Penultimate draft for Arguing about the Mind, Gertler and Shapiro, eds.
Clark and Chalmers argue that the mind is extended – that is, its boundary lies beyond the skin. (Clark and Chalmers 1998, reprinted as Chapter 15 of this volume.1 For brevity, I will refer to the authors as ‘C&C’.) In this essay, I will criticize this conclusion. However, I will also defend some of the more controversial elements of C&C’s argument. I reject their conclusion because I think that their argument shows that a seemingly innocuous assumption, about internal states and processes, is flawed.
The first section of the essay outlines C&C’s argument. In Section 2, I sketch some unpalatable consequences of their conclusion. Insofar as we want to avoid these consequences, we should look for a flaw in the argument. As outlined in Section 1, the argument appears to be valid, so finding a flaw means identifying a premise that it is reasonable to reject. In Section 3, I evaluate each of the major premises of the argument and find that all but one are acceptable; I then explain why I reject the remaining premise. Section 4 briefly defends the picture of the mind that emerges from rejecting this premise.
My goal is not to conclusively refute C&C’s argument. My aim is only to reveal the best alternative for those who remain skeptical about the existence – or, perhaps, even the possibility – of extended minds.
1. Clark and Chalmers’ argument
The authors provide two arguments to show that the mind is extended. First, they argue that the mind’s cognitive processes can at least partially consist in processes performed by external devices. Their examples of such external cognitive processing devices include a computer that you can use to rotate shapes when playing the game Tetris. As they describe this case, the computer’s rotation of a shape plays the same sort of role, in your cognitive economy, as the corresponding internal process (when you simply imagine how the shape would appear if it were rotated in various ways). For instance, the result of this process is automatically endorsed – you believe that the shape would look like that when rotated. And you use this information to guide your behavior, such as moving the joystick to position the shape in a certain place on the screen. They conclude that insofar as the internal process of imagining qualifies as your cognitive process, so should the external computational process.
While I will return to this processing case at various points below, my remarks will focus on the second of C&C’s arguments: that standing beliefs (and desires, etc.) can be partially constituted by factors external to the skin. Standing beliefs include stored memories and other beliefs that are not currently being entertained. The notion of a standing belief contrasts with the notion of an occurrent belief, which is a conviction that you are now entertaining. For instance, you probably have the standing belief that dinosaurs once roamed the earth. At the moment before you read that sentence, the belief was simply a standing belief; it was not occurrent (unless you happened to be thinking about dinosaurs at that moment). But now that you’re thinking about the fact that dinosaurs roamed the earth, that belief is occurrent.
C&C’s principal examples of extended standing beliefs involve a character they call Otto. Otto, who suffers from Alzheimer’s disease, carries a notebook in which he routinely records useful information of the sort that most of us would easily commit to memory. Otto consults the notebook whenever he needs this stored information to guide his reasoning or actions. For instance, on a trip to the Museum of Modern Art in New York, Otto frequently consults the notebook, to remind himself that he is going to the MoMA, that the MoMA is on 53rd Street, etc. C&C claim that the information stored in Otto’s notebook – such as ‘the MoMA is on 53rd Street’ – partially constitutes his standing beliefs, and hence that his mind extends beyond his skin.
Here is my reconstruction of C&C’s argument.
“What makes some information count as a [standing] belief is the role it plays” (p. xx14xx).
“The information in the notebook functions just like [that is, it plays the same role as] the information constituting an ordinary non-occurrent belief”. (p. xx13xx).
The information in Otto’s notebook counts as standing beliefs.2 (from (1) and (2))
Otto’s standing beliefs are part of his mind.
The information in Otto’s notebook is part of Otto’s mind. (from (3) and (4))
Otto’s notebook belongs to the world external to Otto’s skin, i.e., the ‘external’ world.
The mind extends into the world. (from (5) and (6))
In assessing C&C’s extended mind hypothesis, I will focus on the conclusion that Otto’s standing beliefs extend into the world. Later, I will briefly discuss how my assessment applies to the case of cognitive processing.
2. Some worrisome consequences of Clark and Chalmers’ conclusion
C&C’s conclusion is that “the mind extends into the world”, where ‘the world’ refers to what is beyond the subject’s skin. In this section, I will use the example of Otto and his notebook to describe two consequences that seem to follow from this conclusion. Both of these consequences are, I think, worrisome; the second is especially so. Recognizing them will thus cast doubt on the conclusion.
