Sensory substitution devices provide through an unusual sensory modality (the substituting modality, e.g., audition) access to features of the world that are normally accessed through another sensory modality (the substituted modality, e.g., vision). In this article, we address the question of which sensory modality the acquired perception belongs to. We have recourse to the four traditional criteria that have been used to define sensory modalities: sensory organ, stimuli, properties, and qualitative experience (Grice, 1962), to which we have added the criteria (...) of behavioral equivalence (Morgan, 1977), dedication (Keeley, 2002), and sensorimotor equivalence (O’Regan & Noe¨, 2001). We discuss which of them are fulfilled by perception through sensory substitution devices and whether this favors the view that perception belongs to the substituting or to the substituted modality. Though the application of a number of criteria might be taken to point to the conclusion that perception with a sensory substitution device belongs to the substituted modality, we argue that the evidence leads to an alternative view on sensory substitution. According to this view, the experience after sensory substitution is a transformation, extension, or augmentation of our perceptual capacities, rather than being something equivalent or reducible to an already existing sensory modality. We develop this view by comparing sensory substitution devices to other ‘‘mind-enhancing tools’’ such as pen and paper, sketchpads, or calculators. An analysis of sensory substitution in terms of mind-enhancing tools unveils it as a thoroughly transforming perceptual experience and as giving rise to a novel form of perceptual interaction with the environment. (shrink)

The mind-body problem is widely seen as the great remaining challenge to science and philosophy. Why and how did matter evolve to take on the quality of mind? The author takes the reader to the edges of current knowledge and back to the beginning of time, before mind existed, and in doing so constructs a history of consciousness.

It is common to account for our senses on the basis of our sensory organs. One way of glossing why Aristotle famously counted five senses—and why his count became common sense in the West and elsewhere—is because there are five rather obvious organs of sense. In more modern accounts, this organ criterion of the senses has transformed into a neurobiological criterion; that is to say, part of what it means to be a sense is to have an associated organ with (...) appropriate physiological properties. For example, part of the claim that humans have a sense of vision is that we have a non-vestigial organ (the eye) that has cells (photoreceptors) especially sensitive to the properties of electromagnetic radiation. However, the nature of this “organ criterion” is a point of some contention. Is it a sufficient criterion? Necessary? To be called “vision” need the organ mediating it give rise to “visual experiences”? This chapter will consider the neurobiological criterion as it was originally presented in Aristotle and later reconceptualized in 19th-century neurophysiologist Johannes Müller’s “Law of Specific Nerve Energies.” By understanding the role of neurobiology in these accounts, we will be able to explore the deficiencies of contemporary accounts that downplay neurobiology in differentiating the senses. We will consider one of these accounts in detail: Alva Noë’s recent arguments in favor of an enactive approach to perceptual psychology. (shrink)

In this report, the phenomenology of two blind users of a sensory substitution device – “The vOICe” – that converts visual images to auditory signals is described. The users both report detailed visual phenomenology that developed within months of immersive use and has continued to evolve over a period of years. This visual phenomenology, although triggered through use of The vOICe, is likely to depend not only on online visualization of the auditory signal but also on the users’ previous (albeit (...) distant) experience of veridical vision (e.g. knowledge of shapes and visual perspective). Once established, the sensory substitution mapping between the auditory and visual domains is not confined to when the device is worn and, thus, may constitute an example of acquired synaesthesia. (shrink)

Mechanisms of attention play a crucial role in filtering sensory inputs from the external world, allowing information to be prioritised for goal directed behaviour. To what extent might these same capacity-limited processes influence grapheme-colour synaesthesia, in which letters, numbers or words evoke concurrent experiences of colour? Asking synaesthetes themselves whether attention seems important in their experiences has provided a range of answers. On the one hand, for some synaesthetes, diverting attention can diminish the quality of their synaesthetic colours. On the (...) other, there are suggestions that synaesthetic experiences can themselves alter the manner in which attention is allocated to sensory stimuli in the environment. Here, we review a range of empirical investigations that have examined the role of attention in grapheme-colour synaesthesia. A particular focus of these studies has been the extent to which an inducing stimulus - such as an achromatic letter or digit - must be attended or consciously perceived to trigger a concurrent synaesthetic experience. In most cases, limiting attention or masking inducers tends to reduce or eliminate behavioural evidence of synaesthetic experiences. We also discuss how synaesthesia might improve performance in visual search tasks through post-attentive processes such as grouping, or by facilitating decision-making processes. (shrink)

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of (...) acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The out- side world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the gov- erning laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Sev- eral lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual “filling in,” visual stability despite eye movements, change blindness, sensory substitution, and color perception. (shrink)

Standard accounts of the senses attempt to answer the question how and why we count five senses ; none of the standard accounts is satisfactory. Any adequate account of the senses must explain the significance of the senses, that is, why distinguishing different senses matters. I provide such an explanation, and then use it as the basis for providing an account of the senses and answering the counting question.

