Of qualia:
Two philosophical objections
Two further matters should be addressed concerning what we can expect from a theory. First, a common philosophical complaint is that any neurobiological theory of consciousness will always leave something out – something crucial. It will always leave out the feeling itself — the feeling of what it is like to be aware, to see blue, smell mint, and so on (Nagel, 1974; Chalmers, 1996). These are so-called qualia — the experiences themselves — and these are what are important about consciousness. Pursuing this point further, the philosopher may go on to conclude that no science can ever really explain qualia because it cannot demonstrate what it is like to see blue if you have never seen blue; consciousness is forever beyond the reach of scientific understanding.
What is the merit in this objection? It is lacking merit, for if you look closely, you will find that it rests on a misunderstanding. The argument presumes that if a conscious phenomenon, say smelling mint, were genuinely explained by a scientific theory, then a person who understood that theory should be caused to have that experience; e.g., should be caused to smell mint. Surely, however, the expectation is unwarranted. Why should anyone expect that understanding the theory must result in the production of the phenomenon the theory addresses? Consider an analogy. If a student really understands the nature of pregnancy by learning all there is to know about the causal nature of pregnancy, no one would expect the student to become pregnant thereby. If a student learns and really understands Newton's laws, we should not expect the student, like Newton's fabled apple, to thereby fall down. To smell mint, a certain range of neuronal activities have to obtain, particularly, let us assume, in olfactory cortex. Understanding that the olfactory cortex must be activated in manner ? will not itself activate the olfactory cortex in manner ?. We are asking too much of a neuroscientific theory if we ask it not only to explain and predict, but also to cause its target phenomenon, namely the smell of mint, simply by virtue of understanding the theory.
A second and related complaint raised by certain philosophers is that even if neuroscience were to discover with what brain states being aware of a burning pain on one's left ear is identical, we would still not understand why just those brain states are identical with precisely that sensation, as opposed, say, to feeling a desire to void. Neuroscience, it will be averred, will never be able to explain why conscious states Y = brain states X, rather than say, brain state Z. For those who are keen on qualia as metaphysical simples forever beyond the scope of science, the next step may be to infer that we cannot ever hope to understand that identity in neurobiological terms (Chalmers, 1996). Awareness, the claim goes, will always be ineffable and metaphysically basic. This means neuroscience cannot ever really explain consciousness.
This complaint too rests on a misunderstanding. What is an example where a science — any subfield of science — explains why X = Y? Not how we know or why we believe that X = Y, but why X is identical to Y, rather than to Z. Using the examples already at hand, the corresponding questions would be these: why is temperature mean molecular kinetic energy, rather than, say, caloric fluid or something else entirely? Why is visible light actually electromagnetic radiation rather than, say, something else entirely, say, “intrinsic photonicness”? By and large science does not offer explanations for fundamental identities. Rather, the discovery is that two descriptions refer to one and the same thing — or that two different measuring instruments are in fact measuring one and the same thing. Why is that thing, the thing it is? It just is. Science discovers fundamental identities, but the identities it discovers just are the way things are. There is no fundamental set of laws from which to derive that temperature is mean molecular kinetic energy or light is electromagnetic radiation.
Reflection shows this logical point to be acknowledged in an everyday setting. If someone discovers that The Morning Star (Venus) is identical to The Evening Star (Venus), he will explain why he believes this by citing his evidence. But if asked, “why is The Morning Star (Venus) identical to The Evening Star (Venus)”, no answer is appropriate; that is just the way the world is. The question itself is based on the false assumption that identities ought to follow from general laws. But they don’t. We may get an explanation of why people mistakenly thought what they saw in the dusk was not the same as the planet they saw in the dawn, and how they came to realize that what they saw in the dusk is identical to what they saw in the dawn. There is, however, no explanation of why Venus is Venus; of why the Morning Star is identical to the Evening Star. It just is. Or, to put it as the medieval philosophers sagely noted, everything is what it is, and not another thing. Correspondingly, assuming we discover that a certain pattern of activity Naj is identical to smelling mint, there will be no further explanation of why that pattern of activity is identical to smelling mint (why Naj = C).
Such merit as there is in the complaints probably comes merely to this: given the current state of neuroscience, it is very hard to predict what the explanation of conscious phenomena will look like — very hard. But so what? It is always hard to predict the course of a science, and especially hard to predict what an immature science will look like when it matures.
exerpt from:
Churchland, Patricia Smith. (2005) A neurophilosophical slant on consciousness research. Progress in Brain Research, 149, 285-293.