Touch

This paper aims to outline the foundations for an ethics of digital touch. Digital touch refers to hardware and software technologies, often collectively referred to as ‘haptics’, that provide somatic sensations including touch and kinaesthesis, either as a stand-alone interface to users, or as part of a wider immersive experience. Digital touch has particular promise in application areas such as communication, affective computing, medicine, and education. However, as with all emerging technologies, potential value needs to be considered against potential risk. (...) We therefore identify some areas where digital touch raises ethical concerns, and we identify why these concerns arise, based on the distinctive physiological and functional properties of the human somatosensory system. Most scientific research in digital touch has focused on user interaction with external objects (active touch). However, the most pressing ethical concerns with digital touch technologies arise when users are being passively touched. Our analysis identifies several important questions about control, transparency, and epistemic procedure in digital touch scenarios. First, human somatosensation is “always on”, and many digital touch technologies take advantage of this (e.g., alerting systems). As a result, digital touch technologies can undermine individuals’ sensory autonomy (i.e., the right to choose what sensations one experiences). Second, users may reasonably want to know who or what is touching them, and for what purpose. Consent for digital touch will therefore need to be carefully and transparently transacted. Third, because touch gives us a special, direct experience of interacting with our physical environment, digital touch technologies that manipulate this interaction could potentially provide a major epistemic challenge, by changing a user’s basic understanding of reality and their relation to it. Informed by this discussion, we conclude by suggesting a basis for an ethical design framework for digital touch systems. (shrink)

Molyneux’s question asks whether a person born blind who has learned to identify shapes by touch could, if suddenly granted sight, immediately identify shapes visually. This question has often been used to structure discussions of whether there is a “rational connection” between sight and touch—whether it is possible to rationally doubt whether the same shape properties are both seen and felt. I distinguish two questions under this general heading. The first concerns, roughly, whether the visual and haptic perception of shape (...) is rationally connected in normally sighted perceivers. The second concerns, roughly, whether the visual and haptic perception of shape is rationally connected in all possible perceivers. I argue that real-world implementations of Molyneux’s question are irrelevant to the first question, but potentially relevant to the second. However, I also argue that the second question does not have the philosophical significance it is sometimes claimed to have. In particular, it cannot be used to adjudicate debates about whether the phenomenal character of perceptual experience is primarily determined “externally” by the worldly properties we perceive, or “internally” by physiological or functional properties of our brains. (shrink)

Touch is standardly taken to be a proximal sense, principally constituted by capacities to detect proximal pressure and thermal stimulation, and contrasted with the distal senses of vision and audition. It has, however, recently been argued that the scope of touch extends beyond proximal perception; touch can connect us to distal objects. Hence touch generally should be thought of as a connection sense. In this paper, I argue that whereas pressure perception is a connection sense, thermal perception is not. Thermal (...) perception is a proximal sense distinct from touch. One significant consequence of this is that it motivates an alternative explanation of how we detect the thermal properties of the things we touch and what they are. (shrink)

This chapter examines how our sense modalities interact in the perception of persistence. The chapter concentrates on two questions. The first concerns perceptual processing—do perceptual computations of object persistence ever integrate and compute over representations from more than one modality? It argues that this question should be answered affirmatively. The second question concerns perceptual experience—do experiences of object persistence ever exhibit a constitutively multisensory phenomenal character, or is the phenomenology of object persistence always uniquely associated with just one modality? The (...) chapter argues that the available evidence underdetermines the answer to this question, but suggests ways it might be empirically resolved. (shrink)

Higher animals need to identify and track material objects because they depend on interactions with them for nutrition, reproduction, and social interaction. This paper investigates the perception of material objects. It argues, first, that material objects are tagged, in all five external senses, as bearers of the features detected by them. This happens through a perceptual process, here entitled Generalized Completion, which creates the appearance of objects that have properties that transcend the activation of sensory receptors. The paper shows, secondly, (...) that material objects are privileged subjects for perceived motion and interaction. That is, they are perceived as subjects for these properties while their parts seem to be subjects only derivatively. Material objects are the only perceptual subjects that are both multisensory and privileged. (shrink)

