Gerard O'Brien

One of the principal tasks Dennett sets himself in Consciousness Explained is to demolish the Cartesian theater model of phenomenal consciousness, which in its contemporary garb takes the form of Cartesian materialism: the idea that conscious experience is a process of presentation realized in the physical materials of the brain. The now standard response to Dennett is that, in focusing on Cartesian materialism, he attacks an impossibly naive account of consciousness held by no one currently working in cognitive science or the philosophy of mind. Our response is quite different. We believe that, once properly formulated, Cartesian materialism is no straw man. Rather, it is an attractive hypothesis about the relationship between the computational architecture of the brain and phenomenal consciousness, and hence one that is worthy of further exploration. Consequently, our primary aim in this paper is to defend Cartesian materialism from Dennett’s assault. We do this by showing that Dennett’s argument against this position is founded on an implicit assumption (about the relationship between phenomenalexperience and information coding in the brain), which while valid in the context of classical cognitive science, is not forced on connectionism.

In their target article, Hutto and Satne eloquently articulate the failings of most current attempts to naturalize mental content. Furthermore, we think they are correct in their insistence that the only way forward is by drawing a distinction between two kinds of intentionality, one of which is considerably weaker than—and should be deployed to explain—the propositional variety most philosophers take for granted. The problem is that their own rendering of this weaker form of intentionality—contentless intentionality—is too weak. What’s needed is a species of intentionality distinct from both the industrial-strength version beloved by philosophers and the intentionality lite recommended by Hutto and Satne. We briefly motivate and sketch this alternative, and say a few words about the account of cognition that it spawns.

Stich begins his paper "What is a Theory of Mental Representation?" (1992) by noting that while there is a dizzying range of theories of mental representation in today's philosophical market place, there is very little self-conscious reflection about what a theory of mental representation is supposed to do. This is quite remarkable, he thinks, because if we bother to engage in such reflection, some very surprising conclusions begin to emerge. The most surprising conclusion of all, according to Stich, is that most of the philosophers in this field are undertaking work that is quite futile: It is my contention that most of the players in this very crowded field have no coherent project that could possibly be pursued successfully with the methods they are using. (p.244) Stich readily admits that this is a startling conclusion; so startling, he thinks, that some may even take it as an indication that he has simply "failed to figure out what those who are searching for a theory of mental representation are up to" (p.244). But it is a conclusion that he is willing to stand by, and he sets about it defending it in the body of his paper. Stich, I think, is right about this—I do take his conclusion to indicate that he has failed to figure out what those who are searching for a theory of mental representation are up to. And he has failed to do this largely because he has failed to distinguish between the theory of mind that is implicit in our folk psychology and the mental mechanism that is responsible for our capacity to make folk psychological judgements. When this conflation is undone, so too is the reasoning that takes Stich to his startling conclusion. This is not to say that the conclusion itself is clearly false; it is merely to say that Stich has failed to show that it is true. In what follows I will defend this analysis of Stich's self-conscious reflections on what a theory of mental representation is supposed to do. I will begin with a very brief exposition of Stich's survey of the logical terrain in this part of the philosophical landscape and the line of reasoning that subsequently delivers up the aforementioned conclusion. I will then go on to argue that the latter line of reasoning is fundamentally misdirected because of an error in the former survey.

Stich begins his paper "What is a Theory of Mental Representation?" by noting that while there is a dizzying range of theories of mental representation in today's philosophical market place, there is very little self-conscious reflection about what a theory of mental representation is supposed to do. This is quite remarkable, he thinks, because if we bother to engage in such reflection, some very surprising conclusions begin to emerge. The most surprising conclusion of all, according to Stich, is that most of the philosophers in this field are undertaking work that is quite futile: " It is my contention that most of the players in this very crowded field have _no_ coherent project that could possibly be pursued successfully with the methods they are using. " Stich readily admits that this is a startling conclusion; so startling, he thinks, that some may even take it as an indication that he has simply "failed to figure out what those who are searching for a theory of mental representation are up to". But it is a conclusion that he is willing to stand by, and he sets about it defending it in the body of his paper