First consequence: limits on introspection
It is commonly held that, in general, a subject can determine his or her own beliefs and desires by using a method that others cannot use (to determine that subject’s beliefs). Let us use the term ‘introspection’ to refer to this method. Introspection is, in this sense, a necessarily first-person method: it reveals only the introspector’s own states, and not the states of others. Introspection may not be infallible; in fact, it may be no more reliable than third-person methods. The claim is only that each of us has a way of gaining access to our own beliefs that is unavailable to others.
According to C&C, the information in Otto’s notebook partially constitutes some of his standing beliefs. Can Otto introspect these beliefs, in our sense of ‘introspect’? That is, can he identify these beliefs by using a method available only to himself?
I think that he cannot. When Otto tries to figure out what he believes on a particular topic, he consults the notebook. For instance, suppose that he wonders what he believes about the location of the MoMA. He will look in the notebook and conclude: I believe that the MoMA is on 53rd Street. But of course someone other than Otto can determine Otto’s beliefs in precisely the same way: by consulting the notebook, a friend can determine that Otto believes that the MoMA is on 53rd Street. So it appears that, if the entries in Otto’s notebook partially constitute his beliefs, then Otto cannot introspect his beliefs.
Much more could be said here. For one thing, it might be argued that when Otto consults the notebook, in order to determine what he believes about the location of the Museum, he is introspecting. C&C seem to suggest this when they say that treating Otto’s access to the notebook as perceptual rather than introspective would beg the question against the claim that the notebook is part of Otto’s mind. (p. xx16xx) But as I am using this term, ‘introspection’ refers only to those processes that are necessarily first-personal. Someone who claimed that, in consulting the notebook, Otto is introspecting in my sense would have to show that Otto has a unique kind of access to the notebook – or, perhaps, to the fact that the notebook entries play the relevant ‘belief’ role in his cognitive economy. But it is difficult to see how this access could be unique, so long as it was access to a feature external to Otto’s skin.
Another possibility that C&C describe more directly reveals the lack of unique first-person access.
In an unusually interdependent couple, it is entirely possible that one partner’s beliefs will play the same sort of role for the other as the notebook plays for Otto. … [O]ne’s beliefs might be embodied in one’s secretary, one’s accountant, or one’s collaborator. (pp. xx17-18xx)
To flesh out this scenario, suppose that Amanda, an absent-minded executive, uses her assistant Fred as a repository of her daily schedule. Fred knows that Amanda has a 2:00 board meeting on Monday, and stores this information for Amanda. Since this information plays the appropriate role in Amanda’s cognitive economy (it is readily accessible to her, automatically endorsed by her, etc.), it counts as her belief.
Now suppose that Amanda wonders what she believes about her Monday schedule. To determine this, she will consult Fred, to see what he believes about it. But this is the same process that Fred uses to determine what Amanda believes about her Monday schedule. Recognizing that he is a repository for Amanda’s standing beliefs, Fred will determine Amanda’s beliefs about the schedule simply by consulting his own beliefs about it. Amanda’s access to her beliefs, and to the fact that she has those beliefs, proceeds via a method also available to Fred. So Amanda has no uniquely first-personal method of determining what she believes; that is, she cannot introspect her beliefs, in my sense of ‘introspect’.
C&C would likely accept this consequence. They could simply allow that, in general, we have unique introspective access only to our occurrent experiences and our occurrent thoughts, that is, thoughts that we are now entertaining. (Crucially, they do not claim that occurrent thoughts are extended.) The point may be even clearer when applied to cognitive processes such as those involved in the Tetris case. You do not seem to have any special first-person access to how you go about imagining the shape rotated: you simply perform this feat of imagination.3 So C&C can easily allow that those states that are extended – such as standing beliefs and nonconscious cognitive processes – are simply non-introspectible.
Still, for one who thinks that introspectibility is crucial to our basic concept of the mind, this point will cast doubt on C&C’s conclusion that the mind extends into the world. If one can introspect only the non-extended parts of the mind, then why count the external factors as truly part of the mind? (I will return to this point in Section 4.)
I now turn to the second, more troubling consequence of C&C’s conclusion.
