1 Where to Look for the Physical Basis of Phenomenal Experience

The quest for the physical underpinnings of consciousness is still an unresolved one (Koch 2007; Tallis 2010; van Boxtel and de Regy 2010). When one perceives a red patch, what is the necessary and sufficient physical basis of such a phenomenal experience? Indeed what is the physical phenomenon that is one’s phenomenal experience of a red patch? Such questions single out the hard-problem (Chalmers 1996): "From all the low-level facts about physical configurations and causation, we can in principle derive all sorts of high-level facts about macroscopic systems, their organization, and the causation among them. One could determine all the facts about biological function, and about human behavior and the brain mechanisms by which it is caused. But nothing in this vast causal story would lead one who had not experienced it directly to believe that there should be any consciousness. The very idea would be unreasonable; almost mystical, perhaps" (Chalmers 1996, p. 102). More recently, Christof Koch wrote that "How brain processes translate to consciousness is one of the greatest unsolved questions in science. The scientific method […] has utterly failed to satisfactorily explain how subjective experience is created" (Koch 2007).

Such a lack of a physical explanation might be a consequence of one or more ill chosen assumptions as to the nature of the physical world (Strawson 2006; Skrbina 2009; Strawson 2011). Of course, there is plenty of evidence showing that neural activity is correlated and indeed necessary to consciousness. In the last twenty years, several researchers presented outstanding and remarkable results as to the ways in which conscious experience is related with brain activity (Logothetis 1998; Zeki 2001; Andrews, Schluppeck et al. 2002; Crick and Koch 2003; Changeux 2004; Buzsáki 2007; Hohwy 2009; Laureys and Tononi 2009; van Boxtel and de Regy 2010). Yet what is still missing is a theory outlining a conceptual and causal connection between neural activity and phenomenal experience. Thus it may be worth to consider other hypotheses however counterintuitive they may seem to be. After all, "If no theories seem to be capable of accounting for conscious experience, this probably means that there is something inherent in our assumptions that divorce theories from conscious experience" (Rockwell 2005, p. 49).

An assumption that is sometimes taken for granted is that the physical underpinnings of consciousness have to be internal to the nervous system. Neuroscientists like Christof Koch, Atti Revonsuo, Giulio Tononi, Semir Zeki have explicitly made this assumption. For instance, Atti Revonsuo stated that "sensory input and motor output are not necessary for producing a fully realized phenomenal level of organization. The dreaming brain creates the phenomenal level in an isolated form, and in that sense provides us with insights into the processes that are sufficient for producing the phenomenal level" (Revonsuo 2000, p. 58). Along the same line, Christof Koch believes that "The goal [of the scientific study of consciousness] is to discover the minimal set of neuronal events and mechanisms jointly sufficient for a specific conscious percept" (Koch 2004, p. 16). My opinion is that these authors assume that, although the environment has a key role in shaping neural networks during development, once the brain is developed and running, there is a set of neural events sufficient for specific conscious percepts [Crick and Koch 1990]. Such a hypothesis has become widely accepted not only in neuroscience but also in philosophy of mind. Consider a philosopher like Jaegwon Kim stating that "if you are a physicalist of any stripe, as most of us are, you would likely believe in the local supervenience of qualia – that is, qualia are supervenient on the internal physical/biological states of the subject" (Kim 1995, p. 160). Yet, is such an assumption unavoidable? After all, if you are a physicalist, you ought to look for physical phenomena – any kind of physical phenomena – and not just for an "internal physical/biological state of the subject". What occurs outside the body is physical too. Neural processes are only a subset of a much larger domain of feasible physical processes.

Here, I will consider a rather counterintuitive hypothesis – dubbed the spread mind – that might shed a new light on the issue of the physical underpinnings of phenomenal experience (Manzotti 2006c). This hypothesis is a somewhat more radical version of other related views (Varela, Thompson et al. 1991; O'Regan and Noë 2001; Rockwell 2005; Honderich 2006; Thompson 2007; Noë 2009; Velmans 2009). In a nutshell, I will consider whether it makes any sense to suppose that the physical underpinnings of consciousness are temporally and spatially larger than the subject body. Is consciousness situated in the environment?

