47 That is, the meaning of ‘water’—or at least one of its meanings—can be given by a (potentially infinite) description which uniquely identifies water across a range of possible scenarios considered as actual (Lewis 1984, 1994, Kroon 1987, Jackson 1998). The description is generated via a collec tion of properties (or sometimes: platitudes) that the speaker associates with their use of the term.
epistemic role to play as well, besides their role in guiding behaviour, but both kinds o f role are central to understanding what credences are. It is, I think, too much to expect any one representation theorem that it provide the whole story about what it is to have such-and-such credences and utilities— especially in light o f the fact that, as emphasised in §3.3.1, having credences and utilities is not simply a matter of having particular preference patterns. But where credences and utilities are to be understood and characterised in terms o f the roles that they play (or are supposed to play), something like (6) and (7) very plausibly form an important part o f what it is to have those attitudes.
Let us close by considering how this realist position relates to the naturalisation project. As I have explained it, a functional role semantics is not committed to nat- uralisability— although, as a matter o f fact, most functional role semanticists have adopted the position in their search for a fully naturalistic account of the attitudes. In the long run, the naturalistic functional role semanticist will want to cast every thing in terms o f external causal inputs and behavioural outputs, with all reference to intentional or otherwise mental phenomena having been Ramseyfied away (see Lewis 1970, 1972).48
To this end, however, a naturalistic functional role semantics for beliefs and de sires is but a twinkle in the eyes o f some philosophers. It is clear that the commonly noted functional roles for belief and desire are not cast in naturalistic terms: each of (1) to (5) refer to other intentional states, and it’s plausible that reference would need to be made to other mental states to spell out the ‘optimal conditions’ men tioned in (3) and (4). As is widely recognised, the causal properties o f any one men tal state will usually depend on the presence or absence o f a range o f other mental states, and no Ramseyfication can exist without a complete specification o f the rel evant causal role o f each o f the many interconnected mental states which interact
48 Not all philosophers who pursue a broadly functionalist approach wish to further the naturali sation project. Schwitzgebel (2002, 2013), for instance, explicitly opts to set aside naturalisation, and argues instead for what he calls liberal dispositionalism (see also Baker 1995). In outline, Schwitzgebel’s view is that beliefs are dispositions (or collections of dispositions), including dispo sitions to act in such a way as to tend to bring about what one desires a la the Belief-Desire Law. However, liberal dispositionalists allow for the characterisation of what it is for S to believe that P to be given partly in terms o f other propositional attitudes and mental states— including, potentially, other beliefs— while making no promises to eventually naturalise away any reference to those states.
to determine any one mental state’s causal properties. We are a long way from giv ing any such specification for beliefs and desires. At best we have just a rough idea o f how our beliefs and desires connect to behaviour and to the non-intentional world more generally.
Part o f the problem here is that a functional role semantics for belief and desires has no way o f working backwards from facts about behaviour to facts about our beliefs and desires. Appeal to the Belief-Desire Law just doesn’t allow us to con strain the possible assignments of beliefs and desires tightly enough. The promise of a solution to this problem accounts for much o f the appeal of characterisational representationism. Indeed, I suspect a great deal o f progress could be made towards a naturalistic, functionalist construal o f credences and utilities ifwe could prove a representation theorem o f the right kind, which took us from a typical subject’s behavioural preference system— characterised in purely naturalistic terms— to a unique and plausible assignment o f credences and utilities. The development of such a theorem would at least allow us to take steps towards a completely natural istic reduction o f credences and utilities.
Unfortunately, as will become clear in the chapters that follow, such a theorem has yet to be developed. Indeed, it does not appear that decision theorists have even come very close to developing a theorem appropriate for such purposes. We may, one day, have a representation theorem that is well-suited for advancing the natu ralisation project, but it will probably not look much like any o f the theorems which exist today. In particular, it will probably not involve preferences over act-functions or lotteries, for reasons to be discussed in Chapter 5 and Chapter 6. Act-functions and lotteries form the standard way o f characterising the basic objects o f preference in any representation theorem geared towards a behavioural interpretation o f >, but they also lead to the most worrying issues with those theorems with respect to their application to characterisational representationism. The more plausible option, given the theorems we currently have,would be to appeal to a theorem which spec
ifies conditions on mentalistic preferences (see §6.2 and §8.3)— or hold out hope for a new and better theorem. Either option, however, means putting the naturalisa tion project on hold, at least for a time.
