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Thoughts on the Hard Problem

Last updated on 1 Jul 2020

Most of you will already know that David Chalmers, the once-hirsute Australian philosopher of mind (only Rob Wilson seems to remain in the Hirsute Philosopher’s Club these days. God knows I never was) proposed what came to be known as the Hard Problem of Consciousness:

The really hard problem of consciousness is the problem of experience. When we think and perceive, there is a whir of information-processing, but there is also a subjective aspect. As Nagel (1974) has put it, there is something it is like to be a conscious organism. This subjective aspect is experience. When we see, for example, we experience visual sensations: the felt quality of redness, the experience of dark and light, the quality of depth in a visual field. Other experiences go along with perception in different modalities: the sound of a clarinet, the smell of mothballs. Then there are bodily sensations, from pains to orgasms; mental images that are conjured up internally; the felt quality of emotion, and the experience of a stream of conscious thought. What unites all of these states is that there is something it is like to be in them. All of them are states of experience. [Chalmers 1995]

This Hard Problem (the capitals are now de rigueur) is not well defined, though. Nagel’s “what it is like” [to be a bat] presupposes that there is something it is like to be that bat, Chalmer’s problem of experience presupposes there is something that is experience, independent of a physical description of the functioning of the organism. A similar point was made with Frank Jackson’s “Knowledge Argument” (another Australian!): there is some information had by experiencing red that is not encapsulated in knowing all about the physiology and physics of seeing red. The Hard Problem is really the Experience Problem. Experiences in the non-physical sense have a technical term: qualia.

These presuppositions are automatically assumed to be real; after all, we all have experiences of the world, of being ourselves and not someone else. We all have a phenomenologically unique state of awareness of ourselves. Nobody could deny their reality, right? Hold my beer…

I want to suggest three things:

  1. There is no reality to these experiences
  2. They are just names for perspectives
  3. Substantive nouns for processes is where we get confused

Let’s start with a simple case: perspective.

I have a different perspective of the room than you, sitting next to me, do. There is a what it is like to see the room from my position, and another from yours. But there is nothing mysterious about this: it is a matter of geometric states. You can move into my position and see what it is like to see the room from my perspective. This may be a quale (the singular of qualia) but it is obviously not Hard to explain. There is no irreducible quality here. The perspective does not exist apart from the physical room, and I do not experience it in ways that are not physiological (as Chalmers note for other aspects of awareness in his 1995). A digital camera can “experience” that perspective, if by experience we mean that it processes information gained sensorily at that locale and aspect.

Now at this simple end of the spectrum of consciousness problems, there is little (in-principle) mystery, although the neurological details may elude us for a long time. Why, then, at the other end of phenomenological uniqueness, do we presume there is some thing that needs to be explained, and that there is an in-principle problem that will always evade physical explanation?

In recent years this axiomatic presumption of the specialness of qualia, the qualitative ness of consciousness, has led to the revivification in philosophy of a view that I had thought long buried: panpsychism. This is the view that mental phenomenality is a fundamental property of the natural (physical) world, not covered in the laws of physics. I find it so absurd a view that it requires a diagnosis of its etiology, as a medical person might say. And as that person might also say, it is iatrogenic: caused by the very treatment given to cure the problem.

When Hume considered the idea of selfhood (personal identity), a related topic (and ultimately the very same issue as qualia), he wrote:

There are some philosophers, who imagine we are every moment intimately conscious of what we call our SELF; that we feel its existence and its continuance in existence; and are certain, beyond the evidence of a demonstration, both of its perfect identity and simplicity. The strongest sensation, the most violent passion, say they, instead of distracting us from this view, only fix it the more intensely, and make us consider their influence on self either by their pain or pleasure. To attempt a farther proof of this were to weaken its evidence; since no proof can be deriv’d from any fact, of which we are so intimately conscious; nor is there any thing, of which we can be certain, if we doubt of this.

