ONE OF THE GUIDING ideas of this book is that the human mind is embodied in our entire organism and in the world. Our mental lives involve three permanent and intertwined modes of bodily activity—self-regulation, sensorimotor coupling, and intersubjective interaction (Thompson and Varela 2001). Self-regulation is essential to being alive and sentient. It is evident in emotion and feeling, and in conditions such as being awake or asleep, alert or fatigued, hungry or satiated. Sensorimotor coupling with the world is expressed in perception, emotion, and action. Intersubjective interaction is the cognition and affectively charged experience of self and other. The human brain is crucial for these three modes of activity, but it is also reciprocally shaped and structured by them at multiple levels throughout the lifespan. If each individual human mind emerges from these extended modes of activity, if it is accordingly embodied and embedded in them as a “dynamic singularity”—a knot or tangle of recurrent and reentrant processes centered on the organism (Hurley 1998)—then the “astonishing hypothesis” of neuroreductionism—that you are “nothing but a pack of neurons” (Crick 1994, p. 2) or that “you are your synapses” (LeDoux 2002)—is both a category error and biologically unsound. On the contrary, you are a living bodily subject of experience and an intersubjective mental being.
This chapter focuses on the second of these modes of bodily activity—dynamic sensorimotor activity. Earlier in this book we saw that the fundamental logic of the nervous system, its basic “neurologic,” is to couple movement and a stream of sensory activity in a continuous circular fashion. The nervous system links sensory surfaces (sense organs and nerve endings) and effectors (muscles, glands) within the body. In that way, the nervous system integrates the organism, holding it together as a mobile unity, as an autonomous sensorimotor agent. The nervous system establishes and maintains a sensorimotor cycle, whereby what one senses depends directly on how one moves, and how one moves depends directly on what one senses. One manifestation of our biological autonomy is that we meet the environment on our own sensorimotor terms.
In recent years, a new dynamic sensorimotor approach to understanding perceptual consciousness has arisen in cognitive science and the philosophy of mind (Hurley 1998; Noë 2004; O’Regan and Noë 2001a). Rather than appealing to the intrinsic properties of neural activity in order to understand perceptual experience, this approach looks to the dynamic sensorimotor relations among neural activity, the body, and the world. By thus enriching our conception of the biological substrate of perceptual experience, this approach offers new resources for tackling the explanatory gap. My aim in this chapter is to draw on these resources in order to make some headway on the body-body problem—the problem of relating one’s subjectively lived body to the organism or living body that one is.
The body-body problem is a non-Cartesian way of recasting the explanatory gap between the conscious mind and the physical body. As we have seen, in the body-body problem, the gap is no longer between two radically different ontologies (“mental” and “physical”) but between two types within one typology of embodiment (subjectively lived body and living body). The gap is also no longer absolute because in order to formulate it we need to make common reference to life or living being.
The body-body problem concerns the relation between one’s body as one subjectively lives it and one’s body as an organism in the world. This problem is in turn part of the general problem of the relation between oneself and the world, for one’s living body is part of the world and one’s body as one subjectively lives it is part of one’s sense of self. We can thus ask two interrelated questions: how does one’s lived body relate to the world, and how does it relate to itself? Addressing these questions is one way to approach the body’s sensorimotor subjectivity.
The relation between one’s self and the world encompasses the relation between one’s self and one’s body. Descartes, as we saw in the last chapter, pointed out that one’s self is not located in one’s body as a pilot within a ship but instead is “very closely joined” and “intermingled” with it, so that the two “form a unit.” Nevertheless, self and body remain two, not one. Merleau-Ponty, in contrast, rejects this dualism. One’s self is not merely embodied but bodily: “But I am not in front of my body, I am in my body, or rather I am my body” (1962, p. 150).1 Yet Merleau-Ponty also refuses to understand the proposition “I am my body” in a materialist way, as meaning that I am (or my self is) nothing more than a complex physical object. Instead, he maintains the original position that I am a bodily subject. In this way, he rejects the traditional concepts of mind and body, subject and object, as well as the ontologies they imply (dualism, materialism, and idealism) (see Priest 1998, pp. 56–57).
To appreciate the originality of Merleau-Ponty’s position, we need to consider his conception of bodily subjectivity. We can begin with Merleau-Ponty’s likening the unity of the body to the unity of a work of art. He introduces this idea by way of a contrast between the perceptual unity of a physical object through its perspectival variations and the experiential unity of one’s own body. A physical object, such as a cube, stands before me or over against me, and presents various facets to me; what perceptually unites these facets as facets of one and the same cube is the law of their perspectival variation. My body, however, does not stand before me or over against me, and what unites the various experiences I have of my body is not a law or rule of perspectival variation, but rather an integrated perceptual and motor “background of significance” (1962, p. 150). As Merleau-Ponty explains: “What unites ‘tactile sensations’ in the hand and links them to visual perceptions of the same hand, and to perceptions of other bodily areas, is a certain style informing my manual gestures and implying in turn a certain style of finger movements, and contributing, in the last resort, to a certain bodily bearing” (ibid.). It is this elucidation of one’s bodily subjectivity as constituted by a certain style or bearing that leads Merleau-Ponty to liken the body to a work of art:
The body is to be compared, not to a physical object, but rather to a work of art… A novel, poem, picture, or musical work are individuals, that is, beings in which the expression is indistinguishable from the thing expressed, their meaning, accessible only through direct contact, being radiated with no change of their temporal and spatial situation. It is in this sense that our body is comparable to a work of art. It is a nexus of lived meanings, not the law for a certain number of covariant terms. A certain tactile experience felt in the upper arm signifies a certain tactile experience in the forearm and shoulder, along with a certain visual aspect of the same arm, not because the various tactile perceptions among themselves, or the tactile and visual ones, are all involved in one intelligible arm, as the different facets of a cube are related to the idea of a cube, but because the arm seen and the arm touched, like the different segments of the arm, together perform one and the same action. (Merleau-Ponty, 1962, pp. 150–151)
This passage can help us to appreciate that when Merleau-Ponty asserts, “I am my body,” he does not mean that I as a subject am simply my body considered as an object. Rather, I am my body in a way not unlike the way an artwork is what it expresses. My body is an expressive being, and what it expresses is my subjectivity.
