Inês Morais
(Versão em Português / Portuguese translation)
The Oxford Handbook of the Philosophy of Consciousness is an excellent, very comprehensive survey and discussion of recent work in the philosophy of consciousness, with contributions from philosophers, cognitive scientists, and neuroscientists, in the major aspects of an area with ramifications at least into epistemology, metaphysics, ethics, and aesthetics. I strongly recommend it.
The book is divided into three parts. Part I is about ‘varieties of conscious experience’; Part II is about ‘theories of consciousness’; and Part III is about ‘consciousness and neighbouring phenomena’. Here I simply present a brief summary of all the chapters.
The book includes, curiously, two introductions: a general introduction by the editor, titled ‘What is the Philosophy of Consciousness?’, which begins with a metaphilosophical question: ‘What do philosophers have to contribute here?’ (p. 1). Kriegel’s answer suggests a substantial (controversial) definition of philosophy: ‘our empirical knowledge about consciousness is so fragmentary and incomplete, at this early stage of scientific enquiry, that philosophers may be called upon to offer more or less disciplined speculations about the part of the story where we simply do not as yet have sufficient scientific knowledge.’ (ibid.) The suggestion is controversial because it makes philosophers appear as either more insightful than scientists, or as more daring in dealing with the uncertain, the outputs of their work to be seen accordingly. The second introduction (and first numbered chapter), by David Papineau, titled ‘The Problem of Consciousness’, explains briefly the topics to be addressed in the book, with a defence of physicalism: the supposed ‘explanatory gap’ between brain and mind, one of the main problems philosophers of mind need to address, is presented as just a ‘corollary of dualist intuitions’ (p. 32). Most philosophers of consciousness are indeed not dualists, even though the view is suggested in a few chapters, and defended in chapter 13.
Part I: Varieties of Conscious Experience
Chapter 2, ‘Visual Experience’, by Pär Sundström, focuses selectively (and in an interesting way) on the ‘transparency’ of visual experience, on which properties we are presented with in visual experiences, and on whether we are ever presented with outer spatiotemporal particulars in visual experiences. Sundström discusses cases of perceptual learning—such as the case of learning to spot a pine tree or the case of chicken sexing—in which properties become salient. An expert has an experience that non-experts cannot have. While it is uncontentious that visual experiences have phenomenal content, it is a matter of dispute what that content is of: some philosophers entertain the possibility that ‘particular objects and property instances are not directly present in our experiences’ (p. 60) and that our experiences are of nothing more than abstract properties (or ‘universals’).
Chapter 3, ‘Non-Visual Perception’, by Casey O’Callaghan, examines the important topic of perceptual consciousness beyond vision, and the working of the different senses in concert. Sense perception being ‘the most vivid form of lived human consciousness’ (p. 66), with consequences for the justification of empirical beliefs and guiding world-directed action, it has an objective character: ‘perception presents its objects as independent from oneself and one’s experiences or states of consciousness’ (p. 70). The discussion covers the multisensory aspects of perceptual consciousness and concludes that unisensory approaches, that seek to examine perception experience from the point of view of one sense ‘in abstraction or in isolation from the others’ (p. 79), face methodological difficulties, since ‘one sense may causally or constitutively impact experience associated with another’ (ibid.).
Chapter 4, ‘Bodily Feelings’, by Frédérique de Vignemont, addresses the interoceptive system, which ‘we cannot shut’ (p.82), and in particular the first personal character of the phenomenology of bodily awareness, which includes sensations and bodily feelings that according to the author ‘should (…) not be conceived of simply in sensory terms, but also in affective and metacognitive terms’ (p. 98).
Chapter 5, ‘Emotional Experience’, by Julien Deonna and Fabrice Teroni, exemplarily deals with exploring emotion theory through the lens of phenomenology, suggesting that our understanding of value is ‘anchored in the personal perspective offered by emotional experience’ (p. 119). The authors discuss componential, perceptual, and attitudinal accounts of emotional experience and favour the attitudinal account. Our emotional experiences are described as felt attitudes, our evaluative concepts being grounded in them. The case of an emotional zombie, deprived of emotional experience, helps explain how a personal, felt engagement with the world is required for understanding value.
Chapter 6, ‘Imaginative experience’, by Amy Kind, focuses on the differences between imagining and other kinds of conscious experience such as those of perception and memory. Kind describes several proposals to then suggest a general pessimism regarding the description of the phenomenology of imagination. Qualia—the phenomenal properties of experience—are generally considered to be ineffable, and Kind concludes that we are able to experience them but not yet to describe them adequately. Following Nagel, Kind suggests that the subjectivity of the imagination can hardly be described with the general, objective vocabulary of science.
