BEGINQUOTE- Pete Carlton wrote:
In any case, I grant that the blind man's experience would be quite different from someone who's actually looking at the color red. This is just because the functional states of someone who is seeing red are different than those of someone who just understands what it's like-- you can't stimulate your optic nerve just by will alone. It isn't clear that someone could drive their brain into the state of someone who had seen red merely by understanding everything about the process of seeing red. This is also how I respond to Frank Jackson's colorblind Mary experiment..
So you agree that you cannot "drive someone's brain into the state of someone who had seen red merely by understanding everything about the process of seeing red.". That is, you agree that you cannot "see red" unless you do physically "see red". Isn't that somehow in contradiction with your claim below, i.e., that there is nothing else to know beyond the explanation of the physiological response? One thing you seem to agree: you cannot know how red looks like unless you see red. A blind man cannot possibly know that. Now I am aware that "know" may not be the correct term. Maybe experience would be better. -ENDQUOTE
Actually, you probably _could_ drive your brain into "seeing red" if you knew exactly what physical processes occur in the brain in response to a red stimulus, and if you had appropriate neural interface equipment. Such capabilities do not currently exist - not even close - but the idea is the basis of many SF stories (eg. William Gibson, Greg Egan). The same sort of thing frequently occurs naturally: the definition of a hallucination is a perception without the stimulus that would normally give rise to that perception. The point is, even if you knew in perfect detail what happens in your brain when you see red, you would not actually know/feel/experience the qualia unless you ran the software on your own hardware.
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