In this short paper my purpose is to understand how the word ‘qualia’, plural of ‘quale’, is used and to what exactly it refers. In addition I address the question of the phenomenon’s importance.

Qualia are associated intimately with brain states, and never occur in their absence. It is a fair bet there is some corollary brain state (sets of brain states) associated with every quale and the collection of them. It is also the case that, while normally associated with sensory apparatus, it is possible to invoke qualia, even a specific quale like “a flash of red light”, by “poking the brain” direct. What is mysterious about this is that poking the brain (or stimulating a living organism’s more conventional sensory pathways) does something that poking anything other than brains never does. It invokes, a “subjective experience” qualitatively different from the physical qualities either of the brain or of the source of sensory stimulation.

The sound of a middle-C note from a piano is a quale as is the different sound (thanks to harmonic frequencies) of the same note played on a violin. Each is a particular quale. What seems interesting is producing that note from either instrument, the motion of air molecules set up by the vibrating strings, and everything that happens between the instrument and the middle ear is mechanical. Mechanical energy converts to electrochemical energy in the auditory nerve and spreads in that form through the entire brain. From instrument to brain everything is uncontroversially physical and well understood. But what emerges, what is invoked by all of that physical process, a content of subjective experience, is not uncontroversially physical. It has qualities that none of the physical forerunners have. What is it exactly, and how is this possible in a physical universe of causal closure where physical causes have only physical effects? Those questions make qualia interesting.

In a sense, and this is only metaphor, it is as though a threshold is crossed. On one side a certain combination of purely physical (mechanical [hearing], chemical [taste/smell], electrostatic [touch], or photonic [vision]) energy (yes even the physical poking of a brain) is translated or transformed into a subjective experience whose qualities or properties share nothing in common (other than correlation) with the physical properties of their source. The mystery has nothing to do with the transformation’s necessary dependency on a functioning brain. Rather it is that this sort of transformation happens at all; that physics becomes subjective.

Sound, light, feel, smell, taste are all mind-dependent descriptions of phenomena, that in the mind-independent world are nothing but energy of one kind or another. If I say “I see light” we have always to remember that in mind-independent terms, there isn’t any “light”, only “electromagnetic radiation”. The latter is real and exists in the universe whether there are organisms with apparatus sensitive to it or not. Electromagnetic radiation only “becomes light” to a subject. Information bearing patterns in brain states are translated (mapped), via pathways beginning with sensory apparatus, into an “interior experience”. “The light” is that mapping!

The subjective gestalt is composed of qualia similar to the way particles of the Standard Model comprise the mind-independent world. The particles collect in special ways to form atoms while the atoms (sometimes in special states) aggregate to produce everything else. Some of the phenomena of the mind-independent world impinge on certain “biological sensors” associated with brains. Not all mind-independent phenomena impinge to trigger biological sensors. Neutrinos do not, nor photons outside a limited range of wavelengths.

The subjective arena is broader than qualia alone. Intentions, beliefs, emotions, memories, ideas, and so on are not qualia. Qualia comprise only the sensory modalities of the gestalt (and sometimes the effect of brain pokes). Unlike atoms, there are genuine mereological sums of qualia that is itself a singular quale.

The qualia arising most directly from our physical senses, “atomic qualia” like a particular red experience, sum mereologically to a unified gestalt experience, the sensory ingredients of the subjective arena of which we are conscious at any given moment. Nor at any moment is the arena an equal mix of all sensory impingements of which we are aware. If I am driving I am aware of the feel of the wheel in my hands, the pressure of the gas pedal on my foot, the sounds around me and the aroma of the hot pizza on the seat next to me. But I am, for good reason, focused on the visual scene in front of me. My gestalt includes all the sensory modalities of which I am aware, but as I focus my attention on what I see, qualia arising from sight dominate my arena in that moment.

The relation between separate sensory impingements is constantly changing but the effect, subjectively moment to moment, remains always singular. All this singular arena, taken synchronically, is also properly called a quale. By contrast, the mind independent world is particularized. Yes there are aggregates there, but they too are particular instances of their types. Planets and chairs are aggregates of atoms, but they remain, mind-independently, particular planets and chairs. That they are particular totals is recognized in the subjective interior thanks to the distinguishable qualia they invoke (via brain states) and their summation to the interior gestalt. The mind-independent world is essentially particular, while the subjective arena, under normal circumstances, is intrinsically unified.