2 Beyond the Skin

Instead of focusing on the brain and the nervous system, a few authors considered whether the relation between the mind and the environment is closer than traditionally assumed (Varela, Thompson et al. 1991; Clark and Chalmers 1998; O'Regan and Noë 2001; Rockwell 2005; Honderich 2006; Thompson 2007; Noë 2009; Velmans 2009). This insight gave rise to various views both in cognitive science and in philosophy of mind (Rowlands 2003; Robbins and Aydede 2009a; Hurley 2010): the embodied mind, the embedded mind, the extended mind, and the larger stance dubbed situated cognition. The insight has unfolded by degrees. For instance, for some authors, the environment provides the right place for the development of cognitive functions (Anderson 2003; Gallagher 2005) while, for other scholars, the environment allows off-loading cognitive work (Clark 1989; Wilson 2004). Eventually, David Chalmers and Andy Clark suggested that, somehow, the cognitive mind leaks into the world (Clark and Chalmers 1998; Clark 2008). During the last twenty years, many scholars gave rise to a heated debate whether and to what extent the mind may extend into environment (Varela, Thompson et al. 1991; Thompson and Varela 2001; Chrisley and Ziemke 2002; Anderson 2003; Pfeifer, Lungarella et al. 2007; Chemero 2009; Robbins and Aydede 2009a; Robbins and Aydede 2009b; Rupert 2009; Shanahan 2010). Although most of these authors limited their proposal to the cognitive mind (Clark and Chalmers 1998; Wilson 2004; Clark 2008) nevertheless they collected their share of criticism (Rupert 2004; Adams and Aizawa 2008; Rupert 2009). Since they focus on cognitive skills rather than on phenomenal experience, these views may be grouped under the label of situated cognition (Anderson 2003; Robbins and Aydede 2009b). Only a handful of authors ventured to suggest that although the mechanisms of the conscious mind remain safely inside the brain, phenomenal content may literally either depend on or be constituted by the outside world (Dretske 1996; Velmans 2000; Lycan 2001; O'Regan and Noë 2001; Honderich 2006; Noë 2009). Yet, even these phenomenal externalists have continued to distinguish between internal representations and the external world. For instance, Fred Dretske stated that "sensory experience gives primary representation to the properties of distant objects and not to the properties of those more proximal events on which it (causally) depends" (Dretske 1981, p. 165). Three decades later he still remarks that "The experiences themselves are in the head […] but nothing in the head needs have the qualities that distinguish these experiences" (Dretske 1996, p. 144-145). As a result they are often labeled an supporters of phenomenal content externalism – namely the view that although the content of experience depends on states of affairs external to the body, nevertheless the vehicles of experience remains inside the body.

Here, I will venture one step further. I will openly consider a perilous hypothesis: are the vehicles of phenomenal experience spread in time and space beyond the boundaries of the skin? Is phenomenal experience itself extended in time and space? Is consciousness situated in a strong sense? So far, many authors stepped back from this counterintuitive view. For instance, David Chalmers, in the foreword to Andy Clark’s book on the extended mind, wrote that "[the extended mind does] not rule out the supervenience of consciousness on the internal" (Chalmers 2008, p. 6). As we have seen, Kim’s dictum explicitly rules out such a possibility. Likewise, many objections have been raised against the hypothesis that the processes underpinning phenomenal experience might be totally or partially external to the body (Kim 1995; Clark and Chalmers 1998; Wilson 2004; Velmans 2007; Adams and Aizawa 2008; Clark 2008).

And yet, what are the strong arguments against strong situated consciousness – namely the hypothesis that the physical processes constituting consciousness are larger than the nervous system? Here I will venture to consider and put under scrutiny such a hypothesis. I will consider whether our phenomenal experience might indeed be extended in time and space beyond the limits of the nervous system.

3 Towards Situated Consciousness: The Case of the Rainbow

At the onset, I will make use of an example of a physical process in which the traditional separation between subject and object seems to collapse and vanish. Consider a physical phenomenon like the rainbow (Manzotti 2006a), which is not a perceptual phenomenon but a physical coloured shape taking place in its own right. Not only the rainbow is a physical phenomenon, but it cannot be defined autonomously without an observer. In fact, a rainbow is a process that requires a further physical system in order to take place. Where is the rainbow? Where is the experience of the rainbow? Is there a rainbow without an observer? Is there a rainbow-observer without a rainbow in the cloud? As we will see, these questions may have a surprising answer that blurs the traditional boundaries between experience and physical world. I will try to show that the rainbow is a physical phenomenon and yet that it shares many properties of phenomenal experience.

For one thing, although the rainbow is not a hallucination, each observer has her own private rainbow. It is a private physical phenomenon and to be private is usually considered to be a prerogative of phenomenal experience. Let me explain. Call A the cloud at the horizon. Call B the body of an observer. Call C the process that starts from the surface of each reflecting and refracting drop and ends in B. If B were not there staring at the cloud, the process C would not occur. Yet, the rain drops would still float in the air; the sun rays would still meet the drops and bounce back at an angle proportional to their frequency. However, the reflected and refracted rays would not meet anywhere. They would simply scatter around and eventually disperse. The rainbow would not occur. But if B is in the right place at the right time, what happens? A subset of lightrays (those whose origin corresponds to a semicircular distribution of rain drops) enters into the retina of the subject and proceeds, by means of neural signals, up to the cortex where it finally produces a joint effect because of its shape and colours (Manzotti 2006b; Manzotti 2006d; Manzotti 2006c; Manzotti 2009). The rainbow is a process that would not occur if it weren’t for B. This process C is the rainbow. The rainbow is neither A nor B alone. Where is C? C is neither inside the observer B nor in the cloud A. C is spread in time and space.