O f course, to develop a functional role semantics with (6) and (7) characterised in terms o f mentalistic preferences is not incompatible with the naturalisation pro ject— it merely fails to clearly advance that project. (Compare: characterising be liefs in terms o f (1) to (4) does not entail that they cannot be naturalised, but neither does it immediately point the way to naturalisation.) Perhaps the naturalistic phi losopher could seek to characterise credences and utilities in terms o f mentalistic preferences, offering a promissory note to naturalise mentalistic preferences at some point down the line— after all, some such promissory note has been offered by every purportedly naturalistic account o f beliefs and desires yet developed.
I will have more to say on whether the naturalisation o f mentalistic preferences is feasible in Chapter 9; in the interim, the question is whether any current repre sentation theorem has the right properties to be a plausible foundation for charac- terisational representationism.
4.6 Summary
There were three main lessons drawn in Chapter 3. First, credences and utilities are not just preference states, nor does it appear that having any particular pattern o f preferences is sufficient for having such-and-such credences and utilities. Cre dences in particular play an epistemic role, and an adequate account o f what they are should accommodate this fact. Secondly, the proponent o f characterisational representationism ought to avoid theorems with preference conditions that ordinary agents do not come close to satisfying. And thirdly, she also ought to avoid theo rems with excessively restrictive representational resources.
An appeal to a theorem with the right properties would ensure that characterisa tional representationism stays in line with the final two o f these lessons. And, as we have now seen, there are several ways to cash out characterisational representation ism while keeping an agent’s system o f preferences metaphysically and conceptu ally distinct from her system o f credences and utilities, while taking into account the special epistemic role that credences are supposed to play. Psychological non realists aren’t committed to Classical Characterisational Representationism, as they might (like Lewis and other interpretivists) appeal to information which goes be-
yond agents’ preferences. The same, o f course, can be said for psychologically re alist versions o f characterisational representationism, which might (a) appeal only to the normative (rather than actual) roles that credences and utilities have in the production o f preference patterns, and/or (b) appeal also to other factors beyond agents’ preferences. With the right representation theorem, characterisational rep resentationism could avoid the main pitfalls that are notoriously associated with Naive, Extreme, and Classical Characterisational Representationism.
Moreover, the foregoing review gives strong reason to take the characterisational representationist’s approach seriously. We currently have no fully worked out ac count of beliefs and desires; instead, what we have is a number o f rough ideas much in need o f further development. A recurrent theme, though, is that we ought to be able to characterise the propositional attitudes by reference to what they do (or should do, or typically do, or do under certain conditions)— where one o f the most important things that beliefs and desires do involves their role in the explanation of preferences and intentional action. It would be difficult to understate the importance o f the Belief-Desire Law for most attempts to understand and characterise beliefs and desires. As we have seen, it is central to almost all varieties o f Basic Psycho logical Realism regarding those attitudes, where it’s used to characterise both be- lief-like and desire-like roles. It also forms a centrepiece for a functional role se mantics for beliefs and desires, and for each o f the two kinds o f psychological non realism that we looked at in §4.2.
When it comes to the metaphysics o f credences and utilities, it seems fair to expect that the decision-theoretic analogue o f the Belief-Desire Law— the principle o f expected utility maximisation (or something very close to it)— is likely to play just as central a role. While they might do other things besides, if credences and utilities do anything, they are closely connected to our preferences— and plausibly via something which looks roughly like expected utility maximisation. To have a theorem, then, which connects preference patterns to a very limited range o f plau sible credence and utility assignments, would seem a very useful resource for the precise functional characterisation o f those attitudes.
Ch a p t e r f i v e