Shapiro's invocation of wider bodily structures in explaining and understanding the nature of cognitive processes is fairly typical of the embodied genre. However, there are at least three different ways of interpreting Shapiro's claims, one significantly stronger than the others. The first interpretation is what philosophers would call an epistemic one. "Epistemic," here, means roughly "pertaining to our knowledge or what we can know." Understood in this way-epistemically-Shapiro's claim is that it is impossible to understand the nature of cognitive processes without understanding the wider bodily structures in which these processes are situated.2 For example, we cannot understand how the brain computes the direction of a sound without taking into account the facts that (a) the brain is attached to ears, (b) these ears are located at a certain distance from each other, (c) there will typically be a slight difference in the times at which sound arrives at each ear, and (d) this discrepancy in arrival time carries information about the direction of the sound source. We cannot understand how the brain accomplishes the task of identifying the direction of a sound source without knowing these facts, because if the facts were different, the brain would have to do things differently. For example, if we had just one ear, then there would be no disparity information available to us, and the brain would have to do correspondingly more work in order to successfully identify the direction of the sound source.
This epistemic interpretation of the embodied mind thesis is not insignificant, but it does leave much of the traditional conception of cognitive processes intact. It is compatible, for example, with the idea that real cognition occurs in the brain-that it consists in transformations of neural representations-and adds only the qualification that in order to understand the character of these transformational processes in specific cases, we need to understand the wider bodily structures in which these transformations are embedded. The wider bodily structures provide a sort of bodily context in which these cognitive processes are situated, and to properly understand how the processes do what they do we have to understand this context. But this does not mean that there is no distinction between cognition and its bodily context. Real cognition, one, might argue, still occurs in the brain; and this claim is compatible with the epistemic reading of the embodied mind thesis.
The second possible interpretation of the embodied mind thesis is what philosophers might call ontic rather than epistemic. Here, "ontic" means roughly "pertaining to how things are" (rather than to our knowledge of how things are). According to the second interpretation, the embodied mind thesis is a thesis of the dependence of cognitive processes on wider bodily structures. The idea is that cognitive processes are dependent on wider bodily structures in the sense that these processes have been designed to function only in conjunction, or in tandem, with these structures. In the absence of the appropriate bodily structures, an organism may be unable to accomplish its usual repertoire of cognitive tasks because the processes it typically uses to perform such tasks work only in conjunction with the missing structures. One can understand this thesis of dependence in various ways. One way might be to understand it as a contingent claim about the nature of cognitive processes: as a matter of fact, some cognitive processes have developed in such a way that they are dependent for their proper functioning on wider bodily structures. Things did not have to be that way-cognitive processes might have developed to function independently of wider bodily structures-but that is the way things, in fact, turned out. If one were feeling more sanguine, one might try and convert this into a necessary truth. The difference between a contingent and a necessary truth in this context is the difference between does not and could not (see box 3.1). As a claim of necessary dependency, the embodied mind thesis is the claim that some cognitive processes are such that they could not, even in principle, function independently of wider bodily structures. That is, some cognitive processes are such that they could not have been developed to function independently of the bodily context in which they did, in fact, develop. I suspect-strongly-that elevating this claim of dependency to the status of necessary truth is a little too sanguine, but this is not a matter on which we need to adjudicate at the present time.
Again, the dependence interpretation of the thesis of the embodied mind is not insignificant. But there is a clear sense in which it leaves the traditional vision of cognition untouched. Embracing the dependence interpretation still allows one to maintain that real cognition occurs exclusively in the brain. This real cognition may be dependent for its correct functioning on wider bodily structures and processes, but there is no reason for thinking that these wider bodily structures and processes form part of cognition. Dependence, even essential dependence, does not add up to constitution-not without a lot more argument.' Sunburn is (essentially) dependent on solar radiation in the sense that any skin discoloration not produced by solar radiation is not sunburn. But this does not mean that solar radiation is literally part of-a component of-sunburn (Davidson 1987).
