qualia

=Qualia=

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=Overview=

Qualia, singular "quale" from a Latin word meaning for "what sort" or "what kind," is a term used in philosophy to describe subjective conscious experiences. Examples of qualia are the pain of a headache, the taste of wine, the experience of taking a recreational drug, or the perceived redness of an evening sky. Daniel Dennett writes that qualia is "an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us."[1] Erwin Schrödinger, the famous physicist, had this counter-materialist take: "The sensation of colour cannot be accounted for by the physicist's objective picture of light-waves. Could the physiologist account for it, if he had fuller knowledge than he has of the processes in the retina and the nervous processes set up by them in the optical nerve bundles and in the brain? I do not think so." [2]

The importance of qualia in philosophy of mind comes largely from the fact that they are seen as posing a fundamental problem for materialist explanations of the mind-body problem. Much of the debate over their importance hinges on the definition of the term that is used, as various philosophers emphasize or deny the existence of certain features of qualia.

=Definitions= There are many definitions of qualia, which have changed over time. One of the simpler, broader definitions is "The 'what it is like' character of mental states. The way it feels to have mental states such as pain, seeing red, smelling a rose, etc."[3]

Clarence Irving Lewis, in his book Mind and the World Order (1929), was the first to use the term "qualia" in its generally agreed modern sense.

> There are recognizable qualitative characters of the given, which may be repeated in different experiences, and are thus a sort of universals; I call these "qualia." But although such qualia are universals, in the sense of being recognized from one to another experience, they must be distinguished from the properties of objects. Confusion of these two is characteristic of many historical conceptions, as well as of current essence-theories. The quale is directly intuited, given, and is not the subject of any possible error because it is purely subjective.

Frank Jackson (1982) later defined qualia as "...certain features of the bodily sensations especially, but also of certain perceptual experiences, which no amount of purely physical information includes" (p. 273).

Daniel Dennett identifies four properties that are commonly ascribed to qualia. According to these, qualia are:

> 1. ineffable; that is, they cannot be communicated, or apprehended by any other means than direct experience. > 2. intrinsic; that is, they are non-relational properties, which do not change depending on the experience's relation to other things. > 3. private; that is, all interpersonal comparisons of qualia are systematically impossible. > 4. directly or immediately apprehensible in consciousness; that is, to experience a quale is to know one experiences a quale, and to know all there is to know about that quale.

If qualia of this sort exist, then a normally sighted person who sees red would be unable to describe the experience of this perception in such a way that a listener who has never experienced color will be able to know everything there is to know about that experience. Though it is possible to make an analogy, such as "red looks hot," or to provide a description of the conditions under which the experience occurs, such as "it's the color you see when light of 700-nm wavelength is directed at you," supporters of this kind of qualia contend that such a description is incapable of providing a complete description of the experience.

Another way of defining qualia is as "raw feels." A raw feel is a perception in and of itself, considered entirely in isolation from any effect it might have on behavior and behavioral disposition. In contrast, a "cooked feel" is that perception seen as existing in terms of its effects.

According to an argument put forth by Saul Kripke in his paper "Identity and Necessity" (1971), one key consequence of the claim that such things as raw feels can be meaningfully discussed—that qualia exist—is that it leads to the logical possibility of two entities exhibiting identical behavior in all ways despite one of them entirely lacking qualia. While very few ever claim that such an entity, called a philosophical zombie, actually exists, the mere possibility is claimed to be sufficient to refute physicalism.