The so-called problem of consciousness sits at the forefront of research in philosophy and science. It is, perhaps, not really a new problem, being a slightly different focus on the old philosophical chestnut of the mind-body problem. However, whereas Descartes — and those who sought to defend or disprove him — wrestled with how a supposedly ‘immaterial’ mind (or soul) could influence and interact with a material body, the modern debate — which mostly rejects Cartesian dualism — focuses on the role of the physical brain in generating and facilitating conscious experience.

The central question is therefore whether consciousness represents anything over and above the mere physical processes of the brain, and if not, how we may account for it. In the words of Thomas Nagel — who appears to have set the ball rolling here in his article, ‘What is it like to be a bat?’ — isn’t there “something it is like” to be a conscious human being that a purely physical account of brain states and neurons necessarily excludes? For instance, if it were possible to model the human brain, perhaps creating artificially intelligent computers or robots that thought and behaved like conscious intelligent agents (that were able to communicate, deliberate, seek goals, etc.), wouldn’t such a creation still lack the subjective experience of being conscious?

This question has divided philosophers into three main camps (following David Chalmers’ The Conscious Mind): hard-line materialists, who argue that there is no deep problem, and that consciousness may be explained in purely physical terms; dualists, who argue that consciousness exists in some way ‘outside’ of physical reality, and cannot be reduced to it; and non-reductive materialists, who argue that whilst consciousness would seem to have a material basis, it is not identical with it, and we cannot therefore (for various reasons) entirely reduce it to descriptions of physical brain states.

In the context of the above debate Frontiers of Consciousness brings together twelve essays that each began as a contribution to a series of lectures and seminars held at All Souls College, Oxford, from April to June, 2006. Each essay represents a post-conference development of individual contributions, and chapters vary in length between approximately ten and sixty pages (averaging about twenty). Some chapters are therefore more developed and challenging than others, but all represent an interesting perspective on various aspects of the problem. The authors themselves hail from various fields — psychology, neurology, philosophy — and so the book’s approach (and the purpose of the conference) is to approach the problem of consciousness from various interdisciplinary viewpoints in the hope that new light may be shed on what is proving to be an intractable problem.

The first thing to note about the book therefore is that it is not really an introduction to the problem of consciousness. Some chapters are more accessible than others, and the essentials of the debate are addressed in certain places, but most contributions assume a certain level of familiarity and intellectual involvement with the problem that really make it most suitable for those looking to build and extend upon an already established understanding. The language and detail reflect this, and whilst the book’s blurb boasts that it is “distinctive in its accessibility, and unparalleled in its depth of coverage”, this is really only true relative to the more obscure and narrow, purely academic contributions to the subject that readers might otherwise chance upon.

This said, Frontiers of Consciousness is a very useful book. As the title suggests, contributions represent thinkers at the forefront of the debate, and as such, those working in related fields and looking to further their understanding will benefit greatly from the snapshots of current research that the book provides. In fact, the interdisciplinary approach of the book is perhaps its greatest virtue. As a philosopher, whilst I found the philosophical contributions interesting and useful, I had less to learn from these than the contributions which came from neuropsychology — which, incidentally, are the majority, the psychologists and neuroscientists outnumbering the philosophers ten to two). The reason for this bias toward neuropsychology is revealing: Do the editors/conference organizers think that the problem of consciousness is a fundamentally scientific — as opposed to a philosophical — one? Should we look to neuropsychology more than philosophy to provide a solution to the problem? Whatever the reason, the bias is something for which philosophers interested in neuroscience will be grateful, for most will be underinformed regarding developments in this field. On the other hand, the under-representation of philosophy puts a great emphasis on the two chapters that are included to punch their philosophical weight, and so let us look at these first.

In Chapter 1, ‘Consciousness and Explanation’, Martin Davies sets out the philosophical background to the problem in terms of the notion of an “explanatory gap” between our neuroscientific understanding of brain processes and our subjective experience of them. Is there, in fact, such a gap? Davies provides a precise overview of the various responses to this question, whilst showing that no approach is problem free.

In Chapter 2, ‘Explanatory Gaps and Dualist Intuitions’, Martin Papineau takes Davies to task on his use of the term “explanatory gap”, which he sees as falling into a dualist trap (as if the conceptual problem of how mental states and brain states are related is uniquely problematic). He reinforces this point by suggesting that this mistake is based on a deep-seated human “intuition” that mind and brain are separate, and that even “professed physicalists don’t always believe their physicalism” (p.58), often falling back into dualist phraseology where brain states cause or generate consciousness (rather than being identical with it, which is what hard-line physicalism should officially propose). However, he then suggests that the “intuition of distinctness” (between mind and body) that most people feel — and which he sees as fundamentally responsible for the whole problem — is, along with other celebrated “illusions”, one that represents no fundamental problem, and is in fact one that we can live with. Therefore, there is no fundamental “explanatory gap”.

