Inverted Spectrum
If what I call “red” looks blue to you, then this is the inverted spectrum. This would be a problem for materialism if there were no way to tell objectively who was seeing what color “correctly.” However, people can discern more shades of certain colors than others, and so this would be one way of objectively determining who has an inverted spectrum. Thus, this argument is not successful in refuting materialism.
Chinese Nation
If materialism/functionalism is true, then in theory one could create a conscious mind by having everyone in China act as a neuron, using walkie-talkies or whatever. The argument suggests that it would be absurd to suggest that the nation of China would then become actually conscious, as one giant mind.
However, imagine scientists cutting your head open, and stretching out your neurons. They then swap your neurons one at a time with a Chinese person like in the argument. The Chinese people are fulfilling the same function as your neurons, and eventually your mind would be nothing more than people communicating with walkie talkies. But you would still be conscious. So the Chinese Nation argument is not successful against materialism.
Zombie Argument
We can coherently conceive of a world identical to ours, with people living and working and so forth, except that they have no conscious experience. Their minds make them eat when they are hungry and so forth, so they fulfill the same functions, but they are not conscious. This shows that consciousness is over and above the physical facts.
Knowledge Argument (Mary’s Room)
Mary lives in a black and white room her whole life, but learns everything there is to know about color and how people perceive it. She knows every physical fact about color perception. But then she is released from the room and experiences red for the first time; she sees that red looks like this. I.e., she learns a new fact that was not covered by the physical facts. Hence, materialism is false. Nagel makes a similar argument in his essay “What Is It Like To Be A Bat?”
Responses to Mary’s Room:
1. Perhaps we just assume that future neuroscience will not be able to tell you what red looks like. One problem with this is that it is hard to see how it is possible; future neuroscience will still be objective third-person facts, because that’s what science is, whereas “what red looks like” is a subjective first-person fact. Another problem is that future neuroscience may indeed have to postulate consciousness as an additional entity, thus vindicating Mary’s Room.
2. Perhaps Mary doesn’t learn new facts upon leaving the room, but just a new way of those same facts; i.e. knowledge by description is what Mary learns in the room, and then knowledge by acquaintance is what she learns on leaving the room. But surely the fact that red looks like this is a new fact she learned upon leaving the black and white room. Also, Russell held that what we know by acquaintance is not the external world, but merely our qualia that is produced by the external world.
3. Perhaps Mary learns a knowledge of how to do something, rather than just knowledge that something. But, like above, surely the knowledge that red looks like this and not this is new knowledge, not just knowledge in a different way. Also, Mary has new abilities now because she learned what red looks like.
4. Maybe Mary learns a new concept. H20 and water refer to the same thing, but they are different concepts and used in different situations. So you could learn about H20 and then later learn about water. Perhaps Mary learns a new concept of a fact she already knew. However, like the above, Mary just seems intuitively to have learned a new fact, of the kind she didn’t know before. But perhaps intuition is wrong, and she did just learn a new concept of a fact she already knew. However, this isn’t clearly correct. Is 5+7=12 the same fact as that 38 is the square root of 1444? Doesn’t seem to be. These are two different facts, even though they have the same answer.
Subjectivity
Another possible answer to Mary’s Room is that perhaps Mary can deduce what colors look like by their relative position to what other colors, such as the black and white, look like. If she knows that blue is relative in such and such a way between a certain shade of gray and so forth, maybe she can figure out from just the physical facts what blue looks like.
The problem with this response is that it highlights the main problem with materialism, which is that red looks like anything at all. Why is there this subjective experience at all?
Science is in the business of carving off the subjective and describing everything in objective mind-independent facts. You may feel what hot and cold water feels like, and perhaps an alien would feel these the opposite as you do, but science would just describe the same objective facts about what temperature actually is, and ignore what it feels like. Thus, it seems that science can never get a handle on the mind even in principle.
Property Dualism
The idea that there is only the material world, but that there are two kinds of properties: physical and non-physical. Property dualism allows propositional attitudes (your attitude towards propositions, such as belief, desire, etc), but not qualia, to be material. Thus, your belief that it is raining can cause your legs to run inside and so forth, but qualia itself would be epiphenomenal (one way causal) and thus still not cause anything. However, this leads to the absurd consequence that we can’t even think about our qualia, since qualia are epiphenomenal and hence a one way causal relation. Thus, you experiencing the qualia of pain cannot cause you to believe that you have pain.
David Chalmers (one of the main purveyors of property dualism) attempts to deal with this problem by saying that qualia have no causal “chain” at all because they are experienced directly. One problem with Chalmers’ view is that, since propositional attitudes are purely physical, and you can thus reason physically, then even zombies could have beliefs and desires and such. If so, then they can believe they have qualia. And thus, no one could tell if they were a zombie or not.
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