This expressive conception of bodily subjectivity points forward to Merleau-Ponty’s later chapter on “The Body as Expression and Speech” (in his Phenomenology of Perception). At the beginning of that chapter, in a footnote, Merleau-Ponty calls attention to two senses of “being”—a “weak sense of existence as a thing, or that of predication,” and a stronger “existential sense of belonging to . . . , or taking up (I am my body, I am my life)” (1962, p. 174). Clearly, the statement “I am my body,” as Merleau-Ponty means it, must be taken in the existential sense. Moreover, when we understand the statement this way, it becomes compatible with a certain way we can understand the statement “I have a body.” Merleau-Ponty calls attention to the two senses of “being” while discussing Gabriel Marcel’s distinction between “being” and “having.” Marcel uses “being” in the richer existential sense, whereas “having” “designates a proprietary relationship (I have a house, I have a hat)” (1962, p. 174). This proprietary relation is an external one, for my possessions are specifiable independently of me. Merleau-Ponty, however, points out that there is another sense of “having”—“for the relation which the subject bears to the term into which it projects itself (I have an idea, I have a desire, I have fears)” (ibid.). Here the relation is not external but internal, for what I have is not specifiable independently of me. Indeed, it “belongs” to me or I “take it up,” in the existential sense. The link between these senses in which “I am a body” and “I have a body” is precisely the expressive relation between my bodily being and my subjectivity.
In keeping with this original view, which aims “to leave behind us, once and for all, the traditional subject-object dichotomy” (1962, p. 174), Merleau-Ponty maintains that the relation between self and world is not that of subject to object but rather what he calls, following Heidegger, being-in-the-world. For a bodily subject it is not possible to specify what the subject is in abstraction from the world, nor is it possible to specify what the world is in abstraction from the subject: “The world is inseparable from the subject, but from a subject which is nothing but a project of the world, and the subject is inseparable from the world, but from a world which the subject itself projects” (1962, p. 430). To belong to the world in this way means that our primary way of relating to things is neither purely sensory and reflexive, nor cognitive or intellectual, but rather bodily and skillful. Merleau-Ponty calls this kind of bodily intentionality “motor intentionality” (1962,p. 110,137). His example is grasping or intentionally taking hold of an object. In grasping something we direct ourselves toward it, and thus our action is intentional. But the action does not refer to the thing by representing its objective and determinate features; it refers to it pragmatically in the light of a contextual motor goal effected by one’s body (1962, p. 138). In picking up a teacup to drink from, I identify it not by its objective location in space but by its egocentric relation to my hands, and I grasp it in light of the goal of sipping from it.
At the same time, things in my surroundings, such as teacups, computer keys, and door handles, have motor senses or meanings, what Gibson (1979) calls “affordances,” which elicit appropriate actions. Things in the world bring forth suitable intentional actions and motor projects from the subject (the subject is a project of the world), but things in the world have specific motor senses or affordances only in relation to the motor skills of the subject (the world is projected by the subject). This body-environment circuit of motor intentionality belongs to what Merleau-Ponty calls the “intentional arc” subtending the life of consciousness, which integrates sensibility and motility, perception and action (1962, p. 136). The intentional arc and being-in-the-world overall are neither purely first-personal (subjective) nor purely third-personal (objective), neither mental nor physical. They are existential structures prior to and more fundamental than these abstractions. For this reason, Merleau-Ponty maintains that they can “effect the union of the ‘psychic’ and the ‘physiological’” (p. 80) in an existential analysis of bodily subjectivity (and its breakdown in pathology).
In the intentional arc subtending the life of consciousness, one’s body is present “not as one object among all other objects, but as the vehicle of being in the world” (1962, p. 139). But if one’s body is the vehicle of being in the world and is in this way a condition of possibility for the disclosure of the world, how or in what way can it too be given to experience? This question asks about how one experiences oneself as a bodily subject or how a lived body experiences itself as a lived body.
One way to approach bodily self-consciousness is to work back from the world, which transcends the bodily self, to the body as the correlate of its perceptual presence. A familiar theme of phenomenology, going back to Husserl, is that the lived body is a presupposition of the world’s perceptual presence. Things are perceptually situated by virtue of the orientation they have to our moving and perceiving bodies. To pick up the teacup is to grasp it from a certain angle and to hold and manipulate it in a certain manner. To listen to the radio is to hear it from a certain vantage point, which changes as one moves about the room. To see the wine bottle on the table is to view it from a certain perspective and to see it as within or beyond one’s reach. If something appears perspectivally, then the subject to whom it appears must be spatially related to it. To be spatially related to something requires that one be embodied. To say that we perceive a given profile of something, all the while aware that it has other absent but possibly present profiles, means that any profile we perceive contains references to these other profiles; each profile implicates the others. These (noematic) references correspond to our (noetic) ability to exchange one profile for another through our own free movement, by tilting our heads, manipulating an object in our hands, walking around something, and so on.
