To me, the only thing I don't need explained to me is what my own sensations feel like, and what the experience of consciousness is like. But I have no way of knowing if my sense of consciousness is in any way related to anyone else's.
Sorry to reach all the way back to page one for a quote, but it is important.
The HPC is "hard" because it is incredibly poorly phrased, and presupposes a sort of answer that science cannot deliver. "Gives rise to consciousness" implies that this consciousness thingie is of a different sort of stuff than the active body that gives rise to it; that phrase allows the endless consciousness-of-the-gaps arguments we have seen here.
A very serious question for any (like westprog) who are certain of their own sensations: How did you learn to label them? Do you really, honestly believe that the feeling of, say, hunger, comes pre-labeled? Or love? Hatred? Red? It is, of course, quite impossible for us to know whether you and I see the color red identically. (Indeed, there is good evidence that we do not, as I have an abnormal distribution of color photopigments; I am not color-blind, but I am color-anomalous.) There is no single set of physical properties that will always be labeled "red", and indeed no single wavelength that we call "red" (red is odd that way--to get something that appears to be pure red, we must mix at least two wavelengths, unlike the case with green, blue, or yellow). So, then, what is "red"? We simply cannot define it as a qualia, because we cannot know that your red and mine are the same. We cannot define it as a stimulus, because there are countless examples that are sometimes red and sometimes not.
We define these "subjective" (another word that presupposes a different sort of stuff--as dancing david reminds us, "private" is a better word) qualities, like red, love, hunger, or hatred, based on publicly available referents and a history of interaction with a verbal community. Red is red because we agree to call this set of things red. We infer someone is in love (including ourselves) because of how we act. We label the private accompanying feelings accordingly, but once again it is quite impossible for us to know that love feels for one person like it does for another. (Thus, Hallmark makes more than one card.) The HPC is looking for an answer within the person, which is the one place we cannot find an answer. Consciousness arises socially, from the behavior of interacting individuals. It is a label for a fuzzy set of behaviors--behaviors which are not limited to humans.
Can computers be conscious? According to my parents, their computer hates them, and plots against them, and chooses not to let them check their email when out of Texas. Because they don't know the programming, they use internal, conscious terms to "explain" their computer's behavior. My computer is also conscious--and self-aware, to boot! It tells me it is nearly full, and tells me how long it is going to take to download stuff, and all sorts of neat public reports of private processes.
As for Darat's "ran", there is one additional distinction (which I think actually adds to his example); we have sensory neurons in our bodies which report the sensations of running. The brain does not sense itself; all we have access to (and imperfectly at that) is the result of the process, not the process itself. Imagine if your "ran" was invisible, and you simply found yourself in a new location. That would certainly
seem like magic. It would be a very hard problem to analyze.
Lastly... the "rich tapestry of experience" (or whatever phrase was bandied about) that makes up our inner world... is easily shown to be not nearly what it appears to be. If we are trying to explain the mechanisms of consciousness, it might help to start with what it really is, not what it appears to be. The Chalmers question of "why does it not just go on in the dark" can be answered "well, a huge lot of it
does!" The research on blindsight, anterograde amnesia, and other phenomena shows that awareness is not a necessary part of controlling our actions.
Anyway... the other thing worth mentioning is (as others have said) that this question has been wrestled with on this forum many times before. There were some wonderful threads with Interesting Ian, for instance, and frustrating ones with Iacchus. Well worth reading, IMHO, if you have a month or two to spare.
