Could somebody clarify why people believe qualia are incompatible with physical models of the mind?

A problem for modern "science"

Natural science deals with quantified data, consisting in physical entities and interactions understood in terms of mathematical mechanics. There are just particles, bodies, forces, motions and collisions, and that's about it. Even perceived qualities are reduced into those terms; light emitting in a certain frequency, i.e. a quantitative category, giving us the sense of red.

But the qualia argument kicks in right there asking: why should it do so in the first place? Why should there be an experience of red, instead of just retina neurophysiochemically reacting to a particular light frequency?

A similar problem with consciousness

A similar argument is made from consciousness! Why is brain activity accompanied by subjective experience of consciousness? Why not just there be neurons firing, and we be just zombies reacting to "cognitive" input without having any subjective experience?—be like robots really!

You see, something way more fundamental is left unexplained all along, and that's the very thing which has always been on the background doing all the observation, scientific work all along: consciousness itself--which is what by the way makes life so meaningful and interesting! So modern science seems to have missed a lot on this question! So in his struggle to understand everything using his senses and analytic mind, modern man forgot about his own self, which is really just consciousness at the core!

Can idealists explain qualia to the contrary? Well, they do but the outcome doesn't seem satisfactory.

Relation between quality and quantity: another hard problem

Scholastics tended to consider qualities, at least some of them, as fundamental, but they didn't reduce quantity to it. They just considered it a separate category (see this). Modern philosophy which pretty much started out with a quantitative outlook to cosmos, took matter, movement and their quantities as fundamental, and reduced qualities to quantities (see this).

But upon reflecting deeper on the relation between quality and quantity, it seems unlikely that reductionism can work either way. As usual with reductionist attempts, what is reduced "keeps hanging there as part of our epistemic experience" which itself needs explanation, and this is just invoking the qualia problem again.

So it turns out that the relation between quality and quantity looks ineffable. Nonetheless, it looks like a reasonable implication to treat both as fundamental but related to one another. A similar solution has been proposed for the hard problem of consciousness: treating it as a fundamental reality. This is a position that fits in well with a theistic/mystical account of reality in which a cosmic consciousness is postulated as encompassing and yet transcending all phenomena. On this account, phenomena of interest to modern science can be understood as determinations of this cosmic consciousness. This is just a rough sketch of an idealist solution. I've elaborated on it a little bit here.

1. Unfortunately you do not present a quote how people express the belief in the title and how they argue for their belief.

   Hence there lacks the basis to discuss the belief of these people.

2. The problem of qualia can be seen as follows: The function of the human brain is information processing. Many of these processes run as unconscious mental processes. On the opposite, a quale is a conscious experience. The underlying process has the additional quality of being conscious.

   The problem is: What is the biological function and the benefit of some mental processes being conscious?

3. This problem is different from a second problem: To harmonize the subjective experience of agency on the basis of conscious decisions with the determinism of physicalism as supposed in neuroscience.

   Possibly that’s the problem you are referring to in your title.

I think the problem lies in your remark

I see no reason why subjective experience would be any harder to encode and manipulate than any other experience.

Any other experience is a subjective experience too. You are aware of an experience or you are conscious of an experience. Any experience. This being conscious of an experience is still something that needs an explanation in physicalism. This is not to say that this explanation is in principle unobtainable under physicalism.

That our brain works like a neural network is clear. We can understand how it works in that we receive stimuli from our environment that results in behaviour. You get cold, you put something warm on. Nothing mysterious here. But the subjective experience of feeling cold that is something that is as of now inexplicable. How can 'feeling cold' result from neurons firing in the brain? There is no known mechanism for that yet.

These experiences are broader than just sensations. You can feel confident that you know the right answer to this question. You can feel confident that you know who you are. You can also feel surprise if you are wrong. You can feel emotions. In the terminology of Hume these were all perceptions. He also included thoughts. We become aware of thoughts that more or less pop up in our brain. We perceive them and we feel that we are the authors of these thoughts. But we have no access to the mechanism of how these thoughts were produced, so in a way we perceive them. We become aware of them.