The example of the rainbow may suggest an idealist or constructivist standpoint. Yet, this is not the case, since I propose neither that the rainbow is a mental creation of the beholder nor that is anything like a sense datum. On the contrary, I draw attention to the physical nature of the rainbow and I stress that it is a physical process taking place in the environment. The hypothesis under scrutiny here remains safely inside the physicalist domain: it couldn’t be farer from any idealistic perspective. I suggest that phenomenal experience may be a distributed phenomenon and thus that consciousness may be situated in a very strong sense. Nevertheless, it may seem that the above example is concocted to make the reader believe that the rainbow does not exist if no one is looking at it. It is a fair bet. In fact, I suggest that when no suitable physical system (like a human subject) is interacting with the cloud, there is no rainbow. Of course, such a conclusion does not imply that the rainbow is a mental phenomenon. Rather it implies that the rainbow is a physical process that requires the proper physical conditions – among which I would list a cloud, the sun, and a suitable structure where the light rays may meet and produce a joint effect (the last structure is the body of a perceiving observer).

To convince yourself that the rainbow is a physical phenomenon that cannot occur in isolation, it is sufficient to set aside any tentative observer and ask to a physicist where is the rainbow. She would have no way to tell. The fact is that there is no way to single out a rainbow without assuming that the cloud is indeed seen from a certain view point. Without an observer, the rainbow is everywhere in the cloud (or nowhere). There is no way to pinpoint where a rainbow is without including the position and the causal role of the observer. Similarly, there is no way to tell whether a rainbows exists or not, without a proper observer. In short, it is impossible, from a physical perspective, to disentangle the rainbow from its observer. There are many aspects that the rainbow, as a physical phenomenon, nonetheless shares with phenomenal experience. First, the rainbow is a private phenomenon – a property that has always been traditionally attributed to mental states. The same rainbow cannot be seen by two different observers, since each of them will single out a different rainbow due to the fact that they occupy two different positions in space. Processes are necessarily private and yet physical. Secondarily, the rainbow is something that takes place. It is not a static entity. The rainbow takes place and it is extended in time and in space. Third, the rainbow singles out a part of reality bringing into existence a form (the coloured arch) that was not there before. Is it a mental form or the physical occurrence of a form?

In the next seven sections, I will try to show that conscious experience may correspond to a physical process akin to the rainbow. Further, I will suggest that if the physical world is conceived as made of processes, it has the resources to host consciousness once it is accepted that the physical processes which is phenomenal experience, may indeed be larger than those taking place in the nervous system.

4 First Step: Extension in Space

The example of the rainbow outlines a process that is physically extended in space. How much? Well, roughly, from the surface of the object to the neural activity in the brain. Should this extension upset us? I don’t see why. After all, as far as we know, all physical phenomena are extended in space.

For one, neural activity, which is the traditional candidate to underpin phenomenal experience, is extremely extended in space. Consider what happens inside the brain when a signal is received. The nervous signal travels at a speed of 100-120 m/s. The completion of a complex perceptual process such as recognizing a face or a complex scene takes 200-300 msec (Quiroga, Mukamel et al. 2008). This means that signals travels across the brain for roughly 20-30 meters before completing their job. Put simply, a neural implementation of an average perceptual process requires 20-30 meters to complete. The total length required by such a process is much longer than that of the agent’s brain or body. This is not an opinion but a fact that derives out of empirical evidence in neurophysiology (Biederman and Kalocsai 1997; Farah, Wilson et al. 1998; Andrews, Schluppeck et al. 2002). Therefore, in neuroscience a physical process spanning dozens of meters is commonly taken to be capable of producing phenomenal experience. Hence there is no reason to reject other putative physical processes only because they are extended on relatively large spatial distances like the rainbow. The Spread Mind suggests considering a process that is spatially extended to such an extent that it can contain the external object of perception. Put simply, if one perceives a rainbow on a cloud a few kilometers far away, according to the spread mind, the physical underpinnings of her phenomenal experience begins on the cloud and eventually ends in her brain? In principle, what’s wrong with a physical process of a few kilometers instead of dozens of meters?