None of this usage hangs on any particular theory of or philosophy of mind though it does implicitly reject eliminative materialism. It requires only that the word qualia refers to something, not nothing. That something, that to which we give the label ‘qualia’, is both the individual and totalized sensory modalities of our moment by moment experience. If, apart from qualia and besides intentions, thoughts, and so on, there is a “subconscious mind” and perhaps even an “unconscious mind”, there are no subconscious, let alone unconscious, qualia. A sensory experience isn’t a quale unless one is aware of it!

Qualia are nothing like examples of “emergent phenomena” one meets in the science and philosophy literature, for example the relation between statistical mechanics and thermodynamics. Statistical mechanics is about the motion (and density) of atoms; uncontroversially physical. Thermodynamics, temperature and pressure language, frames “another way” to talk about the same phenomenon. Mathematically, one can demonstrably map one into the other.

Qualia certainly rest on the “motion of atoms” (a synecdoche for simplicity’s sake), not only those that stimulate the sense apparatus, but throughout the brain. There is surely a causal relation here. Yet it is not obvious that “qualia language” is merely another way to talk about brain states. Not only has no one connected them mathematically, no one has suggested what the equivalence conditions might look like. David Chalmers, for example, speaks of “bridge laws”, but in several books on the subject has not suggested just how such laws would be subject to equivalency demonstration on either side of “the gap”.

The brain is a species of portal (a metaphor) made of the same stuff as all the mind-independent world. Some of the phenomena of the mind independent world are able to impinge on the portal in such a way as to invoke, a subjective viewpoint, qualitatively different from the electromagnetic, mass-possessing, stuff underwriting it; something, the subjective experience, that isn’t composed of atoms at all! Consider that my experience of red exhibits no third-party measureable quantity despite being the product, a mapping, of electromagnetic energy!

Of course the brain state correlate grounding the quale exhibits energy, even producing heat. But there is no physically measureable quantity on the subjective side of the portal! Brains translate, map, or convert energy of the mind-independent world into subjective experience which, as such, exhibits no energy utilization over and above that energy accounted for in the activity of brains; activity of atoms that hasn’t the slightest resemblance to its mirror on the other side of the curtain.

So why, as philosophers, should we pay any attention to qualia, brain states being obviously necessary and possibly (less obviously) sufficient for their appearance? Supposing we eventually learn exactly which brain states evoke every specific quale of the subjective gestalt, wouldn’t that constitute “knowing enough”? The problem is two-fold. First qualia do not have any of the measurable properties of brain states. At the same time, they do have properties of their own sort. If I ask a philosopher or physicist “to what does the word ‘qualia’ refer?” few would say “nothing”. But if not nothing, then what? My subjective experience of a color, or of my moment by moment phenomenal arena is not “made of atoms” even if it is a specific material organization, living brains made of atoms, whose activity is responsible for them.

Second, doesn’t this phenomenon smack of mystery “begging for explanation”? Why is the quantum mechanical “measurement problem” interesting? Why do we try so hard to understand what is going on? Something is going on about or in the “quantum world” that becomes counter intuitive when it emerges into the macroscopic. We’d like to explain how this transition works and why it comes out in the particular way it does. But we cannot and the most pedestrian of the fundamental reasons for this is that our instruments cannot get there! We cannot probe the quantum world directly. Why is the proton/electron mass ratio interesting? Why does it beg for explanation? Because it is unique and uniform. Every proton throughout the universe weighs the same as every other proton and mutatis mutandis for the electrons. It is that singular uniformity that makes the phenomenon interesting.

Why are these phenomenon any more interesting than qualia? First there is only one material organization in the universe, brains, that mediate between the impinging mind-independent matter-energy universe and a subjective experience of qualia? Second, like the quantum world, our instruments cannot get there! Even if we knew in every instance what brain states evoke what qualia we would be no closer to answering the question: how does physics become subjective?

Chalmers has pointed out many times that this brain state business might go on, like any other complex matter-energy interaction, without evoking a subjective mirror of itself. Biologists surmise that having a consciousness, and therefore a control (presupposing free-will by the way) over behavior beyond what is possible for non-conscious (automatic and deterministic) neural activity has survival advantage. Ironically, biologists have answered a why question. Physics produces the subjective because it has survival advantage! Surely this is so. But it gets no closer to answering the question how physics evokes a subjective? What makes it possible for physics to have that effect?

Every other matter-energy transformation in the universe, every other emergent phenomenon both begin and end with matter-energy. This includes what goes on in brains! And yet at the same time, and only in brains, there comes to be a “subjective viewpoint”, a phenomenon that begins with matter-energy, but does not end with it. Is that not enough to make it interesting?