¿Cuál es la diferencia entre los sentidos de la vista y el tacto si las propiedades espaciales que perciben estos sentidos son, al parecer, las mismas? ¿Cuál es la diferencia entre ver y tocar formas? Este es el tema del artículo “Sight and touch” (1992) de Michael Martin. En este breve texto, es mi propósito concentrarme en algunos desarrollos de Martin sobre el sentido del tacto y poner esos desarrollos en relación con dos experiencias táctiles particulares. La idea principal en (...) la que quiero concentrarme es la del contraste interno-externo como la característica de la conciencia corporal que “proporciona lo que necesitamos para un sentido del tacto” (Martin 1992 203). Las experiencias táctiles particulares con las que quiero relacionar esta idea son la de la ingesta de alimentos y el estar anestesiado. Pretendo ver si estas experiencias pueden constituir algún tipo de objeción a dicho contraste interno-externo. // What is the difference between the senses of sight and touch, if the spatial properties perceived by these senses are apparently the same ones? What is the difference between seeing and touching shapes? This is the subject matter of Michael Martin’s article “Sight and touch” (1992). In this short text, my purpose is to focus on some of Martin’s developments on the sense of touch, and to put those developments in relation with two tactile experiences. The main idea I want to focus on is that of the inner-outer contrast as the characteristic of body consciousness that “provides what we need for a sense of touch” (Martin 1992 203). The tactile experiences with which I want to relate this idea are those of food intake and being anesthetized. I try to see if these experiences can constitute some objection to this inner-outer contrast. (shrink)

Analysis of grip force signals tailored to hand and finger movement evolution and changes in grip force control during task execution provide unprecedented functional insight into somatosensory cognition. Somatosensory cognition is a basis of our ability to manipulate, move, and transform objects of the physical world around us, to recognize them on the basis of touch alone, and to grasp them with the right amount of force for lifting and manipulating them. Recent technology has permitted the wireless monitoring of grip (...) force signals recorded from biosensors in the palm of the human hand to track and trace human grip forces deployed in cognitive tasks executed under conditions of variable sensory (visual, auditory) input. Non-invasive multi-finger grip force sensor technology can be exploited to explore functional interactions between somatosensory brain mechanisms and motor control, in particular during learning a cognitive task where the planning and strategic execution of hand movements is essential. Sensorial and cognitive processes underlying manual skills and/or hand-specific (dominant versus non-dominant hand) behaviors can be studied in a variety of contexts by probing selected measurement loci in the fingers and palm of the human hand. Thousands of sensor data recorded from multiple spatial locations can be approached statistically to breathe functional sense into the forces measured under specific task constraints. Grip force patterns in individual performance profiling may reveal the evolution of grip force control as a direct result of cognitive changes during task learning. Grip forces can be functionally mapped to from-global-to-local coding principles in brain networks governing somatosensory processes for motor control in cognitive tasks leading to a specific task expertise or skill. Under the light of a comprehensive overview of recent discoveries into the functional significance of human grip force variations, perspectives for future studies in cognition, in particular the cognitive control of strategic and task relevant hand movements in complex real-world precision task, are pointed out. (shrink)

The validity of the senses we use to experience the cosmos is something we take for granted. The majority of the people view the senses as the most effective and potentially the only tool they have to reach reality. But as Shestov rightfully questioned, when was the last time the majority decided correctly on an important philosophical problem? The role of science and philosophy is to question the obvious and this is what we should do if we are to uncover (...) the true role of the senses. This paper uses a series of philosophy articles to touch on the problem of the senses and the answer portrayed is exciting as well as terrifying: The senses are not a helpful tool but more of a hurdle when it comes to understanding the cosmos…. (shrink)

Philosophers of perception have been readier to postulate the existence of a visual field than to acknowledge sensory fields in other modalities. In this paper, I argue that the set of phenomenal features that philosophers have relied on when positing a visual field aptly characterise, mutatis mutandis, bodily sensation. I argue, in particular, that in localised bodily sensations we experience the body as a sensory field. I first motivate this claim for the case of haptic touch, and then generalise it (...) to other kinds of bodily sensation. I demonstrate the theoretical fruitfulness of this notion of a bodily field for the debate on the phenomenology of bodily ownership. (shrink)