Standard accounts of the senses attempt to answer the question how and why we count five senses (the counting question); none of the standard accounts is satisfactory. Any adequate account of the senses must explain the significance of the senses, that is, why distinguishing different senses matters. I provide such an explanation, and then use it as the basis for providing an account of the senses and answering the counting question.

I argue that we should reject the sparse view that there are or could be only a small number of rather distinct senses. When one appreciates this then one can see that there is no need to choose between the standard criteria that have been proposed as ways of individuating the senses—representation, phenomenal character, proximal stimulus and sense organ—or any other criteria that one may deem important. Rather, one can use these criteria in conjunction to form a fine-grained taxonomy of (...) the senses. We can think of these criteria as defining a multidimensional space within which we can locate each of the senses that we are familiar with and which also defines the space of possible senses there could be. (shrink)

and apply it to various examples of neural plasticity in which input is rerouted intermodally or intramodally to nonstandard cortical targets. In some cases but not others, cortical activity ‘defers’ to the nonstandard sources of input. We ask why, consider some possible explanations, and propose a dynamic sensorimotor hypothesis. We believe that this distinction is important and worthy of further study, both philosophical and empirical, whether or not our hypothesis turns out to be correct. In particular, the question of how (...) the distinction should be explained is linked to explanatory gap issues for consciousness. Comparative and absolute explanatory gaps should be distinguished: why does neural activity in a particular area of cortex have this qualitative expression rather than that, and why does it have any qualitative expression at all? We use the dominance/deference distinction to address the comparative gaps, both intermodal and intramodal. We do so not by inward scrutiny but rather by expanding our gaze to include relations between brain, body and environment. (shrink)

This volume is about the many ways we perceive. Contributors explore the nature of the individual senses, how and what they tell us about the world, and how they interrelate. They consider how the senses extract perceptual content from receptoral information. They consider what kinds of objects we perceive and whether multiple senses ever perceive a single event. They consider how many senses we have, what makes one sense distinct from another, and whether and why distinguishing senses may be useful. (...) They consider the extent to which the senses act in concert, rather than as discrete modalities, and whether this influence is epistemically pernicious, neutral, or beneficial. They explore both the familiar five sense modalities and other candidate sense modalities, including a sense for flavour, inner senses (e.g., a sense for pain), and various senses that may result from using sensory substitution devices. Contributors often represent competing views, and the methods they deploy sometimes differ from one essay to the next—with some drawing upon the sciences and engineering and others relying upon conceptual analysis. All contributors agree, nonetheless, that traditional theorizing about the senses is hampered by a neglect of the senses other than vision, and by the misconception that vision is a passive receptacle for an image thrown by a lens. And many contributors believe that it is unduly restrictive to think of perception as a collation of contents provided by individual sense modalities; they think that to understand perception properly, we need to build into our accounts the idea that the senses work together. The ambition of the volume is to begin to develop better paradigms for understanding the senses, and thereby to move toward a better understanding of perception. (shrink)

Vision often dominates other perceptual modalities both at the level of experience and at the level of judgment. In the well-known McGurk effect, for example, one’s auditory experience is consistent with the visual stimuli but not the auditory stimuli, and naïve subjects’ judgments follow their experience. Structurally similar effects occur for other modalities (e.g. rubber hand illusions). Given the robustness of this visual dominance, one might not be surprised that visual imagery often dominates imagery in other modalities. One might be (...) surprised, however, that visual imagery often dominates perception in other modalities. This more controversial claim is motivated both by empirical data and by introspection. Some think of perception-perception visual dominance as epistemically good, holding that cases in which visual dominance misleads us (e.g. McGurk and rubber hand illusions) are cases in which the perceptual system resolves conflicts according to principles that are generally reliable. Here, we explore support for the more controversial claim that imagery-perception visual dominance is epistemically good. We suggest that, when the task is richly spatial, requiring for optimal performance the all-at-once identification of macro-spatial and allocentric properties (e.g. identifying the shape or location of a felt or heard object), the visual, whether perception or imagination, should dominate other modalities. Put another way, when identifying objects, one should go and look or, short of that, visually imagine candidate objects, and then follow the visual, even against conflicting perceptions from other modalities. For this broadly-typed category of of cognitive-perceptual task, vision does dominate and it should. (shrink)