The crucial point about the lived body in this context is twofold. First, the body functions as the “zero point,” “null point of orientation,” or absolute indexical “here” in relation to which things appear perspectivally. Second, the lived body cannot be reduced to yet another intentional object of perception but always exceeds this kind of intentionality. The lived body manifests itself in perceptual experience, not primarily as an intentional object but as an implicit and practical “I can” of movement and motor intentionality (Husserl 1989, pp. 266–277). Husserl contrasts this “I can” with Descartes’s famous “I think,” for the intentional structure of bodily subjectivity is not I think a certain thought (ego cogito cogitatum), but rather I can and do move myself in such and such a way (1989, pp. 159, 228, 273; see also Sheets-Johnstone 1999a, pp. 134–135, 230–232). In this way among others, perceptual experience involves a non-object-directed and implicit awareness of one’s lived body, an intransitive and prereflective bodily self-awareness.2
One can, of course, also experience one’s body as an object, for example, by looking directly at it or at one’s reflection in a mirror. In such cases, one is dealing with what has been called the conscious “body image” by contrast with the unconscious “body schema” (Gallagher 1986a, 1995). The body image is the body as an intentional object of consciousness. It is consciousness of the body-as-object (Legrand 2006). In the body image, the body is experienced as owned by the experiencing subject, and the image is typically a partial representation insofar as conscious awareness usually attends to only one part or area of the body at a time. The body schema, however, is not an intentional object of consciousness or a partial representation of the body, but rather an integrated set of dynamic sensorimotor processes that organize perception and action in a subpersonal and nonconscious manner.
This distinction between body schema and body image leaves out a fundamental form of bodily experience, namely, prereflective bodily self-consciousness (Legrand 2006; Zahavi 1999, pp. 98, 240). The body schema is not phenomenologically available to the subject: “The body schema … is not the perception of ‘my’ body; it is not the image, the representation, or even the marginal consciousness of the body. Rather, it is precisely the style that organizes the body as it functions in communion with its environment” (Gallagher 1986b, p. 549). One’s consciousness of one’s body, however, is not limited to the body image, nor is the body image the most fundamental form of bodily consciousness. On the contrary, most of the time one’s body is not present as an intentional object but is experienced in an implicit, tacit, and prereflective way. This kind of experience is consciousness of the body-as-subject. It corresponds to the relation of the lived body to itself, that is, to one’s experience of one’s body as perceiving and acting rather than as perceived.3 Sartre (1956, p. liii) describes this sort of self-consciousness as “non-positional” or “non-thetic” because it does not posit one’s body as an object; Merleau-Ponty calls it prereflective. Authors in the analytic philosophical tradition have described it as a nonobservational form of self-awareness (Shoemaker 1968, 1984).
The term prereflective is useful for our purposes because it has both a logical and temporal sense. Prereflective experience is logically prior to reflection, for reflection presupposes something to reflect upon; and it is temporally prior to reflection, for what one reflects upon is a hitherto unreflected experience.4
Prereflective bodily self-consciousness is evident in touch; not only do we feel the things we touch, but we feel ourselves touching them and touched by them. When I pick up a cup of hot tea, I feel the hot, smooth surface of the porcelain and the heat penetrating my fingers, and these sensations linger for a time after I have put the cup back down on the table. Such bodily experience offers not only the experience of physical events that relate one’s body to things, but also the experience of sensorial events that relate one’s subjectively lived body to itself. Usually these sensorial events are those in which one’s body does not sense itself explicitly. In picking up the teacup, I live through the heat in my fingers, but the perceptual object is the teacup, not myself. But one’s body can also sense itself explicitly, as when one hand touches the other. In this case, the one touching is the thing touched, and the thing touched senses itself as the one being touched.
Phenomenologists have reflected on this sort of bodily self-experience for a number of important reasons. There is a dynamic linkage of outward perception and inward feeling, so that one encounters one’s own bodily sentience directly. One’s body shows itself to be a material thing, but one animated from within by sensation and motility (Husserl 1989, p. 153). This form of bodily self-consciousness makes vividly apparent the lived body’s unique status as a physical subject:
When my right hand touches my left, I am aware of it as a “physical thing.” But at the same moment, if I wish, an extraordinary event takes place: here is my left hand as well starting to perceive my right, es wird Leib, es empfindet [it becomes body, it senses].5 The physical thing becomes animate. Or, more precisely, it remains what it was (the event does not enrich it), but an exploratory power comes to rest upon or dwell in it. Thus I touch myself touching: my body accomplishes “a sort of reflection.” In it, through it, there is not just the unidirectional relationship of the one who perceives to what he perceives. The relationship is reversed, the touched hand becomes the touching hand, and I am obliged to say that the sense of touch here is diffused into the body—that the body is a “perceiving thing,” a “subject-object.” (Merleau-Ponty 1964, p. 166)
Yet the touching and being-touched experiences never absolutely coincide. The two hands are never simultaneously touched and touching in relation to each other, but instead alternate their roles spontaneously (Merleau-Ponty 1962, p. 93). This spontaneous alternation is an expression of the body’s dynamic sensorimotor relation to its own subjectivity, and this kind of self-relation distinguishes one’s body from other things disclosed to one in perception (Husserl 1960, p. 97; Merleau-Ponty 1962, p. 93).
In this experience we can also catch a glimpse of how sensorimotor subjectivity can implicate a kind of sensorimotor intersubjectivity. A dynamic process of “self-othering” takes place in this experience, so that one’s body becomes other to itself. When my left hand touches my right (or when I experience my body in other ways), there arises the possibility of experiencing myself in away that anticipates both the way in which another bodily subject would experience me and the way in which I would experience the other. Bodily self-awareness is in this way conditioned by a form of otherness or alterity. According to Husserl, this self-othering dynamic is a crucial precondition for empathy, in the broad sense of being able to recognize others as subjects like oneself on the basis of their bodily presence (Zahavi 2003a, p. 113). It is precisely the body’s double status of being a “subject-object,” a subjectively lived body and a physical living body, as well as the dynamic interplay between ipseity (I-ness) and alterity (otherness) inherent in this ambiguity, that grounds one’s ability to recognize other bodies as bodily subjects like oneself. I will return to these ideas in the last chapter of this book.