Second consequence: a proliferation of actions
C&C dub their view ‘active externalism’ to highlight what they see as one of its chief benefits: the extended states that it counts as mental play a crucial role in generating action. In marking this benefit, they appear to suggest that this contribution to action is, at least in part, what justifies counting the wide states as truly mental states. But it’s not clear that the wide states play the crucial role C&C ascribe to them.4
A simple thought experiment will convey the basis for doubt on this point. Suppose that, instead of a notebook, Otto uses an external computing device as a repository for important information. Suppose also that he records some of his desires in the device. For instance, he records the desire to make banana bread on Tuesday; the belief that banana bread requires bananas; the belief that the corner grocery store is a good source for bananas; etc. And he allows the device to perform some cognitive processes for him, including devising action plans based on the information it has stored. (C&C would surely allow that a single device could both serve as a repository for standing states and perform cognitive processes as in the Tetris example; after all, the brain accomplishes both of these tasks.) The idea that external devices can devise action plans is nothing new. For example, a dashboard-mounted Global Positioning System records the subject’s desire to reach a particular destination, and uses stored geographical information to devise the most efficient route to fulfilling that desire.
Finally, imagine that this computing device is plugged into a humanoid robot that Otto also owns. In effect, the computing device serves as part of the robot ‘brain’. (Otto’s internal, organic brain may be another part of the robot’s brain.) It uses inputs from the robot’s various detection systems to determine the layout of its environment, and it controls the robot’s movements by sending signals to the robot’s ‘limbs’.
Otto spends Monday asleep in bed. (Or, rather, the organic portion of his body does – after all, if C&C are correct the external device qualifies as part of Otto’s body.) The robot is, however, very active: using the information stored within it, it ‘realizes’ that a trip to the grocery store is in order, since this is the most efficient way to execute the desire to make banana bread on Tuesday. Drawing on various other bits of information, it goes to the grocery store, purchases bananas, and returns home. Alas, the organism’s sleep is very deep, and he (it?) does not awake until late on Tuesday. When he does, he is roused by the tantalizing scent of freshly-baked banana bread.
Now did Otto make the bread? It seems that C&C should say that he did. They claim that, in explaining why Otto walked to 53rd Street, we need not cite the occurrent belief that the MoMA is on 53rd Street, which Otto has (for a fleeting moment) upon consulting the notebook. Instead, they say, an adequate explanation may simply cite the notebook entry itself. Expanding on this claim, it seems that in order to explain the bread-making behavior, we need not cite any occurrent belief or desire of Otto’s; we can simply cite the information and dispositions stored in the robot’s ‘brain’. The implication of premises (1) and (2) of their argument is that these ‘count as’ Otto’s standing beliefs and desires. So long as no occurrent belief or desire needs to be cited in an action explanation, the bits of behavior that directly result from the bits of information stored in the robot – the trip to the grocery store, the making of the banana bread – seem accurately described as Otto’s actions.
To resist this, it may be argued that Otto himself didn’t go to the grocery store, or make the banana bread – for he was asleep in bed. But notice that this reply depends on denying that the robot is part of Otto. And if C&C are correct, there is little support for such a distinction. “Otto himself is best regarded as an extended system, a coupling of biological organism and external resources.” (p. xx18xx) Surely, some of Otto’s actions directly involve only the organic part of Otto; so, on grounds of parity, we should allow that some of Otto’s actions might directly involve only his non-organic part.
Of course, the organism and the robot will constitute the right kind of extended system only if they are related in certain ways. But they do seem to be appropriately related. The information stored in the robot’s ‘brain’ is present because the organism occurrently believed it in the past; it is readily accessible; the organism automatically endorses the information it contains; etc.5 These are the conditions that are met by Otto’s notebook and that, according to C&C, make it the case that Otto’s mind extends to the notebook. On the same grounds, then, we should say that in our story, Otto extends to the external device. We can even imagine that when the organism awakens Otto compliments himself on his baking prowess.
So C&C’s argument suggests that making the banana bread was Otto’s action. If this is correct, there seems no limit to the actions a single person can perform. For imagine that organic Otto programs an enormous fleet of robots, linking them so that they are in constant communication with each other. These robots then engage in widespread, multifarious activities. Some take a slow boat to China; others descend on a neighborhood in Texas and ring all the doorbells at once; others compete in karaoke contests in Tokyo. When we say that all of these activities are Otto’s actions, we are not simply saying that he is somehow responsible for them, or that he did something in the past that causally contributed to them. We are saying that he is, quite literally, performing each of these actions: he is enormously busy (though tireless) and, unlike Superman, he can be in two places at once. Given that Otto’s standing states might extend to a notebook, they can also extend to indefinitely many other external devices. Add to this the claim that Otto’s actions may be the product of his standing states alone, and Otto becomes extraordinarily active.
