If dopamine causes pleasure, then that's by definition a causal relationship. Dopamine causes pleasure, and so do some other neurochemicals. It would be simply correlative if it was only found that dopamine and pleasure tend to occur at the same time. It's shown to be causal if you can take dopamine, give it to someone, and they then experience pleasure right after. Because without the evidence of that type of study, it could have been the case that pleasure causes the release of dopamine.
It is strongly implied that dopamine causes pleasure, but to be honest we don't know how the particles that interact in the different parts of the brain (such as the nucleus accumbens for example) give rise to what we experience as pleasure. Dopamine is simply a neurochemical and that neurochemical attaches to different post synaptic receptors resulting in electrial spikes which give us what we call pleasure. But how those electrical spikes give rise to the inner subjective experience is absolutely unknown. You cannot claim that dopamine causes pleasure, you can simple say that there is a very strong correlation between dopamine and pleasure. You can even say that there is some sort of causal relationship between dopamine and pleasure, but it is partial. To say that dopamine causes pleasure is to bypass the entire ontological gap between physical processes and conscious experience.
There's a part of the brain, originally found in rats and eventually found in humans, where those pleasure chemicals play a role, that if you stimulate it directly, it causes profound pleasure. Rats will literally kill themselves with exhaustion if you give them a lever to stimulate that part of the brain.
Again noone is denying that the brain is one of the components involved in the formation of our conscious experience. This proves that the brain is intricately involved in the formation of conscious experience but we're not debating that. We are debating whether the very essence of the property itself is physical or non physical.
Logic gates such as AND, OR, and NOT gates are not a property of nature. But they're an emergent logical property when you put particles together a certain way. In fact, with just NAND gates in particular, you can build all of the logic that runs the processing and memory of a computer because with NAND gates you can build AND, OR, and NOT gates. So with just immense numbers of highly arranged NAND gates and then some I/O and power systems and all that, you can create the emergent property of software. Things like Windows 8, Starcraft II, or ReligiousForums.com. Is Starcraft II reducible? You could strip out features certainly, or play it on a lower graphics setting, but you can't, say, cut the CPU in half and then play half the game. Most of the hardware needs to be intact for any of the software to run at all, and there's nothing remotely like "Starcraft II" in nature. Software is a very novel idea in nature, with the possible major and relevant exception that brains are basically biological computers apparently running software as well.
Software is algorithmic. Starcraft is algorithmic. As such if something is algorithmic it's reducible. It's easy to break down the software and game into certain patterns which are mapped. Consciousness is non algorithmic because all our perceptions are completely subjective and novel properties which we experience inside and are completely different from the physical processes tied to them.
What constitutes magic is generally defined by what we don't know. Electromagnetic radiation seems magical- you can use it to send information and/or energy at incredible speeds even through a pure vacuum of no particles, and it can be invisible, and it's weightless, and it comes from orthogonal electric and magnetic fields, which are also like magic. It sounds non-physical. The fact that masses curve spacetime around them seems magical. The fact that spacetime itself is apparently expanding, seems magical. The fact that trillions of neutrinos pass through your body every second without being detected is magical. Quantum mechanics is magical. This is all magical from, say, 16th century physics that wouldn't know how to handle most of this yet.
True, which is why during those times any of the ideas being proposed would have sounded ludicrous. But today they are widely accepted. What makes you so sure that a form of dualism won't be widely accepted in the future?
And are qualia irreducible? Can't you have degrees of an emotion, like anger or lust? Can't sound come at different volumes, and can't people lose the ability to hear individual frequencies? Some people are color blind. So they still have vision, but see no colors, so part of "sight" was reduced. And for color specifically, some people are partially color blind, so they might have trouble telling certain colors apart, because it's not as precise for them. Or, in anyone, you can have blindingly bright colors, or colors so dull you can barely see them.
It's not the degrees of perception itself, but the nature of qualia which cannot be reduced. Yes you can feel less love, or hate, or hear different sounds. But how do you break sound down? Or emotions down? They can't be broken down any further because we don't even know what builds them in the first place. You can break down a pyramid into blocks, the blocks into atoms, the atoms into waves or wtv. But you can't break down red into anything because we don't know how energy becomes red.
Isn't consciousness itself reducible? Medically speaking, you can have different levels of consciousness. At a very high level there's like trippy drug consciousness where people report everything seeming far more intricate. Then there's regular wakeful consciousness. Then there's disoriented, then delirious, then stuporous, then comatose. Consciousness and response to stimuli become less and less as you go down the scale, with nuances. And that's for one species- there's also complexity of species to consider from single-cell organisms to sapient creatures, as far as consciousness is concerned.
It depends on how you define consciousness. I define it more along the lines of sentience. You seem to be defining it more along the lines of awareness. Consciousness may be broken down into lesser forms but it comes to a point where it can't be broken down any further because it's very nature is unknown.
I think it's premature to define something like consciousness as non-physical or not an emergent property, simply because nobody knows how it works. The brain has barely begun to be explored in any detail at all, except for much of the causal findings of the brain for personality, memories, mood, senses, and consciousness, plus the ability to fix certain tumors, which large regions tend to do which things, and stuff like that.
I think it's premature to claim that consciousness just arises out of the brain magically out of completely different properties simply because we have evidence that the brain is tied to conscious experience. The brain is simply electrical potentials and neuro transmitters. If these physical properties give rise to what we experience inside, then to me that either
a) matter has astounding aspects to it which give rise to non matter (property dualism)
b) all matter has mind (neutral monism/panpsychism)
In anyway material monism is impossible to defend.
If consciousness exists as something other than an emergent property of the brain, then in your opinion, why is it that if you put a person to sleep for surgery for 8 hours, they will wake up and usually if asked, will say that they had no conception of existence and it felt like they were put to sleep seconds ago. When their brain was partially offline, where was their consciousness in any meaningful form, if consciousness has some independent existence from the brain?
One can argue back that the brain is a filter, which channels the consciousness of the universe into our reality. I don't agree with that notion fully, but then again if you study NDEs and OBEs in enough detail, there are some extraordinary cases where people have conscious experiences for a long time after their brains have no oxygen. The brain is involved in creating what we know as human consciousness, but there might be lesser forms of consciousness as well. For all we know, with anesthesia perhaps we do have a very minimal level of consciousness, incomparable to what we experience now.
