View Qualia
“Qualia,” from the Latin for “what sort” or “what kind,” is a term in philosophy to describe the subjective quality of conscious experience. Examples of qualia are the pain of a headache, the taste of wine, or the 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.”
The importance of qualia in philosophy of mind comes largely from the fact that they are often seen as posing a fundamental problem for materialist explanations of the mind-body problem. Much of the debate over their existence hinges on the definition of the term that is used, as various philosophers emphasize or deny the existence of certain properties.
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.’”
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.
In one argument, a key consequence of the claim that 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. Those who dispute the existence of qualia would therefore necessarily dispute the existence of philosophical zombies.
IEET Links:
Protopanpsychism and the consciousness conundrum, or why we shouldn’t assume uploads
Quantity of Experience: Brain-Duplication and Degrees of Consciousness
Kurzweil’s nano neural nets
Sources:
Wikipedia