5 Second Step: Extension in Time

It may seem odd to suggest that phenomenal experience may be identical with a physical process beginning before the first triggered neural firing. Could consciousness be constituted (at least to a certain extent) also by events that occur before any causal influence is exerted on the nervous receptors? To answer to such a question, I will make use of the same strategy adopted in the first step. I will argue that the same kind of temporal extension required for the rainbow is required for neural processes too. Thus I will argue that there is no reason to reject the hypothesis of temporally extended processes since neural processes are extended too. Consider the evidence provided by Benjamin Libet that a continuous and uninterrupted neural activity of 0,5 sec is required for consciousness: "What the on-time experiments have demonstrated is that threshold awareness pops in rather suddenly when the activities persist for the full 500 msec requirement!" (Libet 2004, p. 112) This evidence has been quantitatively refined by further studies (Libet 1966; Intraub 1980; Quiroga, Mukamel et al. 2008) but it is commonly accepted that there is a minimum temporal threshold during which a sustained neural activity has to occur. This minimum time span entails that the physical underpinning of consciousness takes some time to complete. Whether this time is 30 msec, 500 msec or a different amount of time, it is not going to make any difference as to the issue at stake here. The point is that consciousness is spread in time. Even considering only neural processes, the physical underpinnings of consciousness seem to require a finite time span.

By and large, all physical phenomena require some time to complete. There are no instantaneous phenomena. Most macroscopical phenomena require a lot of time to complete: a gesture, a process of oxidation, the recognition of a face, and the like. There is no reason to fix by fiat a maximum temporal span for "legitimate" process. As far as we know, a 30 msec process is as feasible to foster consciousness as a 30 sec (or longer) process. This may seem a rather bold claim, but the burden of the proof ought to weight on the shoulder of those who deny it. Is there is any know fact or theory that explicitly link phenomenal experience to the duration of the underlying physical process? At the best of my knowledge there isn’t. Of course, there is some evidence as to the temporal length of neural phenomena involved with phenomenal experience, but this is an entirely different matter (Varela 1999; Le Poidevin 2007; Droege 2009; Slagter, Johnstone et al. 2010).

6 Third Step: No Objects But Processes

The rainbow, presented here as a paradigmatic example of coupling between the external world and the neural activity, is a process. It is neither an object in the commonsensical view of a static and autonomous entity nor a mental construct inside the brain. It is not a hallucination concocted by the mind. From a physical point of view, the rainbow is the process taking place from the cloud and ending in the observer’s cortex after passing through her eyes, her peripheral nerves and a few intermediate neural nuclei. Hence, the rainbow is spatially and temporally extended. But is the rainbow a unique and indeed exceptional case – perhaps like reflections, mirror images, and other optical phenomenon – or is it one example of a more general condition?

To a certain extent, isn’t all we are conscious of – namely fields of view, sounds, uttered words, chairs, faces, tactile patterns, tastes, smells, colors, dots of light – like the rainbow? If we consider the alleged external targets of conscious perception, they are all observer-dependent entities: they are wholes whose unity is the result of the interaction with a given observer. For instance, visual patterns require sighted subjects to exert any effect; sound patterns require a certain auditory competence; tactile structures require skills and actual contact. It is a very well known fact that has been pointed out by many scholars (von Uexküll 1909; Gibson 1966; Bateson 1979). Here, I dare to go a little further. Each target of experience is a whole made of a collection of simpler physical phenomena. The occurrence of the whole is made possible by the interaction with the observer’s body and brain.

Consider a face. Does a face exist without someone capable of recognizing it? I suggest a negative answer to this question. If all human subjects in the world were affected by prosopoagnosia, there would be no faces insofar as the facial features on the front side of each head would not be able to produce any effect as a whole. Of course, facial features would remain. Yet, facial features are not faces (van Inwagen 1990; Merricks 2001). The confidence in the existence of faces – and objects – independently of being involved in causal interaction is related with the belief in a world of static and autonomous entities. However, the physical world is not static. It is made of processes. Even stones and static objects are processes. We do not perceive them as dynamic process because of the temporal limitations of our perceptual apparatus (Holcombe 2009). And yet stones and static objects keep changing.

There are also less obvious perceptual targets. For instance, a color is not an absolute perception either of a certain wavelength or of a certain spectral reflectance. Rather a color is the integration of many separate aspects such as the average spectral composition of the background, the received wavelength, certain complex textural features, and so on (Zeki and Marini 1998; Byrne and Hilbert 2003; Hardin 2008). Notwithstanding what the layman believes, a color is not a simple property of the world but rather a whole made of a complex collection of otherwise separate facts and processes coming into existence thanks to a proper physical system.

It might be argued that everything that is perceived is a whole constituted by a process (Manzotti 2009) – a whole that is in the external world in the same sense in which an object is in the external world; yet a whole whose existence is constituted by the completion of the process ending in the beholder’s brain.

Again, let me stress that this is not idealism. It is a very physical framework. I clam neither that the subject creates its objects nor that objects are mental entities. The rainbow is not a mental image but a real physical process made of rain drops, sunrays, an arch shaped collection of drops over a cloud, neural firings, chemical reactions, and so forth. Instead of considering only a portion of it, I suggest to take it as a whole. Rather I point out that the object – in the sense that it is understood by most people – is a conceptual simplification of the actual physical process taking place. Such a process is occurring also because there is the subject’s body. I am trying to stress the continuity between the "external" and the "internal". No preexisting subject is assumed as a necessary condition for the occurrence of reality. Subject and object occur together as the two sides of a coin.