Chapter 7, ‘Conscious Thought’, by Tim Bayne, discusses the varieties of conscious thought, the various views of consciousness (as phenomenality, as cognitive accessibility, and as awareness), the phenomenal dimensions of conscious thought, and the relationship between consciousness and thought, entertaining finally the idea that thought is exclusive to conscious creatures.
Chapter 8, ‘The Experience of Agency’, by Myrto Mylopoulos and Joshua Shepherd, addresses the nature and sources of experience-types associated with the exercise of agency, as with the case of intentional action. The chapter begins with pioneering psychology and neuroscience work from the 1980s to then focus on the philosophy of agentive phenomenology, first making the case for a distinct proprietarily agentive phenomenology—irreducible to perceptual, emotional, or cognitive phenomenology—to then describe it in a taxonomy for the phenomenologist, including ‘purposiveness’, ‘mineness’, ‘execution’, ‘action perception’, ‘action assessment’, and ‘freedom’.
Chapter 9, ‘Temporal Consciousness’, by Philippe Chuard, begins with the fact that perceptual experiences relate to time in the sense that they occur in time, and in the sense that they have intentional or representational content. Accounts of temporal experiences tend to converge on the view that conscious experiences are events, which can be perceived, and that some perceptual experiences give rise to judgements about the temporal properties of those events. Three conceptions of the temporal ontology of experiences and of their temporal content are sketched: as snapshots, as extended experiences, and as extended contents. The chapter’s conclusion is that deciding between these will depend to a great extent on conceptual questions regarding the nature of perception, as well as on empirical issues regarding temporal constraints on perceptual processing and whether we have introspective access to all the experiential features of these experiences.
Chapter 10, ‘The Phenomenal Unity of Consciousness’, by Farid Masrour, articulates and develops the view that experiences ‘seem to form some sort of unified field’ (p. 208); phenomenal unity is not subjective unity, or objectual unity, or access unity, but a monadic property of some sets of experiences that is phenomenally manifest, whose members form a single phenomenal item, which is grounded. The idea that phenomenal unity is a natural feature of consciousness is articulated in terms of necessities. In particular, Masrour argues for the Pure Extrinsic Unity thesis—according to which ‘all experiences are extrinsically unified’ (p. 218)—and for a Leibnizian answer to the grounding question about phenomenal unity.
Part II: Theories of Consciousness
Chapter 11, ‘The Neural Correlates of Consciousness’, by Jorge Morales and Hakwan Lau, is a long and very interesting essay in neuroscience, discussing a selection of influential theories about the neural correlates of consciousness (NCC), focusing on the level of functional anatomy, that is, at the level of the different brain regions (rather than at the neuronal circuitry level). Philosophy can then play a key role in addressing the ‘conceptual and experimental design issues’ (p. 233) that are relevant. Surveying the strongest theoretical predictions regarding the neural correlates of consciousness and arguing from evidence for prefrontal cortex’s involvement in consciousness, encoding specific content, the authors then discuss the architecture of the NCC, before concluding that brain activity in a certain area does not always favour that area being the NCC, and that mapping relevant brain areas is not sufficient to explain the computational architecture that supports consciousness.
Chapter 12, ‘Beyond the Neural Correlates of Consciousness’, by the editor, Uriah Kriegel, maps the possible explanations for the correlation between consciousness and the NCC, linking them to traditional metaphysical positions on the mind-body problem. The conclusion is that the relevant scientific evidence is insufficient to adjudicate between the strongest views, such as the causal-connection view or the constitution-connection view, which suggests that traditional metaphysical positions may be empirically equivalent. The final suggestion is the (useful) diagnosis that consciousness is an elusive phenomenon.
Chapter 13, ‘Dualism’, by Brie Gertler, provides a compelling case for a minority view these days: dualism. To argue for the metaphysical doctrine of naturalist dualism—the thesis that consciousness is a feature of the natural world—Gertler explains how conscious experience cannot be analysed and explained solely in terms of structure and dynamics, and how it is not constituted or necessitated by anything amenable to pure physical analysis (i.e., in terms of structure and dynamics). Invoking classical arguments for dualism (the Knowledge Argument and the Zombie Argument) to suggest that there is a gap between consciousness and what physical theories can explain, Gertler argues that the conceptualization of physical phenomena in terms of structure and dynamics is unable to account at least for the subjective phenomena of consciousness. Her main conclusion will be that where one stands on the dualism – physicalism debate depends on one’s epistemic assumptions. And she suggests (convincingly) that the subjectivity of consciousness is a fact that only dualism can explain.