Unluckily all these positive assertions are contrary to that very experience, which is pleaded for them, nor have we any idea of self, after the manner it is here explain’d. For from what impression cou’d this idea be deriv’d? … It must be some one impression, that gives rise to every real idea. But self or person is not any one impression, but that to which our several impressions and ideas are suppos’d to have a reference. If any impression gives rise to the idea of self, that impression must continue invariably the same, thro’ the whole course of our lives; since self is suppos’d to exist after that manner. But there is no impression constant and invariable. Pain and pleasure, grief and joy, passions and sensations succeed each other, and never all exist at the same time. It cannot, therefore, be from any of these impressions, or from any other, that the idea of self is deriv’d; and consequently there is no such idea. [A Treatise of Human Nature (1739), I. IV. VI: Of Personal Identity, 436f]

In other words, the evidence adduced to support the idea of a unique unitary self fails to do so. I believe that is also true of the notion of consciousness. We are conscious (whatever that may mean – I have something to say about this later) beings, to be sure. The term is designed to name what we are, so it is true by definition. But is there a property, a natural thing or type of thing, that is consciousness? Does the name imply the thing? That is a classical philosophical error (made not only by philosophers): hypostatisation. This is the making of a physical thing to agree with an abstract term, and the usual reason is that the term is anointed by tradition and habit.

When we come to identify and delineate qualitative experiences (as opposed to the pared-down definition I gave above), we find it very hard, if not impossible, to do so. I cannot describe exactly the experience of redness, bat-ness or me-ness. In fact I can only point to the thing that has these experiences and the conditions in which they are had. Now a problem needs to be specified in order to be solved (or declared insoluble). Ineffable problems are, I suggest, not problems at all. If they cease to be ineffable, then they may become soluble, but if you cannot even tell me what it is that is supposed to be problematic, I think there is a failure of reasoning at that point.

So, we think that there is a substantial issue with consciousness not because we have a specified problem set, but because we think our individual experiences are somehow to be treated as properties of the universe (hence panpsychism). But giving the name conscious to behaviours and capacities for information processing in embodied neural systems does not automatically imply the reality of the substantive notion consciousness. If something behave like a conscious thing, it is conscious, and if that thing is a philosophical zombie (with no awareness of inner states) then it is still conscious (and incidentally, if I am right about the unreality of those inner states, we are all p-zombies. There are no p-angels).

Humans tend to project their attributes onto the world around them: agency, spiritual attitudes, even, in extreme cases, our bodily shape (see also here). We call this anthropomorphism, and it is regarded as a failure to properly transcend our own biases when dealing with the world. It is my view that this hypostatic view of being conscious and the subsequent invention of entire metaphysical domains beyond the physical is what Hume would have called a “vulgar error”. We put, as the old joke has it, Descartes before the horse.

Moreover, I do not think, as many seem to do, that dualism is the default view of people everywhere. Apart from the fact that “soul” never had the post-Platonic notion in Hebrew Scriptures – ruach, which is translated as “soul” in the Tanakh, means “breath” or “wind” based on the shared west semitic view that life was a physical thing – similar ideas predate Vedantic religion (the Lok?yata school) in the Indus Valley. Arguably, physicalism of a sort is the default view, and dualistic views of mind-body need an elaboration of doctrines in larger religious-philosophical contexts.

So I think that dualistic metaphysics are, basically, category errors. Whatever the motivations, they are due to mistaking signs for things signified, thingifying nouns with -ness suffixes. As Wittgenstein wrote

Philosophy is a struggle against the bewitchment of our understanding by the resources of our language. [PI §109]

What is it like to be conscious?

So, what are our experiences, and why are they unique? Why are there phenomenologically unique states of awareness? What is it like to be me or a bat or some other conscious thing like HAL9000?

To consider this, we must first ask what it is to be conscious. This is no ordinary question – you’ll get different responses if you ask a cognitive psychology, a social psychologist, a physicalist philosopher, a phenomenological philosopher, and so on. And then there’s the “naive” or vulgar view; the one that nobody can clearly articulate. I feel, therefore, no shame in taking my pared down view above as a minimal account of what it is like to be conscious: it is to receive information from your body and environment, process it, create a map of the world, and use it to inform and motivate actions. The crucial part is “create a map”. We are aware of the world by making models of it, and that includes of our “selves”.

