confutatis said:
What if you could grab the "redness" from other people's minds and find out that no two people see red the same way? Would that change the meaning of the word 'red'? What should we call it now? 'Green' according to John, 'Blue' according to George, 'Violet' according to Paul?
To me the answer is a clear and emphatic NO. The meaning of the word 'red' has nothing to do with your visual experience of it. I am absolutely sure you see this color[/color] as red, and I don't need to look at your mind to know that. That is because the meaning of the word 'red' has nothing to do with your subjective experience.
I would agree in one sense. You do know, trivially, that this color[/color] looks 'red' to me. This is because the basis for my experience of redness ultimately falls back to a source that is shared between us in the external world. In this sense "red" means "light with a wavelength of roughly 600 nm."
Now, here is the thing. The word "red" can be used consistently across people precisely because in the objective, functional sense, red ultimately refers to a common source-- it is always caused by (or always correlated with, whatever) light of wavelength 600nm. But I contend that the way
I use the word red, conceptually, does not refer directly to light of wavelength 600nm. It refers to my visual experience of that color that I call red, which is conceptually distinct from objective light wavelengths, even if we can traverse the causal chain backwards far enough that eventually we reach a description on the level of objective photons.
If you accept even the most basic of covarying relations between brain and mind (which you are basically forced to do by findings in neuroscience), I can state this more concretely. Say there is some neural process N1 such that it is univerally responsible for producing (being correlated with, whatever) the subjective visual experience of this color[/color], and likewise N2 is universally associated with this color[/color]. Say Bob's brain is wired such that 600nm light striking his retina always activates N1 in his brain, and Jane's brain is wired such that 600nm light always activates N2 in her brain. Now, whenever Bob and Jane both see 600nm light, they will both say "I see red." But are they referring to light in this very objective sense of 'photons with a wavelength of 600nm'? No, that is impossible.
They must be referring to the portion of their brain that registers and interprets such light. So in a very direct sense, Bob's "red" refers to N1 and Jane's "red" refers to N2. Accordingly, Bob's "red" refers to subjective experience of this color[/color] while Jane's "red" refers to this color[/color].
In this case, Bob and Jane can act as if there is no difference in their visual experiences and get along just fine, because the source of their perceptions is the same-- they are both 'coding for' the same objective thing. On closer inspection, however, we find there is an internal distinction to be made-- although they are coding for the same thing, they code it in different ways. This makes no practical difference in terms of relating to the external world, but at the same time there is obviously an ontological difference with respect to their internal models of that external world.
No, you claim to know for certain you are a member of set A on the basis of what people tell you you need to have in order to be a member of set A. You're not claiming you are born knowing what the word 'experience' means, are you? And if you have learned the meaning of the word 'experience' from other people, how can you possibly think those people don't know what 'experience' means? Can't you see the nonsense?
You are right to point out that this is a sticky issue, but it is not debilitating. If I am brought up from infancy by a zombie, then it is true that my zombie parent does not know what 'experience' really means. At the same time, however, by way of sheer internal consistency, I
do come to know what experience means-- I come to systematically associate the word with my own subjective experiences.
Now, again, the question arises to what extent I know that the way I use the word is the same as the way others use it. Problematic, perhaps, but as long as I make some rational observations (I learn principles of causality, see that other people by and large have the same internal makeup as I do, and so on) to make some reasonable assumptions (others with normally functioning brains and similar physical and verbal behavior as I have have experiences in roughly the same sense I do), I am back on relatively firm footing. There always remains some doubt, but it isn't unique to this epistemic endeavour. Scientists assume principles of induction all the time without any absolutely certain knowledge-- there is no way to be absolutely sure that tomorrow the laws of gravitation will suddenly cease to function and the Earth will spin off into the void. But still, we can get by even if we leave some room for epistemic doubt, so long as our assumptions are well reasoned and appear to be largely consistent with what observations we can make.
But it is not axiomatic that you cannot know what they know. That is nonsense. If I ask you which alias I use on this forum and you say 'confutatis', what basis do I have to claim you may not know what my alias is? How else could you possibly write 'confutatis'? Mere chance? Come on.
Your alias is identical to the string of letters that appears in the upper left corner of each of your posts, by definition, so I can trivially have certain knowledge in this case. On the other hand, one's own behavior and language are readily demonstrated, from one's own 1st person view, not to be identical to subjective experience, even if the two are intricately related.
The part of your experience which includes any aspect that cannot possibly be known by anybody else does not concern anybody else. Why should you bother which way I see red if that information adds absolutely nothing to your knowledge of anything?
Perhaps it is of no practical use in everyday life, but it is invaluable to know any subjective differences between us if we are to formulate a comprehensive theory of consciousness.
If you claim different people see the world in different ways, what's preventing you from also claiming that vision reveals nothing about the world? Surely if I see a stop sign as red and you see it as yellow, then it is neither red nor yellow. It doesn't even have color. As a consequence, it doesn't also have size, shape, position, mass, relative speed...
The stop sign is not uniquely red or yellow in and of itself, but this should not be surprising since these things are functions of our separate brains interpreting the stop sign, not properties of the stop sign itself. The property that belongs to the stop sign itself is that it reflects light of 600nm wavelength, and this is consistent with both of our perceptions, so long as my 'red' and your 'yellow' are both precipitated by a causal chain beginning with 600nm light striking our retinas. The objective stop sign retains, in entirety, its objective characteristics. We are both coding for the same thing, even if we use slightly different coding strategies.
. When you say, "Nonetheless, if it possible to measure the senario's of consciousness, then it is equally possible to say that they should have a computational formula to equate with brain subjectivity and awareness," the problem I see is that you have assumed what you are able to measure is all there is. It might very well be that all you are measuring is all that's measurable, and after that there's still something left which cannot be measured. In fact, the functionalist model is exactly based on only that which can be measured. However, it still doesn't explain consciousness, which is why some of us believe there is "something more" to consciousness which is unmeasurable.