It's almost a month since we started this discussion, and it's a bit of a struggle to remember what's important and what's incidental. So first, a back-to-basics statement from me.
Colors do exist, appearances do exist; that's nonnegotiable. That they do not exist in an ontology of "nothing but particles in space" is also, fundamentally, nonnegotiable. I will engage in debates as to whether this is so, but only because people are so amazingly reluctant to see it, and the implication that their favorite materialistic theories of mind actually involve property dualism, in which color (for example) is tied to a particular structure or behavior of particles in the brain, but can't be identified with it.
We aren't like the ancient atomists who only had an informal concept of the world as atoms in a void, we have mathematical theories of physics, so a logical further question is whether these mathematical theories can be interpreted so that some of the entities they posit can be identified with color, with "experiences", and so on.
Here I'd say there are two further important facts. First, an experience is a whole and has to be tackled as a whole. Patches of color are just a part of a multi-sensory whole, which in turn is just the sensory aspect of an experience which also has a conceptual element, temporal flow, a cognitive frame locating current events in a larger context, and so on. Any fundamental theory of reality which purports to include consciousness has to include this whole, it can't just talk about atomized sensory qualia.
Second, any theory which says that the elementary degrees of freedom in a conscious state correspond to averaged collective physical degrees of freedom will have to involve property dualism. That's because it's a many-to-one mapping (from physical states to conscious states), and a many-to-one mapping can't be an identity.
All that is the starting point for my line of thought, which is an attempt to avoid property dualism. I want to have something in my mathematical theory of reality which simply is the bearer of conscious states, has the properties and structure of a conscious whole, and is appropriately located in the causal chain. Since the mathematics describing a configuration of particles in space seems very unpromising for such a reinterpretation; and since our physics is quantum mechanics anyway, and the formalism of quantum mechanics contains entangled wavefunctions that can't be factorized into localized wavefunctions, it's quite natural to look for these conscious wholes in some form of QM where entanglement is ontological. However, since consciousness is in the brain and causally relevant, this implies that there must be a functionally relevant brain subsystem that is in a quantum coherent state.
That is the argument which leads me from "consciousness is real" to "there's large-scale quantum entanglement in the brain". Given the physics we have, it's the only way I see to avoid property dualism, and it's still just a starting point, on every level: mathematically, ontologically, and of course neurobiologically. But that is the argument you should be scrutinizing. What's at stake in some of our specific exchanges may be a little obscure, so I wanted to set down the main argument in one piece, in one place, so you could see what you're dealing with.
I will lay down the main thing convincing me that you're correct.
Consider the three statements:
"there's a large-scale quantum entanglement in the brain"
"consciousness is real"
"Mitchell Porter says that consciousness is real."
Your inference requires that 1 and 2 are correlated. It is non-negotiable that 2 or 3 are correlated. There is no special connection between 1 and 3 that would make them uncorrelated.
However, 1 and 3 are both clearly-defined physical statements, and there is no physical mechanism for their correlation. We conclude that they are uncorrelated. We conclude that 1 and 2 are uncorrelated.
...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.