The Spread Mind is totally different from Berkeley’s idealism. His famous claim as to the tree falling in the forest was based on a dualistic ontology and on a British empiricist epistemology. For Berkeley, experience was made of ideas whose existence was possible because of an omnipotent beholder. On the contrary, the model presented here suggests that experience is a dynamic physical process. The Spread Mind is a radical physicalist view suggesting a physical candidate for phenomenal experience. The fact that such a process is constitutive of the subject entails that the beholder is part of the physical reality. Hence the subject’s absence makes a difference or, similarly, a difference in reality makes the subject. To recap, if a tree falls in a forest and no one is around to hear it, does it make a sound? It causes sound waves but sound waves are not "sounds". They are just pressure waves. However, the spread mind does not suggest that sounds are ether "object of senses", or ideas, or sensations, or neural representations. The spread mind suggests that sounds are complex physical processes beginning in the tree crash and ending in someone’s brain – on the one hand, they are partially external and physical; on the other hand, they are also constituted by the beholder’s brain. Thus the answer to the classic question about the tree falling in the forst is negative like in the case of idealism, but the explanation is entirely different.

At the best of our knowledge, the physical world is made of basic entities such as atoms and energy units. However, they are not what we are aware of. Our experience is not made of atoms and energy waves but rather of macroscopic wholes like sounds, colors, chairs, tree, cars, and human beings. The macroscopic world of our everyday experience requires a suitable ontology. I suggest here that such ontology is grounded on processes rather than on perduring or enduring individuals. As to the bottom level, I won’t argue whether such a fundamental level is itself made of smaller processes as the string theory would indeed suggest: I leave the issue to much more skilled physicists than myself. However, whatever the nature of the basic level, physics ought to explain how to step from such a low level to the macroscopic level we experience in our everyday conscious life. The Spread Mind suggests that this issue may be addressed by processes that like the rainbow bring into existence macroscopic wholes. In this regard, the issue of consciousness may help to understand the structure of the physical world rather than being and uninvited nuisance to the physical picture of reality. The physical world may be made of the aforementioned basic stuff (elementary particles and energy packets) and by the processes in which that basic stuff gets involved. In my opinion, processes are perfectly respectable citizens of the physical domain. Yet, processes take place only when there the right conditions are met.

Consider once more the problem of faces. The atoms of the head are the basic stuff. The face is not identical to the atoms of the head; the face is a process in which a subset of the atoms composing the head is the cause of a unified process. The face is akin the sound made by the tree falling in the forest or like the rainbow. Without the right conditions, the process might not take place. Such atoms are not enough. To act as a whole they need something more as it was the case with the rainbow and the tree. A human subject capable of recognizing a face is a suitable candidate. Now call A the subset of atoms of Alex’s head that can be one of the necessary conditions for the perception of a face. Call B Beatrix’s body in normal working conditions. Call C the process you get when B is in front of A and Beatrix perceives Alex’s face. Because of the interaction between B and A, the process C occurs. C is the face and is physical. Yet C would not occur if either only B or only A were there. C is causally akin to the rainbow. The above argument is very important. The world we have an experience of, is made of processes, not of static entities that we observe as such. Rainbows, faces, chairs, and the like are processes that happen in the way they do because of the possibilities that our body offers to them. Let me stress again that this is not, by any means, a profession of idealism. I am not saying that the body (not to say the brain or the mind) creates its world. I am saying that the world we experience is made of physical processes whose occurrence require both the environment and the perceiver’s body.

7 Fourth Step: No More Representations

The Spread Mind suggests that the world is made of processes like the rainbow and that some of these processes are one and the same with the experiences of the subject. Instead of having a physical chair, a neural chair and a phenomenal chair, the Spread Mind suggests that there is only a chair-process occurring. In other words, there is an identity between the world and our representation of it. Hence, we don’t need any longer to assume a separation between the representation and what it represents. The process is, at the same time, the object of representation, the vehicle of that representation as well as the process constituting the subject. These three aspects are allegedly separate entities according to the most widespread view in philosophy of mind, psychology, and neuroscience (Dennett 1991; Searle 1992; Logothetis 1998; Zeki 2001; Kay, Naselaris et al. 2008; Tye 2009, among the many). For the Spread Mind, they are equally partial and incomplete ways to describe a process that is physically unique. The Spread Mind considers seriously the apparently preposterous hypothesis that the representation and the represented external object might be one and the same.

