In his paper, “Facing up to the problem of consciousness”, Chalmers breaks up consciousness into 2 groups. The first are objectively observable. He calls these things “phenomena” which Chalmers labels as “easy”. We should all be able to agree on what is being observing when it comes to these phenomena and they should be accessible to the normal methods of science. Chalmers states:
The easy problems of consciousness include those of explaining the following phenomena:
• the ability to discriminate, categorize, and react to environmental stimuli;
• the integration of information by a cognitive system;
• the reportability of mental states;
• the ability of a system to access its own internal states;
• the focus of attention;
• the deliberate control of behavior;
• the difference between wakefulness and sleep.
All of these phenomena are associated with the notion of consciousness. For example, one sometimes says that a mental state is conscious when it is verbally reportable, or when it is internally accessible. Sometimes a system is said to be conscious of some information when it has the ability to react on the basis of that information, or, more strongly, when it attends to that information, or when it can integrate that information and exploit it in the sophisticated control of behavior. We sometimes say that an action is conscious precisely when it is deliberate. Often, we say that an organism is conscious as another way of saying that it is awake.
Chalmers then quotes Nagel, “What is it like to be a bat?”:
The really hard problem of consciousness is the problem of experience. When we think and perceive, there is a whir of information-processing, but there is also a subjective aspect. As Nagel (1974) has put it, there is something it is like to be a conscious organism. This subjective aspect is experience. When we see, for example, we experience visual sensations: the felt quality of redness, the experience of dark and light, the quality of depth in a visual field. Other experiences go along with perception in different modalities: the sound of a clarinet, the smell of mothballs. Then there are bodily sensations, from pains to orgasms; mental images that are conjured up internally; the felt quality of emotion, and the experience of a stream of conscious thought. What unites all of these states is that there is something it is like to be in them. All of them are states of experience.
In his book “The Conscious Mind”, Chalmers takes a slightly different tact and instead of breaking up consciousness into easy and hard phenomena, he calls them psychological consciousness and phenomenal consciousness (p-consciousness for short) respectively. His book is much more thorough and worth referring to. For p-consciousness, Chalmers lists a number of different “experiences” as follows:
Visual experiences. Among the many varieties of visual experience, color sensations stand out as the paradigm examples of conscious experience, due to their pure, seemingly ineffable qualitative nature. … Why should it feel like that? Why should it feel like anything at all? …
Other aspects of visual experience include the experience of shape, of size, of brightness and of darkness. A particularly subtle aspect is the experience of depth. … Certainly there is an intellectual story one can tell about how binocular vision allows information from each eye to be consolidated into information about distances, thus enabling more sophisticated control of action, but somehow this causal story does not reveal the way the experience is felt. Why that change in processing should be accompanied by such a remaking of my experience was mysterious to me as a ten-year-old, and is still a source of wonder today.
Auditory experiences. In some ways, sounds are even stranger than visual images. The structure of images usually corresponds to the structure of the world in a straightforward way, but sounds can seem quite independent. …
Musical experience is perhaps the richest aspect of auditory experience, although the experience of speech must be close. Music is capable of washing over and completely absorbing us, surrounding us in a way that a visual field can surround us but in which auditory experiences usually do not. …
Tactile experiences. Textures provide another of the richest quality spaces that we experience: think of the feel of velvet, and contrast tit to the texcture of cold metal, or a clammy hand, or a stubbly chin. …
Olfactory experiences. Think of the musty smell of an old wardrobe, the stench of rotting garbage, the whiff of newly mowngrass, the warm aroma of freshly baked bread. Smell is in some ways the most mysterious of all the senses due to the rich, intangible, indescribable nature of smell sensations. … It seems arbitrary that a given sort of molecule should give rise to this sort of sensation, but give rise it does.
Taste experiences. Psychophysical investigations tell us that there are only four independent dimensions of taste perception: sweet, sour bitter, and salt. But this four-dimensional space combines with our sense of smell to produce a great variety of possible experiences…
Experiences of hot and cold. An oppressively hot, humid day and a frosty winder’s day produce strikingly different qualitative experiences. Think also fo the heat sensations on one’s skin from being close to a fire, and the hot-cold sensation that one gets from touching ultra cold ice.
Pain. Pain is a paradigm example of conscious experience, beloved by philosophers. Perhaps this is because pains form a very distinctive class of qualitative experiences, and are difficult to map directly onto any structure in the world or in the body, although they are usually associated with some part of the body. … There are a great variety of pain experiences from shooting pains and fierce burns through sharp pricks to dull aches.
Other bodily sensations. Pains are only the most salient kind of sensations associated with particular parts of the body. Others include headaches … hunger pangs, itches, ticles and the experience associated with the need to urinate. …
Mental imagery. Moving ever inward, toward experiences that are not associated with particular objects in the environment or the body but athat are in some sense generated internally, we come to mental images. There is often a rich phenomenology associated with visual images conjured up in one’s imagination, though not nearly as detailed as those derived from direct visual perception. …
Conscious thought. Some of the things we think and believe do not have any particular qualitative feel associated with them, but many do. This applies particularly to explicit, occurent thoughts that one thinks to oneself, and to various thoughts that affect one’s stream of consciousness. …
Emotions. Emotions often have distinctive experiences associated with them. The sparkle of a happy mood, the weariness of a deep depression, the red-hot glow of a rush of anger, the melancholy of regret: all of these can affect conscious experiences profoundly, although in a much less specific way than localized experiences such as sensations. …
… Think of the rush of pleasure one feels when one gets a joke, another example is the feeling of tension one gets when watching a suspence movie, or when waiting for an important event. The butterflies in one’s stomach that can accompany nervousness also fall into this class.
The sense of self. One sometimes feels that there is something to conscious experience that transcends all these specific elements: a kind of background hum, for instance, that is somehow fundamental to consciousness and that is there even when the other components are not. … there seems to be something to the phenomenology of self, even if it is very hard to pin down.
This catalog covers a number of bases, but leaves out as much as it puts in. I have said nothing, for instance, about dreams, arousal and fatigue, intoxication, or the novel character of other drug-induced experiences. …
I’d like to suggest that p-consciousness can be defined as follows. P-consciousness is a set of phenomena. It is that set of phenomena characterized by phenomenal experiences. The term “phenomenal consciousness” picks out the set of phenomena known as qualia, best described as being subjectively observable but not objectively observable. There is something that occurs during the operation of a conscious brain which cannot be objectively observed. These phenomena are subjective in nature and although they supervene on the brain, they can not be measured or described by explaining what goes on within the brain such as the interactions between neurons, the resulting EM fields produced nor anything that is objectively measurable.
Unfortunately, this definition assumes nature is inherently dualistic (ie: natural dualism) and no one seems to like dualism. The alternative is to either explain phenomenal consciousness in strict physical terms (ie: so the hard problem is just another easy problem) or we dismiss phenomenal consciousness altogether (ie: eliminativism).
Feel free to suggest revisions or alterations to the definition. When doing so, please consider how those alterations mesh with published work on the topic.
Chalmers, David J. "Facing up to the problem of consciousness." Journal of consciousness studies 2.3 (1995): 200-219.
http://consc.net/papers/facing.html