All these experiences are just as subjective as seeing the colour red. They are part of our internal world and they make it feel as if the lights are on.

What is so marvellous about consciousness is not so much that it exists (we have just a tricky a problem with why is there not nothing), but how it exists alongside "unconscious" processes. So you have the problem then of how the experience of conscious pain is generated by the brain, and then you have the question of why the brain generates any subjectivity whatsoever (pain, pleasure, desires, tastes).

Buddhists have some cosmogony whereby disembodied spirits become material via, IIRC, acting on their sense desires, but of course this is the wrong way around for physicalists, and an explanation of why our brains create minds would surely need to, as well as be entirely naturalistic, not step beyond physical processes, just as scientific explanation need not add anything to the mythopoetic (and then the god saw an electron).

I would consider it solved by science alone not when we can say why consciousness is evolutionarily adaptive, maybe when there is a mature science of consciousness making novel empirically supported predictions as to when consciousness can arise. It is plausible that's impossible.

Some explanations, such as an account for subjective experience, seem baffling when incomplete. But then I assume there is no KO argument for there being a hard problem.

There is no colour in the physical universe. There are only wavelengths of light.

The science of physics measures light of 750 nanometers. But you see red.

If we open up your skull, there's no "redness" in there.

So where does the redness exist?

And where is the "you" that is doing the "seeing" of the redness?

There may symbols and signals of redness in the physical universe, but redness as redness does not exist there.

So there must be a non-physical subjective "universe" of some kind.

Decouple the hard problem from determinism

Determinism/indeterminism is a different question than the hard problem. Physics is indeterministic. And both organisms, and our brain module, are both chaotic systems, which can therefore amplify small random inputs to the point of unpredictability. So a physicalist mind should be expected to be indeterministic. Whether a non-physical mind is or isn't indeterministic would depend on the details of how the non-physical ontologies work. But it is very possible a non-physical worldview would be deterministic, while physicalism would be indeterministic.

The things in our observed world are contingent so whether physicalism can explain consciousness is an empirical question

The radical contingency of our world means that we cannot evaluate physicalism vs. consciousness with intuition or rationalism. Physicalists deny there is an independent or causal Popperian world 2 (world of things that have time but no space, such as the way experiences and consciousness appear to us). As a general rule, in physicalist mind theories this is done with Identity claims between some non world 2 aspect of our world (neural states, functions) and consciousness. Critics of these theories note they fail the "identity of indiscernible" principle of identity, so should instead be treated as a "there is some fixed coupling between the non-world 2 feature X and the apparent world 2 feature Y".

The problem for physicalism is failing test cases

The hard problem is that the properties we have observed for consciousness have proven unable to be matched with a physicalist model. All physicalist identity theories have refuting test cases, primarily where consciousness is not present on occasions the model would predict it should be present. Some of these identity theories also predict no consciousness where consciousness is present. Also, as the contingent "just happens to be tied together" aspect of "Identity theories" rather than actual identity, means they logically map onto epiphenomenalism causally, and the causal refutation of epiphenomenalism therefore also applies to the "happen to be coupled" theories. Therefore Identity theory models fail the evolutionary test case which William James articulated against epiphenomenalism, and Karl Popper extended to identity theories.

