scientific theory of language. One might object that externalists do not see their enterprise as scientific and thus it is a moot point to compare it to other scientific pursuits. However, as I show below, there are externalists (Putnam, Davidson, Horwich, Fodor, Burge, et. al.) who explicitly state that their theory is a scientific one. Thus, since both externalists and Chomskyan internalists claim their theories to be scientific, it is possible and illuminating to compare the two from the perspective of scientific explanatory strategies and to ask which of the two is the most promising avenue in regard to constructing an explanatory scientific theory of language.
In other words, while it is true that externalists discuss their theories in terms of the determination of mental content, this does not preclude assessing their theories from the point of view of explanatory scientific strategy. As is the case with Chomskyan internalists, externalists attempt to explain the phenomena of language production and comprehension, and thus it is valid to assess the success of these explanations and compare them to competing theories that also try to explain the same phenomena. That is, substantive theoretical or philosophical differences are necessarily also ones of explanatory strategy. Since the aim of science is to construct theories that explain and predict phenomena, it is valid for one to compare these two approaches that claim to be scientific from the point of view of explanatory strategies.
2.1. Internalism, Externalism, and Science
Debates about the scientific status of linguistic theories are of course nothing new. Robert Lees’s 1957 review of Chomsky (1957) argues that it was one of the first serious attempts at linguistic science “which may be understood in the same sense that a chemical, biological theory is ordinarily understood by experts in those fields” (Lees, 1957, p. 377). Lees is one of the first in a long tradition that has supported the scientific claims of generative linguistics. Recently, John Collins remarked that “the greatest service Chomsky has provided for philosophy is to do philosophy of science via the construction of a new science” (2008, p. 25)[7]
. McGilvray argues in regard to the “cognitive aspect of the faculty of language, or the computational system itself” that “there is a serious scientific enterprise devoted to its investigation, and with respect to capturing its structure, at least, there has been considerable progress” (1998, p. 238). Moreover, he says that he is “perfectly happy to say that the various branches of syntax are physical sciences, even if they are sciences of what is in the head, for all that “physical” means is that one has an honest science” (Ibid., p. 243).
Another example is Alec Marantz, who states that mainstream generative linguistics “operates at the nexus of computation, philosophy of language, and cognitive neuroscience” (2005, p. 431). Boeckx & Piattelli-Palmarini write that “The Chomskyan revolution in linguistics in the 1950s in essence turned linguistics into a branch of cognitive science (and ultimately biology) by both changing the linguistic landscape and forcing a radical change in cognitive science to accommodate linguistics […]”, and thus they “are persuaded, on solid grounds we think, that in the past 50 years [generative] linguistics has progressively established itself as a genuinely scientific discipline” (2005, p. 447).
How should one assess these claims? What definition or methodology of science can one appeal to in order to argue for or against the scientific status of a theory of language? Lees hints at a key distinguishing factor that can identify good science: an axiomatic system and an overarching explanatory theory. He compares Chomsky’s approach to studying language to the development of chemistry: it was only after Lavoisier’s work in the late eighteenth century that chemistry developed from its beginnings in alchemy to a scientific discipline.
Lavoisier’s work allowed chemistry to achieve its scientific status by pushing the discipline to concern itself not so much with the correctness of its postulates - though that is of course essential - but with explanatory theory construction.
The postulation of an overarching explanatory theory and an accompanying axiomatic system, though necessary, is not sufficient to distinguish a fecund and deeply explanatory science from one that is not. Chomskyan internalism proposes an explanatory theory, but, arguably, so does externalism: Putnam remarks that “a better philosophy and a better science of language” must encompass the “social dimension of cognition” and the “contribution of the environment, other people, and the world” to semantics (Putnam, 1975, p. 193, my emphasis). Horwich (2001, p. 371) argues that Davidson’s externalist truth-theoretic program “became widely accepted, instigating several decades of “normal science” in semantics.” Davidson himself is somewhat ambivalent, but still holds that “my own approach to the description, analysis (in a rough sense), and explanation of thought, language, and action has […] what I take to be some of the characteristics of a science” (1995, p. 123). Burge (2003, p. 465) remarks that he sees no reason why formal semantics, which postulates “reference, or a technical analogue, as a relation between linguistic representations and real aspects of the world, should not be an area of fruitful systematic scientific investigation.”
So apart from the construction of a self-consistent explanatory theory, which both externalism and internalism arguably have, what can distinguish the two in regard to their scientific credentials? I propose that the distinguishing criterion should be the subject matter of their theories. It is not enough to have an explanatorily self-consistent theory: your theory must also explain a scientifically tractable aspect of the world. In other words, if your theory fails to divide nature at the joints, then no improvement of its methodology or its explanations will matter. Moreover, observations of the creative aspect of language use imply that if one takes language use as the subject matter of one’s theory, as externalists do, then such a theory is unlikely to yield a deeply explanatory science. Before I offer an argument for this, a few remarks of clarification are in order.
