The theories I have been considering are non-reductive. They suppose that the phenomenal I is something above and beyond the
things experienced by that I. Such theories incur a heavy burden because it is difficult to find anything in experience above
and beyond the items delivered to our senses. All
contents of consciousness seem to be perceptual. If we were to list each perceptual feature that we were experiencing at a
given moment, including sensations of our own bodies, mental imagery, and subvocal speech, there would seem to be no remainder.
This is the central insight behind
Hume’s thesis, and it is very hard to deny. We have just seen two efforts to locate a self that transcends mere perceptual
qualia, but none is convincing. This suggests that
Hume was right. But, recall that
Hume’s thesis has two versions. The weaker version says there is no self
over and above the items we perceive. The stronger version says there is no phenomenal self at all. One could try to challenge the stronger
version by offering a reductive account, on which the phenomenal I gets equated with some subset of the many things we happen
to be perceiving in any given moment. Some privileged subset of conscious perceptions may qualify as the perceiver – the subject
of experience. As
Damasio (
1999) puts it, the I may not be the viewer of an internal movie, but rather an object in the movie. This is the
kind of approach I want to consider now, and
Damasio will be the first example.
Damasio came into widespread recognition because of his (
1994) work on emotions. Here he resuscitated a theory that originates with William James and a Danish physician, Carl Lange. On
the James–Lange theory emotions are not the things that cause us to laugh, or cry, or flee, or fight. Rather, they are perceptions
of patterned bodily changes that include such characteristic responses. When an emotionally significant stimulus is encountered,
it triggers a bodily change that prepares us for a behavioral response, and then the mind perceives this change, and our experience
of that bodily perception is the emotion.
Damasio argues that contemporary research in psychology and neuroscience (including his own field, neurology) supports the
James–Lange theory, and I have argued at great length elsewhere that he is right (
Prinz
2004). But,
Damasio also thinks that this story can help provide an account of
self-consciousness, and here we part company.
Damasio’s (
1999) story goes like this. Emotions are short-lived events that arise in response to specific elicitors, but emotions are not
the only mental events in which we perceive changes in our bodies. In reality, we are perceiving our bodies all the time,
and emotions are just one special case of this broader phenomenon.
Damasio (
1994) calls such perceptions “background feelings” and, despite the term, he thinks these can go on unconsciously. In his (
1999) book, he says we can think of these background feelings as a “proto-self” for reasons that will become clear in a moment.
Background feelings are not constant over time, but rather change incessantly as objects in our environment impinge on our
senses. When we see something or hear something or smell something, the body reacts.
Damasio speculates that the nervous system must keep track of these changes; it must monitor how the world is affecting the
body at all times. To do this, there must be “second-order maps” – representations of the first-order bodily representations
as they undergo changes.
Damasio thinks these second-order representations are conscious, and he thinks they constitute a basic form of self-consciousness
shared by humans and other animals. To experience the feelings constituted by fluctuations in your body is, according to
Damasio, to experience yourself.
Damasio calls this the “core-self” and he distinguishes it from the “autobiographical self” which involves the reliving of
episodic memories. The autobiographical self is not found in all animals, and can be absent in people with anterograde
amnesia. Its status as a form of self-consciousness depends, in part, on the fact that when we relive memories, we experience
the core-self acting in events from the past. The core-self is essential for self-experience. As I understand him,
Damasio thinks the
core-self is necessary and sufficient for having an experience of one’s self as a subject.
Damasio’s account of self-consciousness echoes themes in William James’ discussion of that topic. James is interested in how
we feel like the same self from moment to moment – the qualitative counterpart of personal identity –
and he suggests that continuity of bodily experiences plays an important role: “
Resemblance among the parts of a continuum of feelings (especially bodily feelings) experienced along with things widely different in all other regards,
thus constitutes the real and verifiable ‘
personal identity’
which we feel” (James
1890, 336, original italics).
The bodily feeling proposal has some intuitive plausibility. First of all, the body is part of the person, so an experience
of the body, unlike an experience of some object out there in the environment, is an experience of the self, in some sense.
Second, changes in the body reflect a person’s subjective responses to the world, including emotional responses, as well as
the myriad unnamed responses we have to everything we encounter. Everything makes us feel some way, and tracking those feelings
is, to that extent, tracking subjectivity. Third, there may be repeatable or predictable bodily responses that correspond
to enduring aspects of the self such as values and personality traits, which are part of personal identity. The way my body
reacts reflects something about who I am as a person, and I can recognize those reactions as such. I can also notice that,
on some days, I do not “feel myself” because my reactions are different than they normally are. Here again, we find something
very self-like in the experience of the body.