It seems that there are important differences concerning the way in which space itself is presented in visual and tactile modalities. In the case of vision, it is usually accepted that visual objects are experienced as located in a visual field. However, it is controversial whether similar field-like characteristics can be attributed to the space in which tactile entities are experienced to be located. The paper investigates whether postulating the presence of a tactile field is justified. I argue that the (...) answer is both ‘yes’ and ‘no’ due to the dual nature of touch: touch is both an interoceptive modality that presents states of one’s body and an exteroceptive modality that presents external entities. More specifically, the interoceptive tactile space has a character of a spatial field. On the other hand, the exteroceptive tactile space does not have characteristics necessary for ascribing the field-status. (shrink)

According to the decomposition thesis, perceptual experiences resolve without remainder into their different modality-specific components. Contrary to this view, I argue that certain cases of multisensory integration give rise to experiences representing features of a novel type. Through the coordinated use of bodily awareness—understood here as encompassing both proprioception and kinaesthesis—and the exteroceptive sensory modalities, one becomes perceptually responsive to spatial features whose instances couldn’t be represented by any of the contributing modalities functioning in isolation. I develop an argument for (...) this conclusion focusing on two cases: 3D shape perception in haptic touch and experiencing an object’s egocentric location in crossmodally accessible, environmental space. (shrink)

Molyneux asked whether a newly sighted person could distinguish a sphere from a cube by sight alone, given that she was antecedently able to do so by touch. This, we contend, is a question about general ideas. To answer it, we must ask (a) whether spatial locations identified by touch can be identified also by sight, and (b) whether the integration of spatial locations into an idea of shape persists through changes of modality. Posed this way, Molyneux’s Question goes substantially (...) beyond question (a), about spatial locations, alone; for a positive answer to (a) leaves open whether a perceiver might cross-identify locations, but not be able to identify the shapes that collections of locations comprise. We further emphasize that MQ targets general ideas so as to distinguish it from corresponding questions about experiences of shape and about the property of tangible (vs. visual) shape. After proposing a generalized formulation of MQ, we extend earlier work (“Many Molyneux Questions,” Australasian Journal of Philosophy 2020) by showing that MQ does not admit a single answer across the board. Some integrative data-processes transfer across modalities; others do not. Seeing where and how such transfer succeeds and fails in individual cases has much to offer to our understanding of perception and its modalities. (shrink)

Common everyday materials such as textiles, foodstuffs, soil or skin can have complex, mutable and varied appearances. Under typical viewing conditions, most observers can visually recognize materials effortlessly, and determine many of their properties without touching them. Visual material perception raises many fascinating questions for vision researchers, neuroscientists and philosophers, yet has received little attention compared to the perception of color or shape. Here we discuss some of the challenges that material perception raises and argue that further philosophical thought should (...) be directed to how we see materials. (shrink)

The aim of this chapter is to shed new light on the question of what newly sighted subjects are capable of seeing on the basis of previous experience with mind- independent, external objects and their properties through touch alone. This question is also known as "Molyneux’s question." Much of the empirically driven debate surrounding this question has been centered on the nature of the representational content of the subjects' visual experiences. It has generally been assumed that the meaning of "seeing" (...) deployed in these disputes is more or less clear and unproblematic, and therefore requires no analysis or clarification. In this chapter, we wish to challenge this assumption. We argue that getting clear on the meaning of "seeing" is the only feasible way to determine whether the empirical attempts to answer Molyneux’s question accurately capture what newly sighted subjects are in fact capable of seeing. Specifically, we show that the dominant interpretations of the empirical results from a recent study (Held et al., 2011) fail to take into account that seeing can be not only purely visual but also epistemic in that it requires background knowledge (such as what an object with a particular viewpoint-independent shape looks like from a particular perspective). (shrink)