These brief phenomenological reflections are enough to show that consciousness involves the body in a unique double way. One experiences one’s body as both subject and object. One’s body is the intentional object of one’s consciousness when one attends to one or another aspect or part of it. The content of this kind of bodily awareness corresponds to the body image or one’s body-as-object. Bodily consciousness cannot be reduced to this sort of experience, however, because one also prereflectively and nonintentionally experiences one’s body-as-subject while experiencing objects in the world (one’s body-as-object included). The challenge for any scientific account of consciousness is to preserve this unique double character of bodily self-consciousness. Hence any scientific account must meet these two criteria: it must account for the ways in which one’s body is intentionally directed toward the world, and it must account for a form of self-awareness that does not imply identification of one’s body as an object.
Dorothée Legrand (2006) has worked to give an account of bodily self-consciousness that meets these criteria. She argues that bodily consciousness in the case of action consciousness is reducible neither to awareness of one’s intentions to act nor to proprioception understood as an internal mode of identification of the body. Therefore bodily consciousness, she concludes, cannot be based on either efferent or afferent mechanisms alone. Bodily consciousness consists in experiencing one’s body as a locus of the convergence of perception and action, and therefore depends on a matching of sensory and motor information, so that perception and action are coherent (see also Hurley 1998, pp. 140–143). There must be a specific match between (1) the intention to act, (2) the motor consequences of this intention, including the guidance of bodily movements during the executed action, and (3) the sensory consequences of this action, including both proprioception and exteroception.
An important implication of this account is that neural correlates of self-consciounsess will remain explanatorily opaque with respect to mental life as long as we understand them only in terms of their intrinsic neural properties and not in the dynamic sensorimotor context of the body as a whole (Hurley and Noë 2003; Legrand 2003; Thompson and Varela 2001). This point brings us to dynamic senorimotor accounts of perceptual experience and their significance for the body-body problem.
In a recent article on neural plasticity and the dynamic sensorimotor approach to perceptual experience, Susan Hurley and Alva Noë (2003) distinguish three different types of explanatory gap for consciousness. The first they call the absolute gap: “Why should neural processes be ‘accompanied’ by any conscious experience at all?” (Hurley and Noë 2003, p. 132). The second and third types are comparative gaps. The intermodal comparative gap, on the one hand, is the question of why a certain neural activity gives rise to visual experience, for example, rather than auditory experience. The intramodal comparative gap, on the other hand, is the question of why a certain neural activity gives rise to experience as of red, say, rather than green. Hurley and Noë present the dynamic sensorimotor approach as concerned with these two comparative gaps, not the absolute gap. In other writings, J. Kevin O’Regan and Noë (2001b) present the sensorimotor appproach as also addressing the absolute gap (see also Myin and O’Regan 2002). I will look first at the sensorimotor approach to the comparative gaps and then examine the sensorimotor approach to the absolute gap.
Hurley and Noë address the comparative gaps by examining cases of neural plasticity. They distinguish between two ways in which qualities of perceptual experience can be affected by changes to the normal relation between sensory stimulation and neural activity.
1. “Cortical dominance” occurs when “cortical activation from a new peripheral input source gives rise to experience with a qualitative character normally or previously associated with cortical activity in that area” (Hurley and Noë 2003, p. 133). For example, in certain patients who experience phantom limbs, a stroke to the face is also felt as a stroke to the phantom arm. According to Ramachandran, who has studied such patients, the explanation for this experience is that after the amputation, the tactile area of somatosensory cortex subserving the face takes over the deafferented arm area (Ramachandran and Blakeslee 1998; Ramachandran and Hirstein 1998). When this arm area receives stimulation from its new, nonstandard source (the face), it retains its normal qualitative expression as a touch-to-arm feeling. Thus this cortical area “dominates” in the sense that it “retains its ‘natural sign’ or normal qualitative expression” (Hurley and Noë 2003, p. 133).
2. “Cortical deference” occurs when “cortical activity in a given area appears to take its qualitative expression from the character of its non-standard or new input source” (ibid.). When congenitally blind persons read Braille, for example, the tactile feeling of reading is mediated by activity in the visual cortex (Sadato et al. 1996). In this case, the qualitative expression of activity in visual cortex apparently “defers” to its new input source.
These cases of cortical dominance and deference raise explanatory-gap sorts of questions. Why does activity in somatosensory cortex or visual cortex feel one way rather than another? Why in the phantom-limb case is there touch-to-arm feeling rather than only touch-to-face feeling? Why in congenitally blind Braille readers is activity in visual cortex experienced as tactile feeling rather than visual feeling? “What explains whether qualitative expression goes one way or the other in particular cases? What explains why activity in a certain cortical area is experienced as like this rather than like that?” (Hurley and Noë 2003, p. 139).
The dynamic sensorimotor hypothesis is that “changes in qualitative expression are to be explained not just in terms of the properties of sensory inputs and of the brain region that receives them, but in terms of dynamic patterns of interdependence between sensory stimulation and embodied activity” (Hurley and Noë 2003, pp. 145–146). According to the dynamic sensorimotor approach, in particular O’Regan and Noë’s (2001a) “sensorimotor contingency theory,” perceptual experience is not an inner event or state of the brain but a skillful activity constituted in part by the perceiver’s implicit, practical knowledge of the way sensory stimulation varies with movement. Different senses have different patterns of sensorimotor dependence, and perceivers have an implicit, skillful mastery of these differences. In vision, for example, when the eyes rotate, the sensory stimulation on the retina shifts and distorts in precise ways, determined by the size of the eye movement, the spherical shape of the retina, the varying density of the retinal photoreceptors from fovea to parafovea, and so on. When the body moves forward, the optic flow pattern on the retina expands; when the body moves backward, it contracts. When the eyes close during blinks, stimulation becomes uniform (the retinal image goes blank). These sensorimotor dependencies are distinctively visual, whereas those characteristic of hearing and touch have different structures. To perceive is to rely implicitly and fluently on these patterns of sensorimotor dependencies.
