http://esr.ibiblio.org/?p=1192#more-1192
ADDED: Even if you disagree with ESR's take, and many will, this is the clearest definition I have seen on what qualia is. So it should present a useful starting point, even for those who strongly disagree, to argue from.
Other mental content is expressible propositionally, whereas to duplicate someone's qualia you have to literally duplicate their brainstate (or at least the functional equivalent of their brainstate).
When I say "Greece is in Europe" I am making a propositional claim that is relatively independent of the precise details of how my brain represents that belief, versus how your brain does. Maybe I am picturing a map, while you are remembering Greece's EU membership. For the purposes of communicating that proposition, nobody cares about what your neural activity looks like when you think about Greece being in Europe. The description is higher level: many brainstates map to a single belief state. This is what makes it communicable.
To duplicate something, you of course have to duplicate it. That isn't really the point. What you are tacitly assuming is that qualia cannot be communicated, know or understood without duplication. ie, there is something special about them in that regard. That is how that approach fails as a dissolution. Rather than showing there is nothing special about qu... (read more)