In the opening chapter, I argued that the Cartesian conception of the mind cannot be challenged simply by pointing out the rather obvious fact that that in many cases the environment drives-in the sense of causally contributing to-cognitive processes. Cognitive processes are, thus, dependent on environmental factors. This is an utterly anodyne claim of the sort to which any Cartesian might assent. Even if we try to tighten the connection-perhaps by claiming that some cognitive processes have been designed to function only in tandem with certain environmental circumstances-this does not undermine the Cartesian picture of cognitive processes as occurring in the brain. We can modify Davidson's suntan example to make this point. The transformation of skin color commonly called a suntan has been designed to function only in conjunction with certain environmental circumstances-the presence of UV lightas a mode of protection from those circumstances. But the suntan occurs in the skin and only in the skin (Davidson 1987). To say that cognitive processes are dependent, even essentially dependent, on environmental circumstances does not undermine the claim that they are located in, and only in, the brain of the cognizing subject. We can make precisely the same point with regard to the interpretation of the thesis of the embodied mind as a claim of bodily dependence. The claim that cognitive processes are dependent, even essentially independent, on wider bodily structures and circumstances does not, in any way, force us to reject the claim that cognitive processes occur exclusively inside the brain.
The third-the strongest and therefore most interesting-interpretation of the embodied mind thesis is also ontic, but is based on the idea of constitution or composition rather than dependence.' According to this third interpretation, cognitive processes are not restricted to structures and operations instantiated in the brain, but incorporate wider bodily structures and processes. These wider bodily structures and processes in part constitute-are constituents of-cognitive processes. This final interpretation of the embodied mind thesis is the most interesting because only it directly and fundamentally challenges the Cartesian vision of cognitive processes: the idea that cognitive processes occur exclusively in the brain of cognizing organisms. If the third interpretation of the embodied mind thesis is correct, then, to return to Shapiro's example, the distance between the ears, and the resulting disparity between the arrival times of sound at each ear, can be a literal part, or constituent, of the process of computing the direction of a sound source. This distance, and the resulting disparity, is not something extraneous to cognition, on which cognition merely depends: it is a genuine part of the cognitive process.
This is by far the most radical and interesting interpretation of the embodied mind thesis. For this reason, it is also the most difficult to defend. To endorse this interpretation is to run straight back into what I called, in the final section of the first chapter, the big question. Given that we can understand the embodied mind thesis as a thesis of dependence, what reason-if any-is there for endorsing the thesis of constitution? We might be willing to grant that cognitive processes depend on wider bodily
structures and processes in order to do what they are supposed to do. But, why move from this to the more radical-and for that reason also more intuitively implausible-claim that these wider bodily structures and processes constitute, or are constituents of, cognitive processes? Given that the dependence thesis allows us to hold on to both our Cartesian intuitions and, to a considerable extent, the traditional cognitive science built upon them, endorsing the constitution interpretation seems both unnecessary and unmotivated. More than that, it seems positively capricious.5
Nevertheless, this book is going to defend the constitution interpretation. I shall argue that some-not all by any means, but some-cognitive processes are composed of, constituted by, wider bodily structures and processes.
3 The Extended Mind
The view that I am going to call the thesis of the extended mind goes by a variety of names: vehicle externalism (Hurley 1998; Rowlands 2006), active externalism (Clark and Chalmers 1998), locational externalism (Wilson 2004), and environmentalism (Rowlands 1999). "Extended mind" is a label invented by Andy Clark and Dave Chalmers in their 1998 article of the same name. I think all the labels have their problems, and "extended mind" is no exception. However, it is the name that has come closest to sticking, and I propose to use it in this book. However, though I adopt their terminology, what I call the thesis of the extended mind differs from Clark and Chalmers's position in at least one crucial respect.
First of all, let me say what I am going to mean by the thesis of the extended mind. The general idea is that at least some mental processesnot all, but some-extend into the cognizing organism's environment in that they are composed, partly (and, on the version I am going to defend, contingently), of actions, broadly construed, performed by that organism on the world around it.
The mental processes in question are primarily cognitive ones; and my focus, at least for the time being, is going to be on these. The actions that the organism performs on the world around it are ones of manipulating, exploiting, and/or transforming external structures. What is distinctive of these structures is that they carry information relevant to accomplishing a given cognitive task. And by acting on these structures in suitable ways, the cognizing organism is able to make that information available to itself and to its subsequent cognitive operations. That is, the function of the action performed by a cognizing organism on these structures is to transform information that is merely present in the structures into information that is available to the organism and/or to its subsequent processing operations. This, according to the thesis of the extended mind, can form part a properly cognitive part-of a process of cognition. Thus, as I shall understand it and defend it, the thesis of the extended mind is the thesis that some cognitive processes are made up, in part, of the manipulation, exploitation, and/or transformation of information-bearing structures in the cognizing organism's environment. That is, the thesis of the extended mind is defined by the following claims:
The Extended Mind
1. The world is an external store of information relevant to processes such as perceiving, remembering, reasoning ... (and possibly) experiencing.
