Science has long recognised that every nuance of conscious human thought and experience is embodied in the signals ebbing and flowing in our brains. Indeed, much subconscious or unconscious thought processing goes on of which we are wholly unaware. Dreams represent a kind of halfway state of consciousness. To suggest otherwise is the mark not of the scientist but of the mystic. Technologies such as the electroencephalogram, or EEG, and various modern 3D scanners allows us to monitor and record those signals with ever increasing precision. But philosophers recognise that these objective measurements and subsequent analyses cannot capture one crucial aspect of certain signals, which is the subjective qualities of the experience.
The first and most obvious constituent of a thought is the physical brain in which it occurs. Under the microscope, the fine structure of the nerve connections is revealed as a network of staggering complexity. Further investigation into the workings of living cells show how their metabolism generates waves or pulses of electrochemical activity, which surge through the network in coordinated ways.
These brain waves carry information. In particular they carry semantic or symbolic information, which is to say information about something that is inherently unrelated to the physical character or origin of the wave.
Monitoring these waves, analysing them and talking to the subject about them allows us to deduce their semantic content or meaning, and in this way to correlate specific areas of the brain and signal patterns with specific sensations. By comparing the subjective reports of many subjects under many conditions, we can convert those subjective impressions to an objective statistical database, a generic "mind map". Using techniques such as this, we can not only diagnose medical conditions but are beginning to be able to deduce what the subject is thinking or experiencing before they tell us, to build a telepathy machine and read their mind, no less. We may expect such technologies to continue to advance in sophistication and capabilities.
But there are limits to the science. At the current rather crude level of brain mapping, we consider only bulk processes in significant areas of the brain. The functions of such areas are pretty much constant across all healthy individuals, although gross pathologies may sometimes be revealed. It is relatively easy to build a generic "mind map" at this level, so that a doctor can diagnose a condition or a real-time telepathy machine can refer to it and deduce what the subject is thinking. But that observation can only be as fine-grained as the mind map.
Once you get down into the finer nuances, every brain is different. As the brain grows and learns from its first stirrings, the connections grow individually, driven by an ever-changing combination of nature, environment and chance. The only thing you can do is to stimulate or observe a particular signal in a particular subject and ask then what they feel. And there you must stop. No other subject, no other test condition, can offer further data to build an objectively verifiable mind map. At the microscopic level, there is no objective referent for micro-detailing a personal mind map. So, despite our acceptance of the fact of exact neural correlations between brain signal and experience, we eventually hit a point where science grinds to a halt and we can only take the subject's word for what meaning the signal conveys.
All this is purely objective science, it is not open to question. Some fringe theories seek to embroider and extend it, for example suggesting that microtubules within the nerve fibres might employ nonlocal quantum entanglement phenomena in the mechanisms of memory. But do not mix the science up with the philosophical arguments over free will which tend to motivate these theories. As long as they remain scientifically unproven either way, such theories are very much open to question. But what is still not in question is that the physical aspect of the theory stands or falls solely on the objective science. Any philosophical embellishments must bow to the science.
The subjective element of consciousness constitutes what has come to be called simply "the hard problem" in the philosophical study of the human mind. It seems trite to observe that every conscious brain signal is accompanied by a subjective sensation or experience; indeed, this is what defines the signal as a conscious one. For example every time my objective brain signals it has seen something red, I experience a subjective visual quality of redness. We say that the particular brain signal and the particular experience are "correlates" of one another.
In the past, people tended to associate consciousness with the informational aspects of a thought, as that too appeared to be subjective. The ancient Greek Plato suggested that there was a realm of ideas, independent of our physical world, which we raided when we thought of things. But as neurology, information science and technology have matured, it has become evident that the information aspect is not associated with subjectivity per se. If Plato's ideal realm exists, it is also independent of conscious experience.
The problem is, that no matter how exactly and minutely anyone may describe that pattern of visual information with scientific objectivity, nowhere does the subjective quality of redness appear in that description. Nor does asking me help very much. I will just say, "Yes, it was red", which anybody could have predicted from the brain signal anyway. But what I cannot communicate is what that quality of redness felt like. The conscious experience of that information, of the meaning carried by the brain signal, remains wholly subjective and inaccessible to any scientific enquiry. More specifically, it is the quality of that experience, typically exemplified in the "redness" of a sensation of a red colour. In the twentieth century, CI Lewis (according to Wikipedia) introduced the term "quale" for this subjective quality of experience.
Moreover, no two individuals can communicate their experiences at this deep subjective level. Like me, most people feel an experience of redness when they see something red, but equally they cannot explain its quality to me either. On the other hand, people who are colourblind must experience something else. Worse still, whether you are colourblind or not, there is no way of telling whether your experience and mine are anything like each other's. New Scientist (25 September 2021, p.12) reports on a lady who has no olfactory bulb, the brain's organ of smell. As a child she therefore had no sense of smell. Amazingly, when she grew to adulthood that sense began to appear, smell by smell. She still has no olfactory bulb, some other part of her brain must have taken over the role. She likes curry, but her neural correlate for its smell is wildly different from those of normal folks. Does she experience the same smell, the same quale, as us or a different one? Do even similar neural correlates in different individuals signify similar subjective experiences of it? There is not, even in principle, any way of ever knowing. This yawning chasm, between the physical neural phenomenon and the internal quale of each different person's experience, is the hard problem.