If this result seems implausible, then perhaps we should question whether behavior that results from these extended states truly qualifies as action. We might limit actions in various ways: e.g., by requiring that the organic part of one’s body must be involved in a genuine action, or by requiring that an agent’s occurrent beliefs and desires (which, they assume, are internal to the organic body) be involved in each of her genuine actions. But these moves conflict with C&C’s claim that there is nothing special, vis-à-vis a subject’s agency, about states internal to her organic body.
This second consequence, that actions occur at a distance from the organic agent and proliferate excessively, is more threatening to C&C’s conclusion than the first consequence. I observed that C&C could simply accept that extended states cannot be introspected, while maintaining that they are nevertheless mental. On that view, the distinction between what is introspectible and what is not may parallel the distinction between what is internal and what is extended. Since they claim that some non-introspectible (extended) states and processes are mental, they must use some other feature to distinguish the mental from the non-mental. And given that they stress the ‘active’ nature of these extended states and processes, the relevant feature seems to be this: extended states and processes qualify as mental because a piece of behavior caused by such states and processes (even one in which no occurrent states or processes play a crucial role) qualifies as a genuine, intentional action. So if we are hesitant to describe making the banana bread as Otto’s action, then we have serious grounds for doubt that extended states and processes have the feature that, on C&C’s view, qualifies them as truly mental.
Both of these worrisome consequences derive from an exceedingly liberal conception of mind. If we can restrict the mind – to that which is introspectible, or to states that causally explain bits of behavior that (unlike the robot’s behavior) seem like genuine actions – then we can avoid both of these consequences.
But where did C&C go wrong? Which step of their argument is responsible for this problematic inflation of the mental?
3. Where is the flaw in C&C’s argument?
If one or both of the consequences just outlined seem objectionable, we should find a way to block C&C’s argument for the extended mind hypothesis. As it is outlined in Section 1, their argument seems valid. So we can block its conclusion only by finding fault with at least one of its premises. Two of the premises – namely, (3) and (5) – follow from other premises. To find the flaw in the argument, then, we must look to premises (1), (2), (4), and (6).
We can quickly rule out premise (6) as the source of the problem. For this premise merely stipulates that ‘the world’, in the conclusion, refers to the part of reality that is beyond the skin. We can have little quarrel with such a stipulation.
The major premises remaining are (1), (2), and (4). Let us examine each of these in turn.
Here is premise (1):
“What makes some information count as a [standing] belief is the role it plays”.
Premise (1) suggests that standing beliefs are defined, as such, by their role – loosely speaking, by how they function. It thus amounts to a kind of functionalism about standing beliefs. Given premise (1)’s contribution to this argument, the best way to reject it would be to show that, while playing a certain functional role may be necessary for being a standing belief, it is not sufficient: standing beliefs must not only play the relevant functional role, but must possess certain other features as well. This would mean that, even if the information in Otto’s notebook played the same functional role as his standing beliefs, it might not constitute his standing beliefs because it lacked those other features. Obvious possibilities for such additional features include being constituted by a certain kind of material (e.g., the organic grey matter that makes up the human brain), or being located entirely within the skin. If we require that standing beliefs have one or both of these features, then we will reject premise (1).
C&C resist these further requirements, and many other philosophers would agree with them on this point. Limiting standing beliefs to states that are constituted by a particular kind of material seems unacceptably ad hoc: for instance, it would exclude the possibility that extraterrestrials with very different physical constitutions could have standing beliefs. And the claim that standing beliefs must be located within the skin is question-begging, for the significance of the ‘skin’ boundary is precisely what is at issue here. So we cannot assume that standing beliefs must be internal.
Of course, rather than simply assuming that standing beliefs must be internal, one might argue for this claim. The most straightforward way to do this is to reject premise (2), viz.:
“The information in the notebook functions just like [that is, it plays the same role as] the information constituting an ordinary non-occurrent belief”.
If the information in the notebook does not play the same role as ordinary internal beliefs, this may help to show that the particular ‘belief’ role can be played only by internal states. So let us turn to examining the prospects for premise (2).