2. Cognitive processes are hybrid-they straddle both internal and external operations.
3. The external operations take the form of action, broadly construed: the manipulation, exploitation, and transformation of environmental structures-ones that carry information relevant to the accomplishing of a given task.
4. At least some of the internal processes are ones concerned with supplying the subject with the ability to appropriately use relevant structures in its environment.
As I shall understand it, therefore, the thesis of the extended mind is (1) an ontic thesis, of (2) partial and (3) contingent (4) composition of (5) some mental processes.'
1. It is ontic in the sense that it is a thesis about what (some) mental processes are, as opposed to an epistemic thesis about the best way of understanding mental processes. This ontic claim, of course, has an epistemic consequence: it is not possible to understand the nature of at least some of the mental processes without understanding the extent to which that organism is capable of manipulating, exploiting, and transforming relevant structures in its environment (Rowlands 1999). However, this epistemic consequence is not part of the thesis of the extended mind itself. Indeed, the epistemic claim is compatible with the denial of this thesis.'
2. The claim is that (some) token mental processes are, in part, made up of the manipulation, exploitation, or transformation of environmental structures. There is always an irreducible internal-neural and, sometimes, also wider bodily-contribution to the constitution of any mental process. No version of the extended mind will claim that a mental process can be composed entirely of manipulative, exploitative, or transformative operations performed on the environment.8
3. It is possible to understand the thesis of the extended mind as asserting a necessary truth about the composition of mental processes: that, necessarily, some mental processes are partly constituted by processes of environmental manipulation and so on (see box 3.1).9 It is possible but inadvisable. As we shall see, the underlying rationale for the thesis of the extended mind is provided by a fairly liberal form of functionalism.10 And the entire thrust of liberal functionalism is to leave open the possibility of different ways of realizing the same (type of) mental process. By understanding the thesis of the extended mind as asserting a necessary truth, therefore, the proponent of this thesis is at risk of undermining his or her own primary motivation.
Box 3.1
Necessary and Contingent
To say that a (true) statement is necessary is to claim, roughly, that things have to be that way; things couldn't possibly have been otherwise. The statement, therefore, is not only true, it has to be true. To say that a (true) statement is contingent, on the other hand, is to say that while it is true, it might have been false. Things, in fact turned out the way described in the statement, but they might well have turned out differently.
In this book, I am going to understand the thesis of the extended mind as expressing a contingent truth. Some cognitive processes developed in such a way that, as a matter of contingent fact, they incorporate processes of manipulation, exploitation, and/or transformation of environmental structures. Cognitive processes didn't have to develop in this way. They could have developed as purely internal-neural-processes; but that's not what actually happened-at least not for all cognitive processes. Some may want to elevate the thesis of the extended mind into a necessary truth; but I am not one of them. And I don't think any arguments have ever successfully been advanced defending this stronger claim.
4. The thesis of the extended mind (henceforth simply "the extended mind") is a claim about the composition or constitution of (some) mental processes. Composition is a quite different relation from dependence. Thus, the extended mind is a stronger and more distinctive claim than one of environmental embedding; and it must be clearly distinguished from that of the embedded mind (see section 4). According to the latter, some mental processes function, and indeed have been designed to function, only in tandem with certain environmental structures; so that in the absence of the latter the former cannot do what they are supposed to do or work in the way they are supposed to work. Thus, some mental processes are dependent, perhaps essentially dependent, for their operation on the wider environment. The extended mind, on the other hand, does not simply claim that mental processes are, in this way, situated in a wider system of scaffolding, a system that facilitates, perhaps in crucial ways, the operation of these processes. That would be a claim of dependence. Rather, it claims that things we do to this wider system of scaffolding in part compose or constitute (some of) our mental processes."
Much of the distinctiveness and importance of the extended mind depends, I think, on understanding it as making an ontic (rather than epistemic) claim concerning the partial constitution of mental processes by processes of environmental manipulation (rather than merely dependence on such processes). This
is how I shall understand the thesis of the extended mind. This seems to be the sort of understanding of the extended mind endorsed and defended by Clark and Chalmers in their eponymous (1998) paper (see box 3.2). However, in the version of the thesis I wish to defend, there is a marked difference of at least emphasis. Whether it is more than a difference of emphasis is unclear, but it is useful, at this point, to compare the version of the extended mind defined above with that defended by Clark and Chalmers.
The New Science of the Mind Page 8
