The "Hard Problem" of Consciousness, its Nature and Solution.
The "hard" problem of consciousness can be compared with another "hard" problem in biology, that of bird navigation. It is known that migratory birds from the northern hemisphere want to migrate south in autumn and north in spring. But how do they know the right direction? Experiments show that birds in cages, completely isolated from natural day light, still have a preference for a "south" position in their cage in autumn, and a "north" position in spring. Since there was not any other physical property in their cage than the geomagnetic field to navigate on, it was presumed that the birds must have a sense organ to detect this field. The theory that birds use the geomagnetic field for navigations dates from as early as 1858 (Von Middendorff), the biophysical mechanism of magnetoreception is still not understood. It appears that birds lose their magnetoreception when their ophthalmic nerve is cut, and a recently discovered photoreceptor cryptochrome in the bird's retina could be involved. A quantum mechanic mechanism of electrons with "radical pairs with anisotropic hyperfine coupling" is suggested to be a possible biophysical mechanism of magnetoreception (A Model for Photoreceptor-based Magnetoreception in Birds, Biophysical Journal Volume 78 February 2000 707â€“718), but this is still very unsure. We know the birds are using the geomagnetic field, we know their eyes must be involved, we probably know the molecules involved, yet the biophysical explanation is extremely difficult. The reason is that our understanding of physics on quantum scale is still very limited. We tend to believe that we have to explain everything in biology with "classic" Newton physics. But why would organisms stick to Newton physics? With the bird navigation we know what physical property is involved, the geomagnetic field. We can search for molecules and mechanisms in migratory birds that interact with this field. But imagine how difficult the bird navigation problem would be if we had not discovered geomagnetism yet. How would we ever discover the geomagnetic field if the bird's navigation system was the only way to detect it? Imagine humans had this magnetoreceptive navigation system, but we had no magnets or other devices to detect magnetism. We would just "feel" or "see" North and South, and despite solving all "neural and sensory correlates of navigation" we would still end up with a "hard" problem, so long we failed to discover magnetism. Discovering the geomagnetic field by intensively studying the molecules involved (the photoreceptor cryptochromes) could be possible, but would require a very good understanding of the universe at its very elementary level, far beyond our present knowledge of it. This is the kind of challenge we are facing with solving the "hard" problem of consciousness.
It is already predicted by most philosophers and scientist that resolving all "easy" problems of consciousness will leave us with an "explanatory gap" leaving the main issue of "what is the physical substrate of phenomenal consciousness" unsolved. Dennett denies such "explanatory gap" will occur and Chalmers suggests only "non-physical" properties could give an explanation. For the "hard problem" of bird navigation we needed to discover geomagnetism to solve the problem. But for phenomenal consciousness we should not look for an external physical property that can be detected by our senses, but an internal one that is an elementary property of our Universe. Neurobiological and biochemical analysis of the brain may finally give some clues what to look for when the "explanatory gap" has become evident. I think the final explanation of phenomenal consciousness will require a good understanding of our Universe at its elementary level. Although there was some optimism a few decades ago about finding a Theory Of Everything (TOE) of the Universe within a short period of time, it now seems the Universe is a lot more complicated than we previously thought, and we are still far away from this to happen. But I am confident phenomenal consciousness is a physical property of the Universe that organisms during their billion years of evolution have integrated in their information processing systems, to unify this information and associate it with qualia to give the information a subjective value.
I think our present understanding of the Universe is still very limited, we have just began exploring it and we still do not even know the most basic properties of it like how many dimensions it has and how its structure looks like at its most elementary level. Without this knowledge it is impossible to come to a theory that fully explains phenomenal consciousness. But I am quite sure we will finally find a physical explanation, like we will find physical explanations for the many other mysteries of our Universe. Research should focus on fundamental Physics, Neuro- and Molecular Biology.