This chapter distinguishes between two kinds of ordinary multisensory experience that go beyond mere co-consciousness of features (e.g., the experience that results from concurrently hearing a sound in the hallway and seeing the cup on the table). In one case, a sensory experience in one modality creates a perceptual demonstrative to whose referent qualities are attributed in another sensory modality. For example, when you hear someone speak, auditory experience attributes audible qualities to a seen event, a person’s speaking motions. The (...) second kind of multisensory experience attributes features experienced in several sensory modalities to one and the same object via a process of amodal perceptual integration, i.e., integration that occurs separately from processing within the individual sensory modalities. Multisensory experiences arising from holding and seeing a tomato or from seeing the Indian curry boil and smelling it are examples of the second kind of multisensory experience. At the end of the chapter we look at synesthesia, a kind of atypical multisensory experience, and argue that one version of this phenomenon may be able to shed light on the neural mechanism underlying amodally integrated multisensory experience. (shrink)

The sense of touch provides us knowledge of two kinds of events. Tactile sensation (T) makes us aware of events on or just below the skin; haptic perception (H) gives us knowledge of things outside the body with which we are in contact. This paper argues that T and H are distinct experiences, and not (as some have argued) different aspects of the same touch-experience. In other words, T ≠ H. Moreover, H does not supervene on T. Secondly: In T, (...) we are aware of immanent, phenomenal qualities; in H, we come to know of transcendent qualities in things that exist independently of ourselves. Finally: T is non-spatial; it is indexed by parts of the body, but not by position in space. H, by contrast, is spatial. This brings to mind Kant’s contention that things are presented as existing objectively when they are represented spatially. (shrink)

Touch seems to enjoy some epistemic advantage over the other senses when it comes to attest to the reality of external objects. The question is not whether only what appears in tactile experiences is real. It is that only whether appears in tactile experiences feels real to the subject. In this chapter we first clarify how exactly the rather vague idea of an epistemic advantage of touch over the other senses should be interpreted. We then defend a “muscular thesis”, to (...) the effect that only the experience of resistance to our motor efforts, as it arises in effortful touch, presents us with the independent existence of some causally empowered object. We finally consider whether this muscular thesis applies to the perception of our own body. (shrink)

A common sense view is illustrated by Doubting Thomas, and surfaces in many philosophical and psychological writings : Touching is better than seeing. But can we make sense of this privilege? We rule out that it could mean that touch is more informative than vision, more ‘objective’ or more directly in contact with reality. Instead, we propose that touch offers not a perceptual, but a metacognitive advantage: touch is not more objective than vision but rather provides comparatively higher subjective certainty.

Samuel Johnson claimed to have refuted Berkeley by kicking a stone. It is generally thought that Johnson misses the point of Berkeley's immaterialism for a rather obvious reason: Berkeley never denied that the stone feels solid, but only that the stone could exist independently of any mind. I argue that Johnson was on the right track. On my interpretation, Johnson’s idea is that because the stone feels to resist our effort, the stone seems to have causal powers. But if appearances (...) are to be taken at face value, as Berkeley insists, then the stone has causal powers. I argue that such causal powers threaten not only Berkeley’s view that only minds are active, but also, and more fundamentally, his central claim that sensible things depend on perception. (shrink)

This chapter explores how our understanding of Molyneux’s question, and of the possibility of an experimental resolution to it, should be affected by recognizing the complexity that is involved in reidentifying shapes and other spatial properties across differing sensory manifestations of them. I will argue that while philosophers today usually treat the question as concerning ‘the relations between perceptions of shape in different sensory modalities’ (Campbell 1995, 301), in fact this is only part of the question’s real interest, and that (...) the answer to the question also turns on how shape is perceived within each of sight and touch individually. (shrink)