Given all this, it is very tempting to adopt the Damasio–James approach and identify the phenomenal I with the experience of bodily feelings, associated with second-order
bodily maps in the brain. But I think this temptation should be resisted. I think the experience of our bodily feelings is
neither necessary nor sufficient for a phenomenal experience of one’s self as a subject.
Let us begin with necessity. The intuition that bodily feelings contribute to self-awareness is strongest when we imagine
encounters with physical objects that matter to us. If a loud noise startles me, for instance, I will feel a strong sudden
response in my body. Attention is drawn inward as I feel my body reacting to the sound. But there are many other cases where
the experience of the body is less pronounced without any loss in the impression that I am the subject of my experiences.
Consider intellectual exercises such as reflecting on philosophy, answering crossword puzzle questions, or performing calculations
in your head. Such activities might engage the body but, intuitively, they need not. To take one simple case, imagine
counting backwards from 100. It seems very plausible that, while doing this, one periodically loses conscious experience of
the body for brief moments. Indeed, there is evidence that tasks involving working memory tend to suppress activity in brain
structures associated with emotion and bodily experience (
Yun
et al.
2010). But, when that happens, the task seems no less agentic, no less self-involving. I am not claiming that there is some phenomenal
I present in counting backwards, which is preserved when we stop experiencing the body. I think there is no experience of
an I in either case. My present point is that
Damasio’s theory predicts that a phenomenal I should disappear when body awareness does, and this seems implausible. Body
awareness does not seem necessary at all.
Nor does body awareness seem sufficient for a sense of self. To see this, consider the phenomenon of emotional contagion (
Hatfield
et al.
1993). Emotions are catching. If I see you grimace in anger, I will undergo the corresponding bodily change, and feel a flash
of anger too. It turns out that this capacity may play a crucial role in emotion attribution. My ability to know what you
are feeling depends to some degree on my ability to catch your emotions. We use our own bodily switchboard to attribute feelings
to others. This is confirmed in many neuroimaging studies, showing that the same brain structures are used to both experience
emotions and to recognize them in others, and injuries to these structures result in deficits of both experience and attribution
(
Adolphs
2002). Now, imagine a case where I recognize an emotion in you. Perhaps I see that you are mad. The science suggests that I do
this by first mirroring your bodily expression in my own body and then feeling that change in me. Still, there is no temptation
for me to say, I am mad. I might not be. I feel madness, but I do not feel like it is mine. The madness I feel is, in some
sense, yours. I feel through myself; but it does not feel like myself that I am feeling. There is no subjective ownership
of the felt state. This suggests to me that we can feel patterns of change in our own bodies without that feeling constituting
a phenomenal I. This may sound paradoxical (how can I feel my body as you?), but perplexity subsides when you recall that
a bodily feeling is just an inner state that registers basic physiological facts: a heart is racing, muscles are tensed, breathing
is constrained, and so on. It seems plausible that one could become aware of those facts without thereby experiencing them
as facts about me. For example, if my brain could get wired to your heart, I could feel your heartbeat, just as I do when
I put a stethoscope to your chest.
Finally, it should be pointed out that, if bodily feelings were the basis of
self-consciousness we should find a correlation between these feelings and the degree to which one experiences a sense of
self. But that does not seem to
be the case. The sense of self neither increases or decreases with felt bodily changes. For example, consider very intense
emotions. These do not seem to engender a greater phenomenal sense of self than mild emotions do. Terror after hearing an
intruder enter your house does not feel more self-like than does mild delight while strolling on the beach. Indeed, with intense
emotions focus is often more outward than inward: the terror makes you forget yourself for a moment and focus intensely on
the sounds coming from the intruder. Conversely, a sense of self can increase without a change in the intensity of bodily
experience. Emotions, again, can illustrate. Consider a familiar contrast between shame and guilt. With guilt we focus on
some offending act, and, with shame, we focus on the self. When ashamed, one feels like a bad person. Both emotions can be
equally intense, and hence the bodily feelings are equally vivid, but one seems to involve a greater degree of self-awareness.
I am not suggesting that there is a phenomenal I in either of these emotions (I am skeptical about the phenomenal I), but
if there is anything at all to the idea that experiences can relate to the self, shame seems to be a better case than guilt.
The difference may involve the thoughts and actions that come to mind when shame is experienced: there is a desire to conceal
one’s self, a feeling of being impure, and a self-conceptualization as a bad person. These specific contents, not the degree
of bodily involvement, add up to a pattern of behavior and judgment that can be characterized as self-focused. The intuition
that some mental states involve a greater degree of self-awareness seems to track the degree to which those states lead us
to think about ourselves, not anything about their bodily character.