This fourth step may appear as irredeemably wrong. It seems to run against one of the most entrenched assumptions both of philosophy of mind and cognitive science – namely that the mind "deals with" representations which are numerically and physically separate from what they represent. The claim that the apple one is perceiving is the same as the perception of the apple is rather hard to swallow: one may be tempted to believe that the suggested identity is an elementary slip-up – how could it be that perceiving a X is identical with X? The identity does not make any sense taken literally insofar as it is assumed that X is an entity existing autonomously and that X is different from Y. However, accepting such assumption would beg the question. Once more, consider a face. The Spread Mind suggests 1) reconsidering what conscious experience is and 2) reconsidering what the physical world is (what the face is). The notion of separate representation may be akin to that of center of mass. They are handy notions that, nevertheless, do not correspond to anything real. The center of mass is a useful concept that simplifies many calculations. However, it does not exist in a physical sense. It is just an epistemic shortcut that allows tackling with a more complex state of affairs. The notion of representation may play the same role. It may simplify the way in which describe the causal entanglement between subject and object. And yet, it may not correspond to anything in ontological terms.

If the standpoint endorsed by the Spread Mind is somewhat correct, the issue of representation would be swept away, at least in the case of mental representations, since it would suggest that a representation and the represented thing are not physically different, rather they are conceptually different. My representation of the rainbow (when I look at it) is not something stemming out of the neural activity taking place in my brain. My representation of the rainbow is literally the rainbow. It is the process taking place from the cloud and concluding into my visual cortex.

Consider again A, B, and C, as in the previous section. Beatrix watches Alex and sees a face. It may be misleading to assume that there is a face to be seen and that Beatrix concocts either a neural or a mental representation of the face – a representation that is nonetheless separate from Alex’s face. The Spread Mind tells a different story. Neither A nor B are a face. The face is C, the process. C is a process that is at the same time the face and the representation of the face.

Hence the Spread Mind suggests that identity is the solution to the issue of representation. To represent something is to be that something. To represent the world means to be identical to that world. Consciousness is situated in the strongest possible sense – it is literally spread in the environment. The mind spreads into the world since it is made of those processes that made the particular world one has an experience of. After all, it is well known that individuals with different motor and sensor apparatuses live in different worlds (von Uexküll 1909). Faces, chairs, colors, sounds, and the like would not exist as wholes without a body that allows them to take place. Once they take place, they are what the mind is made of.

8 Fifth Step: No More Separation Between Phenomenal World and Physical Reality

It is sometimes assumed that the physical world does not have the same properties attributed to phenomenal experience – this is indeed one of the assumption of the abovementioned hard problem (Chalmers 1996). Philosophers stress properties that do not seem to match between the physical and the phenomenal domain such as quality, perspectivalness, and unity – among the others. For instance, consider colors. Our phenomenal chromatic space is closed while the electromagnetic spectrum is open. As a result, some have argued that light cannot be literally colored (Beau Lotto and Purves 2002; Cohen 2007; Hardin 2008) – which is true. So far, other proposed physical spaces haven’t scored much better. Surprisingly one of the better account of phenomenal experience takes into consideration the sensorimotor contingencies between the properties of the surfaces, the actual reflected light, the ambient light, and the observer’s perceptual skills (Bompas and O'Regan 2006) a result that may support the present paper.

Conceiving consciousness as a situated and indeed spread physical phenomenon may offer significant advantages as to the issue of the phenomenal character of experience. The phenomenal experience of something might not entail the emergence either of an unexpected phenomenal world or of a phenomenal character out of a physical world, rather it might mean that certain parts of the physical world act together – this unity might be consciousness. What has been called phenomenal character may be the result of the way in which processes constitutes wholes out of simpler parts.

Consider this example. You look around in a room. You see a flower in a vase, a computer and a bookshelf overflowing with books. Because of you, those things – which are processes according the argument defended above – take place at once. If you were not there, those processes would remain isolated. If you were not conscious of your visual field as a whole, those processes would not intermingle together. At least from a behavioral perspective being unable to react to the room as a whole is a sign of a lack of consciousness of it. I skip other possibilities such as blindsight. Hence there is a macroscopic and physical difference. Your physical presence – your conscious presence – makes the difference. I would dare to say that consciousness is precisely that difference. To be conscious of something is to allow to that something to act as a whole. To be conscious of a room is to allow that room to take place as a whole. This wording unfolds in a different way an insight that I believe to share with recent Ted Honderich’s work (Honderich 2006). Of course, this belief of mine does not entail anything on Honderich’s behalf. His formulation is that "to be conscious of a room is a way for that room to exist". I fear that the emphasis of existence may underestimate the importance of the dynamic character of reality.

Moreover, the objects of the above examples are not unities in themselves. They are wholes occurring because of your body and your nervous system. They would not take place without your body in that room. The hypothesis is that their occurrence is coextentive with what you call your conscious experience of the room. Thus, conscious experience might be identical with the process-unity resulting from a collection of scattered events.

