The problem of meaning

Let us start by considering the two main theories of the meaning of mental states in contemporary philosophy of mind. The first is commonsense (or analytic) functionalism6. Historically, this account descends from logical behaviourism and dispositionalism. According to the former doctrine, mental states have a purely behaviourist meaning. For instance, preferences mean nothing but choice behaviour. Instead, according to the latter doctrine, mental states are conceived as dispositions towards some behavioural output. For instance, according to a narrow dispositional account, the meaning of preference is that of a disposition towards choice behaviour. On the other hand, according to a broad dispositional account, the meaning of preference is that of a disposition not only towards choice behaviour, but also towards other behavioural expressions.

As philosophers of mind have recognised long time ago, both accounts face some problems. Let us consider dispositionalism as a paradigmatic example. According to this doctrine, when we say that an individual prefers taking the umbrella rather than not taking it, we mean that the individual has a disposition to perform an action of the relevant type in suitable circumstances. However, this is the case only provided that we also assume that the individual’s other relevant mental states remain the same. Indeed, when we say that an individual prefers taking the umbrella rather than not taking it, we would not mean that the individual has a disposition to perform the relevant action if we also thought that the individual believes that such an object is a baseball bat.

The lesson is that the meaning of mental states cannot be defined independently from other mental states. Thus, some philosophers of mind have recommended the adoption of a different, functionalist, account of the meaning of mental states. Such an account takes into consideration the interdependencies between different mental states, while, at the same time, preserving a moderate behaviourist account of their meaning. More precisely, according to functionalism, the meaning of a mental state is given by the set of causal laws in which that mental state figures. Such causal laws specify how each mental state is related to environmental inputs, other mental states and behavioural outputs. The meaning of a mental state is then entirely exhausted by the causal relations in which it figures7. It may be the case that the agent employing mental concepts is incapable of specifying all these constitutive causal relations. Indeed, this may require a sophisticated analysis. If we think of the defining causal relations as forming a theory that the agent possesses, then we can say that such a theory operates tacitly, or, equivalently, that the theory is tacit.

There are at least two reasons to be interested in the prospects that functionalism offers for solving the problem of IUCs. First, functionalism has been the dominant view of the meaning of mental states, in philosophy of mind, for the past thirty years. Recently, attempts have been made to characterise preferences as well in functionalist terms8. It is natural to ask how this affects the traditional debate about IUCs. Second, since the origin of decision theory, beliefs and degrees of belief have been typically given a functionalist understanding9. Thus, conceiving preferences and degrees of preference along the same line is a way of maintaining a consistent understanding of the meaning of mental states.

Preferences can be defined in functionalist terms as mental states that are causally related to certain inputs, and that, in combination with other mental states, produce certain behavioural outputs10. What are these causal relations? According to some authors, decision theory is the research area that attempts to specify some of the relevant relations11. In particular, decision theory conceives preferences as mental states that lead

7 Thus, the functionalist theory of the meaning o f mental states goes beyond the dispositional theory in one crucial respect: it includes the relationship with environmental inputs and with other mental states as part o f the definition o f a mental term, in addition with its relationship with behavioural outputs.

See Pe t t it, P. [2006].

9 See Ra m sey, F. P. [1990].

10 The relation that preferences have with both inputs and outputs may turn out to be indirect, that is, mediated by other mental states that are connected to preferences.

to choices, in combination with beliefs and desires12. If we define preferences in functionalist terms, the property of preferential strength can be seen as a causal property of preferences. In other words, preference strength is the causally efficacious property that leads an individual to behave in a certain way, when subject to specific circumstances and in the presence of other mental states.

Functionalism is not unchallenged13. For instance, Goldman discusses three general difficulties that a functionalist account faces14. First, functionalism has trouble in specifying the laws in which mental states are supposedly embedded. The fact that even the “experts”, e.g. philosophers and social scientists, have poor explicit knowledge of the causal relations that define mental terms seems to cast doubt on whether ordinary people’s understanding of mental concepts is governed by knowledge, even if implicit, of functional laws.

Second, functionalism seems to be unable to capture the qualitative features of some of, or perhaps all, our mental states. Consider the ‘inverted spectrum’ problem. Two individuals may be functionally identical and yet they may have radically different subjective mental experiences. For instance, although functionally identical, they may have colour experiences that lie at the opposite poles of the colour spectrum. If this is a genuine possibility, it appears that functionalism sanctions the use of identical mental terms for mental states that are drastically different, because of its inability to register qualitative differences between mental states.

Third, functionalism does not seem to offer a plausible account of self-ascription of mental states. In order for an individual to classify one of his own mental states as, for instance, a headache, functionalism requires that he be able to identify the causes of such a headache, the relationship with other, both occurrent and non-occurrent, mental states and the behavioural headache expressions. This seems to burden self-ascription with excessive computational requirements. At least phenomenologically, it seems plausible that the individual can identify a mental state of his as a headache without undergoing this complex series of computations.

12 Roughly speaking, there are three possible ways to conceive the relationship between desires and preferences. First, one can be eliminativist about preferences and claim that the notion o f preferences is syncategoramatic. It is simply a way to conveniently describe an individual’s desires and their relations. However, there are no real mental states corresponding to preferences. Second, one can be reductivist and claim that preferences are real mental states but mental states that reduce to desires in one sense or another, e.g. they constitute a specific, e.g. relational, class o f desires. Finally, one can maintain that preferences are derivative on desires, in the sense that they are related to, and determined by, them; but they do not reduce to desires, except in the loose sense that they are both pro-attitudes o f some sort. I think that the functionalist position fits more comfortably with the latter position, which I shall thereby adopt in what follows.

13 The locus classicus for a critique o f functionalism is BLOCK, N. [1980],

In opposition to functionalism, Goldman recommends the adoption of an experientialist theory of the meaning of mental states. According to it, the meaning of a mental state is given by the more or less conscious experiences that the subject has of it15. An equivalent definition is that the meaning of a mental state is given by the agent’s experience of ‘what it is like’ to have that mental state. Thus, according to this account, mental states are phenomenologically real and the agent has introspective - privileged, although not infallible - access to them. Likewise, the strength of a mental state is a real psychic magnitude, which the subject experiences and can introspectively discriminate.

Preferences can be defined in experientialist terms as mental states that give raise to certain experiences in a subject. It may be the case that there is no unique phenomenal experience that different individuals have in common when they are in a preference- state. However, it is enough that there is a family of experiences that are sufficiently similar to constitute a preference-type. According to an experientialist understanding, then, preference strength is a felt property, a qualitative experience of the individual that has preferences. The subject has introspective access and can discriminate the strengths of his preferences. As such, the meaning of preference strength arises “from points or intervals on the experiential scale” 16 that the term denotes.

There is at least one direct reason to be interested in experientialism for the problem of IUCs, together with the indirect reasons provided by the limits of functionalism. According to Goldman, experientialism offers a better account of what people means when they make ICs of preferences than functionalism and, ultimately, promises a solution to the problem of IUCs in combination with an ST account of mindreading.