http://plato.stanford.edu/entries/mental-representation/#6 Stanford Encyclopedia of Philosophy version history last substantive A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X content change HOW TO CITE | Y | Z DEC THIS 18 ENTRY 2002 This document uses XHTML-1/Unicode to format the display. Older browsers and/or operating systems may not display the formatting correctly. Mental Representation If a representation is an object with semantic properties, then a mental representation is a mental object with semantic properties. According to the Representational Theory of Mind (RTM), psychological states are to be understood as relations between agents and mental representations: for an agent to be in a psychological state Ψ with semantic property Φ is for that agent to be in a Ψ-appropriate relation to a mental representation of an appropriate kind with semantic property Φ. Historically, RTM (which goes back at least to Aristotle) is a theory of commonsense psychological states, such as belief, desire (the propositional attitudes), and perception. According to RTM, to believe that p, for example, is, in part, to bear the belief-relation (whatever that may be) to a mental representation that means that p. To perceive that a is Φ is, in part (propositional attitudes may also be involved), to have a sensory experience of some kind which is appropriately related (however that may be) to a’s being Φ. The leading contemporary version of RTM, the Computational Theory of Mind (CTM), makes the further claims that the brain is a kind of computer and that mental processes are computations on mental representations. According to CTM, cognitive states are constituted by computational relations to mental representations of various kinds, and cognitive processes are rule-governed sequences of such states. CTM develops RTM by attempting to explain all psychological states and processes in terms of mental representation. In the course of constructing detailed empirical theories of human and animal cognition and developing models of cognitive processes implementable in artificial information processing systems, cognitive scientists have proposed a variety of types mental representations. While some of these may be suited to be mental relata of commonsense psychological states, some — so-called “subpersonal” or “sub-doxastic” representations — are not. Though many philosophers believe that CTM stands to provide the best scientific explanations of cognition and behavior, there is disagreement over whether or not such explanations will vindicate the commonsense psychological explanations (and representations) of prescientific RTM. Mental representation has also been of interest to philosophers who hold that the semantic properties of expressions of natural language (and many non-linguistic symbols as well) are inherited from the mental states of their users. For these theorists, RTM is a component of a complete theory of linguistic meaning. l 1. Propositional Attitudes l 2. Computation and Cognition l 3. Content Determination l 4. Internalism and Externalism l 5. Phenomenal and Non-phenomenal Representation l 6. Imagery l 7. Thought and Language l Bibliography l Other Internet Resources l Related Entries http://plato.stanford.edu/entries/mental-representation/#6 1. Propositional Attitudes Intentional Realists such as Dretske (1988) and Fodor (1987) argue that explanations and predictions of human behavior must quantify over inner states that are both causally efficacious and contentful, and have their causal powers (their causal roles) in virtue of having the content they do (i.e., the generalizations that describe the interaction of such states apply to them in virtue of their content: the desire that q and the belief that not q unless q cause (ceteris paribus) the desire that q, for example, because they are the desire that q and the belief that not q unless p). The generalizations we apply in everyday life in explaining others’ behavior (often collectively referred to as “folk psychology”) are both remarkably successful and indispensable. What a person believes, doubts, desires, fears, etc. is a highly reliable indicator of what he will do; and we have no other way of making sense of his behavior than by ascribing such states to him and applying the relevant generalizations. We are thus committed to the generalizations of commonsense psychology and, hence, to the existence of the states they quantify over. Such states, the propositional attitudes, are individuated by their contents and their characteristic psychological roles: they are relations to mental representations. Some realists (such as Fodor) also hold that commonsense psychology will be vindicated by cognitive science, given that propositional attitudes can be construed as computational relations to mental representations. Intentional Eliminativists, such as Churchland, Stich and (perhaps) Dennett argue that no such things as propositional attitudes (and their implicated representational states) are necessary to the explanation of our mental lives and behavior. Churchland denies that the generalizations of commonsense propositional-attitude psychology are true. He (1981) argues that folk psychology is a theory of the mind with a long history of failure and decline, and that it resists incorporation into the framework of modern scientific theories (including cognitive psychology). As such, it is comparable to alchemy and phlogiston theory, and ought to suffer a comparable fate. Commonsense psychology is false, and the states (and representations) it quantifies over simply don’t exist. (It should be noted that Churchland is not an eliminativist about representation tout court. See, e.g., Churchland 1989.) Dennett (1987a) grants that the generalizations of commonsense psychology are true and indispensable, but denies that this is sufficient reason to believe in the entities they seem to quantify over. He argues that to give an intentional explanation of a system’s behavior is merely to adopt the “intentional stance” toward it. If the strategy of assigning contentful states to a system and predicting and explaining its behavior (on the assumption that it is rational — i.e., that it behaves as it should, given the propositional attitudes it should have in its environment) is successful, then the system is intentional, and the propositional-attitude generalizations we apply to it are true. But there is nothing more to having a propositional attitude than this. (See Dennett 1987a: 29.) Though he has been taken to be thus claiming that intentional explanations should be construed instrumentally, Dennett (1991) insists that he is a “moderate” realist about propositional attitudes, since he believes that the patterns in the behavior and behavioral dispositions of a system on the basis of which we (truly) attribute intentional states to it are objectively real. In the event, however, that there are two or more explanatorily adequate but substantially different systems of intentional ascriptions to an individual, Dennett claims, there is no fact of the matter about what the system believes (1987b, 1991). This does suggest an irrealism at least with respect to the sorts of things Fodor and Dretske take beliefs to be, though it is not the view that there is simply nothing in the world that makes intentional explanations true. (Davidson (1973, 1974) and Lewis (1974) also defend the view that what it is to have a propositional attitude is just to be interpretable in a particular way. It is, however, not completely clear whether they intend their views to imply irrealism about propositional attitudes.) Stich (1983) argues that cognitive psychology does not (or, in any case, should not) taxonomize mental states by their semantic properties at all. The generalizations of a scientific psychology will not quantify over http://plato.stanford.edu/entries/mental-representation/#6 representational states qua representational, and commonsense psychology will not be vindicated by CTM (properly understood). Attribution of psychological states by content is, Stich believes, sensitive to factors that render it problematic in the context of a scientific psychology — viz., relations between an organism and its environment, and relations among psychological states. Cognitive psychology seeks systematic causal explanations of behavior and cognition, and the causal powers of a mental state are determined by its intrinsic “structural” or “syntactic” properties (Stich calls this “the principle of psychological autonomy.” See Stich 1978.) The semantic properties of a mental state (paradigmatically, its reference), in contrast, are determined by extrinsic properties — viz., its history and environmental relations. Thus, such properties cannot figure in causal explanations of behavior. Moreover, to ascribe a psychological state to an individual by content is (roughly) to say that the individual is in a state content-identical to the sort of state that typically causes one’s own utterances of the sentence appearing in the content clause of the attribution. But the appropriateness of such ascriptions depends on what other psychological states the ascribee is (or is disposed to be) in. Since attribution by content is thus holistic, content- based psychological explanation of subjects who differ substantially from the ascriber(s) in their total system of beliefs is precluded (the generalizations will not apply). Finally, ascription of a psychological state by content is sensitive