C&C outline the functional role that both the notebook entries and ordinary (internal) standing beliefs play, with the following four conditions.6
They are consistently available.
They are readily accessible.
They are automatically endorsed.
They are present (in the brain or notebook) because they were consciously endorsed in the past.
Now according to premise (2), the notebook entries play the same role as ordinary internal standing beliefs. There are two ways to reject this premise. We can deny that the notebook entries meet (i)-(iv); or we can claim that internal standing beliefs meet some further condition(s) not on this list, which the notebook entries do not meet.
The first option is a difficult one. C&C devised the Otto case specifically to meet (i)-(iv); and even if there might be some doubts about how well the notebook entries satisfy each of them, such questions could easily be answered by modifying the example. For instance, C&C observe that it might be awkward to carry a notebook into the shower. But we can imagine that Otto carefully laminates the notebook’s pages, or that he adopts some more high-tech solution. It seems clear, in any case, that an external device could contain information that meets (i)-(iv).
Now consider our second option for rejecting premise (2): to claim that internal standing beliefs meet some other condition, not included in (i)-(iv), that is necessary for being a standing belief, and that the notebook entries do not meet. I know of two candidates for such further conditions. The first, noted by C&C, is that there is a phenomenal difference between recalling an ordinary standing belief (e.g., that dinosaurs once roamed the earth), and looking up this information in a notebook. Ordinary recall has a kind of effortless immediacy: when the issue arises, I simply find myself occurrently thinking that dinosaurs roamed the earth. But it feels different to consult a notebook.
C&C acknowledge that there is some phenomenological difference between these, but they characterize this difference as ‘shallow’, for they deny that having a particular kind of phenomenological feel is necessary for being a standing belief. You might disagree, and see the phenomenological difference as deep and important. I will remain neutral on this issue for reasons that will become clear below. But suppose, for the moment, that there is a deep, important phenomenological difference between ordinary recall and consulting a notebook. In that case, we should add a fifth condition to our characterization of the functional role standing beliefs play.
Recalling them has a particular phenomenology: roughly, the phenomenology of effortless immediacy.
Dan Weiskopf7 suggests a second possible difference between internal standing beliefs and notebook records. Weiskopf points out that internal standing beliefs are automatically revised in light of new information. Here is a slightly modified version of an example he gives: when you learn that Sam and Max are married, you will probably come to believe that they live at the same address. If you then learn that they are no longer married, you will likely abandon the belief that they live at the same address. These further revisions in your beliefs are automatic, that is, they occur without deliberation. Weiskopf points out that Otto’s notebook is not ‘informationally integrated’ in this way. When he writes in his notebook that Sam and Max are married, no entry reading “Sam and Max share an address” automatically appears. Otto may, of course, write this entry as well – Weiskopf’s point is just that this further revision requires an extra, deliberate step. Similarly, when Otto learns that MoMA has temporarily moved to Queens, the sentence “MoMA is on 53rd St.” does not instantly vanish from the notebook.
Here, then, is another condition we might add to the original four:
They are informationally integrated.
Let us take stock. Ordinary internal standing beliefs meet conditions (v) and (vi) whereas the entries in Otto’s notebook do not. Whether we should reject premise (2) for this reason depends on two questions. First, are (v) and (vi) necessary to being a standing belief? Second, granting that Otto’s notebook entries do not satisfy (v) and (vi), might these conditions be satisfied by information stored in a different type of external device?
I suggest that the answer to the second question is ‘yes’, and that we can therefore ignore the first question. Suppose that, instead of a simple paper notebook, Otto carries an external computing device that is linked to his brain. In a lucid moment, or perhaps before he succumbs to full-blown Alzheimer’s, Otto programs the device to constantly scan his thoughts and to perform as follows. When the device detects that Otto is thinking about dinosaurs, or about prehistoric times (etc.), it causes him to occurrently believe that dinosaurs roamed the earth. This process has the phenomenology of ordinary recall: the occurrent belief seems to come to him immediately and without effort. He also programs the device to be sensitive to additions or alterations of information. So when Otto learns that MoMA has moved to Queens, the device automatically adds or modifies any bits of stored information that are relevant to this new fact: e.g., it stores the information that MoMA is no longer on 53rd St. Arguably, then, the information in this external device now meets conditions (v) and (vi).