In this paper, we introduce and defend the recurrent model for understanding bodily spatial phenomenology. While Longo, Azañón and Haggard (2010) propose a bottom-up model, Bermúdez (2017) emphasizes the top-down aspect of the information processing loop. We argue that both are only half of the story. Section 1 intro- duces what the issues are. Section 2 starts by explaining why the top- down, descending direction is necessary with the illustration from the ‘body-based tactile rescaling’ paradigm (de Vignemont, Ehrsson and Haggard, (...) 2005). It then argues that the bottom-up, ascending direction is also necessary, and substantiates this view with recent research on skin space and tactile field (Haggard et al., 2017). Section 3 discusses the model’s application to body ownership and bodily self-representation. Implications also extend to topics such as sense modality individuation (Macpherson, 2011), the constancy- based view of perception (Burge, 2010), and the perception/cognition divide (Firestone and Scholl, 2016). (shrink)

Our perception of where touch occurs on our skin shapes our interactions with the world. Most accounts of cutaneous localisation emphasise spatial transformations from a skin-based reference frame into body-centred and external egocentric coordinates. We investigated another possible method of tactile localisation based on an intrinsic perception of ‘skin space’. The arrangement of cutaneous receptive fields (RFs) could allow one to track a stimulus as it moves across the skin, similarly to the way animals navigate using path integration. We applied (...) curved tactile motions to the hands of human volunteers. Participants identified the location midway between the start and end points of each motion path. Their bisection judgements were systematically biased towards the integrated motion path, consistent with the characteristic inward error that occurs in navigation by path integration. We thus showed that integration of continuous sensory inputs across several tactile RFs provides an intrinsic mechanism for spatial perception. (shrink)

This paper is a defense of an internalist view of the perception of shapes. A basic assumption of the paper is that perceptual experiences have certain parts which account both for the phenomenal character associated with perceiving shapes—phenomenal shapes—and for the intentional content presenting shapes—intentional shapes. Internalism about perceptions of shapes is defined as the claim that phenomenal shapes determine the intentional shapes. Externalism is defined as the claim that perceptual experiences represent whatever shape the phenomenal shape reliably tracks. The (...) argument against externalism proceeds in three steps. First, it is argued that phenomenal shapes are modality specific, such that a phenomenal shape that features in a visual perceptual experience cannot feature in a haptic perceptual experience, and vice versa. Second, it is argued that intentional shapes are amodal. Third, it is argued that externalism is incompatible with the fact that phenomenal shapes are modality specific and intentional shapes amodal. (shrink)

The first part of this survey article presented a cartography of some of the more extensively studied forms of multisensory processing. In this second part, I turn to examining some of the different possible ways in which the structure of conscious perceptual experience might also be characterized as multisensory. In addition, I discuss the significance of research on multisensory processing and multisensory consciousness for philosophical debates concerning the modularity of perception, cognitive penetration, and the individuation of the senses.

Seeing one’s laptop to be missing, hearing silence and smelling fresh air; these are all examples of perceptual experiences of absences. In this paper I discuss an example of absence perception in the tactual sense modality, that of tactually perceiving a tooth to be absent in one’s mouth, following its extraction. Various features of the example challenge two recently-developed theories of absence perception: Farennikova’s memory-perception mismatch theory and Martin and Dockic’s meta-cognitive theory. I speculate that the mechanism underlying the experience (...) is a body schema that has failed to update itself. (shrink)

It remains controversial whether touch is a truly spatial sense or not. Many philosophers suggest that, if touch is indeed spatial, it is only through its alliances with exploratory movement, and with proprioception. Here we develop the notion that a minimal yet important form of spatial perception may occur in purely passive touch. We do this by showing that the array of tactile receptive fields in the skin, and appropriately relayed to the cortex, may contain the same basic informational building (...) blocks that a creature navigating around its environment uses to build up a perception of space. We illustrate this point with preliminary evidence that perception of spatiotemporal patterns on the human skin shows some of the same features as spatial navigation in animals. We argue (a) that the receptor array defines a ‘tactile field’, (b) that this field exists in a minimal form in ‘skin space’, logically prior to any transformation into bodily or external spatial coordinates, and (c) that this field supports tactile perception without integration of concurrent proprioceptive or motor information. The basic cognitive elements of space perception may begin at lower levels of neural and perceptual organisation than previously thought. (shrink)