Examples of falsified test cases

The earliest physicalists were neuro-reductionists Identity theorists. They assumed that conscious states were identical to a certain energized state of a specific neural structure. This identity came under attack through multiple realizability. Our own neural structures undergo continual rebuild, die-off of cells, and the energizing pattern moves around drastically and continually -- yet our thoughts and knowledge stay pretty stable through all this tumult. Additionally, we can communicate thoughts to others, who have very different neural structures, and other creatures can also do what clearly is equivalent thinking (say counting, or an effort to deceive showing theory of mind) despite even more radically different neurology. Within our own thinking, the "logic state" has to be maintained as a homeostasis by a brain, and therefore the logic condition becomes a causal driver of changes in the neural state. Additionally, while we built our digital computes based on our introspection of how we consciously reason, there is no digital computer architecture anywhere in our brains. Reasoning explicitly cannot reduce to neurology, based on what we discovered about how our neurology is wired. The criticality of logic sates and functions to how we do homeostasis, how we communicate, and why we think other creatures are conscious, and the ability to describe reasoning functionally, are why most physicalists have switched from neural identity theory to functional identity theory. If one maps this to Popper's 3 worlds, this is a world 3 coupling to world 2, as opposed to a world 1 coupling.

Paul Churchland, one of the remaining neuro-reductionists, asserted that conscious just IS our recursive neural nets processing. However, ALL of our brain processing is the operation of recursive neural nets, and 99.99% of that processing is not conscious. Churchland's model is easily falsified by the simplest of observations.

Functional identity theory has a very similar problem to Churchland. 99.99% of the functions our brains perform are unconscious. Plus it has another problem, in that all sorts of other things do functions, but do not appear to be conscious.

AI theorists initially addressed why their computers were not conscious despite doing functions, by postulating that some additional feature, such as through put rate, was necessary for the coupling between functions and consciousness to emerge (an emergent throughout could also explain why leaves waving in the wind, and rocks breaking apart were also not conscious). But after many orders of magnitude increase in our computer speed, with no consciousness appearing, this idea has been abandoned as refuted.

Alternate theories have been proposed. One such is that only functions that self-reference -- higher order processing -- could be conscious. But sit on a mislaid pin, and one is VERY aware of the pain and leap back to one's feet, well before one starts doing any higher order processing about it! Alternatively, Global Workspace Theory holds that the shared data between processing modules is what we are conscious of. But GWT would hold us to be conscious of driving, and NOT of daydreams, but all of us who drive have at times gotten lost in daydreams WHILE driving! Integrated Information Theory holds that only functions which run on a high Phi network are conscious -- but again ALL of our brain's functions run on the same high Phi network, but 99.99% of them are not conscious.

Many of the philosophic thought problems that have driven philosophy of mind in the last several decades have focused on qualia, as qualia are non-functional in functionalism, and are therefore a challenge to functionalism. Mary the Color Scientist gains knowledge when she finally has a color experience. Whether one's experiential spectrum is inverted or not is a "fact of the matter" but cannot be established functionally or neurologically. The Chinese room can do the function of communicating in Chinese, but there is no qualia experience of knowledge of Chinese in it. These all are test cases against functionalism.

These problems for physicalism have led to the rise of "Delusionists", who hold that physics tells us physicalism must be true, so if consciousness data refutes this, then consciousness data must itself be in error -- a delusion. See Susan Blackmore's A Very Short Introduction to Consciousness for a very clear argument for throwing out consciousness data on these grounds. This is, of course, to reject science, as in science data is king, and theories (such as physicalism, dualism etc) are what one throws out when data contradicts them, not the other way around.

Where is the philosophic community on physicalism?

Among philosophers of mind, there are advocates of every one of these physicalist views, who argue that THEIR version of their preferred model stands up to these refuting test cases. As a general rule, however, each of these claimants has not been able to convince even their physicalist rivals. So while physicalism remains popular, there is a wide consensus within philosophy that every specific attempt to address the hard problem of consciousness has failed, even though most physicalists may think THEIR approach works.

Note that all theories are capable of being "vagueified" to the point when they are not testable/refutable. Vaguification is also done by many physicalists who admit that specific physicalist theories are unable to address the failing test cases. Vaguification is also often coupled with the "someday somebody may find an answer" embrace of the Duhem-Quine thesis. Duhem-Quine IS True -- every theory is infinitely modifiable, hence someday someone may find a way to make physicalism compatible with consciousness. But empiricists don't resort to Duhem-Quine, and instead use the models that actually fit the data. Rejecting empiricism based on the Duhem-Quine "maybe someday" is always possible. But it is to reject science, because one can resort to Duhem-Quine to reject every science theory as well.