Of course, the notebook example is much closer to the kinds of external information storage mechanisms that are in common usage today. So if (v) or (vi) is required for being a standing belief – an issue on which I’ll remain neutral – then C&C have shown only that minds can be extended, not that they are currently extended. (Weiskopf recognizes this point, and argues only that minds are not, in fact, extended. He allows that they could become extended.) Still, the mere possibility of extended minds is all that’s needed for what is perhaps C&C’s central contention, that “when it comes to belief, there is nothing sacred about skull and skin”. (p. xx8xx)
There may be further conditions that are necessary for being a standing belief, which an external device could not meet. But none comes easily to mind. Nor do I expect one to emerge: for standing beliefs do seem to be defined, as such, by their causal relations to other states and processes, including occurrent ones. And there seems no principled reason to deny that something beyond the skin could play the same type of causal role as internal standing beliefs. So I suggest that it is reasonable to accept premise (2).
This leaves us with premise (4). Premise (4) may seem the least suspect of C&C’s three major premises. But I will argue that, in fact, it is the most objectionable.
4. The Narrow Mind
Premise (4) is that Otto’s standing beliefs are part of his mind. Now this may seem almost a definitional truth; after all, what is a belief except a mental state, and what is a mental state except part of a mind? But I will argue that, to avoid the consequences discussed in Section 2, we should deny that standing beliefs are part of the mind.
I think that C&C’s examples are persuasive in illustrating the close affinity between internal standing beliefs and a variety of external states. In particular, I think that C&C make a compelling case for the following conditional.
If standing beliefs are part of the mind, then the mind can be indefinitely extended: to notebooks, external computing devices, and even parts of others’ minds.
I think that their parallel argument, regarding the affinity between processes performed by external devices and processes performed internally, also succeeds. It establishes this conditional:
If nonconscious cognitive processes are part of the mind, then the mind can be indefinitely extended: to external computing devices and even parts of others’ minds.
The consequents of both these conditionals – that the mind can extend to notebooks, external computing devices, and even parts of others’ minds – have the worrisome consequences discussed in Section 2.
I suggest that we accept these conditionals, on the basis of C&C’s ingenious arguments. But to avoid those worrisome consequences, we should reject their consequents and, hence, reject their antecedents. In other words, we should reject premise (4).
C&C have shown, I think, that internal standing states and nonconscious processes are essentially similar to states of notebooks and external computational processes. From the fact that the latter, external states and processes are non-introspectible, we can infer that their internal equivalents are also non-introspectible. (There is independent reason to believe that standing states and nonconscious processes are nonintrospectible.8) And from the fact that behavior produced by external states and processes is not truly action (e.g., the robot’s behavior, caused by Otto’s external standing states and nonconscious processes, is not Otto’s action), we can infer that behavior produced by internal standing states and nonconscious processes is not truly action.
The worrisome consequences that result from C&C’s conclusion do not derive from the fact that the allegedly mental states and processes are external. Rather, they derive from the fact that the allegedly mental states and processes are standing states and nonconscious processes. Whether the states are internal or external is then unimportant; for, I think, C&C have shown that “when it comes to belief, there is nothing sacred about skull and skin”. (p. xx8xx)
The best option, then, is to reject premise (4). This means that the internal equivalents of notebook entries and external computing processes – namely, internal standing beliefs and nonconscious cognitive processes – are not, strictly speaking, part of the mind. On this view, the mind is made up entirely of occurrent states and conscious processes. These include beliefs or desires that are now being entertained, conscious thoughts, emotions, and sensations, and conscious cognitive processes.
C&C are well aware of the alternative I am suggesting. They recognize that “it may be the most consistent way to deny Otto’s belief”, but reject it as “extreme” (p. xx16xx).
To consistently resist this conclusion [that Otto himself is an extended system], we would have to shrink the self into a mere bundle of occurrent states, severely threatening its deep psychological continuity. (p. xx18xx)
This is a serious worry for my position. But it is worth noting that the problem is also faced by some familiar views about the mind, including Derek Parfit’s bundle theory (Chapter 19 of this volume).
I will close by briefly sketching how a mind, understood as a series of (sets of) occurrent states, can enjoy the psychological continuity we think ourselves to enjoy. The approach uses states that are not part of the mind as the causal ground for its psychological continuity.