This leaves us with just one question. Why do we use locutions such as, “I don’t feel like myself today” when our bodily responses
depart from their usual pattern? Doesn’t this suggest that feeling one’s self is a matter of feeling one’s body? I do not
think so. When one says, “I don’t feel like myself today,” one is comparing a current experience to the past. It does not
require a feeling that is feeling myself in the past, but rather the knowledge that certain feelings are typical for me, and
the judgment that those typical feelings are not arising in the present. Recognizing variation in feelings is no more self-involving
than recognition of variation in behavioral performance. Suppose I am a good ping-pong player and have an off day. I can say
“I’m not playing like myself today.” And, in saying this, I am not implying that there is subjective feeling of self-ness
present on most days but absent on this one. I am saying that my response patterns are diverting from the statistical norm.
By analogy, if I am normally giddy but feel depressed today, I might say, “I don’t have those feelings I usually feel.” In
saying this,
I am not saying I have lost my phenomenal I. Perhaps there was never one to lose.
One difficulty with identifying the phenomenal I with feelings and emotions is that there seems to be nothing paradoxical
about an unfeeling self. Another difficulty is that the mere presence of feelings does not yet decide between self and other:
we need a story about what makes feelings count as mine. Both of these concerns are addressed by another approach to the phenomenal I, which has been gaining momentum in cognitive science. It is the view that the experience of a self can be reduced
to a feeling of body ownership. The phenomenal I emerges when we feel our own bodies and feel them as belonging to ourselves.
This view bears a resemblance to the view advocated by James and Damasio, because it places emphasis on the body, but it shifts from inner feelings and emotions, which are associated primarily
with visceral changes, and focuses on bodily position and location. Here, the most relevant sensory qualities are proprioception
and kinesthesia, which help us determine the configuration of our limbs and torso in space. By shifting away from the viscera,
the view avoids an implausible commitment to the view that emotions and feelings are essential to the experience of selfhood.
Perception of body position can be present even when experience of emotions and feelings is not.
That said, a mere feeling of a body in space is not sufficient for a sense of selfhood. Just as you can feel emotions without
feeling them as yours, you can feel a body without feeling it as yours, even if it happens to be your own body. This may seem
paradoxical, but the possibility is brought out clearly in some pathological cases. Consider, for example, alien hand syndrome
in which a person comes to believe that one of his or her own hands belongs to someone else. For example,
Moro
et al. (
2004) describe patients with right brain injuries who suffer from a lack of feeling in their left arms (a syndrome often co-morbid
with unilateral visual neglect); when these patients cross their arms, some feeling is restored, but they continue to insist
that the affected limb does not belong to them. Healthy people may also be capable of experiencing bodily sensations without
feeling a sense of self. Indeed, this may be commonplace in social cognition. Just as we use our own emotion systems when
perceiving emotions in others, we use our own capacity for bodily sensation when perceiving the bodies of others. For example,
Keysers
et al. (
2004) found activation in somatosensory cortex when individuals
watched another person’s leg being touched. Thus, any theory that identifies the phenomenal I with perception of bodily position
needs a further element: an account of how the body feels like it is mine. This is often called a sense of ownership.
Body ownership has been intensively studied in recent cognitive neuroscience. One popular strategy is to investigate cases
where the ordinary sense of ownership breaks down. Consider out-of-body experiences, in which one seems to occupy a ghostly
imaginary body that hovers in the air or stands beside one’s real body. This may sound dubiously mystical, but actually such
experiences are relatively common. Moreover, they can be induced in the laboratory, and they can also arise with high prevalence
after certain brain injuries.
Blanke and
Metzinger (
2009) review this literature, and they argue that research on out-of-body experiences can help us identify brain structures associated
with body ownership. Normally, people feel as if they own their real bodies, but in these exotic cases, ownership shifts to
a new imagined body.
Blanke and
Metzinger reason that the underlying mechanism may be the neural correlate of felt body ownership, which they regard as a
minimal form of the phenomenal self. (More elaborate forms of phenomenal selfhood arise when this minimal self is integrated
into a global workspace.) To find the mechanism, we can look for the brain area that is active when people have out-of-body
experiences and that leads to such experiences when damaged. Here, all signs point to the right temporoparietal junction (de
Ridder
et al.
2007). This,
Blanke and
Metzinger surmise, is the neural correlate of the phenomenal I.
There is a problem with this inference, however, and it has to do with what we know about the right temporoparietal junction.