Both these chapters are interesting, and Papineau’s contribution is punchy and concise, but Davies’s — which is obviously meant to act as a detailed introduction to the subject — is too closely argued to be useful to anyone not already fairly familiar with the philosophical landscape.

From the perspective of neuropsychology, the remaining ten chapters present different aspects of consciousness research. In chapter 3, ‘Emotional Colouration of Consciousness: How Feelings Come About’, Joseph LeDoux details the role of unconscious emotion in shaping and influencing conscious action. Based in the amygdalae (small, almond-shaped areas of the brain, located towards the latter part of the temporal lobe of the cerebrum), such basic emotional reactions as fear and anger draw conscious brain resources to their aid, directing their application in line with our most fundamental needs — such as reproduction and survival — all without conscious control or knowledge. Hereby, LeDoux proposes a “working memory” model of consciousness, whereby such unconscious processes work to shape the context of awareness.

Responding to this in Chapter 4, ‘Emotion, higher-order syntactic thoughts, and consciousness’, Edmund T. Rolls considers this working memory account of consciousness inadequate, arguing that “higher-order thoughts” (thoughts about other thoughts or states) are also required. In fact, Rolls goes so far as to suggest that “if a system were doing this type of processing (thinking about its own thoughts), it would then be very plausible that is should feel like something to do this”, and even that “it is not plausible to suggest that it would not feel like anything to a system if it were doing this” (p.147) — which, in effect, seems like an argument for strong AI (i.e. that not only can machines think, but they can be as conscious as humans are), for this “higher-order thought” model of consciousness would seem to be amenable to computer modeling. Rolls therefore sees qualia (subjective qualitative mental experiences) as a product of this: we are aware of what it is like to have certain feelings, sensations, etc., because we can ‘step back’ via higher-order thought. However, this still seems to sidestep or underestimate the problem, for it is not the role or origins of qualia in the conscious process that is the real issue, but how such subjectivity exists at all. So, to say that qualia exist because we can be aware of them is not really to solve any deep mysteries.

Chapter 5 (‘Consciousness and unconscious visual processing in the human brain’, by A. David Milner), looks at the different roles played by separate areas of the brain in aspects of visual awareness and processing, arguing for a dualistic split between unconscious visuomotor processing (e.g. grasping, throwing, etc.), and perceptual awareness. Milner concludes that the former processes are not only unconscious, but inaccessible to consciousness. In other words, I can be aware of grasping, throwing, etc., but not of the processes and visuomotor calculations (such as object recognition, hand-eye coordination, and so on) which allow me to do so (these remain unconscious abilities).

Responding to this, in Chapter 6 (‘Vision, Action, and Awareness’), Manos Tsakiris and Patrick Haggard largely agree with Milner’s proposed division of visual processing duties, but criticize the “Cartesian theatre” model of consciousness that he seems to favor, whereby the subject is a passive observer of conscious experience. In its place, they propose a view of consciousness in sympathy with that of Martin Heidegger, which sees consciousness as embodied and embedded in our actions and experience of the world.

Perhaps the most philosophically interesting contribution is Chapter 7, ‘The Social Functions of Consciousness’, where Chris D. Frith sets out some of the extraordinary findings of psychological studies concerning agency. For instance, via hypnosis or precisely constructed experiments, it is possible to show that subjects can either be disassociated from their own actions (such as being convinced that they have no control over the movement of their own arms), or associate themselves with actions over which they have no control (such as pre-programmed computer sequences). Frith also points out the relevance of such issues for practical decision-making, citing problems faced (for example) in attempting to communicate with patients with ‘locked in’ syndrome or autistic children. Frith concludes therefore that consciousness and agency are very closely linked concepts, and that, as a result, we need to think of consciousness as a “joint endeavor”, for, as with agency, how we ascribe consciousness (even our own) is as much determined by social practices and the attitudes of others as it is by the existence of any internal subjective experiences.

In Chapter 8, ‘Are We Studying Consciousness Yet?’, Hakwan C. Lau provides a perceptive critique of the various attempts to isolate the “neural correlate of consciousness” (NCC) — that is, which parts of the brain are active when we are conscious. Lau points out that, to date, this holy grail of neuroscience and philosophy has focused mainly on objective measures, such as a subject’s task performance, whereas actually what we need is to isolate the neural correlate of subjective awareness itself. Lau makes an important point here: task performance is not identical to perceptual awareness. I could perform well at a task unconsciously, or display knowledge of something I claim to have no conscious awareness of. However, this merely informs us of the brain’s capacity for unconscious information processing and task performance, and does not necessarily shed direct light on what subjective consciousness actually is. Therefore, greater care is needed to isolate this subjective state and to divorce it from non-conscious brain processes.

