This is why I said (to TheOtherDave, and not in these exact words) that the mental can be identified with the physical only if there is a one-to-one mapping between exact physical states and exact conscious states. If it is merely a many-to-one mapping - many exact physical states correspond to the same conscious state - then that's property dualism.
Since there's a many-to-one mapping between physical states and temperatures, am I a temperature dualist? Would it be any less dualist to define a one-to-one mapping between physical states of glasses of water and really long strings? (You can assume that I insist that temperature and really long strings are real.)
[this point has low relevance]
Believe what I quoted, and that qualia exist, and you're a dualist; believe what I quoted, and deny that qualia exist (which amounts to saying that consciousness and the whole world of appearance doesn't really exist, even as appearance), and you're an eliminativist.
It seems like we can cash out the statement "It appears to X that Y" as a fact about an agent X that builds models of the world which have the property Y. It appears to the brain I am talking to that qualia exist. It appears to the brain that is me that qualia exist. Yet this is not any evidence or the existence of qualia.
"Degrees of existence", by the way, only makes sense insofar as it really means "degrees of something else". Existence, like truth, is absolute.
Degrees of existence come from what is almost certainly a harder philosophical problem about which I am very confused.
My guess that quantum entanglement matters for conscious cognition is an inference from facts about our phenomenology, not facts about our programming.
Facts about your phenomenology are facts about your programming! If you can type them into a computer, they must have a physical cause tracing back through your fingers, up a nerve, and through your brain. There is no rule in science that says that large-scale quantum entanglement makes this behavior more or less likely, so there is no evidence for large-scale quantum entanglement.
But my meta-answer is that these are solely issues about computation, which have no implications for consciousness until we adopt a particular position about the relationship between computation and consciousness.
My point is that the evidence for consciousness, that various humans such as myself and you believe that they are conscious, can be cashed out as a statement about computation, and computation and consciousness are orthogonal, so we have no evidence for consciousness.
If someone tells me that the universe is made of nothing but love, and I observe that hate exists and that this falsifies their theory, then I've made a judgement about an ontology both at a logical and an empirical level. That's what I was talking about, when I said that if you swapped and , I couldn't detect the swap, but I'd still know empirically that color is real, and I'd still be able to make logical judgements about whether an ontology (like current physical ontology) contains such an entity.
A: "The universe is made out of nothing but love"
B: "What are the properties of ontologically fundamental love?"
A: "[The equations that define the standard model of quantum mechanics]"
B: "I have no evidence to falsify that theory."
A: "Or balloons. It could be balloons."
B: "What are the properties of ontologically fundamental balloons?"
A: "[the standard model of quantum theory expressed using different equations]"
B: "There is no evidence that can discriminate between those theories."
... if gensyms only exist on that scale, and if changes like those which you describe make no difference to experience, then you ought to be a dualist, because clearly the experience is not identical to the physical in this scenario. It is instead correlated with certain physical properties at the neuronal scale.
I'm a reductive materialist for statements - I don't see the problem with reading statements about consciousness as statements about quarks. Ontologically I suppose I'm an eliminative materialist.
Since there's a many-to-one mapping between physical states and temperatures, am I a temperature dualist? Would it be any less dualist to define a one-to-one mapping between physical states of glasses of water and really long strings? (You can assume that I insist that temperature and really long strings are real.)
The ontological status of temperature can be investigated by examining a simple ontology where it can be defined exactly, like an ideal gas in a box where the "atoms" interact only through perfectly elastic collisions. In such a situ...
...at least not if you accept a certain line of anthropic argument.
Thomas Nagel famously challenged the philosophical world to come to terms with qualia in his essay "What is it Like to Be a Bat?". Bats, with sensory systems so completely different from those of humans, must have exotic bat qualia that we could never imagine. Even if we deduce all the physical principles behind echolocation, even if we could specify the movement of every atom in a bat's senses and nervous system that represents its knowledge of where an echolocated insect is, we still have no idea what it's like to feel a subjective echolocation quale.
Anthropic reasoning is the idea that you can reason conditioning on your own existence. For example, the Doomsday Argument says that you would be more likely to exist in the present day if the overall number of future humans was medium-sized instead of humongous, therefore since you exist in the present day, there must be only a medium-sized number of future humans, and the apocalypse must be nigh, for values of nigh equal to "within a few hundred years or so".
The Buddhists have a parable to motivate young seekers after enlightenment. They say - there are zillions upon zillions of insects, trillions upon trillions of lesser animals, and only a relative handful of human beings. For a reincarnating soul to be born as a human being, then, is a rare and precious gift, and an opportunity that should be seized with great enthusiasm, as it will be endless eons before it comes around again.
Whatever one thinks of reincarnation, the parable raises an interesting point. Considering the vast number of non-human animals compared to humans, the probability of being a human is vanishingly low. Therefore, chances are that if I could be an animal, I would be. This makes a strong anthropic argument that it is impossible for me to be an animal.
The phrase "for me to be an animal" may sound nonsensical, but "why am I me, rather than an animal?" is not obviously sillier than "why am I me, rather than a person from the far future?". If the doomsday argument is sufficient to prove that some catastrophe is preventing me from being one of a trillion spacefaring citizens of the colonized galaxy, this argument hints that something is preventing me from being one of a trillion bats or birds or insects.
And this could be that animals lack subjective experience. This would explain quite nicely why I'm not an animal: because you can't be an animal, any more than you can be a toaster. So Thomas Nagel can stop worrying about what it's like to be a bat, and the rest of us can eat veal and foie gras guilt-free.
But before we break out the dolphin sausages - this is a pretty weird conclusion. It suggests there's a qualitative and discontinuous difference between the nervous system of other beings and our own, not just in what capacities they have but in the way they cause experience. It should make dualists a little bit happier and materialists a little bit more confused (though it's far from knockout proof of either).
The most significant objection I can think of is that it is significant not that we are beings with experiences, but that we know we are beings with experiences and can self-identify as conscious - a distinction that applies only to humans and maybe to some species like apes and dolphins who are rare enough not to throw off the numbers. But why can't we use the reference class of conscious beings if we want to? One might as well consider it significant only that we are beings who make anthropic arguments, and imagine there will be no Doomsday but that anthropic reasoning will fall out of favor in a few decades.
But I still don't fully accept this argument, and I'd be pretty happy if someone could find a more substantial flaw in it.