Summarizing where things presently stand then, the view I’m defending is a forms of commonsense, real essence functionalism which follows Lewis’s method for deriving functional definitions, except that it identifies mental properties themselves (to a first approximation) with the entities that Lewis takes to be the meanings of mental terms. I now want to turn to what is really the central issue of this chapter, the nature of the clauses that comprise the specifying psychological theory.
According to most standard functionalists, the clauses of the specifying theory will all be causal in nature. For instance, Sydney Shoemaker writes in setting out his view that
One starts off with a theory which incorporates propositions stating all of the causal facts about mental states – about their relations to inputs, outputs, and one another – in terms of which one proposes to define them. One then constructs the Ramsey Sentence of this theory . . .56
What one does next was described in the previous section; the point I’m calling attention to here is just that Shoemaker envisions the specifying psychological theory as being composed entirely of propositions stating causal facts about mental states. Call this view, that the clauses of the specifying theory are all causal in nature, causal functionalism. I take most standard functionalists to be causal functionalists like Shoemaker.57
In contrast to causal functionalism – perhaps – the view I will be defending in this work is that at least some of the clauses that comprise the specifying psychological theory are normative in nature, by which I mean that they ascribe properties that are uncontroversially normative to the subjects of mental states. The type of normativity at issue here is that specifically pertaining to rationality, both practical and theoretical.58 In the discussion that follows, however, I will generally leave this qualification implicit by speaking just of normativity.
It is along these lines that I will be understanding the (CRT). More specifically, I will take the (CRT) to be true just in case the psychological theory specifying the essences of mental states contains normative clauses. In defining the (CRT) in this way, I’ve abstracted away from my own commitment to commonsense, real essence functionalism. As I’ve put the (CRT), a psychofunctionalist or a nominal essence functionalist could accept it. Throughout the remainder of this work, however, I will generally take my commonsense, real essence functionalist perspective for granted. And so, for instance, I will drop the neutrality that comes with speaking of the specifying psychological theory, and instead just speak of folk psychology.
Let me now say a few things about the nature of the normative clauses I’m envisioning. I take folk psychology to contain a number of different types of normative clauses, ascribing a number of different sorts of normative properties to the subjects of mental states. For presentational purposes, I will restrict my attention here to two different types of clauses that involve rational obligations. This focus on obligation shouldn’t be regarded as a commitment to the view that obligation is in some sense the fundamental normative notion, or to the view that that all of folk psychology’s normative clauses involve obligations somehow. Clauses of the first type, which I will be calling obligation-imposing clauses, can be illustrated with examples like the following.
(OI): If a subject’s total evidence supports the proposition that P, then that subject ought to believe that P.
This clause counts as normative by the criterion provided above because it ascribes to subjects the property of being such that they ought not to do something, a property which is uncontroversially normative in nature.
Clauses of the second type, which I will be calling obligation-satisfying clauses, can be illustrated with examples like the following.
(OS): A subject who believes that P will believe many of the things that she ought to believe, given P – for instance, she will believe many of P’s logical consequences.
This clause counts as normative because it ascribes to subjects who believe that P the property of being such that they believe a number of the things they ought to believe given P, which again is uncontroversially normative.
Obligation-imposing clauses impose rational obligations on the subjects of mental states (hence the name), obligations which those subjects may then go on to meet or fail to meet. Such clauses entail nothing about how rational subjects actually are. They do entail that the subjects of mental states are appropriate targets for evaluation with respect to rationality, however. Imagine a subject who believes that ~P while possessing a mountain of evidence in favor of P and not a shred of evidence in favor of ~P. According to (OI) this subject has failed in a way. She does not believe what she ought to believe.
Obligation-satisfying clauses, by contrast, state that it is a condition on entering into a given mental state that subjects satisfy certain rational obligations (hence the name). So, for instance, if (OS) is true then it is a condition on a subject’s believing that P that she believe a number of P’s logical consequences. Subjects who don’t do this are, ipso facto, not believers of P. Obligation-satisfying clauses, then, do entail something about how rational subjects actually are. If (OS) is true, then there is a minimal threshold of rationality below which no believers of P fall.
Those philosophers most often associated with the idea that the mental realm is governed by constitutive principles of rationality – philosophers like Davidson, Lewis, and Daniel Dennett59 – typically focus on the claim that believers must meet certain standards of rationality. To whatever extent this claim provides a reason to accept the (CRT),60 it does so by providing a reason to hold that folk psychology contains obligation-satisfying clauses, not obligation-imposing clauses. Again, obligation-satisfying clauses entail that the subjects of mental states are in fact rational in certain ways, while obligation-imposing clauses do not.
Conversely, when critics object to the claims advanced by the philosophers in question, they don’t generally mean to be denying that the sorts of propositions expressed by obligation-imposing clauses are true, they mean to be denying only that the sorts of propositions expressed by obligation-satisfying clauses are true. For instance, such critics generally wouldn’t want to deny the truth of (OI). They often would want to deny the truth of (OS) though. Such critics often do want to claim that a subject can believe P without believing a good number of P’s logical consequences.
The point here, in short, is that obligation-satisfying clauses rather than obligation-imposing clauses seem to be the focus of most discussions of constitutive rationality and the mental. Again though, I take normative clauses of both sorts to be contained in folk psychology. Thus, when I turn to argue for the truth of the (CRT) in Chapter 3, I will appeal to considerations based on both sorts of clauses.