This region is also known to be active in mental-state attribution (
Saxe and
Powell
2006), and when subjects imagine another person performing an action (
Ruby and
Decety
2001). Such findings suggest that the region has more to do with a sense
of the other than a sense of the self. And, indeed, this makes sense in the case of out-of-body experiences. Such experiences typically
involve seeing one’s real body (or sometimes the imaginary body) as if it were another person. So the temporoparietal junction
may not be the seat of body ownership after all. To find the mechanism, we must consult other research.
The most promising line of investigation involves a class of perceptual illusions that are, in a way, the inverse of out-of-body
experiences. When people have out-of-body experiences, they can see their real bodies without a sense of ownership. But there
are also cases in which persons experience artificial bodies or body parts as their own. Under certain conditions, we can
be made to feel like we are located in the body of a mannequin, a virtual
avatar, or even a block of wood. The most studied demonstration of this phenomenon is the rubber hand illusion (
Botvinick and
Cohen
1998). Here, a rubber hand is placed in front of a person while that person’s real hand is hidden from view. Then both the real
and the rubber hand are stroked using a paintbrush at the same time. After a short time, many people begin to experience the
rubber hand as if it were their own. They even misremember the location of their real hand after the procedure is finished,
locating it closer to the rubber hand than it actually was. The rubber hand illusion is well suited to study the sense of
body ownership because it involves both a feeling of the body in space and an impression that the body belongs to the self.
Tsakiris
et al. (
2007) set out to identify the neural correlates of body ownership by inducing the rubber hand illusion inside an fMRI scanner.
In comparison to a control condition in which the rubber and real hand are stroked out of sync, the illusory sense of ownership
was associated with activity in the right posterior insula and the right frontal operculum. The frontal operculum has been
associated with motor planning in a TMS study (
Tunik
et al.
2008), and the insula is associated with body perception and control (
Critchley
et al.
2004). Indeed, the right posterior insula has been directly implicated in other research as a basis of ownership.
Farrer
et al. (
2003) found that activation in this region correlates with a sense of control in a task involving a virtual hand.
Karnath
et al. (
2005) found that injuries here are associated with anosagnosia for paralyzed limbs, suggesting that an inability to monitor limb
ownership results in a failure to recognize when an owned limb is not responsive.
To understand the role of the right posterior insula, it is helpful to understand how the rubber hand illusion works. We can
experience our bodies using a number of senses: we can see a limb, feel something touching a limb, and experience position
through proprioception. Normally such experiences converge on a single location in space, but, in illusory cases, that fails
to happen. Seeing a rubber hand while feeling a paintbrush shifts the proprioceptive sense of location into the region occupied
by the rubber hand. The visual representation of location dominates the proprioceptive, causing the shift. Against this background,
it is reasonable to speculate that the right posterior insula plays a role in sensory integration. It brings the different
sources of information together and facilitates the proprioceptive shift. The feeling of ownership may arise when senses are
brought together. I can feel a hand without it feeling like mine (as in alien hand syndrome), but if the hand I feel is integrated
with the hand I see in the right way then it feels like mine.
The results of the
Tsakiris
et al. (
2007) experiment may seem somewhat puzzling at first. The authors found
more activation in the right posterior insula when subjects experience the rubber hand illusion than in the control condition
when there is no illusion. But, in both conditions, subjects presumably have a sense of ownership; the difference concerns
only the accuracy of that sense. Moreover, in the control condition, there is greater activation in somatosensory cortex than
in the illusion condition, even though both conditions involve a tactile feeling on the hand. Perhaps what is going on here
is a shift in attention. In the control condition, subjects may be focused on the sensation in the hand, and then in the illusion
condition they focus on the sense of ownership because they are surprised to feel the rubber hand as their own. In addition,
the increased insula activation may reflect the extra neural work that is involved in forcing visual and proprioceptive information
to come into alignment, despite the initial mismatch.
In summary, then, it does seem that the right posterior insula is playing a role in sensory integration and that integration
of bodily representations supports judgments of ownership. Tsakiris et al. regard this as a kind of self-consciousness, and surely, in some sense, they are right. When I experience a body (real or otherwise) as mine, I am
experiencing something as relating to myself. But things get a little bit thorny when we try to unpack that relation. Ownership
is normally thought of as a two-place relation. Body ownership is a relation between a body and a self. It cannot be, however,
that the phenomenal experience of body ownership involves two relata: a feeling of the body and a feeling of a self. Those
interested in the feeling of ownership want to explain the latter in terms of the former. Thus, the feeling of ownership has
to be understood in a non-relational way, if that makes any sense. Or rather, it is experienced in the integration of multiple
experiences as of a body. Thus, there is an n-place relation here but no component is privileged as owner of the other components.