Of course, there is more to experience than models. We also have affects: defined by Merriam Webster as “the conscious subjective aspect of an emotion considered apart from bodily changes”. An aspect of experience is to say there is something that the bearer of the emotion or feeling uniquely has. And of course every individual system, whether it is a dualistic system or a monistic system, has a unique aspect or two. That is what defines an individual. My experience of pain is mine simply because it occurs within my neural system; its properties are the properties of my system. Just like a perspective in vision, it is uniquely defined by my physical properties, and my location and history (of development). There is simply no need to posit an entire metaphysical realm other than these to “explain” my feelings of pain or pleasure. That is beyond onerous.

And in what way would a “mental” or “spiritual” realm do any explaining anyway? So far as I can tell, it is simply a “dormative virtue”, using different terms to express ineffable causes. In short, it simply restates what we already know, that there is an individual aspect to individual aspects, in more portentous terms.

And finally, what is it that unifies experiences of pain, shame or any other experience? Obviously there is some commonality in the physiology of experiential systems (although what I might use to be in pain would be wildly different to what an artificial person, or even a cephalopod, might use), and of course there is the behavioural side of it (aversion and distress behaviours), but that is not enough, and here, I think, we find the second main philosophical error perpetrated in these debates.

To illustrate, let me recall Alfred Russel Wallace, coformulator of natural selection. Wallace was at first a hard naturalist (in the philosophical as well as the then-current biological sense). But he had a problem:

A brain slightly larger than that of the gorilla would, according to the evidence before us, fully have sufficed for the limited mental development of the savage; and we must therefore admit, that the large brain he actually possesses could never have been solely developed by any of those laws of evolution [The Limits of Natural Selection as Applied to Man (1870), 343]

In other words, given that selection is all about survival, and gorillas survive (that dated well), we cannot give a naturalistic account of our mental faculties, and so it must be Spirit. Darwin’s reaction was barely masked horror:

I hope you have not murdered too completely your own & my child. [Letter to Wallace 27 March 1869, meaning the theory of natural selection]

When I first read Wallace’s argument in Contributions and other sources (1870, 1889), I was struck how, if one substituted “Society” for “Spirit”, one got a nice argument for what has come to be called the Machiavellian Hypothesis of human encephalisation (Dunbar & Shultz 2017) [Wallace’s error is to think that selection is about individual survival, not reproductive success overall, in my view]. And this presents a clue to what makes fear and shame those emotions and not something else when the underlying physiology diverges: it is because they play social roles that are categorised on various criteria but for social purposes to be so classified. Society makes all cases of seeing red the “same”, as well as all other mental categories.

But given Wallace’s cultural (not to mention developmental and education) milieu, he was led to posit something that I think is onerous but which culturally we think is a live option: that metaphysical profligacy I mentioned above.

The so-called “explanatory gap” (Levine 1983) is an illusion, I think, based on some assumptions that are simply not justified. I can be conscious without there being “consciousness”, and I can have a unique experience without there being “qualia”. And most of all, I can be “like me” without there being a “what-it-is-like”. So to answer Nagel’s question-begging question: To be like a bat is to be a bat.

[A friend once called me a “club-footed physicalist”. I am proud to wear that epithet.]


Chalmers, David J. 1995. “Facing up to the Problem of Consciousness.” Journal of Consciousness Studies 2 (3): 200–219.

Dunbar, R. I. M., and Susanne Shultz. 2017. “Why Are There so Many Explanations for Primate Brain Evolution?” Philosophical Transactions of the Royal Society B: Biological Sciences 372 (1727).

Hume, David. 1739. A Treatise of Human Nature. Vol. 1. London: John Noon.

Levine, Joseph. 1983. “Materialism and Qualia: The Explanatory Gap.” Pacific Philosophical Quarterly 64 (4): 354–61.

Nagel, Thomas. 1974. “What Is It Like to Be a Bat?” The Philosophical Review 83 (4): 435–50.

Wallace, Alfred Russel. 1870. Contributions to the Theory of Natural Selection: A Series of Essays. London: Macmillan.

———. 1889. Darwinism: An Exposition of the Theory of Natural Selection, with Some of Its Applications. London: Macmillan.

Wittgenstein, Ludwig. 1968. Philosophical Investigations. Repr. of [3rd ed.] English text, with Index. Oxford: Basil Blackwell.

Featured image from The Basic Theory of Mind.