Let us begin with an analogy. Consider an automobile factory – call it Factory A – that produces several different models of cars. The cars may bear the factory’s trademark, ‘A’, in which case they share an internal feature that reflects their common origin. Or they may be etched with consecutive numbers (e.g.,‘7691’, ‘7692’,…) so that their internal features compose a recognizable pattern, regardless of whether there are more specific features they have in common. But even if they bear no such internal marks, they still form a unified, causally salient class, viz., the class ‘Products of Factory A’. The factory’s causal continuity grounds the causal salience of that class, as products of the same cause.
For instance, suppose that the machine that produces disc brakes is gradually deteriorating. The deterioration leads each disc brake it produces to be a bit less round – slightly further from perfect roundness – than the last. Now while the machine itself does not belong to the class ‘Products of Factory A’, the cars that are part of that class are causally unified in that they are all products of a common cause. The decreasing roundness of their brakes, due to the ongoing deterioration of the machine, is one illustration of this causal unification. The deterioration merely reflects the causal unity: the cars would be causally unified, in the sense that I intend, even if the machines were always in ideal working order.
A similar picture applies to occurrent states. (For simplicity here, I’ll assume materialism about standing states; the picture could be adjusted to apply to dualism about such states.) Suppose that a number of occurrent states have a shared origin. They spring from states, including standing beliefs and non-mental states, of a persisting physical organism, perhaps together with salient features of its environment. This shared origin may produce occurrent states that share internal features: e.g., one’s occurrent states may share a quality of hopefulness because they spring from physically-based dispositions to be optimistic. Or they may have complex rational interrelations that depend on non-mental states: e.g., yesterday’s occurrent belief ‘It will rain tomorrow’ may cause a standing belief to that effect, which the next day causes the occurrent belief ‘it will rain today’.
But as in the factory case, it is the causal continuity of the shared origin itself that renders the states causally unified. Any shared internal features or coherent rational structure is unnecessary – for instance, it is not present in the presumably jumbled occurrent states of Alzheimer’s patients like Otto. And the shared origin needn’t be included in the class of occurrent states in order to ground the class’s causal unity, any more than the factory needs to be included in the set of cars to ground that set’s causal unity.
How much psychological continuity do we possess? Some of us are psychologically stable, consistent, and predictable. These steady types experience occurrent states that follow previous occurrent states in fairly predictable ways. (Modulo the continuity of external stimuli, of course.) So the claim that the mind or self is constituted by occurrent states does not raise the specter of radical discontinuity, when applied to these stable individuals.
The more problematic cases are those individuals who undergo a series of radically disparate occurrent states. Taking these unstable minds to be constituted by the series of sets of occurrent states seems to threaten psychological continuity, just as C&C allege. But I don’t think that this is a problem. First, I think that it makes sense to deny that unstable characters enjoy one sort of psychological continuity, viz., the continuity involved in one’s experiences and thoughts seeming, to one, to have a rational structure. The lack of apparent rational structure among occurrent experiences and thoughts is, after all, why dementia and Alzheimer’s disease leave their victims so bewildered.
But there is another sense of ‘psychological continuity’ that even the least stable individuals possess. This is the continuity that is responsible for the fact that the succession of wildly varying, seemingly unrelated states is fully explainable. The factors that explain it are underlying physical states and processes. The point of contention between my view and C&C’s concerns whether these underlying factors – which include standing states and nonconscious processes – are themselves part of the mind. I have argued that, in a strict, principled sense of ‘mental’, they are not. They are outside the realm of introspectibility; and including them within the mind will extend the range of a subject’s actions to staggering proportions. There are therefore strong reasons to deny that merely standing states and nonconscious process are, strictly speaking, part of the mind.
Obviously, many questions remain. But I hope to have shown that a serious alternative to extending the mind is to reject premise (4) of C&C’s argument, and to limit the mind to occurrent, conscious states and processes. In fact, I think that this fits with their claim that “when it comes to belief, there is nothing sacred about skull and skin”. I fully agree with this conclusion, but I draw a different moral from it. They conclude that some external states and processes are mental; I conclude that some internal (standing) beliefs and (nonconscious) cognitive processes are non-mental.
It is surprising to think that standing beliefs and nonconscious processes lie outside the mind, even if they are inside the brain. Still, on balance, this conclusion seems less costly to intuitions and hence ultimately more credible than the claim that our mind can extend to notebooks, external computing devices, and others’ minds.9