Once we see this, we can see a problem for any attempt to explain the phenomenal I in terms of body ownership. For the question
arises, where is the I in experience? The I cannot be identified with any part, because each bodily perception on its own
can be had without a sense of it belonging to the self. So the I must be experienced in the relation or, more plausibly, in
the various components as they are related to one another. But what is it to experience two bodily perceptions as related
in this way? It will not do to say we experience them as belonging to the same self, because then we need to experience a
separate self to which they are related. Instead, we must just experience them as bound together like two features of an object.
Perhaps
we achieve this using a map strategy – perhaps visual, tactile, and proprioceptive experiences can be linked to a shared unconscious
body map. This analysis treats bodily unity in the same way unity is explained more broadly. Body perceptions are bound together
the way color is bound to shape. If this is right, it may cast doubt on the view that the experience of body ownership can
be accurately described as a phenomenal experience of the self. Instead, it seems to be an experience of a bound whole, with
no more claim to being me than my polysensory experience of your body when I simultaneously see you and shake your hand. In
other words, what began as a theory of ownership turns out to be no such thing. It is just another case of polysensory binding
and does nothing to bring anything especially self-like into experience.
Now hold on, you might object, surely when you unify the sensory components of your own body it feels more like yourself than
when you unify the sensory components of someone else’s body. After all, I do not confuse myself for you. True enough, but
this objection only serves to highlight the deeper concern. The question is, why don’t I confuse myself for you? One might
think that the answer has to do with the specific qualities that get bound together. Proprioceptive and tactile sensations,
in particular, seem to be uniquely self-involving. But this possibility has already been rejected. I can experience these
qualities without experiencing them as me. Indeed, it may well be that when I form an integrated representation of someone
else’s body, I do so by generating an integrated mental image using my own proprioceptive and tactile mechanisms. I may simulate
what it is like to be the other. If so, when I encounter another I may have two tactile-proprioceptive unities in mind, and
there may be nothing in those polysensory bundles as such that determines which one is me. This problem comes out all too
vividly in the case of out-of-body experiences. The person who drifts outside of her own body will experience two polysensory
somatic bundles. The fact that they are unified is not what makes her identify with one of these bundles as opposed to the
other. She might feel both bundles simultaneously, but only identify with one. Thus, identification cannot simply be a matter
of sensory integration. Something else must be going on.
I am arguing, in effect, that the phenomenal sense of ownership cannot simply be a matter of integrating multiple bodily representations.
More pointedly, I think it is misleading to ever talk about phenomenal ownership of the body, because there is nothing like
an experience of an owner bearing a relation to bodily perceptions. I am not denying that we can form
judgments about ownership. I know that my limbs belong to me. But there may
be no
experience of ownership. There may be an experience on the basis of which we
infer ownership, but the experience must involve more than an integrated body-representation. Such a representation is not sufficient.
Moreover, even if an integrated bundle of bodily perceptions were sufficient for a sense of ownership, it is far from obvious
that it would be sufficient for having a sense of one’s self as a subject, as opposed to an object. If I feel a pain in the
foot, I might be able to perceive that the affected foot is mine, but it does not follow that I experience the foot as a subject
of thought, experience, and action. The foot does not correspond to the “I” in the ascription “I have a pain in my foot.”
There is a gulf between “my” and “I.” The thesis of this chapter is that there is no phenomenal I, and integrated bodily representations do not allay that skepticism. If there were a phenomenal sense of ownership
(which I doubt), it would not qualify as a phenomenal experience of being a subject.
I would add that having integrated bodily representations is also not necessary for having a sense of self. It seems perfectly
possible to have one kind of bodily perception in the absence of others. An anesthetized person may lose the sense of touch,
a severely dizzy person may lose coherent proprioceptive information, and a blind person will have no visual experiences of
the body. Yet none of these conditions prevents a person from using the intact faculties to identify the self. This point
is poignantly illustrated in the case of
Ian Waterman, who lacks proprioception and touch (
Cole
1995). Waterman locates his body using vision, and has as much claim to knowing where he is and how his body is positioned as
someone with a more diverse sensory repertoire. He faces challenges in the dark, of course, but, when vision is available,
he can recognize that his limbs are his own.
In summary, I see several serious hurdles for those who want to find the phenomenal I in the experience of body ownership.
First, a sense of ownership would not be sufficient for a sense of self as subject. Second, the leading theory of body ownership
– integration of bodily perceptions – is not sufficient for explaining how we judge that a given bundle of bodily experiences
are mine. Third, integration of bodily perceptions is not necessary for making such judgments. Fourth, there may not even
be such a thing as the phenomenology of ownership.