Chapter 14, ‘Russellian Monism’, by Philip Goff and Sam Coleman, presents a mid-way view between physicalism and dualism, stemming from a novel approach to the mind-body problem presented by Russell in The Analysis of Matter (1927). In essence, it agrees with dualism that the dispositional properties of physics alone cannot explain consciousness; and it agrees with physicalism that consciousness is part of the physical world. Philip Goff discusses panpsychism, the view that consciousness is fundamental and ubiquitous in nature, and panpsychist Russellian monism in particular: the view that the properties that physics sees in behaviouristic terms are forms of consciousness. Sam Coleman discusses panprotopsychism, which agrees with panpsychists that the austere universe given by physics would be unable to support consciousness, and agrees with physicalism that to explain human consciousness, consciousness need not be fundamental. The chapter concludes with the modest and honest claim that both theories are worth taken seriously as alternatives to hegemonic physicalism.
Chapter 15, ‘Idealism’, by Michael Pelczar, discusses metaphysical idealism, that is, the view that physical facts supervene on mental facts: the fundamental features of the world are mental. Pelczar begins by discussing Kant’s metaphysics, which, not being itself idealistic, is between two major idealisms: traditional idealism such as the one of Leibniz and Berkeley; and the phenomenalism of J. S. Mill and the theorists of sense-data from the early 20th century.
Chapter 16, ‘Eliminativism about Consciousness’, by Elizabeth Irvine and Mark Sprevak, focuses on eliminativism about phenomenal consciousness and consciousness discourse eliminativism (Eliminativism is the physicalist doctrine that defends the elimination of everyday psychological concepts, to be replaced with concepts from neuroscience). The most influential arguments for entity eliminativism about consciousness are discussed: Dennett’s eliminativism about qualia, and ‘illusionism’, the view that our phenomenal feelings are illusory. In the last section, discourse eliminativism about consciousness is discussed: the view that talk of consciousness ‘generates unproductive debates and miscommunication; it blocks the generation of useful predictions and generalizations; and it promotes misapplications of research methodologies and heuristics’ (p. 367). Although I believe that talk of consciousness is ineliminable from theorizing and useful to it, and that the concept of consciousness is so ubiquitous that its elimination is also unfeasible, I think this is a very informative chapter about this view.
Chapter 17, ‘A Priori Physicalism’, by Frank Jackson, defends the very interesting thesis that physicalism must be a priori: a sufficiently rich account of a subject in physical terms must entail the mental and, especially, it must include the phenomenal conscious aspects of our mental lives. Physicalism is either true a priori, or it is false (Jackson claims that he (now) believes it to be true). The options are, therefore, between those who think that the mental is (a priori) nothing in addition to the physical, and those (like dualists and panpsychists) who believe that there is a distinctively mental realm, which for the dualist is over and above the physical.
Chapter 18, ‘A Posteriori Physicalism’, by Joseph Levine, discusses ‘type B materialism’, concluding that the best explanation for the existence and persistence of an explanatory gap between the physical and the mental is that there is a genuine metaphysical gap (Levine favours a version of emergentism). Not only the conceivability of zombies presents a real problem for type B materialists, but the irreducibly qualitative nature of (Levine’s example) a reddish qualitative character, that cannot be fully identified with patterns of neural firing, suggests that conscious experience involves acquaintance with the contents of experience, that are not purely physical.
Chapter 19, ‘Representationalism about Consciousness’, by Adam Pautz, makes the case for representationalism as an inference to the best explanation. Given the essentially spatial character of visual consciousness, and the fact that visual experiences must be something more than just neural patterns, and the ‘overwhelming’ arguments against the sense datum view, representationalism says that the ‘something more’ involved in visual consciousness are representational states enabled by the neural states but distinct from them, a view that Pautz takes to generalize to all forms of consciousness. Then two forms of representationalism are considered and internalist representationalism is preferred. I find something akin to representationalism plausible, and the case made is very strong, except that I do not find the arguments against sense datum theory particularly ‘overwhelming’.
Chapter 20, ‘Higher-Order Theories of Consciousness’, by Josh Weisberg, discusses theories holding that ‘a mental state is conscious when it is appropriately represented by a higher-order state’ (p. 438). These theories are generally motivated by the ‘transitivity principle’, according to which ‘a mental state is conscious when one is appropriately conscious of oneself as being in that state’ (p. 440). Weisberg considers, and responds to, various challenges to the transitivity principle and to the HO theory, to conclude that empirical data from psychology and neuroscience supports the HO approach. In particular, one guiding principle of cognitive science, according to which most of mental processing occurs outside of conscious awareness, helps explaining why qualia, and consciousness in general, seem at first intractable.