Vaguification, and invoking Duhem-Quine, can be appropriate if there are no good alternatives to an otherwise useful theory. Physicalism IS useful -- that was Papineau's point in his excellent paper "The Rise of Physicalism". But the limits of reductionism, the reality of emergence, the adoption of scientific pluralism, and the widespread rejection of scientism are all subsequent to "The Rise of Physicalism", and suggest that physicalism is a useful heuristic, but not a global Truth -- decreasing the strength of the argument for ignoring a failing test case.

This is why alternative ontologies have increasingly been considered as live options in philosophy:

• Fregean triplism.

• Scientific pluralism.

• Popper's emergent dualism.

• Eccles substance dualism.

• Property dualism.

• Russellian monism.

• Various pan-psychisms.

• Mathematical idealism as with Tegmark and Hoffman.

• Mental idealism as in the Perennial Philosophy.

The spectrum of live options to physicalism has opened dramatically in the last several decades among philosophers.

Three cents and some..

The hard problem of consciousness (Chalmers)(1) is nothing but the recognition of the explanatory gap, that stems from the inability of a theory that, according to some, is supposed to be already a complete and final description of physical reality, based on current physics (what Strawson calls physicSalism in contrast to physicalism), to account for the most basic of facts, conscious experience.

Qualia is the term used to denote the what-it-feels-like quality of conscious experiences that is, up to now, left unaddressed in that context.

There is no denying of the explanatory gap so far. But this does not necessarily mean that theories like Cartesian dualism are the only option, and that conscious experience cannot be physical, in some sense.

In this sense, Strawson (2) has argued that experiential phenomena are given and must be addressed. Emergence, as postulated by some approaches, shows Strawson, can only work for some properties, not any conceivable property can be emergent (eg length cannot emerge from lengthless processes). In this sense, he investigates conditions for experiential phenomena to be able to emerge from wholly non-experiential phenomena, and it turns out that either conditions for emergence to happen cannot be satisfied, else one can only invoke emergence as a miracle.

It is concluded that consciousness cannot emerge, it must be there already, irreducible and primitive. In this sense, physicalism (about experiential phenomena) entails a form of panpsychism. Panpsychism is one physicalist answer to the hard problem, since conscious experience is an aspect and part of the physical. Loosely speaking, "panpsychism" can be seen as a more plausible form of "emergence", in the sense that various types and levels of consciousness emerge, evolve and arise out of more basic and primitive types of consciousness, from extremely basic and primitive types, rather than out of nothing not even remotely resembling experiential phenomena (see above).

Finally, the question of determinism is a different matter. Current physics are not completely deterministic, and, on top of that, consciousness would be a rather useless artifact with no place in a completely deterministic world. In any case, determinism is not necessary for physicalism to address conscious experience.

References:

1. "Facing Up to the Problem of Consciousness", David J. Chalmers
2. "Realistic Monism: Why Physicalism Entails Panpsychism", Galen Strawson

Frank Jackson defined qualia as "certain features of the bodily sensations especially, but also of certain perceptual experiences, which no amount of purely physical information includes". Philosophers such as Jackson believe that there is something in the red glow of a sunset, the taste of wine or the pain of a headache that no description in purely physical or neurological terms can capture.

For physicalists (such as Daniel Dennett) there can be no attribute of sensation or experience that is outside of a physical or neurological description of the sensation/experience. From that point of view qualia - a non-physical attribute of a physical sensation - are a contradiction in terms and therefore cannot exist. And arguments against physicalism that are based on the unquestioned existence of qualia are circular and therefore ineffective.