The notion of ownership has been contrasted in cognitive neuroscience with the notion of authorship.
Ownership is the feeling associated with a
mental state belonging to me.
Authorship, also called “agency,” is the feeling associated with being the author of physical and mental acts. It is identified
with a feeling of control. I experience some thoughts and actions as issuing from me. Like ownership, agency involves a kind
of possession: the acts I control are mine. But it is an active form of possession, and this, one might think, introduces
an entry point for the self. With passive perception, the world can pass by the senses without any sense of being a subject,
but with active agency, the self seems to come in essentially. Perhaps the phenomenal I is an experience of oneself as the
author.
This proposal overcomes the four problems adduced in response to the suggestion that the phenomenal I derives from a sense
of ownership. First, I said that ownership is not sufficient for a sense of oneself as subject, but, as just intimated, authorship
is a form of subjectivity par excellence; to experience oneself as author is to experience oneself as the subject of an act – as the I, as opposed to the me. Second, I said the leading theory of ownership could not explain how a bundle of experiences feel like they are mine. Authorship
may provide the solution. If I experience two separate bundles of bodily perceptions, I can figure out which one is mine by
figuring out which one I control. A sense of control can provide a greater sense of mineness than mere sensory integration because it brings in a motor element that provides for a robust sense of possession; my body is the one that
obeys my intentions in predictable ways. The element of control may help explain why the frontal operculum, a motor control
structure, is active in the rubber hand studies. We imagine owning the rubber hand, in part, by preparing to issue action
commands. Third, I said that sensory integration is too demanding, because people with just one bodily sense have no difficulty
judging which body is theirs. Authorship handles this easily, because one can recognize one’s control over a single dimension
of bodily perception, without reference to any others. Ian Waterman can confirm his bodily control using vision to see that
his limbs obey his movements. Finally, I raised doubts about whether there even can be a phenomenology of ownership, because ownership requires an owner. With authorship, things are easier, because there is a functional and anatomical
separation between the intentions or commands we issue and their subsequent effects.
One might try to argue against this approach by maintaining that authorship is never directly experienced but only inferred.
One such argument can be distilled from Wegner’s (
2002) critique of the conscious will.
Wegner argues that we derive a sense of control when we experience a conscious intention that meets three conditions: it occurs
just before an observed effect (priority), it is consistent with the observed effect
(consistency), and it is the only salient event that meets these first two conditions (exclusivity). Wegner’s main point is
that the sense of control can be an illusion, because these three conditions can occur even when there is no causal link between
intention and effect. Suppose, for example, that my limbs are controlled by unconscious motor commands, but those commands
also generate conscious intentions to move – intentions that dangle idly without having any impact on my behavior. The intentions
occur before the movement, are consistent with it, and are the only conscious precursor, so I conclude that my intentions
are efficacious. Wegner’s theory can also be adapted to raise a skeptical worry about the phenomenology of authorship. If
he is right, control might not be something we experience; it may be something that we simply infer from conscious intentions
and conscious bodily movements. This would spell trouble for defenders of the
phenomenal I, because one can surely experience an intention or a movement without feeling any quality that corresponds to
being a subject. Indeed, as Wegner points out, in some cases we experience intentions and actions without inferring control
because alternative explanations become available. In one experiment, he asks subjects to press True or False on a keyboard
in response to questions, but subjects are instructed to provide answers on behalf of another person by feeling minute muscle
movements in that person’s hand, rather than providing their own answers. In actuality, the other person cannot even hear
the questions, so the answers derive entirely from the subjects, but they nevertheless believe that the other person is selecting
the answers. Intention and action are both experienced but subjects infer a lack of control (
Wegner and Wheatley
1999). This experiment shows that control is not part of the phenomenology, but is only inferred by an argument to the best explanation.
The Wegner story gives us reason to be cautious in assuming that there is a phenomenal experience corresponding to authorship.
It is possible that, in many cases, authorship is merely inferred. But Wegner’s theory is not the only game in town
. In cognitive neuroscience there has been an active campaign to find the neural correlates of authorship, and the people
conducting this research think that authorship can be phenomenologically experienced and they even have an explanation of
how this occurs. The leading story stems from research on motor control. According to prevailing theories of motor control,
intentional action begins when an intention is converted into a motor command by a mechanism called a “controller” (or sometimes
an “inverse model”). The controller outputs motor commands, and it also sends “efference copies” of those commands to a mechanism
called a “forward model” which uses the copy of a command to generate a
prediction of how the body will move when the command is carried out. Meanwhile, the body carries out the command, and sensory
transducers register the resultant changes, which are called reafferent signals. The reafferent signals are compared to the
predicted outcomes by means of a
comparator – a mechanism that determines whether predicted and actual movements are alike. This account has been adapted to
explain the phenomenology of authorship (
Wolpert
et al.