Any creature that must move around in its environment to find nutrients and mates, in order to survive and reproduce, faces the problem of sensorimotor control. A solution to this problem requires an on-board control mechanism that can shape the creature’s behaviour so as to render it “appropriate” to the conditions that obtain. There are at least three ways in which such a control mechanism can work, and Nature has exploited them all. The first and most basic way is for a creature to bump into the things in its environment, and then, depending on what has been encountered, seek to modify its behaviour accordingly. Such an approach is risky, however, since some things in the environment are distinctly unfriendly. A second and better way, therefore, is for a creature to exploit ambient forms of energy that carry information about the distal structure of the environment. This is an improvement on the first method since it enables the creature to respond to the surroundings without actually bumping into anything. Nonetheless, this second method also has its limitations, one of which is that the information conveyed by such ambient energy is often impoverished, ambiguous and intermittent

Dienes & Perner offer us a theory of explicit and implicit knowledge that promises to systematise a large and diverse body of research in cognitive psychology. Their advertised strategy is to unpack this distinction in terms of explicit and implicit representation. But when one digs deeper one finds the “Higher-Order Thought” theory of consciousness doing much of the work. This reduces both the plausibility and usefulness of their account. We think their strategy is broadly correct, but that consensus on the explicit/implicit knowledge distinction is still a fair way off.

Cognitive science is founded on the conjecture that natural intelligence can be explained in terms of computation. Yet, notoriously, there is no consensus among philosophers of cognitive science as to how computation should be characterised. While there are subtle differences between the various accounts of computation found in the literature, the largest fracture exists between those that unpack computation in semantic terms (and hence view computation as the processing of representations) and those, such as that defended by Chalmers (2011), that cleave towards a purely syntactic formulation (and hence view computation in terms of abstract functional organisation). It will be the main contention of this paper that this dispute arises because contemporary computer science is an amalgam of two different historical traditions, each of which has developed its own proprietary conception of computation. Once these historical trajectories have been properly delineated, and the motivations behind the associated conceptions of computation revealed, it becomes a little clearer which should form the foundation for cognitive science

Reformers urge that representation no longer earns its explanatory keep in cognitive science, and that it is time to discard this troublesome concept. In contrast, we hold that without representation cognitive science is utterly bereft of tools for explaining natural intelligence. In order to defend the latter position, we focus on the explanatory role of representation in computation. We examine how the methods of digital and analog computation are used to model a relatively simple target system, and show that representation plays an in-eliminable explanatory role in both cases. We conclude that, to the extent that biologic systems engage in computation, representation is destined to play an explanatory role in cognitive science.

When it comes to applying computational theory to the problem of phenomenal consciousness, cognitive scientists appear to face a dilemma. The only strategy that seems to be available is one that explains consciousness in terms of special kinds of computational processes. But such theories, while they dominate the field, have counter-intuitive consequences; in particular, they force one to accept that phenomenal experience is composed of information processing effects. For cognitive scientists, therefore, it seems to come down to a choice between a counter-intuitive theory or no theory at all. We offer a way out of this dilemma. We argue that the computational theory of mind doesn't force cognitive scientists to explain consciousness in terms of computational processes, as there is an alternative strategy available: one that focuses on the representational vehicles that encode information in the brain. This alternative approach to consciousness allows us to do justice to the standard intuitions about phenomenal experience, yet remain within the confines of cognitive science

When cognitive scientists apply computational theory to the problem of phenomenal consciousness, as many of them have been doing recently, there are two fundamentally distinct approaches available. Either consciousness is to be explained in terms of the nature of the representational vehicles the brain deploys; or it is to be explained in terms of the computational processes defined over these vehicles. We call versions of these two approaches _vehicle_ and _process_ theories of consciousness, respectively. However, while there may be space for vehicle theories of consciousness in cognitive science, they are relatively rare. This is because of the influence exerted, on the one hand, by a large body of research which purports to show that the explicit representation of information in the brain and conscious experience are _dissociable_, and on the other, by the _classical_ computational theory of mind – the theory that takes human cognition to be a species of symbol manipulation. But two recent developments in cognitive science combine to suggest that a reappraisal of this situation is in order. First, a number of theorists have recently been highly critical of the experimental methodologies employed in the dissociation studies – so critical, in fact, it’s no longer reasonable to assume that the dissociability of conscious experience and explicit representation has been adequately demonstrated. Second, classicism, as a theory of human cognition, is no longer as dominant in cognitive science as it once was. It now has a lively competitor in the form of _connectionism; _and connectionism, unlike classicism, does have the computational resources to support a robust vehicle theory of consciousness. In this paper we develop and defend this connectionist vehicle theory of consciousness. It takes the form of the following simple empirical hypothesis: _phenomenal experience consists in the explicit_ _representation of information in neurally realized PDP networks_..