Hurley and Noë use this framework to explain the dominance/deference distinction. They take deference to be the norm and dominance the exception. There are other cases of deference besides tactile sensation being mediated by visual cortex in proficient Braille readers. For example, auditory neurons can develop visual properties as a result of surgical neural rerouting of visual stimulation to auditory cortex in newborn ferrets (Roe et al. 1990, 1992; Sur, Angelecci, and Sharma 1999). Another example comes from tactile-vision subsitution systems (TVSS), in which visual input to a camera that produces tactile stimulation on the skin leads to a kind of “tactile seeing” once subjects are able to control the camera’s movements (Bach-y-Rita 2002). Such cases cannot be explained simply by reference to which particular cortical areas are activated because the endogenous or exogenous rerouting of sensory-cortical pathways changes the dynamic sensorimotor patterns in which those cortical areas participate.
According to this account, deference is predicted when sensorimotor patterns are systematically transformed by rerouting, and the agent is able to learn the new patterns and their relations to the old ones (as happens, for example, with TVSS). When either of these conditions is not met, however, then dominance is predicted. The second condition is not met when the agent is passive or unable to move. For example, TVSS brings about quasivisual experiences of being able to perceive the shape and movement of objects at a distance only if the subject is able to exercise active control of the camera and thereby integrate it into his or her sensorimotor repertoire. If, however, the rerouted sensory stimulation gives rise only to “dangling” cortical activity—activity that is not integrated into a dynamic sensorimotor pattern—then the first condition is not met and again dominance is predicted. For example, phantom-limb sensations can arise when a particular area of somatosensory cortex is taken over by an adjacent area as a result of deafferentation. If such dangling activity could be reintegrated into a dynamic sensorimotor pattern, then dominance would be predicted to give way to deference. This sort of reintegration seems to occur partially and temporarily in Ramachandran’s mirror-box experiments, in which the patient is given illusory visual feedback from his intact hand when instructed to move his phantom hand (Ramachandran and Blakeslee 1998).
The psychologist Nicholas Humphrey, in his writings on the explanatory gap, has remarked that “there can be no hope of scientific progress so long as we continue to write down the identity [mental state m= brain state b] in such a way that the mind terms and the brain terms are patently incommensurable. . . We shall need to work on both sides to define the relevant mental states and brain states in terms of concepts that really do have dual currency—being equally applicable to the mental and the material” (Humphrey 2000, pp. 7, 10).
This strategy of working on both sides of the gap is precisely the strategy pursued by the dynamic sensorimotor approach.6 Rather than looking to the intrinsic properties of neural activity—for example, the firing patterns of neurons in a given cortical area—this approach looks to the dynamic sensorimotor relations among neural activity, the body, and the world. The concept that has dual currency for this approach is the concept of dynamic sensorimotor activity. On the mental side, perceptual experiences are explicated as ways of acting, constituted in part by the perceiver’s implicit and practical knowledge, or skillful mastery, of the relation between sensory experience and movement (Noë 2004; O’Regan and Noë 2001a). The senses have different characteristic patterns of sensorimotor dependence, and perceivers have an implicit, skillful mastery of these differences.
It is important to note that this account of the mental side does not identify perceptual experience with the occurrence of the sensorimotor dependencies themselves, but instead with the perceiver’s exercising his or her skillful mastery of the invariant patterns of sensorimotor dependencies. Contrary to behaviorism, perceptual experience, being in part constituted by endogenous knowledge (skillful mastery), mediates between sensory stimulation and motor behavior. Contrary to cognitivism, however, experience does not intervene in a linear causal fashion between sensory “input” and motor “output.” Sensory stimulation does not cause experience in us, which in turn causes our behavior, because “skillful activity (consisting of behavior and sensory stimulation) is the experience” (O’Regan and Noë 2001b, p. 1015). In other words, as a skillful activity of the whole animal or person, perceptual experience emerges from the continuous and reciprocal (nonlinear) interactions of sensory, motor, and cognitive processes, and is thereby constituted by motor behavior, sensory stimulation, and practical knowledge. On the brain side, neural states are described not at the level of their intrinsic neurophysiological properties or as mere neural correlates of mental states, but rather in terms of how they participate in dynamic sensorimotor patterns involving the whole active organism.
The dynamic sensorimotor approach is best understood not as an attempt to close the comparative explanatory gaps in a reductionist sense, but instead as an attempt to bridge these gaps by deploying new theoretical resources for understanding perceptual experience and neural processes in a coherent and overarching sensorimotor framework. For each modality of perceptual experience—seeing, hearing, touching, and so on—there is a corresponding pattern of sensorimotor interdependence that is constitutive of that modality. What it is to experience the world perceptually is to exercise one’s bodily mastery or know-how of certain patterns of sensorimotor dependence between one’s sensing and moving body and the environment. If distinct sensorimotor patterns are in this way constitutive of seeing, hearing, and so forth, then it does not make sense to ask, “Why do these sensorimotor patterns go with what it is like to see, rathen than to hear or to touch?” By contrast, one can always raise this sort of question with regard to neural activity in a particular brain area: “Why should brain activity in this region of cortex go with what it is like to see, rather than to hear or to touch?” The way to satisfy the hunger behind this sort of question is to give an account that embeds local neural activity in its dynamic sensorimotor context. For these reasons, sensorimotor patterns (encompassing endogenous neural activity) seem more promising than mere neural correlates of consciousness (Hurley and Noë 2003, pp. 146–147; Noë and Thompson 2004a, 2004b).