In this essay, I review Matthew Fulkerson's The First Sense: A Philosophical Study of the Sense of Touch. In this first philosophical book on the sense of touch, Fulkerson provides an account of the nature and content of tactual experience. Central to Fulkerson's view is the claim that exploratory action plays a fundamental role in touch. In this review, I put pressure on two of his arguments: the argument that tactual experience is unisensory and the argument that tactual experience does (...) not depend on explicit bodily awareness. (shrink)

Multisensory processing encompasses all of the various ways in which the presence of information in one sensory modality can adaptively influence the processing of information in a different modality. In Part I of this survey article, I begin by presenting a cartography of some of the more extensively investigated forms of multisensory processing, with a special focus on two distinct types of multisensory integration. I briefly discuss the conditions under which these different forms of multisensory processing occur as well as (...) their important perceptual consequences and interrelations. In Part II, I then turn to examining of some of the different possible ways in which the structure of conscious perceptual experience might also be characterized as multisensory. In addition, I discuss the significance of research on multisensory processing and multisensory consciousness for philosophical attempts to individuate the senses. (shrink)

A recent empirical study claims to show that the answer to Molyneux’s question is negative, but, as John Schwenkler points out, its findings are inconclusive: Subjects tested in this study probably lacked the visual acuity required for a fair assessment of the question. Schwenkler is undeterred. He argues that the study could be improved by lowering the visual demands placed on subjects, a suggestion later endorsed and developed by Kevin Connolly. I suggest that Connolly and Schwenkler both underestimate the difficulties (...) involved in rectifying the study they seek to fix. The problem is that the experimental paradigm under consideration fails to account for the role that rational inference plays in newly sighted subjects’ ability or inability to recognize spatial properties across modalities. Since answering Molyneux’s question requires establishing whether spatial properties can be recognized, across modalities, by newly sighted subjects without recourse to rational inference, this is a problem. Indeed, it is a problem that may be worsened by Schwenkler and Connolly’s suggestions regarding the lowering of visual demands on subjects in cross-modal matching tasks. (shrink)

What would happen if one morning you wake up clumsy, as if your sense of touch were unreliable, arbitrarily on and off? And what would this clumsiness look like if we could transfer it to the moral sense? The article expounds an interesting analogy between the sense of touch, loosely construed, and the moral sense: just as a sort of consistency is necessary for the sense of touch to do its job, so it is for the moral sense to play (...) its part. Touch enables us to navigate the everyday world of coffee pots and staircases; our moral sensibility comes into play when we act or when we judge our actions and those of others, and plays a directive role in what we feel, how we feel it, and how we react to it. Taking the analogy further, I will suggest that inconsistency causes, in both cases, a certain clumsiness, and that clumsiness is linked to arbitrariness – like the person that helps others in dire need, but only does so on some rainy days. (shrink)

In the first Enquiry, Hume takes the experience of exerting force against a solid body to be a key ingredient of the vulgar idea of power, so that the vulgar take that experience to provide us with an impression of power. Hume provides two arguments against the vulgar on this point: the first concerning our other applications of the idea of power and the second concerning whether that experience yields certainty about distinct events. I argue that, even if we accept (...) Hume’s conception of the vulgar’s approach, neither of Hume’s arguments succeeds. The first argument can be resisted either by using the very arguments Hume provides concerning other causal representations or by simply rejecting Hume’s strict empiricism. The second argument can be resisted on epistemological grounds: there is no reason to think that an experience of a maximally-strong metaphysical connection would provide a maximally-strong epistemological connection. Unlike some recent neo-Anscombean responses to the second argument, my response does not require challenging Hume’s view that causal relations are strictly necessary. Though I do not attempt to translate the resilience of the vulgar view into contemporary terms, the failure of Hume’s arguments challenges one of the long-standing motivations for Humean approaches to causation. (shrink)

