The mind only exists in the mind?
The intuitive notion of "mind" exists only in the physical manifestation of the mind.
Or to put it (perhaps) more clearly: the only reason we think dualism exists is because our (non-dual) brains tell us so. Like beauty, it's in the eye of the beholder.
Our judgment of whether something is intelligent or sentient is based on an opaque weighing of various sensory criteria, that tell us whether something is likely to have intentions of its own. We start out as children thinking that almost everything has this intentional quality, and gradually learn the things that don't.
It's as if brains have a built-in (at or near birth) "mind detector" circuit that triggers for some things, and not others, and which can be trained to cease seeing certain things as minds.
What it doesn't do, is ever fire for something whose motions and innards are fully understood as mechanical - so it doesn't matter how sophisticated AI ever gets, there will still be people who will insist it's neither conscious nor intelligent, simply because their built-in "mind detector" doesn't fire when they look at it.
And that's what people are doing when they claim special status for consciousness and qualia: elevating their genetically-biased intuition into the realm of physical law, not unlike people who insist there must be a soul that lives after death... because their "mind detector" refuses to cease firing when someone dies.
In short, this intuitive notion of mind gets in the way of developing actual artificial intelligence, and it leads to enormous wastes of time in discussions of dualism. Without the mind detector -- or if the operation of our mind detectors were fully transparent to the rest of our mental processes -- nobody would waste much time on the idea that there's anything non-physical. We'd only get as far as realizing that if there were non-physical things, we'd have no way to know about them.
However, since we do have an opaque mind-detector, that's capable of firing for the wind and the rain and for memories of dead people as easily as it does for live animals and people in front of us, we can get the feeling that we are having physical experiences of the non-physical... when that's a blatantly obvious contradiction in terms.
It's only by elevating your feelings and intuitions to the level of fact (i.e. abandoning science), that you can continue to insist that non-physical things exist in the physical world. It's pointing to reality and saying, I feel X when I look at it, therefore it is X.
(A bit like the religious fundamentalists who say that they feel icky when they see gays, therefore homosexuality is disgusting.)
(A bit like the religious fundamentalists who say that they feel icky when they see gays, therefore homosexuality is disgusting.)
I would have said, "A bit like philosophers of free will who say that they feel like they could have done something else, and therefore determinism must be false". (:
...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.