Chapter 21, ‘Self-Representationalist Theories of Consciousness’, by Tom McClelland, discusses another meta-representationalist alternative to higher-order representationalism: self-representationalism. While HOR has trouble with the intimacy of consciousness (the idea that there cannot be a gap between how a conscious state seems to a subject and how it really is), self-representationalism (SR) holds that a mental state is conscious because it represents itself, a theory that thereby respects the intimacy of consciousness. While McClelland admits that so far, no SR, be it structured (when higher-order and lower-order components can be distinguished) or unstructured, has been able to deliver the promises of transitivity and naturalizability, the hope is that some new member of the SR might be able to achieve that.
Chapter 22, ‘The Epistemic Approach to the Problem of Consciousness’, by Daniel Stoljar, is, we are told, about a minority way of doing philosophy—not Carnapian, not Quinean. The epistemic view of the hard problem of consciousness is that we do not know (or, for some, that it is impossible to know) how to solve the hard problem of consciousness, that is, the problem of how neural information processing objectively observed should give rise to the subjective experience of consciousness. Two objections to the epistemic approach are considered: the relevance objection (that we are not ignorant of anything that is relevant to consciousness) and the no-answer objection (that the epistemic approach does not provide a solution to the hard problem, so it doesn’t contribute genuinely to the debate). The main conclusion is that in the last hundred years we have settled into ways of doing philosophy that are not congenial to epistemic approaches to the hard problem.
Part III: Consciousness and Neighbouring Phenomena
Chapter 23, ‘Consciousness and Attention’, by Christopher Mole, addresses a central topic for experimental psychology: the relationship between attention and consciousness. Based on experiments that consider and test the possibilities of inattentive consciousness and of unconscious attention, it is suggested that attention does something for consciousness, but that attention may not be an entirely conscious phenomenon. Several experiments show that the allocation of attention can be unconscious (attention can have unconscious influences); that consciousness does not play an essential role in explaining attention’s allocation (the subject can attend to items he is not conscious of, and he may be unaware of attention taking place); and that the effects of attention, although they are often effects on consciousness, can also be effects on unconscious processes. To conclude, attention should not be identified as a cause for consciousness.
Chapter 24, ‘Consciousness and Memory’, by Christopher S. Hill, addresses the relationships between three forms of consciousness—introspective consciousness, access consciousness, and phenomenal consciousness—and three types of memory—long term memory, working memory, and iconic memory. The conclusions are that working memory is a necessary condition for introspective consciousness; that making a representation available to higher cognitive activities just involves, in some cases at least, the encoding of the representation in working memory; and that ‘representations can be present in a memory register without being phenomenally conscious’ (p. 529).
Chapter 25, ‘Consciousness and Action: Contemporary Empirical Arguments for Epiphenomenalism’, by Benjamin Kozuch, considers epiphenomenalism, ‘the view that conscious mental states have no physical effects’ (p. 538), but in particular contemporary forms of epiphenomenalism, based on experiments in neuroscience and psychology that challenge the view that the mental is causally efficacious. Research in psychology has suggested that neural activity initiating voluntary actions precedes our conscious willing of the actions, which means that it is not our conscious will that causes the actions. And research in vision science has shown cases in which the content of visual consciousness and motor action dissociate, which goes against the view that visual consciousness is what guides visually based motor action.
Chapter 26, ‘Consciousness and Intentionality’, by Angela Mendelovici and David Bourget, discusses the relationship between intentionality and phenomenal consciousness, that is, between the ‘aboutness’ of mental states and their qualitative nature. The chapter defends the phenomenal intentionality theory, ‘the view that the most fundamental kind of intentionality arises from phenomenal consciousness’ (p. 559), i.e., from the felt, qualitative nature of mental states. The main conclusion is a defence of a strong version of the phenomenal intentionality theory, according to which ‘All instances of intentionality arise from phenomenal consciousness alone’ (p. 580).
Chapter 27, ‘Consciousness and Knowledge’, by Berit Brogaard and Elijah Chudnoff, focuses on the relationship between perceptual experiences and justified beliefs and on the idea that ‘being conscious in a certain way itself constitutes the basis we have for some of our knowledge about the world’ (p. 586). It also considers the possible distinction between sensations and seemings as different states (for example, when one sees a hen with 48 speckles, one has a visual sensation as of 48 speckles, but it may not seem that the hen has exactly 48 speckles (as opposed to 47 or 49), so sensations appear to be different than seemings. This is the only chapter that (just) alludes to aesthetic properties ‘(e.g., being gloomy)’ (p. 601), as an example of higher-level properties. In the conclusion, an analogy is considered between perception and another kind of experience, intuition, and in particular the intuition of abstract matters, such as when we form beliefs about mathematics, metaphysics, or morality.