Perception is the ultimate source of our knowledge about contingent facts. It is an extremely important philosophical development that starting in the last quarter of the twentieth century, philosophers have begun to change how they think of perception. The traditional view of perception focussed on sensory receptors; it has become clear, however, that perceptual systems radically transform the output of these receptors, yielding content concerning objects and events in the external world. Adequate understanding of this process requires that we think (...) of perception in new ways—how it operates, the differences among the modalities, and integration of content provided by the individual senses. Philosophers have developed new analytic tools, and opened themselves up to new ways of thinking about the relationship of perception to knowledge. The Oxford Handbook of the Philosophy of Perception is a collection of entries by leading researchers that reviews these new directions in philosophical thought. The Introduction to the Handbook reviews the history of the subject from its beginnings in ancient Greece to the nineteenth century, and the way that science and philosophy have together produced new conceptions during the last hundred years. It shows how the new thinking about perception has led to a complex web of theories. (shrink)

Aristotle’s treatment of tactility is at odds with the hierarchical order of psyche’s faculties. Touching is the commonest and lowest power; it is possessed by all sentient beings; thinking is, on the contrary, the highest faculty that distinguishes human beings. Yet, while Aristotle maintains against some of his predecessors that to think is not to sense, he nevertheless posits a causal link between practical intelligence and tactility and even describes noetic activity as a certain kind of touch. This essay elucidates (...) Aristotle’s analysis of the sense of touch in De anima and argues that tactility provides a paradigm for sensitivity in general and in particular for the reflexivity of sensation whereby the senses disclose not only what they are sensing but also that they are sensing. This feature, it is argued, has epistemological and ontological consequences. The sense of touch testifies to the physical presence of material beings and provides an empirical verification of substance’s essential feature, namely, self-reference. (shrink)

Do spatial features appear the same whether they are perceived through vision or touch? This question is at stake in the puzzle that William Molyneux posed to John Locke, concerning whether a man born blind whose sight was restored would be able immediately to identify the shapes of the things he saw. A recent study purports to answer the question negatively, but I argue here that the subjects of the study likely could not see well enough for the result to (...) have been meaningful. I then propose a way to improve the study, by including cues from object motion. (shrink)

This thesis vindicates the common-sense intuition that touch is more objective than the other senses. The reason why it is so, it is argued, is that touch is the only sense essential of the experience of physical effort, and that this experience constitutes our only acquaintance with the mind-independence of the physical world. The thesis is divided in tree parts. Part I argues that sensory modalities are individuated by they proper objects, realistically construed. Part II argues that the proper objects (...) of touch are pressures and tensions, defined as pairs of real and antagonist forces. Part III argues that experiences of pressures are an essential part of the experience of physical effort and that the experience of physical effort (which amounts to the experience of resistance to our will), constitutes our only immediate access to the mind-independence of the physical world. (shrink)

Our thesis is that proprioception is not a sixth sense distinct from the sense of touch, but a part of that tactile (or haptic) sense. The tactile sense is defined as the sense whose direct intentional objects are macroscopic mechanical properties. We first argue (against D. Armstrong, 1962; B. O'Shaughnessy 1989, 1995, 1998 and M. Martin, 1992, 1993,1995) that the two following claims are incompatible : (i) proprioception is a sense distinct from touch; (ii) touch is a bipolar modality, that (...) intrinsically has both a subjective-bodily pole and objective pole. We then argue that the bipolarity of touch should be preferred over the introduction of a sui generis sense of the body. We try to revive Aristotle suggestion according to which the body is the tactile medium (like the air for sight). Since this medium is constantly changing its shape, we need some specific channel of information about its state : proprioception, functionally defined, is that part of touch which informs us about the state of this changing tactile medium. Though muscular and articular receptors are usually dedicated to inform us about the mechanical properties of the tactile media, and the skin receptors about the mechanical properties of the tactile objects, this is not essentially so. In weighting or wielding experiments we access the weight of external objects even when skin sensitivity is absent; in prosthetic touch, the skin receptors play the role usually assigned to muscle and articular receptors, namely to inform us about the mechanical state of the tactile medium. So proprioception, anatomically defined, can play both the role of informing us about the tactile medium, or about the tactile objects. That other sensory modalities also rely on proprioceptive information should be understood in terms of cross-modal dependencies: of sight, hearing, smell, taste...on touch. (shrink)