Online research in philosophy

The sensation-perception distinction did not appear before the seventeenth century, but since then various formulations of it have gained wide acceptance. This is not an historical accident and the article suggests an explanation for its appearance. Section 1 describes a basic assumption underlying the sensation-perception distinction, to wit, the postulation of a pure sensory stage--viz. sensation--devoid of active influence of the agent's cognitive, emotional, and evaluative frameworks. These frameworks are passive in that stage. I call this postulation the passivity assumption. Section 2 suggests three major reasons for the emergence of this assumption in the seventeenth century: the mental-physical gap, the causal theory of perception, and epistemological considerations regarding the status of the sensory given. In the last section a critical discussion is presented. The passivity assumption is found to have serious empirical and theoretical flaws.

When you suffer a pain are you suffering a sensation? An emotion? An aversion? Pain typically has all three components, and others too. There is indeed a distinct sensory system devoted to pain, with its own nociceptors and pathways. As a species of somesthesis, pain has a distinctive sensory organization and its own special sensory qualities. I think it is fair to call it a distinct sensory modality, devoted to nociceptive somesthetic discrimination. But the typical pain kicks off other processes too. For one it can grab your attention in a distinctive way, alerting you to its presence and sometimes obliging you to focus attention on the damaged member. Intense pain can eliminate your ability to think about anything else. Pain typically has direct and immediate motivational consequences: one wants it to stop, has an incentive to do whatever one can to reduce it, and is gratified by its termination. As these desires and motives collide with neural reality, emotional components of mental anguish, anxiety, and dread arise. The suffering involved in suffering from pain has multiple strands: it is not just the painfulness of the sensation, or the frustration of the desire that it end, but also the anguish over the possibility that it will never end, and the impossibility, if the pain is sufficiently intense, of focusing one’s attention on anything else.

We enjoy modes of sensory imagining corresponding to our five modes of perception - seeing, touching, hearing, smelling and tasting. An account of what constitutes these different modes of perseption needs also to explain what constitutes the corresponding modes of sensory perception. In this paper I argue that we can explain what distinguishes the different modes of sensory imagination in terms of their characteristic experiences without supposing that we must distinguish the senses in terms of the kinds of experience involved. thus the fact that we enjoy different modes of sensory imagining poses no threat to someone who thinks that the five senses are to be distinguished by appeal to the kinds of mechanism or psychological capacities their exercise involves, and not by appeal to experience.

Austen Clark offers a general account of the forms of mental representation that we call "sensory." Drawing on the findings of current neuroscience, Clark defends the hypothesis that the various modalities of sensation share a generic form that he calls "feature-placing." Sensing proceeds by picking out place-times in or around the body of the sentient organism, and characterizing qualities (features) that appear at those place-times. The hypothesis casts light on many other troublesome phenomena, including the varieties of illusion, the problem of projection, the notion of a visual field, and the existence of sense-data.

One of the central assumptions made in much of contemporary philosophy of mind is that there is no appearance-reality distinction when it comes to sensory states. On this assumption, sensory states simply are as they seem: consciousness is an intrinsic property of sensory states—that is, all sensory states are conscious—and the consciousness of one’s own sensory states is never inaccurate. For a sensation to be felt as pain, for example, is for it to be pain. This assumption, which I call the Cartesian assumption, can be seen everywhere from the standard arguments against physicalism—such as those advanced by Kripke, Nagel, and Levine—to current theorizing about consciousness. I here argue that this assumption is false and that it goes wrong in two ways. I further argue that the appeal of the Cartesian assumption is due to a commitment many still have to a poorly motivated and misguided Cartesian model of consciousness and its relation to mental states. As an alternative to this Cartesian concept of mind, I argue for a theory of consciousness which claims that the “phenomenal character” of a sensation or perception—the “what it’s like” to have that sensation—is determined by the content of a higher-order thought one has of that sensory state.

I address this talk to anyone who believes in the possibility of an informative empirical science about sensory qualities. Potentially this is a large audience. By "sensory quality" I mean those qualities manifest in various sensory experiences: color, taste, smell, touch, pain, and so on. We should include sensory modalities humans do not share, such as electro-reception in fish, echolocation in bats, or the skylight compass in birds. Those pursuing empirical science about this large domain might pursue it in the halls of experimental psychology, psycho-physics, psychometrics, psycho-physiology, sensory physiology, neuroscience, neuro-biology, comparative psychology, neuro-anatomy, and so on and on. These days even molecular genetics has kicked in with some notable recent contributions to the sequencing of genes for photopigments and for olfactory receptors. But to all those investigators in all those halls I bring bad news. Your discipline is _a priori_ impossible. Philosophers whom you do not know have uncovered _a priori_ proofs that empirical investigation which proceeds along the lines currently underway, or which will proceed along lines that are currently _imaginable_, does not, will not, and cannot explain the sensory qualities of experience. Or at least so they say. You might as well give up now.

Often, sensory input underdetermines perception. One such example is the perception of illusory contours. In illusory contour perception, the content of the percept includes the presence of a contour that is absent from the informational content of the sensation. (By “sensation” I mean merely information-bearing events at the transducer level. I intend no further commitment such as the identification of sensations with qualia.) I call instances of perception underdetermined by sensation “underdetermined perception.” The perception of illusory contours is just one kind of underdetermined perception. The focus of this chapter is another kind of underdetermined perception: what I shall call "active perception". Active perception occurs in cases in which the percept, while underdetermined by sensation, is determined by a combination of sensation and action. The phenomenon of active perception has been used by several to argue against the positing of representations in explanations of sensory experience, either by arguing that no representations need be posited or that far fewer than previously thought need be posited. Such views include, but are not limited to those of Gibson (1966, 1986), Churchland.

In Clark (2000), Austen Clark argues convincingly that a widespread view of perception as a complicated kind of feature-extraction is incomplete. He argues that perception has another crucial representational ingredient: it must also involve the representation of "sensory individuals" that exemplify sensorily extracted features. Moreover, he contends, the best way of understanding sensory individuals takes them to be places in space surrounding the perceiver. In this paper, I'll agree with Clark's case for sensory individuals (.

Descartes is often thought to bifurcate sensory experience into two distinct cognitive components: the sensing of secondary qualities and the more or less intellectual perceiving of primary qualities. A closer examination of his analysis of sensory perception in the Sixth Replies and his treatment of sensory processing in the Dioptrics and Treatise on Man teIls a different story. I argue that Descartes offers a unified cognitive account of sensory experience according to which the senses and intellect operate together to produce a fundamentally imagistic representation of the world in both its primary and secondary quality aspects. At stake here is not only our understanding of the cognitive structure of sensory experience but the relation of sense and intellect more generally in the Cartesian mind. The deep bifurcation in the Cartesian mind is not between the sensory perception of primary and secondary qualities but between sensory perception and purely intellectual perception.

In theorizing about perception, philosophers have often multiplied qualities. To perceptible qualities of external objects, like colors and shapes (‘sensible’ qualities), have been added qualities of experiences (‘sensory’ qualities) or of sense-data (‘sensational’ qualities). Start with sensory qualities. The phrase ‘sensory quality’ is not much in use these days, having lost out to ‘phenomenal character,’ ‘phenomenal property,’ ‘qualitative character,’ or ‘quale.’ But whatever sensory qualities are called, pinning them down is no easy matter.