So we can set up state machines that behave like people talking about qualia the way you do, and which do so because they have the same internal causal structure as people. Yet that causal structure doesn't have anything to do with the referent of 'redness'. It looks like your obvious premise that redness isn't reducible implies epiphenomenalism. Which is absurd, obviously.
No, it just means that plays a causal role in us, which would be played by something else in a simulation of us.
There's nothing paradoxical about the idea of an unconscious simulation of consciousness. It might be an ominous or a disconcerting idea, but there's no contradiction.
I claim that mental states can be regarded as causes, that they are indeed a shorthand for immensely complicated physical details (and significantly less but still quite a lot complicated computational details), and claim further that they cause a lot of things. For instance, they're a cause of this comment. I claim that the word 'cause' can apply to more than relationships between fundamental particles: for instance, an increase in the central bank interest rate causes a fall in inflation.
So, which do you disagree with: that interest rates are causal influences on inflation, or that interest rates and inflation are shorthand for complicated physical details?
See what I just said to William Sawin about fundamental versus derived causality. These are derived causal relations; really, they are regularities which follow indirectly from large numbers of genuine causal relations. My eccentricity lies in proposing a model where mental states can be fundamental causes and not just derived causes, because the conscious mind is a single fundamental entity - a complex one, that in current language we might call an entangled quantum system in an algebraically very distinctive state, but still a single entity, in a way that a pile of unentangled atoms would not be.
Being a single entity means that it can enter directly into whatever fundamental causal relations are responsible for physical dynamics. Being that entity, from the inside, means having the sensations, thoughts, and desires that you do have; described mathematically, that will mean that you are an entity in a particular complicated, formally specified state; and physically, the immediate interactions of that entity would be with neighboring parts of the brain. These interactions cause the qualia, and they convey the "will".
That may sound strange, but even if you believe in a mind that is material but non-fundamental, it still has to work like that or else it is causally irrelevant. So when you judge the idea, remember to check whether you're rejecting it for weirdness that your own beliefs already implicitly carry.
My eccentricity lies in proposing a model where mental states can be fundamental causes and not just derived causes, because the conscious mind is a single fundamental entity - a complex one, that in current language we might call an entangled quantum system in an algebraically very distinctive state, but still a single entity, in a way that a pile of unentangled atoms would not be.
So you're taking the existing causal graph, drawing a box around all the interactions that happen inside a brain, and saying that everything inside the box counts as one thing.
That's not simplification, it's just bad accountancy.
...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.