1995). We experience actions as our own when a predicted action and a perceived action match. If our bodies move in unpredictable
ways, we lose the sense of agency. This happens, for example, when something pushes into us, causing the body to move without
a prior motor command
.
The comparator model explains a number of interesting phenomena. It explains why it is so hard to tickle yourself (
Blakemore
et al.
2000). Tickling seems to depend crucially on unpredictability. If you try to tickle yourself, your motor system will accurately
predict the hand movements, and you will lose the crucial element of surprise. The comparator model also explains some striking
pathologies in the
phenomenology of agency. There are cases of alien and anarchic hand syndrome where patients feel that an appendage is not
in their control even though they can feel its movements (
Biran and
Chatterjee
2004). These patients characteristically describe the disobedient hand in the third person, as if it did not belong to them. The
syndrome is typically associated with damage to the corpus callosum, which allows for communication between the hemispheres.
That damage may prevent one hemisphere from predicting actions controlled by the other, giving rise to the experience of alien
control.
So far, the cases I have been discussing involve motor behavior. A nice feature of the comparator model is that it can be
adapted to explain the experience of authorship in cognitive processes as well (
Frith
et al.
2000; Hohwy
2007; though see
Vosgerau and
Newen
2007). One can explain the sense that a thought is my own by supposing that prior to generating a conscious experience of the
thought, we anticipate what that experience will be like. The two are then compared, and if the thought is as predicted, it
seems to belong to us. If not, it seems to come unbidden.
Frith
et al. (
2000) use this model to explain the experience of thought insertion in schizophrenia. A thought that comes without being predicted
may seem to come from some external source, as if it has been planted in the head. People with schizophrenia may experience
their own thoughts this way because of a malfunction in their comparator mechanisms.
The extension of the comparator account to thought is a big advantage. One problem with the ownership theory discussed in
the
last section, as well
as
Damasio’s account of
self-awareness in terms of feelings, is they place too much emphasis on the body. If there is a
phenomenal I, it would be extremely surprising that it could manifest itself only through the body (see also
Strawson
1999). After all, we are subjects of thought just as much as we are subjects of physical actions. There may even be conditions
under which all bodily
phenomenology is lost (sensory deprivation tanks? locked-in syndrome?), but there is no reason to think that such conditions
essentially involve any less sense of selfhood than we find in the case of physical actions. For those who think the body
is inessential to the sense of selfhood, the comparator model is surely attractive.
In sum, the comparator model provides an elegant and unified account of authorship. It locates the experience of authorship
in a process that is well motivated by theories of motor control, and it extends nicely to cases of cognitive ownership as
well. It also offers a tidy explanation of cases in which authorship seems to be lost. All this is very good news for those
who want a reductive account of the phenomenal I. In authorship, unlike mere ownership, the self functions as the subject
of a thought or act. Thus, authorship gives us an I rather than a mere me. It is, therefore, tempting to equate the phenomenal
I with the phenomenology of authorship, which, in turn, can be equated with the experience of a successful matching process in an output/input
comparator.
This account of agency differs from Wegner’s in that it treats authorship as an experience, rather than as a mere inference.
But it can be easily reconciled with Wegner’s experimental findings and his skeptical hypothesis about free will. The comparator
model does not presuppose the causal efficacy of conscious intentions, because it is consistent with the view that motor commands
are initiated unconsciously. Wegner may be right that conscious intentions lack efficacy and are linked to actions through
an inferential, rather than phenomenological process. Wegner’s experiments on erroneous lack of control may appear to conflict
with the comparator model, but this appearance can be explained away by a more careful look at the findings. In Wegner’s true-or-false
study, subjects judge that they did not choose which answer to type into the keyboard, but, if asked, they probably would
not deny feeling a sense of control when pressing the keys. They feel like the initial choice of which key to press has an
external source, but once that choice is registered, the subjects press the keys themselves and might experience a sense of
authorship in doing so. In other words, these studies do not show that authorship is inferential, rather than phenomenal;
they merely show that we can have false beliefs about the factors that lead us to carry out the controlled actions that we
experience.
It may look like we have found the phenomenal I at last. Appearances, however, can be deceiving. I think the comparator model
does offer a plausible theory of the processes by which we recognize agency and disruptions to agency, but I do not think it gives us the coveted I-qualia. I have two reasons for this disheartening assessment.
