Here’s Mark’s intro from his paper from a special issue of Zygon on The Extended Mind and Religious Thought from a few years back.
The view known as the extended mind, following Andy Clark and David Chalmers (1998), also goes under a number of aliases. Clark and Chalmers themselves also refer to their view as active externalism. Vehicle externalism is employed by Susan Hurley (1998) and Mark Rowlands (2006). Locational externalism is the epithet preferred by Robert Wilson (2004). The early appellation of Rowlands (1999), environmentalism, never really caught on, perhaps because the term was already in use.
None of these labels is entirely satisfactory. It is arguable, for example, that the only things wrong with the extended mind are the words extended and mind. The view concerns mental processes, primarily, and perhaps states, but not the mind—at least not if we understand this as the subject of mental states and processes. The standard arguments for the extended mind apply to mental processes, and possibly to mental states, but not, without a lot of further argument, to the subjects of those processes and states. And the term extended conjures up images of mental states and processes somehow expanding outward from their cranial prison and occupying a definite, if somewhat elongated, spatial position, like a stretched rubber band. But perhaps one of the principal implications of the view that goes by the name of the extended mind is that rather than being extended in this sense, mental processes have no determinate spatial position. Nevertheless, for the purposes of this essay I use the label the extended mind, which seems to have caught on more than any of the others (and, anyway, a rose by any other name . . .). Underlying the profusion of names is a reasonably well-defined view that can be represented by way of the following claims:
• The world is an external store of information relevant to processes such as perceiving, remembering, reasoning, and (perhaps) experiencing.
• At least some mental processes are hybrid, straddling both internal and external operations.
• The external operations take the form of action: manipulation, exploitation, and transformation of environmental structures that carry information relevant to the accomplishing of a given task.
• At least some of the internal processes are concerned with supplying subjects with the ability to appropriately use relevant structures in their environment.
This view is not particularly new. James Gibson (1966; 1979) essentially defends it, and a position that is at least on nodding terms with the one described is found in A. Luria and L. Vygotsky ( 1992). It has clear affinities with those of Martin Heidegger ( 1962), Jean-Paul Sartre ( 1957), M. Merleau-Ponty ( 2002), and Ludwig Wittgenstein (1953).
As I understand it, 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. The thesis is ontic in the sense that it is 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 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 consequence is not part of the thesis of the extended mind itself. Indeed, the epistemic claim is compatible with the denial of the thesis 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 claims that a mental process can consist entirely of manipulative, exploitative, or transformative operations performed on the environment.
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 forth. It is possible to understand it in this way but, I think, inadvisable. As we shall see, the underlying rationale for the thesis of the extended mind is provided by a liberal form of functionalism.6 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.
4. The thesis of the extended mind (henceforth, just “the extended mind”) is a claim about the composition or constitution of (some) mental processes. Composition is a relation quite different 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 the thesis of the embedded mind. 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. For example, if we focus on cognitive processes, and think of these as information-processing operations, the idea would be that in accomplishing cognitive tasks an organism can use structures in its environment in such a way that the amount of internal processing it must perform is reduced. Some of the complexity of the task is thereby offloaded onto the environment. This is an interesting thesis in its own right, but it is not the thesis of the extended mind. The claim that mental processes are embedded is a claim of dependence—that at least some mental processes are essentially dependent on environmental structures in that they need such structures in order to perform their characteristic proper functions. The thesis of the extended mind is a thesis of constitution, not dependence. At least some mental processes are literally constituted, in part, by the manipulation, exploitation, and transformation of appropriate environmental structures; that is, some mental processes contain these operations as constituents. Although the idea that mental processes are embedded is an interesting one, in the recent literature this idea figures largely as a way of attacking the idea that mental processes are extended. The arguments that are presented as showing that mental processes are extended, it is argued, in fact show no more than that they are environmentally embedded. Thus, the claim that mental processes are embedded is presented as a way of both acknowledging and defusing the force of the various arguments for the extended mind (Rupert 2004, for example). We return to this issue later.
5. Finally, as if it needed saying (and if my jaunts around the conference circuit in recent years are anything to go by, it does need saying), the thesis of the extended mind does not claim that all mental processes are partly constituted by processes of environmental manipulation; it claims only that some of them are. When I remember where I left the car keys by mentally picturing myself dropping them into the kitchen drawer, there is no need to suppose that there must be some environmental manipulation going on there. Indeed, the extended mind is perfectly compatible with the existence of a brain in a vat, merely adding the qualification that, at most, the brain might not be able to engage in some cognitive processes— although even this inability may be eliminated by suitably sympathetic adjustments on the part of the scientists stimulating the brain.