Chapter 28, ‘Consciousness, Introspection, and Subjective Measures’, by Maja Spener, discusses the so-called ‘subjective measures of consciousness’ and the central worry of response bias, to then examine the question of whether such measures are introspective. The methodological challenge that the science of consciousness faces is examined—that is, the problem that arises from the fact that data about consciousness seems to require reliance on subjective experience and subjective reports, whereas scientific investigation would require objective measures of consciousness that are not available. At the end of the chapter, it is claimed that lack of progress in this area is largely due to objections regarding subjective measures of consciousness, which echo objections to introspectionism in psychology at the turn of the 20th century.
Chapter 29, ‘Consciousness and Selfhood’, by Dan Zahavi, begins with the claim that studies of identity have shifted their focus from diachronic to synchronic analyses, giving rise to debate regarding the link between phenomenal consciousness and selfhood. Those denying the phenomenal presence of the experiencer are contrasted with those highlighting the first person perspective. Zahavi defends ‘experiential minimalism’, according to which ‘experiential processes are characterized by an inherent reflexive (not reflective) or pre-reflective self-consciousness in the weak sense that they are like something for the subject’ (p. 637). It is also emphasized that phenomenality is not only ‘about what is being presented, but also about how it is being presented’ (p. 638). The basic idea behind experiential minimalism is that experience is irreducibly first personal, that is, phenomenal consciousness is ineliminably perspectival (p. 643).
Chapter 30, ‘Consciousness and Morality’, by Joshua Shepherd and Neil Levy, addresses the relevance of consciousness for questions regarding moral status, moral responsibility, and moral knowledge. One aspect common to all three discussions is the appeal to phenomenal states that are broadly evaluative, which prompts the suggestion that ‘it is evaluative phenomenology that is, in the first instance, intimately connected to morality’ (p. 669), which makes evaluative phenomenology appear as especially important, not just for the philosophy of mind, but also for ethics. However, the chapter also contains an anti-phenomenalist thread: access consciousness (rather than phenomenal consciousness) seems crucial for high degrees of moral status; for some authors, functional aspects of cognition seem to be more important than phenomenal consciousness for moral responsibility; and the thesis of moral perception—the thesis that ‘perceptual experience presents us not only with events, objects, and their properties [but also] presents these events and objects as morally good or bad, right or wrong, and it does so, arguably, in a way that underwrites moral judgement’ (p. 664)—faces objections. For instance, it faces the objection that such a view commits one to a controversial view of perception, namely that perceptual experience contains high-level content (I don’t see a problem with this view of perception, and the phenomenon of aesthetic perception may lend support to it). The second objection is that bad actions and good actions may have the same phenomenology (the example given is that a shooting may be a (bad) act of violence or a (good) act of self-defence). I find the moral perception thesis plausible, as well as the views that give phenomenal consciousness a central epistemic role, and I think an analogous discussion in aesthetics, in a separate chapter in the Handbook, would have been useful, although this chapter does address these issues (for morality) in a clear and well-directed fashion (it is true that non-evaluative perception leaves out the moral).
The last chapter, chapter 31, ‘Embodied Consciousness’, by Mark Rowlands, identifies consciousness with the lived body, both being ‘revealing activity’ (p. 683), thereby dissolving the ‘hard problem of consciousness’ (Chalmers, D. 1995. ‘Facing up to the problem of consciousness’, Journal of Consciousness Studies 2: 200-219.), that is, the problem of understanding how the electro-chemical activity in the brain can produce or constitute ‘the glorious, multi-hued, multi-textured phenomenology of consciousness’ (p. 685). Rowlands’ dissolution of the problem comes with a difficulty, however, that of ‘understanding how intentional directedness arises from actual or potential objects of such directedness’ (pp. 686–687), a problem that is arguably as hard to (dis)solve as the hard problem of consciousness that forms the crux of the matter in this area.
My only disappointment with this book was that there is not a chapter dedicated to aesthetics, which is an important area for the understanding of the phenomena surrounding consciousness. Apart from this absence, the book is an excellent read and a first-rate reference book. It informs the reader about many issues that are relevant to philosophers, but also to psychiatrists, psychologists, as well as the general public. This book is therefore very good news. Now plenty of teaching is to be done more largely, to be applied, also so that the work of psychologists, psychiatrists, and people in general is properly adjusted to what the mind (and consciousness) is.