The catastrophe of the eye -- A new view of seeing -- Applying the new view of seeing -- The illusion of seeing everything -- Some contentious points -- Towards consciousness -- Types of consciousness -- Phenomenal consciousness, raw feel, and why they're hard -- Squeeze a sponge, drive a porsche : a sensorimotor account of feel -- Consciously experiencing a feel -- The sensorimotor approach to color -- Sensory substitution -- The localization of touch -- The phenomenality plot -- (...) Consciousness. (shrink)

The senses, or sensory modalities, constitute the different ways we have of perceiving the world, such as seeing, hearing, touching, tasting and smelling. But how many senses are there? How many could there be? What makes the senses different? What interaction takes place between the senses? This book is a guide to thinking about these questions. Together with an extensive introduction to the topic, the book contains the key classic papers on this subject together with nine newly commissioned essays.One reason (...) that these questions are important is that we are receiving a huge influx of new information from the sciences that challenges some traditional philosophical views about the senses. This information needs to be incorporated into our view of the senses and perception. Can we do this whilst retaining our pre-existing concepts of the senses and of perception or do we need to revise our concepts? If they need to be revised, then in what way should that be done? Research in diverse areas, such as the nature of human perception, varieties of non-human animal perception, the interaction between different sensory modalities, perceptual disorders, and possible treatments for them, calls into question the platitude that there are five senses, as well as the pre-supposition that we know what we are counting when we count them as five.This book will serve as an inspiring introduction to the topic and as a basis from which further new research will grow. (shrink)

This book is a tour-de-force on how human consciousness may have evolved. From the "phantom pain" experienced by people who have lost their limbs to the uncanny faculty of "blindsight," Humphrey argues that raw sensations are central to all conscious states and that consciousness must have evolved, just like all other mental faculties, over time from our ancestorsodily responses to pain and pleasure. '.

How ought we differentiate the senses? What, say, distinguishes vision from audition? The question comes in two versions. First, there is the traditional problem of individuating the senses in humans. Second, there is also an important question about what sensory modalities we ought to attribute to non-human animals, a version of the question that has been virtually ignored by philosophers. Modality ought to be construed as an “avenue into” an organism for information external to the central nervous system. Six proposed (...) criteria found in the philosophical literature concerning the senses are reviewed. Initially, four criteria—physics, neurobiology, behavior, and evolutionary or developmental dedication—are shown to be individually necessary and jointly sufficient. Next, two criteria—Aristotle's proper objects of sensation criterion and Grice's sensation or qualia criterion—are considered and rejected. One overarching goal here is to show that there is interesting contemporary work left to be done on this ancient philosophical question. (shrink)

Philosophers and scientists have studied sensory perception and, in particular, vision for many years. Increasingly, however, they have become interested in the nonvisual senses in greater detail and the problem of individuating the senses in a more general way. The Aristotelian view is that there are only five external senses—smell, taste, hearing, touch, and vision. This has, by many counts, been extended to include internal senses, such as balance, proprioception, and kinesthesis; pain; and potentially other human and nonhuman senses. This (...) “multisensory turn” has been driven partly by developments in contemporary psychology and neuroscience, which have revealed a host of complex interrelations and interactions between sensory modalities previously thought to be distinct. Contrasts between modalities and other crossmodal phenomena, including multisensory integration, synesthesia, and sensory substitution, have also begun to receive more attention in a burgeoning scientific and philosophical literature on multisensory perception and other crossmodal effects. This article focuses on recent empirically informed contributions to the philosophy of perception, as well as key scientific works that provide important background information and insights into the nature of the senses and sensory perception. Indeed, one of the lessons of the multisensory turn, and of contemporary philosophy of mind more generally, is that philosophers ignore this body of empirical research at their peril because many human and animal senses turn out to be richer and more complex than philosophers and scientists had previously imagined, making this a fruitful area for interdisciplinary interaction and research. (shrink)

Sensory substitution devices are a type of sensory prosthesis that (typically) convert visual stimuli transduced by a camera into tactile or auditory stimulation. They are designed to be used by people with impaired vision so that they can recover some of the functions normally subserved by vision. In this chapter we will consider what philosophers might learn about the nature of the senses from the neuroscience of sensory substitution. We will show how sensory substitution devices work by exploiting the cross-modal (...) plasticity of sensory cortex: the ability of sensory cortex to pick up some types of information about the external environment irrespective of the nature of the sensory inputs it is processing. We explore the implications of cross-modal plasticity for theories of the senses that attempt to make distinctions between the senses on the basis of neurobiology. (shrink)