First, I think that the comparator model cannot, in the end, give us a phenomenology of subjectivity in the required sense; it continues to present the self as object rather than subject. To see
this, we need to consider the neural correlates of the comparison process (focusing here on the case of physical actions,
as opposed to thoughts). One might think that comparison involves a conscious experience of a motor command being matched
against a perceived movement. This would be something like an experience of authorship, because one would be experiencing
the command that created an action together with the action caused. The command could stand proxy for the self, in an act of agentic control. But,
in reality, the experience cannot be an experience of a motor command. For one thing, there is no evidence that we have motor
phenomenology. The best theories of phenomenology are theories of sensory phenomenology, and every experience associated with
motor response can be chalked up to a sensory experience of the corresponding movements. For another thing, the motor command
cannot be directly matched against a perceived action, because motor command and action perceptions are couched in different
neural codes; to make a match, we need to generate an anticipatory image of what the action will feel like perceptually and
then compare that to the actual perception. And finally, neuroscientific research on comparator models using fMRI and cell recordings in animals suggests that the comparison takes place in the posterior parietal cortex – a somatosensory
area – rather than motor cortex. If this is right, the feelings associated with authorship are really not experiences of an
author and an authored act; rather, they are experiences of an anticipated act and a real act. To experience the body acting,
whether through perception or anticipatory imagination, is to experience the self as object rather than as subject. Such an
experience is not a phenomenal correlate of the “I” in first-person reports. It is a correlate of the me. When I say, “I feel myself act,” what I report is an action, not an actor. Put more pointedly, there is no experience of
authorship. To suppose otherwise is to mistake a feeling that occurs when we are the authors of our actions for a feeling
of authorship itself. It is to mistake the effect for the cause. When we use the experience generated by the comparator to
judge that we are in control, the judgment is inferential, rather than a direct report of the phenomenology.
The second complaint I want to advance against the comparator theory of phenomenal authorship is that its defenders give the
erroneous impression that the comparison process itself has a phenomenal character. If authorship had a phenomenology and the comparator theory of that phenomenology were true, then we might expect to find, in controlled action,
a phenomenal experience of an anticipatory image being compared with a perceptual input from the body. But when we act, we
find no such thing. We experience only our bodies in action. There is one experience, not two. It is a single unified perceptual
experience of action, not a comparison between image and percept. It is the same for the phenomenology of thought. When we
experience subvocal speech, for example, we do not experience an anticipation of this silent narrative, followed by the narrative
itself – much less a matching between two verbal streams. We just experience one stream of speech. This suggests either that
the comparison process is entirely unconscious, or that the anticipated act and the experienced act blend into each other
seamlessly in experience. Either way, there is no hook to hang the selfy hat on. There is no item or process in experience
that we can label the I. There is an experience of the action, but not the actor.
Against this deflationary reading, one might object that we must be able to experience ourselves as actors because, otherwise, we would not be able to consciously distinguish cases of control
from cases where others act upon us. It does seem that we can tell the difference between lifting an arm and having an arm
lifted by another, but, if my arguments succeed both should be alike; in both we just experience the movement. It will not
help here to say that our own actions are accompanied by feelings of effort while externally caused actions come accompanied
by resistance, for some self-controlled actions are effortless and some other-controlled actions meet with no resistance.
The puzzle can be put like this: the distinction between internally and externally generated actions seems to be phenomenologically
available, and the comparator model offers a good explanation, but on my account of the phenomenology of the comparator model,
internally and externally generated actions should be phenomenologically alike because the matching process is unconscious.
I think we can solve the puzzle by considering what happens when the unconscious comparison process fails to find a match
between anticipated acts and perceived acts. Presumably, the experience of an uncaused action sets off a kind of alarm signal
that tells the body it has come under external influence. To cope with this fact effectively, the source of that influence
must be identified. So, if your body moves in an unpredictable way, your mind goes searching for the cause. You may find the
cause – perhaps
something or someone is forcing your body to move – and you may not – perhaps you had a spasm or a twitch. Either way there
may be a conscious experience associated with the recognition that an external source caused a movement. And there is no special
puzzle about having a phenomenal experience of external causes. You can experience someone or something acting on you, even
if you cannot experience yourself acting. Thus, there is a fundamental asymmetry here. We cannot be conscious of ourselves
as agents, but we can be conscious of others as agents. There is no phenomenology of being a controller, but there is a phenomenology
of being controlled. Ironically, we can feel the absence of the self (or rather, the presence of some external cause), but
not the presence of the self
.