  1. I mostly agree with your take on this. There are a few places where I could quibble, but I won’t.

    Nagel asked “What is it like to be a bat”, but you have changed that to “What is it to be like a bat”. I’m guessing that Nagel would not approve of that change.

    When I think of The Hard Problem, I always suspect that those proposing the problem really want the design plans for a conscious computer-based robot. And you have not come close to providing that.

    My own view is that a conscious robot cannot be designed. As I see it, a conscious system can arise from evolution, but not from design.

    • What I gave was my answer to “what it is like to be a bat”: “To be like a bat is to be a bat”. But I take your point.

      Of course I haven’t come close to giving a Hard Problem design. I’m saying that HP is ill-formed. But while I am open to the claim only evolution can make a conscious being, I do not see why that must be true. Or do you include cultural and scientific evolution in that?

    • Discovered Joys Discovered Joys

      My slightly tongue in cheek observation is that we already have designed conscious robots. My dishwasher alters the length of various stages of the wash programme according to sensors like turbidity of wash water and temperature of the cold water supply.

      Now admittedly my definition of ‘conscious’ is remarkably loose but that is a good part of the Hard Problem – people really don’t say clearly what they are talking about and so biases and assumptions creep in and we end up begging the question.

      I often use the Centre of Gravity as a way of thinking about things. It doesn’t exist as a concrete object, it is an abstract idea and cannot be found, yet it can be useful to observers. Perhaps consciousness is the same, an abstract idea that is useful but cannot be found. Asking what is it like to be an abstract noun is hard – because it is not meaningful.

      • And that is exactly the issue with hypostatisation: abstract things are not causal.

  2. A designed system will be built to meet the needs and requirements of the designer. An evolved system will evolve to meet needs of the system itself. And I see that as an important difference.

    In a way, you are probably saying something similar. The way consciousness looks to the conscious organism itself is different from the way it looks to the third party observer.

    • Clem Stanyon Clem Stanyon

      So what’s to stop AI from evolving? It will then be as conscious as the system in which it evolves; the closer that is to reality, the more human-like a state will its consciousness evolve to become. The major failure of AI in the latter years of the 20th century was due to rule-based systems – designed systems – and the major breakthrough of the current round of AI development has been the use of statistical sampling algorithms. This is much the same way that babies learn what is language and what is noise.

  3. davidlduffy davidlduffy

    This is all 100% correct 😉

    Re “dualistic views of mind-body need an elaboration of doctrines”, Popper points to the fact that “a magical transformation of the body, a metamorphosis which leaves the mind unchanged, [is] one of the oldest and most widespread topics of fairy tales and folklore. In [the Odyssey], almost the oldest extant literary document of our Western civilization, it is explicitly stated that the magical transformation of the body leaves the self-identity of the mind, of consciousness, intact. The passage, in the tenth book…, describes how Circe smote some of the companions of Odysseus with her wand: ‘They had the head, and voice, and bristles, and the body (demas) of swine; but their mind (nous) remained unchanged, as before. So they were penned there, weeping.’ Clearly, they understood their frightful situation, and remained conscious of their self-identity…the conscious self is not an artefact of Cartesian ideology. It is the universal experience of mankind, whatever contemporary anti-Cartesians may say…”

  4. Michael Fugate Michael Fugate

    I remember a computer programmer who styled himself a philosopher, who commented on Jason Rosenhouse’s old blog, and who floated the analogy of the brain as a radio receiver and the mind as a radio broadcaster. Somehow your brain was tuned to one special individual mind channel. Dementia was a receiver error and multiple personalities was too. This allowed the mind to live on without a body. No known means of broadcast was mentioned, but tinfoil played a role somewhere.

    David, doesn’t the same occur during development?

    • davidlduffy davidlduffy

      Hi Michael – “the same during development”?

      If one is a functionalist, so that multiple realization can occur, then one would also think some kind of uploading should be possible, so one can be that kind of dualist without needing the supernatural.

      It would be a pretty funny receiver error that led you to repeat yourself when concussed, or cause hemi-neglect for recalled imagery (eg – you can only remember the buildings on your imaginary left, including after you perform a 180 degree mental rotation. I reckon these entail that the soul at the least has to rely on the brain to store all memories (except the Forms, of course).

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