Chapters 9 and 10 consider problems related to the question of animal consciousness. As Cecilia Heyes argues (‘Beast Machines? Questions of Animal Consciousness’), it is most tempting to argue by analogy: animals do or don’t behave like us, therefore there is something similar (or not) happening ‘inside’ them. However, as she points out, the question is not so easily decided, and this and other common approaches either demonstrate serious flaws or require accepting as-yet-unproven assumptions, leaving the most important question — whether animals possess anything like human phenomenal consciousness, or are just unconscious “beast machines” — undecided. Heyes believes, intuitively, that they do (and I agree), but that, whilst some approaches promise more than others (namely, testing for consciousness in the form of “higher-order thinking” — that is, thinking about thoughts), science is yet to find a means of conclusively establishing this.

Taking issue with Heyes’ conclusions, Anthony Dickinson (‘Why a Rat is not a Beast Machine’) argues that animals do not require second- or higher-order thought in order to possess phenomenal consciousness, which can accompany “first-order representation” or thought. This is because phenomenal consciousness can fulfill a functional role for animals. So, a rat may not be aware that it’s aware, or have a concept of self, but there may still be, in Nagel’s phrase, “something it is like” to be that animal via its possession of phenomenal experiences — desires or emotions — that serve various purposes and goal-directed behavior. The question of whether an animal possesses this form of consciousness is therefore dependent on whether, in analyzing its behaviour, we can identify a functional role for such phenomenal consciousness (and which would also rule out it being possessed by more rudimentary species for which phenomenal consciousness would fulfill no functional role).

In Chapter 11, ‘Does Consciousness Spring from the Brain? Dilemmas of Awareness in Practice and in Theory’, Adam Zeman provides a neurologist’s take on consciousness, suggesting that the problems we face in accounting for it spring from the traditional medical dichotomy between psychology and neurology — between the study of the mind and the body. In a fascinating and extremely useful overview, and perhaps the best general contribution to the book, Zeman shows how again and again we are faced with phenomena which are most fully understood through being approached from a combination of both perspectives. Therefore, the most fruitful approach to consciousness is not one which attempts to ground a theory in one or other aspect (mind or body), but that seeks to understand the phenomenon as a whole from these two differing perspectives: our subjective experience cannot be completely reduced to the physical (we cannot have a “neurology of the soul”), but neither can we hold on to the old Cartesian notion of a private, immaterial, separate sense of self. Of course, even this approach has its problems, but it is one that promises a greater reward than any one-sided theory can offer.

In the final chapter, ‘On the Ubiquity of Conscious-Unconscious Dissociations in Neuropsychology’, Lawrence Weiskrantz’s reviews various instances where, after damage to the relevant parts of the brain, subjects nonetheless retain certain functions at an unconscious level. The most celebrated example of this is of course ‘blindsight’, a phenomenon that Weiskrantz himself discovered, where subjects retain unconscious processing and knowledge of visual information after damage to the visual cortex. It is these phenomena that Weiskrantz sees as central to a possible understanding of consciousness, and — he implies — in the search for its neural correlate.

In Summary, Frontiers of Consciousness presents a varyingly readable and useful account of contemporary work in the various fields of consciousness research. In this sense, it succeeds, in that it covers the spectrum of the debate, and someone with an interest in focusing in on one or more of these aspects — the role of emotion, the relation of consciousness to perception, the question of animal consciousness, and so on — will find here a good account of where the latest research is at. Also, for those with a more general interest, certain chapters (most notably Chapters 1 and 11), provide a useful overview of the main philosophical, neurological and psychological obstacles we face in arriving at a successful theory. However, as already noted, chapters vary in both their readability and their general relation to the central question: some contributions will be hard or tedious going for readers from other disciplines or non-specialists, and others either construe the problem differently, or do not seem to recognize its full extent. Therefore, for those looking for an introduction to the subject there exist more accessible and useful books; however, for those with a specialist or academic interest, whilst it would have been nice if the various contributions had been interlinked more closely, there will be something here of both use and interest.

 

© 2010 Gareth Southwell

 

Gareth Southwell is a philosopher and author based in Wales, UK. He is currently writing a series of introductory philosophy books for Wiley-Blackwell, a book explaining the origin and meaning of philosophical quotations for Quercus, and developing the website www.philosophyonline.co.uk. His research interests include controversies to do with the definition of death (the subject of his PhD thesis), and the problem of consciousness. He is also a freelance illustrator.