Thus, is phenomenal experience of a room different from the room? Yes and no. The room, without being engaged with a perceptual system of a conscious being, is a scattered collection of relatively simpler processes. When you look at it, you allow the occurrence of a new and much larger process that, in turn, permit to a significant subset of those processes to act as a whole. This process would not have happened without your body in that room. The room we have an experience of is that process too. Is there any true difference between your conscious experience of a room and that process? They occur at the same time, in the same place. Furthermore, they put together the same aspects of reality (the books, the computer screen, the shelf, the flower in the vase, and the like). Why should we consider you’re your experience and the room you have an experience of are ontologically and numerically different?

9 Sixth Step: World and Body in Time

Take a conscious human subject. Each moment of consciousness corresponds to the occurrence of a world – something that William James called a "specious present" (James 1890). Yet, such a world is not a phenomenal world neither in the traditional phenomenological nor in the reflexive sense suggested by Max Velmans (Velmans 2007). The world considered here is a physical world taking place and having at its center the subject’s body. Each cognitive agent defines a world which is not made of qualitative phenomenal ghosts, but of physical processes. We act in the world of our experience and we see things happen. Hence, if we take the body to be the physical portion of reality that is identical with a subject, a conceptual revision is mandatory – there are two notions of the body to consider. On one hand, there is the traditional body singled out by the skin boundaries. On the other hand, there is the Spread Mind that is made, at each moment of time, by all those processes that identify the subject’s consciousness.

The Spread Mind is thus at the same time the world, our consciousness, and, in a subtle sense, the subject’s instantaneous body. It is a body that includes part of the traditional environment and that it may eschews components of the traditional body. For instance, at a given moment, consciousness might be the same irrespective of organs that, although very useful to preserve the subject’s life, do not intermingle with our awareness.

The identity between our experience and the world is consistent with the often mentioned transparency of perception (Harman 1989; Tye 2002) that suggests that there is nothing between the subject and the perceived object. The Spread Mind takes this insight at face value. There is literally nothing since the perceived object (which is the process) is part of the instantaneous body of the subject. If consciousness is literally situated, it follows that the environment we have an experience of, the world of our experience, and the body are one and the same.

10 Seventh Step: Everything Is Perception

Optimistically, so far the model may be worth of some consideration. Yet a potentially fatal blow lies ahead. How does the model explain all those cases where it seems that there is no conceivable continuity with the external world? For instance, consider dreams, mental imagery, hallucinations, after images, phosphenes, and the like. Surprisingly, the Spread Mind tackles easily with these alleged counterexamples. In essence, the proposal is that every phenomenal experience is a case of perception. After all, aren’t all cases of mental imagery closely constrained by actual past encounters with the corresponding external entities? Didn’t we get personally acquainted with everything we later imagine, dream or hallucinate? Consider dreaming someone who died long ago. Isn’t true that we spoke with him a few years ago? Hasn’t taken place an uninterrupted causal chain from the time when we’ve been talking with that person in the past up to the time in which we dream of him? Hasn’t a physical process occurred spanning along a few years and ending right now while we sleep and we dream? The Spread Mind suggests that this process, that lasted years instead of milliseconds, is identical to our dream of him. Put simply, dreaming and memory may be cases of postponed and scattered perception. When one’s dreaming X, one’s perceiving X. Below I will say something as to the possibility that one may dream a conversation never occurred or the traditional flying pink elephant.

I am aware that this final step might seem the most counterintuitive of all. Yet, why should a 30 msec process be scientifically more respectable than a 30 yrs long one? Of course, the shorter the process, the greater its survival value, since a shorter process allows to react to what is taking place to one’s temporal and spatial proximity. Yet, as to the contribution to phenomenal experience, there is no known law of nature that gives legitimacy only to relatively short processes. Irrespective of its temporal length, a process may be part of consciousness because of the proper kind of causal entanglement.

In fact, consider dreams. As is well known, far from being that bizarre repertoire of unconstrained imagination that literature and commonsense have always assumed, dream content is extremely conservative. Dream content is creative and productive only insofar as reassembles previous perceptual content. For instance, congenitally born blind subjects do not dream of colors or visual content (Bértolo, Paiva et al. 2003; Lopes da Silva 2003; Kerr and Domhoff 2004).

