The comments in this thread have been concerned with "the experience of redness" and whether this exists or not or is a real physical phenomenon or not. The answers appear to be straight-forward (yes, and yes) and I am left wondering what the dualism debate is all about. Below, I even argued that dualism may be obsolete. Dualism is obsolete if dualism = {the experience of redness is a metaphysical phenomenon}. But then I remembered some ideas (15 years ago for me) from, "Zen and the art of motorcycle maintenance". Dualism is not really about whether neuronal activity can account for all subjective experience. (It can, and a dualist need not object to this.) It's about whether redness exists. Redness does exist, so redness is not the best example of qualia for understanding dualism. Consider the quale emphasized in Pirsig's book, "quality". We all agree quality exists in some sense (we'd all like to have quality posts on LW) but dualists want to think that "quality" exists in a real sense out in the territory. A quality book and a quality cheese have something in common; an essence of "quality" attached to them. My two cents on the issue: I think that some qualia might exist in the territory, in some complicated way. But if they do, they're physical and we just haven't figured out how yet. I've babbled before about how I think qualia like "beauty" are concerned with the subjective experience of patterns, so these qualia are going to be more difficult to describe physically than, say, the experience of redness. We have no well-developed scientific theory for pattern recognition. We can write a code that recognizes a pattern (e.g., the letter "A"), but we don't have any idea what a pattern is.

One such point of view is that currently all existing explanations for qualia - even the ones that try to be materialistic - are actually dualist. For instance, suppose we have a materialist-computational explanation of the brain, which explains how each neuron performs a certain type of computation, and how certain activity patterns in the neurons correspond to specific mental states. We find the model to be good and to accurately predict what people will do. So far, so good. Yet here we run into a problem - we can now fully explain the brain and one's doings in terms of the computational model, without needing to include actual qualia or subjective feelings in the explanation at all. The model works just as well regardless of whether or not we experience phenomenal consciousness, or are p-zombies. In trying to explain mental states, we have actually explained them away and created a theory that has no need for them. Therefore, the argument goes, assuming we don't deny the existence of qualia entirely, we must dualists. After all, we now have two models, one physical model which doesn't include qualia, and one which assumes their existence but provides no physical explanation.