In working to bridge the comparative explanatory gaps, the sensorimotor approach contributes to the body-body problem. Yet Hurley and Noë’s account does not fully address the core of the body-body problem—the problem of sentience. They admit that to use a dynamic sensorimotor approach to bridge the comparative explanatory gaps is not to bridge the absolute gap of why there is experience at all. Their aim is to explain why the agent has experience like this rather than like that, but not to explain what makes the agent a conscious subject in the first place. Indeed, their account presupposes sentience because they start from the assumption that the agent already has experience of one sort or another.
O’Regan and Noë (2001b), however, argue that the sensorimotor approach is also able to explain why the agent has experience at all, and Myin and O’Regan (2002) repeat this argument.7 Their proposal is relevant to the body-body problem. Examining their account will serve to indicate why and how the dynamic sensorimotor account should be combined with both an enactive account of autonomous selfhood and a phenomenological account of bodily self-consciousness.
O’Regan, Noë, and Myin’s strategy is to give a sensorimotor account of certain characteristic properties of sensory experience. These properties are “ongoingness,” “forcible presence,” “ineffability,” and “subjectivity,” and they are supposed to constitute the phenomenal character of conscious experience:
Ongoingness means that an experience is experienced as occurring to me, or happening to me here, now, as though I was inhabited by some ongoing process like the humming of a motor. Forcible presence is the fact that, contrary to other mental states like my knowledge of history, for example, a sensory experience imposes itself upon me from the outside, and is present to me without my making any mental effort, and indeed is mostly out of my voluntary control. Ineffability indicates that there is always more to the experience than what we can describe in words. Finally, subjectivity indicates that the experience is, in an unalienable way, my experience. It is yours or mine, his or hers, and cannot be had without someone having it. But subjectivity also indicates that the experience is something for me, something that offers me an opportunity to act or think with respect to whatever is experienced. (Myin and O’Regan 2002, p. 30)
Ongoingness and forcible presence are to be explained in terms of “bodiliness” and “grabbiness,” two complementary features of the operation of sensorimotor systems. These features distinguish perceptual awareness from nonperceptual awareness or thought (O’Regan and Noë 2001b). Bodiliness is the dependence of sensory stimulation on one’s bodily movements. The greater the change is to sensory stimulation as a result of bodily movement, the higher the degree of bodiliness. Thus our visual experience of a book that is in front of us has a high degree of bodiliness, compared with our nonperceptual awareness of a book in the next room. Blinking, eye movements, and head and torso movements modulate the way the book affects one’s sensory apparatus, but they make no difference to the book in the next room. Grabbiness is the tendency of something to attract one’s attention. Vision has high grabbiness, for sudden changes in the visual scene around us immediately attract our attention. Thus movements or changes in the book in front of us will immediately affect our sensory apparatus in an attention-grabbing way, whereas movements of the book in the next room will not. Bodiliness and grabbiness are supposed to explain forcible presence and ongoingness in the following way:
(1) the book forces itself on us because any movement of the book causes us to direct our attention (our processing resources) to it. (2) The slightest movement of the relevant parts of our bodies modifies the sensory stimulation in relation to the book. Metaphorically, it is as if we are in contact with the book . . . [W] e can explain ongoingness in a similar way . . . The sense of an ongoing qualitative state consists, (a) in our understanding that movements of the body can currently give rise to the relevant pattern of sensory stimulation (bodiliness), and (b) in our understanding that the slightest change in what we are looking at will grab our attention and in that way force itself on us. In this way we explain why it seems to us as if there is something ongoing in us without actually supposing that there is anything ongoing, and in particular, without supposing that there is a corresponding ongoing physical mechanism or process. (O’Regan and Noë 2001b, p. 1012)
There remain the two characteristics of ineffability and subjectivity. According to the sensorimotor approach, perceptual experiences are active manifestations of a kind of skillful knowledge and are defined in terms of potential for action. In general, it is difficult to describe the knowledge underlying a skill. Thus ineffability is explained by our being unable to describe verbally our implicit, practical knowledge of the sensorimotor patterns constitutive of perceptual experience. Subjectivity is explained in the following way:
Someone is perceptually aware of something because she is interacting with it. It is her putting all the resources she has onto whatever she is conscious of that makes her conscious of it. So, once she is conscious of it, it is “for her”—it is her subjective project to which she is devoting all her capacities. So, consciousness is, by definition, “for the subject.” (Myin and O’Regan 2002, p. 39)
This account is illuminating to the extent that it accounts for important characteristics of experience in dynamic sensorimotor terms. It is incomplete in two ways, however. First, it needs to be underwritten by an enactive account of selfhood or agency in terms of autonomous systems. Second, it needs to enrich its account of subjectivity to include prereflective bodily self-consciousness.
The dynamic sensorimotor approach needs a notion of autonomous selfhood or agency because to explain perceptual experience it appeals to sensorimotor knowledge. Knowledge implies a knower or agent or self that embodies this knowledge. What organization does a sensorimotor system need to have in order to be a genuine sensorimotor agent with a correlative sensorimotor environment?