Nevertheless, qualia remain poorly understood by many, both proponents and critics of the idea, for whom the taint of the underlying neural mechanism is conceptually inseparable. Many materialistic scientific rationalists in particular still cling to this naive understanding and seem unable to grasp the distinction. They look at the advances in neuroscience and imagine that, with the information aspect of brain function fully objectified, the Hard Problem of qualia will cease to exist. Anil Seth's aspirational tract on "Illuminating Consciousness" (New Scientist 4 September 2021, pp.44-48) provides a typical example. The more one explains to such materialists the idea of subjective experience as distinct from its objective neural correlate, the more they argue that advances in the study of those neural correlates will eradicate the distinction. That is nonsensical. It is like arguing that the more one describes the head of a coin in detail, the more one is describing the whole coin and ultimately the tail will simply cease to be distinguishable. Quite the reverse is true; advances in mind mapping will only highlight the distinction more and more starkly.
Some people prefer to more directly deny that there is any problem. They see a complete, logical identity between the brain signals and the inner experience: there is no gap because they are just the one thing. And indeed, any good logician will tell you that if two things are, by any applicable yardstick, identical in character, then they must be the same thing. The next step goes that, since inner experience is inaccessible to objective science, the only possible scientific yardstick is the measured brain signal. This signal can then be correlated anecdotally to some imagined quale, but that is just how the brain signal manifests in the mind, it is not something additional or of a wholly different kind. The feeling of redness is just a delusion, it does not exist in reality. Thus, the whole problem is a delusion. But this argument has two major flaws. First, any illusion has its own information structure in the physical world. That structure is real, even though the information it carries up is not. But consider the experience of such an illusion, such as a mirage or a hallucination. The argument then becomes that the conscious experience of the illusion is a second illusion. But that is nonsense; it is the reality of the conscious experience which defines the false perception as an illusion in the first place. The second flaw lies in subtly insinuating the assumption that objective physical reality is the only reality, and using that assumption to argue that, therefore, qualia must be unreal. That is like arguing that the heads is the only real part of a coin and therefore the tail does not exist, it is designed to brush aside any inconvenience to one's entrenched materialism - and, because it does, that proves it is sound logic. However, it is no such thing.
Half a century after qualia came under the spotlight, Richard Dawkins coined the term "meme" for an idea that replicates between human minds, undergoing a process of more or less Darwinian evolution as it does so.
The other day I noticed a curious phenomenon. The main protagonists of qualia have little time for memes. The main protagonists of memes are philosopher Daniel Dennett and psychologist Susan Blackmore. They have little time for qualia, yet are puzzled why their memes are not widely accepted. Memes and qualia are not at all the same thing, so why are both teams so sniffy about each other? Anybody who has ever studied academic philosophy will know that arguments between competing theories often become endless and vicious wars, fuelled more by ego, ideology and rhetoric than by a spirit of open enquiry. I posted about the fringe status of memes a while ago at Why Meme?, and one additional suggestion must be that they are a victim of the qualia wars. Having looked at some of the arguments on both sides of the debate, I find them both equally full of holes, each side constructing straw opponents and demolishing them with glee, while at the same time being wrong-footed by the subtlety of the straw versions of their own theories being thrust back at them from the other side (and note in passing that I am myself hypocritically constructing and demolishing straw philosophers with glee, I like to pose as having at least some professional credentials!).
So if the divide is purely a sociological one, what then of a coherent synthesis?
The scientific view today is that any identifiable experience is associated with some particular physical brain signal called its "neural correlate". Modern brain scanners are beginning to be able to identify such correlates and enable the researcher to discover what the subject is thinking. But "correlate" is a loaded word, it presupposes something that the brain must correlate with, and for some of us that is a presupposition too far. Perhaps one should call them neural signatures, or just signatures for short.
The picture then becomes one of a given thought in somebody's mind, embodying or instantiating a given abstract idea. Any such thought displays two further aspects, neither of which can occur without the other. One is its objective neural signature, the other its subjective quale of experience. Each aspect may be treated as inhabiting its own realm or dimension, one physical and the other experiential. A coin provides an apt analogy. It has two faces, which are inseparable aspects of it. One might in a treatise on numismatism find separate chapters on the heads and tails of coins, treating them as distinct realms of study. But that is not to say that they really inhabit distinct realms of existence, the chapters are just a convenience for the sake of understanding. This suggests to me that the same thing might apply to signatures and qualia, they may be two aspects of thought conveniently divided for the sake of study, but they need not in any way be distinct existential realms.
Where do memes come into it? It seems straight forward enough to say that a meme is an atom or nugget of information, wherever that atom may be found, while a quale is the subjective quality of experiencing that information when it appears in a conscious mind. As I suggested before, most philosophers do perfectly well with thoughts and ideas, they have no need to call them memes. It is only when studying the spread and evolution of ideas in a social context that a Darwinian approach becomes significant and calling an idea a meme becomes a useful reminder of that approach.
I look forward to a day when everybody can focus on the useful bits of each other's theories and work together on taking forward such a richer, dare one say holistic, theory of mind. For example does a thought really have three faces, more like a three-sided die than a two-sided coin, comprising all of idea, signature and quale? I have begun to explore this model in The Three Levels of Being.
Updated 27 Sept 2021