During everyday perception, causal processes are usually constrained by proximal surroundings. Because of this tight coupling with one’s temporal and spatial vicinity, what is perceived is strictly ordered by the structure of the proximal environment. This is not the case when processes, which originated long ago, get to completion in situations in which the causal strength of proximal surroundings is greatly diminished. This diminution of the causal strength of proximal surroundings occurs during sleep or because of some intoxication. Consider sleep. Due to both external and internal reasons, the causal efficacy of proximal surroundings is weakened if not suspended altogether. Yet, this does not mean that what takes place inside the brain, all of a sudden, is autonomous. On the contrary, brain activity is still the result of past experiences and of past moments of acquaintance with the environment. The physical continuity with past events is not lost. The processes taking place inside a brain during a dream are all legitimate physical processes that have began at a certain time and place and that are reaching a conclusion in the subject’s brain – not differently from what happens in everyday perception. Consider that everyday normal perception is not instantaneous either. There is a temporal lag between external causes and neural endings in everyday perception, too. It is well known that "What we become aware of has already happened about 0,5 sec earlier. We are not conscious of the actual moment of the present" (Libet 2004, p. 70). So, why should the hypothesis that all mental content is the result of ongoing perceptual processes be so upsetting?

As to the fact that in a dream it is possible to experience a pink elephant, this is the effect of a process that is singling out events that are usually separate in the proximal surrounding. Yet, when the causal ordering effect of surroundings is set aside, past events with no real unity may be unified by new processes. This is something akin to what happens when you look at a landscape. Because of your point of view, buildings that are far away from each other may be perceived as contiguous. Events which occurred in separate instants of time and far away from each other may be perceived as a unity.

11 What is Missing?

The Spread Mind does not require any new unexpected physical phenomenon. The physical world is already equipped with stuff and processes. This is just standard physics. Nothing more than that is required. The Spread Mind suggests that consciousness is situated and physically larger than the body of the subject. Surprisingly, it might turn out that the conscious mind is larger than the cognitive one which is made of the cognitive gears mostly located inside the skull (Adams and Aizawa 2008; Adams and Aizawa 2009).

What is still missing from the sketchy outline presented here? For one, the picture it provides is still incomplete. Many details are still missing. How does this model match with the wealth of evidence provided by neuroscience and psychology? Can the theory fit the available empirical data? Luckily, the Spread Mind model is not vague as to the emergence of phenomenal experience and their necessary conditions. For instance, the model requires that any phenomenal experience is indeed a process singling out something in the external world.

Every phenomenal content ought to be explained as an actual perception. So, the theory is falsifiable insofar as it makes prediction about the conditions in which consciousness may occur. For instance, a prediction is that no brain in a vat ought to be possible. If any phenomenal content were to take place without a corresponding physical cause, the Spread Mind would be false. Of course, physical events taking place inside the body may still be accounted by the theory insofar as they provide the origin of a suitable process. Henceforth the Spread Mind is amenable to empirical verification.

As a result, it ought to be verified whether there are cases of alleged purely endogenous phenomenal content. Are there any? At the best of my knowledge, there is only a handful of cases that might qualify as valid counterexamples. Among the few, I quote phosphenes due to migraine in congenitally blind subjects, phantom limbs in congenitally limbless patients, phantom penises in female-to-male transsexuals (Saadah and Melzack 1994; Brugger, Kollias et al. 2000; Melzack 2001; Mulleners, Chronicle et al. 2001; Ramachandran and McGeoch 2008). However, these cases are all extremely rare conditions and often rather difficult to interpret. Of course, I don’t’ want to dismiss them. I am only suggesting a more careful examination of such rather unusual cases. These cases can’t be discussed at length here. Yet, just to have an idea how it could be difficult to interpret such remarkable findings, consider that it has hitherto been impossible to settle definitively the debate as to the visual content of congenitally blind subjects (Bértolo, Paiva et al. 2003; Lopes da Silva 2003; Kerr and Domhoff 2004) which is a relatively more common and well-known condition. By the way, on this last issue, the Spread Mind is unambiguous: a congenitally blind subject should not have any visual phenomenal content in her dreams or in other psychological states. Of course she can have experience of space, shapes, and movement due to her historical continuity with such phenomena by means of other senses like proprioception, hearing and touch. Finally I would like to mention another often quoted alleged counterexample to a situated view of consciousness: the direct stimulation of the cortex (for instance, Penfield 1958). Although direct stimulation is considered as an example of autonomous phenomenal experience produced by the brain, I am doubtful. In fact, direct stimulation requires a physical stimulation provided by the experimenter – thus there is an external phenomenon. It is true that the causal path does not pass through the usual sensory nervous paths, yet the cause of the direct stimulation is a physical phenomenon external to the nervous system. Furthermore, the elicited content appears to be derived from past experiences.

A final issue that has not received enough attention is a thorough causal modeling of the processes involved in building up consciousness. Clearly, there are some causes that play a crucial role in cutting the physical world at its joints, so to speak. When and where does a process begin and when and where does a process end? This is not a minor issue and it will need a very careful future examination in order to fulfill all the expectation of a complete theory.

Acknowledgements. My writing has been supported by the bilateral project Italy-Corea ICTCNR and KAIST. Moreover, I would like to thank two anonymous reviewers for their helpful comments and suggestions.