2.2. Internalism versus Individualism
Putnam constructs various thought experiments to argue for the externalist claim that the individuation of meanings is impossible if one only considers thinkers in isolation, and thus a semantic theory must consider the person’s interaction with the environment and with other language users. The Twin Earth thought experiment is the most famous, but there are others that make the same point. One of which concerns the difference between an elm tree and a beech tree. Putnam claims to have the same concept for both elm trees and beech trees because, unlike botanists, he cannot tell them apart. But Putnam claims that “elm” and “beech” nevertheless have different meanings when he utters them. This is so even though, ex hypothesi, his mind-internal phenomena are identical whenever he utters “elm” or “beech”. Therefore, according to Putnam, considering the mind-external environment - the expert botanists, in this case - is the only way to discern the meaning of his utterance of “elm” or “beech”. He argues that one’s “individual psychological state certainly does not fix its extension; it is only the sociolinguistic state of the collective linguistic body to which the speaker belongs that fixes the extension” (1975, p. 146, emphasis in original).
It is hard to argue with such a claim; of course one can only discern what a person’s utterance refers to by consulting the external environment. In order to determine the extension of Putnam’s utterance of either “elm” or “beech” one must consult not only Putnam’s mind-internal states and knowledge but also the knowledge of an expert who can distinguish between an elm and a beech, as well as the environment in which the utterance was produced. Be that as it may, however, the question arises as to the relation between such a search for individuation conditions and a science of language. That is, what is the relation, if any, between the search for the conditions under which one is justified in ascribing a particular meaning to an utterance, and a science of language that seeks to explain how linguistic utterances are produced and comprehended? I argue that studying the mechanisms in the mind by which meaning is made possible is one enterprise, the ascription of meaning to particular utterances another[8]
.
Millikan (2004, p. 227) concurs when she says in regard to Putnam’s argument that if “we explain the externalist idea in this crude way […] it becomes hard to see how anyone could deny it.” That is, “If the question were, merely, how are the referents or extensions of thoughts determined, it seems patently obvious that nothing inside someone’s head could, by itself, determine that anything in particular existed outside the head.” Millikan says that externalism so defined should not be so obviously true, but instead of turning against externalism she clings to it. But her remedy does not help and in fact complicates the matter further. Her externalist theory defines “inner representations by the way they function, not just in the head, but as parts of much larger systems that include portions of the environment” (Ibid., p. 229). The functions of the inner representations, on Millikan’s account, were selected by natural selection in the course of the organism interacting with its environment in a “Normal” way. Thus, it is “this reference to a certain kind of history of selection and/or development that adds the radically externalist twist to this theory of mental representation” (Ibid.).
Millikan believes that mental representations can only be individuated by reference to their function, and thus she argues that we must adopt an externalist and evolutionary stance to individuation because “What a thing was designed to do is not always evident just from its inner function, even from its inner function plus the structure of its current environment” (Ibid.)[9]
She remarks that “whether an inner happening or structure is a representation is not merely a matter of its inner structure.” But the question again arises as to whether this claim is relevant to scientific theories of meaning or mental representations that attempt to discover the mechanisms by which language production and comprehension are possible? Externalists claim that the criteria of the ascription of meaning or of function belong in a scientific theory of language, but I argue below that this will not yield a fruitful science.
As a final remark, it should be noted that Chomskyan internalism is compatible with the view that the individuation of meanings is impossible without considering the environmental context of an utterance. If the aim of your theory is to discover the conditions under which an outside observer can make a correct judgement as to the meaning of a specific utterance (relative to the way the meaning is used within the linguistic community of the speaker), then of course such a theory must include within its domain the environment outside the head. But such a claim has little to do with a scientific theory of meaning. The externalist claim that it does follows from their glossing over an important distinction between the theory itself and the way in which the theorist uses and interprets the theory to achieve certain explanatory goals (cf. Egan, 1995; 1999; 2003). This ambiguity is evident in remarks such as Ben-Menahem’s (2005), who notes in regard to one of Putnam’s examples that “to speak of coffee tables it does not suffice for us merely to have the concept of a coffee table, but we must be in contact with actual coffee tables” (p. 10, emphasis in original). In other words, there’s an ambiguity between a theory that explains our ability to have the concept of, say, a coffee table, and a theory that purports to explain how it is that we use this concept to talk about actual coffee tables. Or, more generally, the difference is between a theory of the mechanisms in virtue of which language production and comprehension is made possible, and a theory of the use of those mechanisms in, say, social interaction. When externalists claim that a science of language must encompass the social dimension of linguistic behaviour, it is not clear whether the claim is that this aspect of linguistic behaviour must be included within the scope of the theory itself, or whether this aspect can be connected to the theory by what Egan calls the theory’s interpretation function. This distinction is important, for failure to adhere to it results in a defective explanatory theory.