According to the enactive approach, agency and selfhood require that the system be autonomous. The minimal case of autonomy, as we have seen, is a living cell. A cell is an autopoietic system. It is a self-organizing network of biochemical reactions that produces a membrane boundary that regulates external boundary conditions and makes possible the internal reaction network. A cell actively relates to its environment so as to satisfy a viability constraint. Its “sensory” responses serve to trigger “motor” behaviors subject to the maintenance of autopoiesis (robustness) and regulated by internal norms of adaptivity (flexibility). We have also seen that this circular organization and mode of coupling with the environment are recapitulated in a more complex form by the nervous system. The nervous system establishes and maintains a sensorimotor cycle, whereby what one senses depends directly on how one moves, and how one moves depends directly on what one senses. Whereas biological selfhood in its core cellular form is brought forth by the operational closure of the autopoietic network, sensorimotor selfhood results from the operational closure of the nervous sytem (Varela 1997a). In either case, it is legitimate to invoke the notion of “self” because the dynamics of the system is characterized by an invariant topological pattern that is recursively produced by the system and that defines an outside to which the system is actively and normatively related.
Compare these cases to O’Regan and Noë’s example of a missile guidance system. They write that this system “‘knows all about’ or ‘has mastery over’ the possible input/output relationships that occur during airplane tracking” (O’Regan and Noë 2001a, p. 943). In this case, however, unlike the case of a motile bacterium or metazoan organism, the “sensorimotor knowledge” is merely attributed to the system by the observer, not original to the system itself. There is no genuine sensorimotor knowledge or mastery in this system because the system is not autonomous (does not have an autonomous organization). It is not a self-producing and self-maintaining system that actively regulates its own boundary conditions so as to ensure its continued viability. It does not produce and maintain its own sensorimotor identity as an invariant of its sensorimotor interactions with the environment. Hence it has no genuine sensorimotor agency or selfhood, and it cannot be said to be actively and normatively related to the world.
Adding an enactive account of selfhood to the dynamic sensorimotor approach goes only part way toward addressing the body-body problem. In addition, we need to include subjectivity in the sense of prereflective bodily self-awareness.
When I pick up a bottle and grasp it with my hands, I experience the bottle as other to me, but the feeling of grasping the bottle is immediately and noninferentially experienced as mine.8 The intentional object of my tactile experience is the bottle, but at the same time I live through my grasping feeling in a nonintentional (non-object-directed) manner. To experience the feeling as mine I do not have to identify it as mine. Rather, the feeling comes with an intrinsic “mineness” or “first-personal givenness” or “ipseity” (I-ness) that constitutes its subjectivity (Kriegel 2003a, 2003b; Zahavi 2002a, 2003c).
Myin and O’Regan (2002), as we have seen, claim to account for the subjectivity of perceptual experience. Their strategy, following O’Regan and Noë (2001b), is to “de-reify” experience by teasing apart its different phenomenal characteristics—subjectivity, ongoingness, forcible presence, and ineffability. Yet ongoingness and forcible presence involve subjectivity in a constitutive way: “Ongoingness means that an experience is experienced as occurring to me, or happening to me here, now, as though I was inhabited by some ongoing process like the humming of a motor. Forcible presence is the fact that… a sensory experience imposes itself upon me from outside, and is present to me without any mental effort, and indeed is mostly under my voluntary control” (Myin and O’Regan 2002, p. 30; emphasis added). Each italicized phrase describes an aspect of the subjectivity or first-personal character of experience. Similarly, ineffability means that my perceptual experience seems indescribable to me in certain respects.
Myin and O’Regan devote most of their efforts to explaining ongoingness and forcible presence. What they write about subjectivity does not address the first-personal character and non-object-directed or intransitive self-awareness proper to experience (or experiencing), but instead deals with the subject’s conscious access to the intentional objects of perceptual experience. They propose that consciousness is “for the subject,” because to be conscious of X is to put all one’s skillful sensorimotor and attentional resources onto X, such that one is aware not simply of X but also of the opportunities for further action or thinking that X affords. This explanation is plausible as an account of what it is for a given object X to be “for the subject” (or accessible to the subject): X is the intentional object of the subject’s attention (or is available to attention). But this account does not explain what it is for one’s perceptual experience of X to be intransitively self-aware and thus to have first-personal givenness. For example, this account might explain what it is for the woolly red of the carpet to be the content of my current visual experience, but it does not explain what it is for the experience of seeing the woolly red of the carpet to be phenomenally manifest as mine. In other words, we are given an account of conscious access to the intentional objects of perceptual experience, but not of subjectivity in the sense of the first-personal quality of experience as such. Thus there remains a significant gap in this account.
A related problem is that this account identifies all consciousness with transitive or object-directed experience and all consciousness with attention (O’Regan and Noë 2001a, pp. 944, 955, 960). These identifications are too narrow.
Consider first the identification of consciousness with attention. Ned Block gives the example of being engaged in an intense conversation while a drill rattles away outside the window (Block 1997, pp. 386–387). Engrossed in the conversation, one does not notice the noise, but then eventually and all of sudden one does notice it. Block uses this example to illustrate the distinction between a mental state’s being “phenomenally conscious” (subjectively experienced) and its being “access conscious” (accessible to thought, verbal report, and action guidance). His proposal is that insofar as one is aware of the noise all along, one is phenomenally conscious of it but not necessarily access conscious of it. When one notices the noise, one becomes access conscious of it (and perhaps also realizes that one has been hearing it all along), so that one now has both phenomenal consciousness and access consciousness of the sound.
O’Regan and Noë (2001a, p. 964) dispute this description, claiming that one does not hear the drill until one notices and attends to it. One’s auditory system may respond selectively to the noise, but one makes no use of the information provided thereby, nor is one poised to make any use of that information until one notices the drill. Hence there is no ground for thinking we have a case of phenomenal consciousness without access consciousness. In the absence of access, there is no phenomenal consciousness.