(1) The induced colours led to perceptual grouping and pop-out, (2) a grapheme rendered invisible through ‘crowding’ or lateral masking induced synaesthetic colours — a form of blindsight — and (3) peripherally presented graphemes did not induce colours even when they were clearly visible. Taken collectively, these and other experiments prove conclusively that synaesthesia is a genuine percep- tual phenomenon, not an effect based on memory associations from childhood or on vague metaphorical speech. We identify different subtypes of number–colour synaesthesia (...) and propose that they are caused by hyperconnectivity between col- our and number areas at different stages in processing; lower synaesthetes may have cross-wiring (or cross-activation) within the fusiform gyrus, whereas higher synaesthetes may have cross-activation in the angular gyrus. This hyperconnec- tivity might be caused by a genetic mutation that causes defective pruning of con- nections between brain maps. The mutation may further be expressed selectively (due to transcription factors) in the fusiform or angular gyri, and this may explain the existence of different forms of synaesthesia. If expressed very diffusely, there may be extensive cross-wiring between brain regions that represent abstract concepts, which would explain the link between creativity, metaphor and synaesthesia (and the higher incidence of synaesthesia among artists and poets). Also, hyperconnectivity between the sensory cortex and amygdala would explain the heightened aversion synaesthetes experience when seeing numbers printed in the ‘wrong’ colour. Lastly, kindling (induced hyperconnectivity in the temporal lobes of temporal lobe epilepsy [TLE] patients) may explain the purported higher incidence of synaesthesia in these patients. We conclude with a synaesthesia-based theory. (shrink)

Philosophers and cognitive scientists of perception by custom have investigated individual sense modalities in relative isolation from each other. However, perceiving is, in a number of respects, multimodal. The traditional sense modalities should not be treated as explanatorily independent. Attention to the multimodal aspects of perception challenges common assumptions about the content and phenomenology of perception, and about the individuation and psychological nature of sense modalities. Multimodal perception thus presents a valuable opportunity for a case study in mature interdisciplinary cognitive (...) science. This chapter aims to raise these issues against the background of unimodal approaches in the study of perception. It presents some of the central empirical findings concerning multimodality, and it explains the philosophical implications of these findings. Foremost, it aims to encourage and open avenues for future research. (shrink)

Alva Noë’s _Action in Perception _offers a provocative and vigorous defense of the thesis that vision is enactive: visual experience depends on dispositional motor responses. On this view, vision and action are inextricably bound. In this review, I argue against enactive perception. I raise objections to seven lines of evidence that appear in Noë’s book, and I indicate some reasons for thinking that vision can operate independently of motor responses. I conclude that the relationship between vision and action is causal, (...) not constitutive. I then address three other contentious hypotheses in the book. Noë argues that visual states are not pictorial; he argues that all perception is conceptual; and he argues that the external world makes a constitutive contribution to experience. I am unpersuaded by these arguments, and I offer reasons to resist Noë’s conclusions. (shrink)

After first noting that I seek to broaden the definition of science fiction to a little more loosely defined speculative fiction, this essay explores four different ways in which fiction can work together with both the sciences and the philosophy of perception. This cooperation is needed because there is much about the sensory worlds of humans and non-human animals of which we continue to be ignorant. First, speculative fiction can be a source of hypotheses about the nature of the senses. (...) Second, it can help us understand the inner worlds of beings different from us. Third, speculative fiction often pushes us to investigate the ethical and social dimensions of sensory difference. Finally, speculative fiction can play an important role in reconciling our scientific understanding of the senses with a more commonsense understanding of same. (shrink)

How many senses do humans possess? Five external senses, as most cultures have it—sight, hearing, touch, smell, and taste? Should proprioception, kinaesthesia, thirst, and pain be included, under the rubric bodily sense? What about the perception of time and the sense of number? Such questions reduce to two. 1. How do we distinguish a sense from other sorts of information-receiving faculties? 2. By what principle do we distinguish the senses? Aristotle discussed these questions in the De Anima. H. P. Grice (...) revived them in 1967. More recently, they have taken on fresh interest as a result of a collection of essays edited by Fiona Macpherson. This entry reviews some approaches to these questions and advances some new ideas for the reader’s consideration. It proposes that the senses constitute an integrated learning system, membership in which answers question 1. It also proposes that the modalities can be distinguished from one another in two ways, by the means of information pick-up and by the kinds of activity that a perceiver undertakes to make use of them. (shrink)

Scepticism about the possibility of machine consciousness comes in at least two forms. Some argue that our neurobiology is special, and only something sharing our neurobiology could be a subject of experience. Others argue that a machine couldn't be anything else but a zombie: there could never be something it is like to be a machine. I advance a dynamic sensorimotor account of consciousness which argues against both these varieties of scepticism.