From the point of view of phenomenological analysis, both descriptions seem rather flat. The experiential difference between not noticing and then noticing a noise is treated statically, as if it were a discrete state transition, with no extended temporal dynamics, and there is no differentiation within the temporal dynamics of the experience between implicit and explicit aspects. One may notice a noise in an implicit way, in which case one lives through the sound without grasping it as a distinct object. One may also notice a noise in the sense of turning one’s attention to it or having one’s attention be captured by it, in which case the noise is grasped as a distinct object. Finally, at an implicit level, it is important to differentiate between moments of comparatively weak and strong affective force on the part of the noise as the experience unfolds.9
Two distinctions from Husserlian phenomenology, mentioned in Chapter 2, are relevant here. The first is between activity and passivity. “Activity” means taking a cognitive position in acts of attending, judging, valuing, wishing, and so forth. “Passivity” means being involuntarily influenced and affected by something. The second distinction is between receptivity and affectivity. “Receptivity” means responding to something that is passively affecting one and hence presupposes a prior affection (Zahavi 1999, p. 116). “Affection” means being affectively influenced or perturbed. The idea is that whatever becomes noticeable must already have been affecting one and must have some kind of affective force or allure, or affective “grabbiness,” in relation to one’s attention. As psychologists know, typically attention is affectively motivated (Derryberry and Tucker 1994). Affective allure or grabbiness implies a dynamic gestalt or figure-ground structure: something becomes noticeable, at whatever level, owing to the strength of its allure or grabbiness, emerging into affective prominence, salience, or relief, while other things become less noticeable owing to the comparative weakness of their allure. This dynamic interplay of passivity and activity, affectivity and receptivity, expresses an ongoing “operative intentionality” underlying object-directed or intentional consciousness (Merleau-Ponty 1962, pp. xviii, 418).
These considerations suggest that hearing the sound before noticing it should be counted as a case of phenomenal consciousness. One does consciously hear the sound before noticing it, if “noticing” means turning one’s attention to it. The sound is experienced implicitly and prereflectively. One lives through the state of being affected by the sound without thematizing the sound or one’s affectedness by it. This prereflective consciousness counts as phenomenal consciousness because the sound’s appearance and affective influence have a phenomenal character, though an indeterminate one. As Merleau-Ponty states, “attention … is the active constitution of a new object which makes explicit and articulate what was until then presented as no more than an indeterminate horizon” (Merleau-Ponty 1962, p. 30). Hence it does not seem right to say that one has no experience of the sound at all until one notices it. Nevertheless, there is no reason to believe that this experience is not also a case of access consciousness. After all, one is poised to make use of one’s implicit and prereflective hearing of the sound. The content of the experience is at least accessible, even if it is not accessed explicitly.10 If we imagine, however, that one is not cognitively poised in any way to rely on the sound, then we would need a reason to believe that one is nonetheless phenomenally conscious of it rather than simply discriminating or differentially responding to it nonconsciously, but no reason is forthcoming simply from this example.
Consider now the claim that all consciousness is transitive consciousness. We have already seen that intransitive or nonintentional bodily self-consciousness is constitutive of perceptual experience. When I see the woolly red of the carpet, I am transitively conscious of the woolly-red carpet, but I also consciously experience my seeing (my seeing is intransitively self-aware). When I grasp the bottle, I am transitively aware of the bottle, but I also consciously experience my grasping (my grasping is intransitively self-aware). It does not seem right to maintain either that my seeing or grasping is not conscious or that I am merely poised to become transitively conscious of them.
The first interpretation looks incoherent. It is hard to make sense of the idea that one could have a conscious perception of X without experiencing one’s perception of X.
The second interpretation is conceptually and phenomenologically unclear. Does one’s being poised to become transitively aware of one’s perceiving (through an attentional shift) itself have a phenomenal or subjective character? If it does not, then it would seem to be an unconscious disposition or a subpersonal disposition of one’s nervous system. The problem then is to explain how a completely unconscious or subpersonal disposition can account for the apparently occurrent character of nonintentional bodily self-consciousness. But if one’s being thus poised does have a phenomenal and subjective character—if one feels thus poised—then that feeling needs to be accounted for as part of the subjective character of experience. This feeling cannot be accounted for simply in terms of transitive consciousness, precisely because it does not have a transitive or subject-object structure. On the contrary, it would seem to be another way of describing or getting at the phenomenon of intransitive and nonintentional bodily self-consciousness.
These reflections show that a complete account of perceptual experience requires an account of nonintentional (intransitive, non-object-directed), prereflective bodily self-consciousness. Although the dynamic sensorimotor approach has made significant progress in accounting for transitive perceptual consciousness, further work needs to be done to address bodily self-consciousness. This work will be crucial for progress on the body-body problem.
In this chapter I hope to have shown that the dynamic sensorimotor approach to perceptual experience can be profitably combined with an enactive account of selfhood and a phenomenological account of bodily self-consciousness. I also hope to have shown that this synthesis is needed in order to make headway on the explanatory gap recast as the body-body problem.
Central to the enactive approach is the idea that mind science and phenomenology can be linked in a reciprocal and mutually illuminating way (Varela, Thompson, and Rosch 1991). The enactive approach uses phenomenology to explicate mind science and mind science to explicate phenomenology. Concepts such as lived body and organism, bodily selfhood and autonomous agency, the intentional arc and dynamic sensorimotor dependencies, can thus become mutually illuminating rather than merely correlational concepts (Gallagher 1997; Varela 1996). This idea of the mutual illumination between phenomenology and mind science figures prominently in the remaining chapters of this book.
The next chapter continues the phenomenological analysis of consciousness begun in this chapter and puts this analysis to work in the scientific debate about mental imagery.